life processes class 10 chapter 1 full pptx

This is a pptx where you will find all the important topics of life processes

1. LIFE PROCESSES NUTRITION

2. NUTRITION RESPIRATION CIRCULATION EXCRETION DEFINATION : IT CAN BE DEFINED AS ALL THE BASIC LIFE PROCESSES WHICH ARE REQUIRED TO CARRY OUT DAILY ROUTINE ACTIVITIES OF AN ORGANISM AND TO MAINTAIN ITS DYNAMIC EQUILIBRIUM WITH SURROUNDING ENVIRONMENT

3. METABOLISM : THE SUM TOTAL OF ALL THE CHEMICAL REACTIONS OCCURING IN A LIVING ORGANISM. THERE ARE TWO TYPES OF CHEMICAL REACTIONS IN METABOLISM : 1. Anabolism : the metabolic synthesis of complex molecules from simpler ones .it requires intake of energy. ……. e.g .Photosynthesis : 6CO2 + 12H20 = C6H12O6+602 +12H20 (reaction occurs by consuming 18atp & 12nadph in presence of sunlight) 2. Catabolism : The metabolic breakdown of complex molecules into the simpler ones with the release of energy . e.g.. Cellular respiration : C6H12O6 = 6C02 + 12H20 + 36-38 ATP ATP (Adenosine Tri Phosphate) energy unit

4. NUTRITION : Sum total of the processes by which living organisms obtain those substances which are necessary for their growth and maintenance and for meeting their energy needs. NUTRIENTS : The chemical substance present inside the food are nutrients ,they are further classified into two : Macronutrients : These nutrients provide energy and are required in larger quantities . e.g., Carbohydrates, lipids & proteins Micronutrients : Although they do not provide energy but their deficiencies cause specific diseases & abnormalities . e.g., Minerals,Vitamins

5. AUTOTROPHIC : Those organisms who synthesize their own food. PHOTOAUTOTROPHS (photo means light): In this mode plants use light energy to make complex molecules . e.g., Green plants synthesize food in presence of chlorophyll pigment which absorbs sunlight. CHEMOAUTOTROPHS (chemical synthesis) :few microorganisms such as bacteria use inorganic energy sources such as hydrogen suplhide,ammonia,etc to make complex molecules. e.g., Nitrogen fixing bacteria HETROTROPHIC : Those organisms which are dependent on other living organisms for their nutrition requirement. They are of various types: SYMBIOTIC : When two organisms are mutually benefitted by living in association. E.g. Lichen Parasitic : organisms obtain food from the body of host without killing them.e.g.,Ticks,Lice Saprophytic : those organisms who derive nutrients from dead & decaying organic matter . E.g.,bread moulds,yeast,mushrooms . HOLOZOIC : This mode involves 5 steps Ingestion: Intake of complex food Digestion: Process of breakdown of complex food into simple molecules Absorbtion : absorbed by body cells Assimilation : utilization of absorbed food Egestion : removal of unabsorbed food e.g., Amoeba ,Human beings

6. Photosynthesis : (Derived from Greek word : phos or photos means light and synthesis-putting together ) it is an enzyme regulated anabolic process of manufacture of organic compounds inside the chlorophyll containing cells from water and carbon dioxide with the help of sunlight as source of energy . chlorophyll,enzymes,radiant energy 6CO2 + 12H20 C6H12O6 + 6H2O + 602 Plants trap solar energy and convert it into ATP (adenosine triphosphate) & NADPH ( nicotinamide adenine dinucleotide phosphate) which are used in formation of carbohydrates. The carbohydrates are stored in plants in form of starch and in animals in form of glycogen which serves as a source of internal energy. Structures involved in photosynthesis are : STOMATA : Plants obtain CO2 through tiny pores called stomata. It occurs Is in the epidermis of leaves and soft parts of plant body. Each stomata consists Of a stomatal aperture and two surrounding guard cells. Guard cells are the Only epidermal cells that contain chloroplasts, their outer and lateral wall is Thin and inner wall is thick . Closing and opening of stomata leads to Exchange of gases .

7. CHLOROPLAST : These are the cell organelles which perform photosynthesis . Structurally they are double membrane bound cell organelles containing sac like structures called thylakoids. These are present in stroma of chloroplast either in a stacked manner called granum or single, they are connected to each other by lamella. The thylakoid membrane contains chlorophyll pigments

8. PHOTOSYNTHETIC PIGMENTS : These are those pigments which are present on surface of thylakoids of chloroplast and take part in absorption of light energy for the purpose of photosynthesis . Photosynthetic pigments are of two types chlorophyll and carotenoids Chlorophyll pigments are of 5 types ( a,b,c,d,e ). Chlorophyll pigment absorbs red light while blue light is absorbed by carotenoids and few chlorophyll. Photosynthetic pigments do not absorb green colour so it is reflected back . Pigments Chemical formula Chlorophyll a - C55H72O5N4Mg Chlorophyll b - C55H70O6N4Mg Chlorophyll c - C35H32O5N4Mg Chlorophyll d - C54H7006N4Mg Chlorophyll e - C55H74O6N4Mg Carotene - C40H56

9. MECHANISM OF PHOTOSYNTHESIS Photosynthesis occurs in 2 phases Photochemical phase/ Light dependent phase / Hill’s Reaction : It occurs in thylakoid membrane. It occurs only when plants are illuminated with light . In this first step in absorption of light by chlorophyll pigment. Photolysis of water – Absorbed light energy is used for splitting water molecule into its components (hydrogen & oxygen) releasing electrons 4H2O 4H+ 4OH- ENZYMES 4OH- 2H2O O2 4e-

10. PRODUCTION OF ASSIMILATORY POWER (NADPH & ATP ) FORMATION OF NADPH : The released hydrogen ions are used to reduce NADP+ ( nicotinamide adenine dinucleotide phosphate ) forming NADPH which is a strong reducing agent NADP reductase NADP+ 2e- 4H+ NADPH PHOTOPHOSPHORYLATION : process of formation of ATP (adenosine tri phosphate ) from ADP (adenosine di phosphate) and inorganic phosphate is called photophosphorylation. The energy required to perform photophosphorylation is obtained from electrons released during photolysis. ENERGY ADP Pi ATP (Pi is inorganic phosphate )

11. 2)Biosynthetic phase / Light independent phase/Dark reaction /Blackman’s reaction : It occurs in stroma . The reactions in this phase do not require light but it requires product of light reaction (NADPH & ATP ).Dark reaction occurs through calvin cycle. CALVIN CYCLE

12. CALVIN CYCLE : This cycle is functional in all plants having photosynthetic pigments. It was studied by CALVIN ,BENSON & ASSOCIATES. Carboxylation (addition of CO2 to another molecule) -  A CO2 molecule combines with a five-carbon acceptor molecule, ribulose-1,5-bisphosphate ( RuBP ). This step makes a six-carbon compound that splits into two molecules of a three-carbon compound, 3-phosphoglyceric acid (3-PGA). This reaction is catalyzed by the enzyme RuBP carboxylase/ oxygenase , or  rubisco . (RUBISCO is the most abundant protein of biological world ,it constitutes 16% of chloroplast proteins ) Reduction.   In the second stage, ATP and NADPH are used to convert the 3-PGA molecules into molecules of a three-carbon sugar, glyceraldehyde-3-phosphate ( G3P ). This stage gets its name because NADPH donates electrons to, or  reduces , a three-carbon intermediate to make G3P. 3-phosphoglyceric acid + ATP 1,3Bisphosphoglyceric acid 1,3Bisphosphoglyceric acid + NADPH glyceraldehyde-3-phosphate ( G3P ). Regeneration .  Some G3P molecules go to make glucose, while others must be recycled to regenerate the RuBP acceptor. Regeneration requires ATP and involves a complex network of reactions. NOTE: For synthesis of one glucose molecule total six round of calvin cycle Each cycle requires 2 ATP and 2 NADPH units for reduction and 1 ATP for regeneration So 1 GLUCOSE MOLECULE = 6 CALVIN CYCLE : 18 ATP : 12 NADPH

13. overview of photosynthesis The overall reaction of photosynthesis describes an oxidation reduction reaction in which H2O donates electrons for the reduction of CO2 to form carbohydrates. 6CO2 + 12H20 C6H12O6 + 6O2 + 6H20

14. INFORMATION : CALVIN CYCLE occurs in C3 Plants, while there is another cycle known as HATCH SLACK PATHWAY for C4 Plants. C 3 PLANTS C 4 PLANTS C3 plants uses C3 or CALVIN CYCLE for dark reaction of photosynthesis C4 plants uses C4 or HATCH SLACK PATHWAY for dark reaction of photosynthesis First stable product of C3 cycle is phosphogylceric acid (PGA) First stable product of C4 cycle is oxaloacetic acid (OAA) C3 are cool seasonal plants C4 are warm seasonal plants Majority of plants are C3 (95%) C4 plants are lesser in number(5%) C3 plants requires optimum temperature range (18 to 25 degree celcius ) C4 plants requires optimum temperature range (32 to 55 degree celcius ) C3 Plants(e.g., WHEAT, RYE , RICE,COTTON etc ) C4 Plants (e.g., SUGARCANE,MAIZE,SORGHUM)

15. HUMAN DIGESTIVE SYSTEM Human digestive system follows holozoic mode of nutrition and it comprises of two main parts: 1)Alimentary Canal 2)Digestive Glands 1)ALIMENTARY CANAL : It comprises of following parts: Vestibule - The vestibule is a slit-like space bounded externally by lips and cheeks and internally by the gums and teeth. Oral/ Buccal Cavity - It is inner portion of the mouth which has the following parts. a) Palate : the roof of oral cavity ,anterior part of palate is known as hard palate and posterior part is smooth so soft palate. The hinder free part of the soft palate hangs known as UVULA.

16. b ) Tongue : it is attached to floor of mouth by a fold called lingual frenulum. The upper surface of tongue has papillae (little projections responsible for sensation of touch and taste ) 5 types of taste buds are their SWEET, SALTY, SOUR, BITTER UMAMI : respond to glutamates especially found in meat Function: To taste food, help in swallowing & chewing food , in speech production. NOTE : Cranial Nerve VII (FACIAL) & CN IX (GLASSOPHARYNGEAL) are the nerve responsible for sensation of taste c) Teeth : Dental arrangement in humans can be explained by : Thecodont : Each tooth is embedded in a socket of jaw bone. Diphyodont : Majority of mammals forms two sets of teeth during their life temporary milk teeth replaced by permanent teeth. Heterodont : An adult human has 32 permanent teeth which are of 4 different types i.e.,Incisors (I),Canine (C),Pre molars (PM),Molars(m). Milk teeth : 20 in number , (8-I : 4-C : 8-M) Pre molars are absent Permanent teeth : 32 (8-I : 4-C : 8-PM : 12-M)

17. DENTAL FORMULA : It gives half the number of teeth Upper jaw/lower jaw = ICPmM / ICPmM Milk teeth = 2102/2102 Permanent teeth = 2123/2123 12 Teeth (8 premolars & 4 molars grow only once in life and hence are known as MONOPHYODONT ) 4 MOLARS which grow later in age (18-25yrs) are also known as WISDOM TOOTH STRUCTURE : a typical tooth consist of 3 regions : CROWN : the part which projects above the gum, it is covered with the hardest substance of body ENAMEL .It covers and protects crown. Beneath enamel DENTINE is present which is made up of hard substance similar to bone. NECK : Part surrounded by the gum ROOT : Part embedded in the jaw bone. Dentine forms the bulk of root. There is a pulp cavity inside dentine which carries nerve fibres ,blood vessels and sensory cells. CEMENTUM : Substance around root which holds tooth in its socket. NOTE : CRANIAL NERVE V – TRIGEMINAL NERVE responsible for sensation of teeth.

18. PHARYNX (THROAT) : a muscular tube that connects the oral and nasal cavity to the larynx and oesophagus . OESOPHAGUS : Also known as food pipe is 25cm long. It lies behind trachea and heart. The oesophagus passes through the diaphgram and opens into the stomach. Circular and longitudinal smooth muscles helps in transfer of food from pharynx to the stomach. STOMACH : it is J shaped organ and has 4 parts ; Cardia – It is so called because it is present near the heart . Fundus – It is commonly filled with air and gas. Body – it is main part of stomach which occupies almost 85% of total space. Pylorus – it is the posterior part of stomach which opens into small intestine. Function of stomach : It stores food for some time. It churns and breaks up food and mixes them with gastric juices It produces Castle’s Intrinsic Gastric factor which is necessary for absorption vitamin B12 in small intestine. It also secretes proenzyme such as pepsinogen & prorennin and enzymes such as gastric lipase and gastric amylase.

19. SMALL INTESTINE : It is so named because it has smaller diameter. It is longest part of the alimentary canal. It is about 6.25m long. It comprises of 3 parts: DUODENUM – It is C-shaped and about 25cm long, shortest widest part of intestine. The HEPATOPANCREATIC AMPULLA opens into duodenum. This ampulla receives both bile duct from liver and pancreatic duct from pancreas. JEJUNUM – It is middle part of small intestine and is about 2.5metres long . Its wall is thick and is highly vascular. ILEUM – It is the longest part of small intestine and is about 3.5m long. Its wall is thinner than jejunum. Both ileum & jenunum are super coiled and are suspended by MESENTRY (double fold of tissue). Finger like projections of mucosa ,the VILLI are present in the small intestine. Each Villus is covered with epithelium and contains a lymph capillary (lacteal ) and blood capillaries . FUNCTION : It completes digestion of proteins ,fats ,carbohydrates. It absorbs nutrients into blood and lymph . It secretes few hormones and digestive enzymes.

20. LARGE INTESTINE : Its diameter is larger than small intestine and is about 1.5m long and divided into 3 parts: Caecum & Vermiform appendix : Caecum is pouch like structure about 6 centimeters long. The vermiform appendix is an outgrowth of caecum, it is coiled tube of 8cm long Appendix is vestigial and its inflammation is APPENDICITIS. Caecum and vermiform appendix are well developed in herbivores. Colon : caecum leads to colon it is divided into 4 parts : ascending , transverse , descending and sigmoid colon. Rectum : the sigmoid colon opens into rectum. The rectum comprises last 20cm of digestive tract and terminates in the 2cm anal canal. FUNCTION : The chief functions of large intestine are absorption of water and removal of solid waste. However moderate amount of vitamin K & B complex are produced by bacteria inside large intestine

21. DIGESTIVE GLANDS : 1.Salivary Glands – It discharge their secretion into the oral cavity. In man, the salivary glands are 3 pairs – (a)Parotid Glands – largest salivary glands ,which are situated near the ears. Their ducts open into the oral cavity near the upper second molars. Duct is called Stenson’s Duct. (b)Sublingual Glands – These are smallest which are located beneath the tongue and their ducts called sublingual ducts . (c)Submandibular/ Submaxillary Glands – These are medium sized salivary glands which are located at the angles of lower jaw and duct is named as Wharton’s Duct. THE PAROTID SECRETE MUCH OF SALIVARY AMYLASE(ptyalin). SUB-LINGUAL & SUB-MANDIBULAR SALIVARY GLANDS SECRETE SALIVARY AMYLASE & MUCUS. ph of saliva is slightly acidic 6.8. About 1000-1500ml of saliva is secreted per day and is a mixture of electrolytes (Na+, K+, Cl -, HCO3-) and it contains Lysozyme (antibacterial agent ). The disease mumps is a viral infection that involve parotid glands. Breakdown of larger food particles into smaller units and mixing it with saliva is known as mastication ..the masticated food is now rolled into a bolus by tongue and passed through pharynx into oesophagus by swallowing.

22. Gastric Glands : These are numerous microscopic, tubular glands formed by the epithelium of stomach. Gastric glands are 3 major types of cells. Chief Cells/Peptic cells(Zymogenic cells) - secrete gastric digestive enzymes as proenzymes : pepsinogen and prorennin . It also produce small amount of gastric amylase and gastric lipase. Gastric lipase contributes to digestion of fat. Prorennin is secreted in young mammals. Oxyntic Cells (Parietal Cells) – are large and are most numerous on side of walls of the gastric glands. They secrete hydrochloric acid (HCL) and Castle Intrinsic Gastric Factor that helps in the absorption of vitamin B12 in the ILEUM. FUNCTION OF HCL: Necessary for the activation of inactive proenzyme pepsinogen. Pepsinogen Pepsin Prorennin Rennin It softens the food. It kills most of the harmful bacteria ingested with food and disinfects the food. It makes the food acidic(pH- 1.8),which facilitates the action of enzyme PEPSIN & RENNIN. Proteins Peptides Caesin protein Peptides (c) Mucous Cells (Goblet cells) – present throughout the epithelium and secrete mucus. The secretions of these cells form gastric juice pH 1.5 -2.5 (very acidic). (d)Stem cells – are undifferentiated cells ,they multiply and replace other cells .They increase in number when gastric epithelium is damaged (during ulcer) and help in healing. In stomach food is churned by the muscular activity of the stomach to a creamy fluid CHYME .The food remains in stomach for 3 hours and is periodically poured through the pyloric into duodenum in small amounts.

23. LIVER – It is the largest gland of body, it lies in the upper right side of abdominal cavity just below the diaphragm. It is heavier in males (1.4 – 1.8 kg) than females (1.2 – 1.5 kg). The liver is divided into two main lobes – right & left lobes separated by falciform ligament. Structural and functional units of liver are known as hepatic lobules containing hepatic cells arranged in the form of cords. Each lobule is covered by thin connective tissue sheath called GLISON’S CAPSULE (Characteristic feature of mammalian liver). Bile is secreted by liver cells (hepatocytes). Gall Bladder – a pear shaped sac like structure attached to the posterior surface of the liver by connective tissue. It stores bile secreted by liver Ducts – The right and left hepatic ducts join to form the common hepatic duct . The latter joins with cystic duct from gall bladder and forms bile duct which then join the main pancreatic duct to form hepatopancreatic duct which opens into duodenum. LIVER POSSESS HIGH POWER OF REGENERATION.

24. FUNCTIONS OF LIVER Production of bile – secretes bile (pH- 8.6), and is stored in gall bladder where (gall bladder bile pH- 7.6). 500-1000ml bile is secreted by liver in each day. Bile salts (sodium bicarbonate, sodium glycocholate , sodium taurocholate ) helps in the digestion of fats by emulsification(conversion of large fat droplets into smaller ones). Excretion – the bile contains bile pigments (bilirubin yellow and biliverdin green) are excretory products. They are eliminated alongwith certain other waste products like cholesterol,metal ions, and dead damaged RBC’s. The waste products and bile pigments reach duodenum and are removed with faeces . Detoxifiaction – liver converts toxic substances into harmless products. Haemopoiesis – the process of formation of blood cells ,and liver produces blood cells in embryo stage. Synthesis of Vitamin A – liver syntheizes vitamin A from b-carotene found in carrots. Synthesis of blood protein- prothrombin & fibrinogen that help in blood clotting. Synthesis of heparin – it produces heparin ( anticoagulant ). Phagocytosis – liver contains Kupffer’s cells that engulfs disease causing microorganisms, dead cells and foreign matter. Production of heat – due to high metabolic activities of liver heat is produced which is required to maintain optimum body temperature. Storage – it stores glycogen, fats,vitamins like A,D,E,K & B12, bile in the gall bladder, blood, water, iron ,copper and potassium.

25. Functions of bile It is a watery fluid mixture containing bile salts, bile pigments, cholesterol and phospholipids. Its sodium bicarbonate neutralizes HCL of chime. Sodium glycocholate and sodium taurocholate break large fat droplets into smaller ones. Its salts help in the absorption of fat and fat soluble vitamins(A,D,E,K) in small intestine. Bile is alkaline hence it prevents the decomposition of food by preventing growth of bacteria in it. NOTE : Obstruction of hepatic or bile duct causes JAUNDICE , in this disease bile is absorbed instead of going to duodenum causing yellowing of eyes and skin Pancreas It is soft, lobulated, greyish pink gland which weighs about 60 grams . It is about 2.5cm wide and 12 to 15cms long ,located posterior to the stomach in the abdominal cavity. Internal structure of pancreas are divided into 2 parts : Exocrine part : it consists of rounded lobules that secrete an alkaline pancreatic juice with pH- 8.4, 500-800 ml juice is secreted everyday. It is carried by main pancreatic duct into duodenum through the hepatopancreatic ampulla. The pancreatic juice contains sodium bicarbonate and proenzymes trypsinogen , chymotrypsinogen and some enzymes such pancreatic @amylase , pancreatic lipase etc. This juice helps in digestion of starch , fats ,proteins and nucleic acids. Endocrine part : It consists of group of Islets Of Langerhans, each contains 3 types of cells which secrete hormones in blood Alpha cell – produce glucagon hormone which converts glycogen into glucose. Beta cell – produce insulin hormone ,which converts glucose into glycogen in liver and muscles. Delta cell – produce somatostatin which inhibits secretion of both glucagon and insulin.

26. INTESTINAL GLANDS These are formed by the surface epithelium of the small intestine. These are of two types: crypts of Lieberkuhn and Brunner’s glands. The crypts of Lieberkuhn are simple, tubular structures which occur through­out the small intestine between the villi. They secrete digestive enzymes and mucus. The Brunner’s glands are found only in the duodenum and are located in the submucosa . They secrete a little enzyme and mucus. The mucus protects the duodenal wall from getting digested. The secretion of intestinal glands is called intestinal juice or succus entericus with pH 7.8. About 2,000-3,000 ml of intestinal juice is secreted per day. The intestinal juice contains many enzymes— maltase, sucrase , enterokinase , aminopeptidases , dipeptidases , nucleotidases , nucleosidases and intestinal lipase. NOTE : TRYPSINOGEN released by pancreas gets activated by enterokinase secreted by intestinal glands and form TRYPSIN which further helps in digestion of protein.

27. Proteins, proteoses and peptones (partially hydrolysed proteins) in the chyme reaching the intestine are acted upon by the proteolytic enzymes of pancreatic juice forming dipeptides. Carbohydrates in the chyme are hydrolysed by pancreatic amylase into disaccharides. Fats are broken down by lipases with the help of bile into di-and monoglycerides . Nucleases in the pancreatic juice acts on nucleic acids to form nucleotides and nucleosides The enzymes in the succus entericus act on the end products of the above reactions to form the respective simple absorbable forms.

28. DIGESTION OF FOOD Carbohydrates, fats, proteins and nucleic acids occur in food in the form of large and complex insoluble macromolecules . These macromolecules are converted into small molecules by the action of enzyme. In Buccal Cavity , teeth and tongue help in mastication and mixing of food. Mucus in saliva mix with masticated food to form bolus . 30% DIGESTION OF STARCH TAKES PLACE IN BUCCAL CAVITY IN PRESENCE OF SALIVARY AMYLASE . Salivary amylase breaksdown starch into maltose. Bolus is passed to pharynx and Oesophagus by swallowing or deglutition. In Oesophagus peristalsis occurs due to which food is passed to stomach In Stomach : Mucosa of stomach have gastric glands having three types of cells- mucus neck cells that secrete mucus, peptic or chief cells that secretes proenzyme pepsinogen and oxyntic cells that secretes HCl . Food mixes with gastric juice due to churning action of muscular wall to form chyme . HCl activates the pepsinogen to pepsin to digest protein into peptones  and proteoses Mucus and bicarbonates present in gastric juice play important role in lubrication and protecting inner wall of stomach from the action of HCl . Renin is a proteolytic enzyme found in gastric juice of infants to digest milk protein. In Small Intestine The Bile, pancreatic juice and intestinal juice are released in small intestine. Pancreatic juice contain inactive trypsinogen , chymotrypsinogen , amylases, lipases and nucleases. Trypsinogen is activated by enzyme enterokinase in to trypsin, which further activates the other enzyme of intestinal juice.

29. Bile contains bile pigments ,bile salts, cholesterol and phospholipids which help in emulsification of fats. Secretion of brush border cells of mucosa and goblet cells contain enzyme   succus entericus , containing variety of enzymes to complete the process of digestion. So now digested nutrients are in form of glucose ,amino acids, fatty acids, sugars etc which cannot be further digested ABSORPTION OF DIGESTED FOOD: A bsorption i s the process by which the products of digestion are carried into the blood to be supplied to the rest of the body. No absorption takes place in mouth or stomach, practically all food is absorbed in small intestine.  The small intestine offers a large surface area for absorption.  The apparent surface area is increased several times (3-12 times) by the presence of finger-like projections called  Villi,  which project into the lumen of the small intestine. Most absorption takes place through these villi it possess microscopic projections called microvilli . In the center of each  villus  (singular of villi), a vessel called  lacteal  is present which is filled with  lymph  (a colorless fluid). Around the lacteal, a network of capillaries is present by means of which blood is brought very near to the surface of the membrane of the small intestine. ABSORPTION OCCURS BY DIFFUSION,ACTIVE TRANSPORT,PASSIVE TRANSPORT ETC

30. Assimilation  is the movement of digested food molecules into the cells of the body and their utilization. For example, glucose is used in respiration to provide energy. Amino acids are used to build new proteins. EGESTION : The elimination of faeces from the alimentary canal is known as egestion and defecation. MECHANISM :Peristalsis pushes indigestible material from small intestine to large intestine (1500ml per day). Colon absorbs water and electrolytes(Na+ , Cl -) . Epithelial wall of colon also excretes certain salts such as iron and calcium. Escherichia coli(bacterium ) lives in wall of small intestine and feeds on undigested matter and in return produces vitamin B12,K,B1,B2 which are absorbed by COLON. Now chyme is converted into semisolid waste and as the pellets of faeces enter the rectum ,rectal wall distension occurs which initiates defecation reflex. This reflex initiates peristalsis of sigmoid colon and rectum and forces faeces towards anus. As the faeces reaches anus it causes involuntary relaxation of internal and external sphincter muscles cause defecation.

31. RESPIRATION It is an energy releasing enzymatically controlled catabolic process which involves a step wise oxidative breakdown of food substances inside living cells. Living organism require energy for all activities like absorption, movement, reproduction or even breathing. Energy required is obtained from oxidation of food during respiration. Cellular respiration  is the mechanism of breaking down of food materials within the cell to release energy for synthesis of ATP. Breaking down of complex molecules takes place to produce energy in cytoplasm and in the mitochondria. Breaking down of C-C bond of complex compounds through oxidation within the cells leading to release of energy is called  respiration.  The compounds that get oxidized are called  respiratory substrates . Energy released during oxidation is not used directly but utilized in synthesis of ATP, which is broken down when energy is required. Therefore,  ATP is called energy currency  of cells. energy ADP + (P) ATP ATP produced can further be used in several endothermic reactions such as Calvin cycle leading to formation of ADP free (P)inorganic substance and 30.5kJ/ mol

32. ON THE BASIS OF OXYGEN UTILIZATION , RESPIRATION IS OF TWO TYPES : AEROBIC RESPIRATION : The respiration which uses oxygen is called aerobic respiration. In aerobic respiration, the glucose food is completely broken down into carbon dioxide and water by oxidation. Aerobic respiration produces a considerable amount of energy for use by the organism which gets stored in the ATP molecules. Mitochondria are the sites of aerobic respiration in the cells. Thus, the breakdown of pyruvate to give carbon dioxide, water and energy takes place in mitochondria.     Pyruvate : CH3COCOOH , So 1molecule of glucose(C6H12O6) in glycolysis breakdown and form 2 molecules of pyruvate.

33. ANAEROBIC RESPIRATION The respiration which takes place without oxygen is called anaerobic respiration. The microscopic organisms like yeast and some bacteria obtain energy by anaerobic respiration (which is called fermentation). In anaerobic respiration, the microorganisms like yeast break down glucose (food) into ethanol and carbon dioxide, and release energy. Anaerobic respiration produces much less energy which gets stored in the ATP molecules. glycolysis in absence of O2 GLUCOSE PYURUVATE ETHANOL + CO2 + 2/4ATP C6H12O6 2CH3COCOOH fermentation C2H5OH (partial combustion of glucose molecules occur) Sometimes, when there is lack of oxygen in our muscle cells, another pathway for the breakdown of pyruvate is taken. Here the pyruvate is converted into lactic acid (which is also a three-carbon molecule) with the release of small amount of energy. GLUCOSE PYURUVATE 2LACTIC ACID + 2/4ATP C6H12O6 2CH3COCOOH MUSCLE TISSUE 2C3H6O3 (partial combustion of glucose molecules occur)

34. HUMAN RESPIRATORY SYSTEM STRUCTURE OF RESPIRATORY SYSTEM 1)Respiratory Tract (Conducting Zone) 2)Lungs (gaseous exchange zone) RESPIRATORY TRACT AN EXTERNAL PASSAGE FROM NASAL OPENING TO LUNGS : NOSE & NASAL PASSAGE – it possess external nares which opens into nasal chamber, both nasal chambers are separated from each other by HYALINE CARTILAGE. The anterior small part of nasal chamber is called nasal vestibule which contains sebaceous glands secreting mucus and hair. It prevents entry of dust particles. Nose is guarded by 3 bones nasal, maxilla, ethmoid . Bucco -pharyngeal cavity : Uvula divides into 2, upper chamber is known as NASOPHARYNGEAL CHAMBER and lower chamber is known as OROPHARYNGEAL CHAMBER At the time of swallowing of food, the Uvula lifts up and covers the internal-nares and so prevents the food from entering the nasal-passage. In the pharyngeal chamber, 2 slit like apertures are present.

35. Ventral-pore is called the glottis ; and it opens into the Larynx ; and so this is the respiratory-passage. Near the glottis a flat cartilage called the Epiglottis is present. At the time of swallowing food this cartilage covers the glottis, So the food does not reach the air passage. Pharynx is the only part where food and air passage mix together. Larynx (voice producing organ):  It is present in anterior part of trachea so it is considered as modification of trachea. It is a box like structure composed of cartilage and these cartilage of larynx are held together by ligament & membranes.  In human males, ventral surface of thyroid cartilage makes a process called as ADAM'S APPLE which is a secondary sexual character of male. TRACHEA: It is a 10-12 cm long tube like structure present  in complete length of neck upto anterior part of thoracic cavity. -In complete length of trachea 16-20 'C' shaped rings are present which prevent  trachea from collapsing. These are composed of hyaline cartilage . These rings are incomplete on dorsal surface of trachea. -On dorsal surface, trachealis muscles are present which are involuntary in nature & help in the dilation of trachea during forceful breathing.

36. When trachea enter into thoracic cavity, it divides in two branches called as primary bronchus. Branches of primary bronchus upto terminal bronchioles  makes bronchial tree. Terminal bronchioles divide to form respiratory bronchioles & branches of respiratory bronchioles makes respiratory tree. In bronchiole tree, cartilage rings are present, while these are absent in respiratory tree. Gaseous exchange occurs in respiratory tree while it is absent in bronchial tree. Volume of air which is filled in B.T. is a part of dead space volume. which doesn't take a part in gaseous exchange. (150 ml)

37. 2)Gaseous exchange zone Lungs:  A pair of lungs are present in the thoracic-cavity. Lungs are covered by a double-membrane which are called the Pleural-membranes. Outer membrane is the Parietal Pleura and inner-membrane is the Visceral pleura. n between both the membranes a very narrow cavity called Pleural-cavity is present. In this cavity, a very thin layer of pleural fluid is present (about 150 ml). In human being right lung made up of 3 lobes & left lung made up of 2 lobes. HUMAN Right lung (625 gm )                                 3 lobes                                                         anterior lobe middle lobe  posterior lobe Left lung (575 gm ) 2 lobes  left anterior   left posterior  

38. Alveoli:   Each lobe is further divided into several lobules by septa of connective tissue. Each lobule is further divided into several air-sacs; and in the end, each air-sac is lastly divided into 3 or 4 alveoli; which are also termed as the units of lungs. Structural & functional unit of lungs is called alveoli Approximately 300 million alveoli are present in both lung. Alveoli internal surface of is termed as the Respiratory surface. It is richly supplied with blood capillaries, a dense network of blood capillaries is found in alveoli. These blood capillaries come from pulmonary artery. Pulmonary artery divides into blood capillaries after reaching in lungs. These capillaries from a dense network in the walls of alveoli. All these capillaries combine to form pulmonary vein at the another end. These veins carry pure blood to the left auricle of the heart. There are small pores present in the walls of alveoli. These pores make diffusion of gases easy. These pores are called pores of Kohn. It is the characteristic feature of mammalian lungs.

39. Thoracic cage:  Coverings of thoracic cavity makes thoracic cage. Anterior surface:- Clavicle bones , Neck Posterior surface:- Diaphragm. Dorsal surface:- Vertebral column & Ribs Ventral surface:- Sternum & ribs. Lateral surface:- Ribs Diaphragm:  A muscular septum which is found only in mammals (and crocodile). Normal shape of it is dome like which divides body cavity in two parts upper thoracic cavity & lower abdominal cavity.  Intercostal muscles (ICM): Space between two ribs is called inter costal space in which 2 types of muscles are present –  External ICM. (EICM)  –  Internal ICM. (IICM)  EICM:   By the contraction in this muscles, rib & sternum shifts upward & outward. So they helps in inspiration. IICM:   By the contraction in these muscles, ribs & sternum shifts downward & inward respectively. so  it helps in forceful expiration which is a voluntary activity.

40. MECHANISM OF BREATHING : Lungs cannot contract or expand of their own. The contraction and expansion of lungs are brought about by diaphragm muscles and external inter coastal muscles. INHALATION (INSPIRATION) Intake of fresh air from outside to the alveoli of lungs. It occurs by expansion of lungs which is brought about by enlargement of thoracic cavity. Inhalation involves following steps : The diaphragm muscle contracts so that diaphragm lowers down and becomes flat. Lowering of diaphragm pushes the abdominal viscera downward resulting in the enlargement of thoracic cavity vertically. External intercostal muscles contract so that the ribs and sternum are pulled upward and outward. This causes enlargement of thoracic cavity. Enlargement of thoracic cavity results in expansion of lungs. Expansion of lungs reduces the pressure of air inside so that the fresh air is pulled from outside into the lungs passing through nostrils, trachea and bronchi. Fresh air has a rich supply of O2 which goes into the blood passing through thin membranes of alveoli and blood capillaries.

41. EXHALATION (EXPIRATION ) : The mechanism of breathing out of CO2 is called exhalation. During exhalation the muscles of diaphragm pushes relaxes so that the abdominal viscera pushes upward, making it convex. The external intercostal muscles relax resulting in reduced thoracic cavity and lungs also contract. Contraction of lungs raises the air pressure so that foul air moves out. An average rate of breathing in a normal adult man is 15 to 18 times per minute. Boyle's law states  that at constant temperature the volume of a given mass of a dry gas is inversely proportional to its pressure.

42. RESPIRATORY VOLUME AND CAPACITIES Respiratory Volumes and Capacities Tidal Volume (TV): Volume of air inspired or expired during a normal respiration. It is approx. 500 mL. , i.e., a healthy man can inspire or expire approximately 6000 to 8000 mL of air per minute. Inspiratory Reserve Volume (IRV) : Additional volume of air, a person can inspire by a forcible inspiration. This averages 2500 mL to 3000 mL. Expiratory Reserve Volume (ERV): Additional volume of air, a person can expire by a forcible expiration. This averages 1000 mL to 1100 mL. Residual Volume (RV): Volume of air remaining in the lungs even after a forcible expiration. This averages 1100 mL to 1200 mL Inspiratory Capacity (IC): Total volume of air a person can inspire after a normal expiration. This includes tidal volume and inspiratory reserve volume ( TV+IRV) .

43. Expiratory Capacity (EC): Total volume of air a person can expire after a normal inspiration. This includes tidal volume and expiratory reserve volume (TV+ERV). Functional Residual Capacity (FRC): Volume of air that will remain in the lungs after a normal expiration. This includes ERV+RV. Vital Capacity (VC): The maximum volume of air a person can breathe in after a forced expiration. This includes ERV, TV and IRV or the maximum volume of air a person can breathe out after a forced inspiration. Total Lung Capacity: Total volume of air accommodated in the lungs at the end of a forced inspiration. This includes RV, ERV, TV and IRV or vital capacity + residual volume.

44. GASEOUS EXCHANGE : Alveoli are the primary sites of exchange of gases. Exchange of gases also occur between blood and tissues. O2 and CO2 are exchanged in these sites by simple diffusion mainly based on pressure/concentration gradient. Pressure contributed by an individual gas in a mixture of gases is called partial pressure and is represented as pO2 for oxygen and pCO2 for carbon dioxide.

45. The diffusion membrane is made up of three major layers namely, the thin squamous epithelium of alveoli, the endothelium of alveolar capillaries and the basement substance in between them. However, its total thickness is much less than a millimetre . Therefore, all the factors in our body are favourable for diffusion of O2 from alveoli to tissues and that of CO2 from tissues to alveoli. CONDITIONS FAVOURABLE FOR DIFFUSION : Partial pressure of gases Solubility of gases Moist surface Membrane should be thin for diffusion

46. TRANSPORT OF OXYGEN GAS Haemoglobin is a red coloured iron containing pigment present in the RBCs. O2 can bind with haemoglobin in a reversible manner to form oxyhaemoglobin . Each haemoglobin molecule can carry a maximum of four molecules of O2 . Binding of oxygen with haemoglobin is primarily related to partial pressure of O2 & Partial pressure of CO2 O2 gets bound to haemoglobin in the lung surface and gets dissociated at the tissues. Every 100 ml of oxygenated blood can deliver around 5 ml of O2 to the tissues under normal physiological conditions. TRANSPORT OF CARBON DIOXIDE CO2 is carried by hemoglobin as carbamino -hemoglobin . When pCO2 is high and pO2 is low as in the tissues, more binding of carbon dioxide occurs whereas, when the pCO2 is low and pO2 is high as in the alveoli, dissociation of CO2 from carbamino-haemoglobin takes place, i.e., CO2 which is bound to hemoglobin from the tissues is delivered at the alveoli. Every 100 ml of deoxygenated blood delivers approximately 4 ml of CO2 to the alveoli.

47. Respiration in Animals The mode of external respiration varies greatly from organism to organism. The basic process of respiration (cellular respiration) is similar in all  living organisms . The process of exchange gases varies in different animals. 1. Through Plasma Membrane In unicellular animals, such as amoeba, exchange of gases takes place through cell surface. They absorb  oxygen  from the surrounding air or water and give out carbon dioxide through plasma membrane by  diffusion . 2.Through Body Wall or Skin (CUTANEOUS RESPIRATION) Tapeworms, earthworms, and leeches use their skin for the exchange of gases. The skin of Earthworms is very thin and moistened. Many blood cells are spread on this skin. These  blood cells  are known as capillaries. The exchange of gases occurs at capillaries. They die of suffocation if their skin is dried up. Amphibians such as frogs use more than one organ of respiration during their life. They breathe through gills while they are  tadpoles . Mature frogs breathe mainly with lungs and also exchange gas with the environment through skin.

48. 3. Through Tracheal System (TRACHEAL RESPIRATION) In insects like cockroaches, grasshopper, transportation of gas or gaseous exchange take place by a special type of fine tubes is called tracheae. Opening of these tubes is known as spiracles. 4. Through Gills (BRANCHIAL RESPIRATION) A majority of aquatic animals like fish and prawns breathe through special organs called gills. Gilla are projections of the skin that help in using oxygen dissolved in water. Gills contain blood vessels which help in exchange of gases.

49. 5. Through lungs (PULMONARY RESPIRATION) Amphibians, mammals, and birds exchange gases through special respiratory organs called lungs. Lungs are air-filled sac-like structures in the chest cavity. They are connected to the outside by a series of tubes and small opening. 6. Through book lungs Arachnids, such as scorpions and spiders. Their name describes their structure. Stacks of alternating air pockets and tissue filled with haemolymph give them an appearance similar to a folded book.

50. Respiration In Plants Like animals, plants also need energy. The plants get this energy by the process of respiration. Plants also use oxygen of air for respiration and release carbon dioxide. Plants get Oxygen by Diffusion: Plants have a branching shape, so they have quite a large surface area in comparison to their volume. Therefore, diffusion alone can supply all the cells of the plants with as much oxygen as they need for respiration. Diffusion occurs in the rots, stems and leaves of plants. Respiration in Roots: Air occurs in soil interspaces. Root hairs of the roots are in direct contact with them. Oxygen of the soil air diffuses through root hair and reaches all internal cells of the root for respiration. Carbon dioxide produced by root cells diffuses in the opposite direction. In water-logged conditions, soil air becomes deficient. In the absence of oxygen, metabolic activity of the root declines and the plant may wither. Respiration in Stems: The stems of herbaceous plants have stomata. The oxygen from air diffuses into the stem of a herbaceous plant through stomata and reaches all the cells for respiration. The carbon dioxide gas produced during respiration diffuses out into the air through the same stomata.

51. Respiration in Leaves: The leaves of a plant have tiny pores called stomata. The exchange of respiratory gases in the leaves takes place by the process of diffusion through stomata. THEORIES SUPPORTING GASEOUS EXCHANGE VIA STOMATA 1.The Starch - Sugar interconversion Theory Steward (1964) holds that during the day the enzyme phosphorylase converts starch to sugar, thus increasing osmotic potential of guard cells causing entry of water. The reverse reaction occurs at night bringing about closure. 2.Proton - Potassium Pump Hypothesis Levit in 1974 combined the points in Scarth’s and Steward’s hypothesis and gave a modified version of the mechanism of stomatal movement which was called the proton - potassium pump hypothesis . According to this hypothesis K+ions are transported into the guard cells in the presence of light. K+ions react with the malate ions present in the guard cells to form potassium malate. Potassium malate causes increase in the osmotic potential of guard cells causing entry of water into the guard cells as a result of which the stomata opens. At night the dissociation of potassium malate takes place and K+ions exit out of guard cells causing loss of water from guard cells and so the stomata closes

52. Respiration with Lenticels lenticels  promote gas  exchange  of  oxygen , carbon dioxide, and water vapor. ...  Lenticels  are found as raised circular, oval, or elongated areas on stems and roots. In woody plants,  lenticels  commonly appear as rough, cork-like structures on young branches. Net gaseous exchange in the leaves of the plant: During day time, when photosynthesis occurs, oxygen is produced. The leaves use some of this oxygen for respiration and rest of the oxygen diffuses out into air. Again, during the day time, carbon dioxide produced by respiration is all used up in photosynthesis by leaves. Even more carbon dioxide is taken in from air. Thus,  net gas exchange in leaves during day time is: O 2  diffuses out ; CO 2  diffuses in. At night time, when no photosynthesis occurs and hence no oxygen is produced, oxygen from air diffuses into leaves to carry out respiration. And carbon dioxide produced by respiration diffuses out into air. Thus,  net gas exchange in leaves at night is: O 2  diffuses in; CO 2  diffuses out. Compensation point   :The  point  reached in a  plant  when the rate of photosynthesis is equal to the rate of respiration. This means that the carbon dioxide released from respiration is equivalent to that which is taken up during photosynthesis.

53. RESPIRATION IN FISHES Respiration in fish takes with the help of gills. Most fish possess  gills  on either side of their head. Gills are tissues made up of feathery structures called  gill filaments  that provide a large surface area for gas exchange. A large surface area is crucial for gas exchange in aquatic organisms as water contains very little amount of dissolved oxygen. The filaments in fish gills are arranged in rows in the  gill arch.  Each filament contains  lamellae , which are discs supplied with  capillaries . Blood enters and leaves the gills through these small blood vessels. Although gills in fish occupy only a small section of their body, the immense respiratory surface created by the filaments provides the whole organism with an efficient gas exchange.

54. MECHANISM : Fish take in oxygen-rich water through their mouths and pump it over their gills. As water passes over the gill filaments, blood inside the capillary network picks up the dissolved oxygen. The  circulatory system  then transports the oxygen to all body tissues and ultimately to the cells. While picking up carbon dioxide, which is removed from the body through the gills. After the water flows through the gills, it exits the body of the fish through the openings in the sides of the throat or through the  operculum , a flap, usually found in bony fish, that covers and protects the fish gills. Some fish, like sharks and lampreys, possess multiple gill openings. However, bony fish like Rohu, have a single gill opening on each side

55. TRANSPORTATION IN HUMAN BEINGS Oxygen, carbon dioxide ,digested food ,hormones , excretory products are transported by blood. Blood is a special connective tissue consisting of a fluid matrix, plasma, and formed elements . PLASMA :a straw coloured , viscous fluid constituting nearly 55 per cent of the blood. 90-92 per cent of plasma is water and proteins contribute 6-8 per cent of it. Fibrinogen, globulins and albumins are the major proteins. Fibrinogens are needed for clotting or coagulation of blood. Globulins primarily are involved in defense mechanisms of the body and the albumins help in osmotic balance. Plasma also contains small amounts of minerals like Na+ , Ca++, Mg++, HCO3 – , Cl– , etc. Glucose, amino acids, lipids, etc., Plasma without the clotting factors is called serum. BLOOD CELL OR CORPUSCLES : There are 3 types of blood cells which contributes total 45% of blood. Erythrocytes or red blood cells (RBC) are the most abundant of all the cells in blood. A healthy adult man has, on an average, 5 millions to 5.5 millions of RBCs mm–3 of blood. RBCs are formed in the red bone marrow in the adults, process is known as erythropoiesis. Circular , enucleated and biconcave in shape. A red coloured , iron containing complex protein called haemoglobin , hence the colour and name of these cells. A healthy individual has 12-16 gms of haemoglobin in every 100 ml of blood. Less amount of haemoglobin leads to a condition known as ANAEMIA. RBCs have an average life span of 120 days after which they are destroyed in the spleen (graveyard of RBCs). Abnormal increase in RBC (POLYCYTHEMIA) & decrease in RBC (ERYTHROCYTOPENIA).

56. Leucocytes : also known as white blood cells (WBC) as they are colourless due to the lack of haemoglobin , Irregular in shape. They are nucleated and are relatively lesser in number which averages 6000-8000 mm–3 of blood Life span of few hours or 2-3 days. WBCs mainly contribute to immunity and defence mechanism. Types of White Blood Cells There are five different types of White blood cells and are classified mainly based on the presence and absence of granules. Granulocytes Agranulocytes Granulocytes They are leukocytes, with the presence of granules in their cytoplasm. The granulated cells include- eosinophil, basophil, and neutrophil. Eosinophils They are the cells of leukocytes, which are present in the immune system. These cells are responsible for combating infections in parasites of vertebrates and for controlling mechanisms associated with the allergy and  asthma . Eosinophil cells are small granulocyte, which is produced in the bone marrow and makes 2 to 4 per cent of whole WBCs. These cells are present in high concentrations in the digestive tract.

57. Basophils They are the least common of the granulocytes, ranging from 0.01to 0.3 per cent of WBCs. They contain large cytoplasmic granules, which plays a vital role in mounting a non-specific immune response to pathogens, allergic reactions by releasing histamine and dilates the blood vessels. Around 20 to 25 per cent of basophils are present in WBCs. These white blood cells have the ability to be stained when exposed to basic dyes, hence referred to as basophil. These cells are best known for their role in asthma and their result in the inflammation and bronchoconstriction in the airways. Neutrophils They are normally found in the bloodstream. They are predominant cells, which are present in pus. Around 60 to 70 per cent of WBCs are neutrophils with a diameter of 10 to 12 micrometres . The nucleus is 2 to 5 lobed and cytoplasm has very fine granules. Neutrophil helps in the destruction of bacteria with lysosomes, and it acts as a strong oxidant. Neutrophils are stained only using neutral dyes. Hence, they are called so. Neutrophils are also the first cells of the immune system to respond to an invader such as a bacteria or a virus.

58. Agranulocytes They are leukocytes, with the absence of granules in their cytoplasm. Agranulocytes are further classified into monocytes and lymphocytes. Monocytes These cells usually have a large bilobed nucleus, with a diameter of 12 to 20 micrometres . The nucleus is generally of half-moon shaped or kidney-shaped and it occupies 3 to 8 per cent of WBCs. They are the garbage trucks of the immune system. The most important functions of monocytes are to migrate into tissues and clean up dead cells, protect against the bloodborne pathogens and they move very quickly to the sites of infections in the  tissues . These white blood cells have a single bean-shaped nucleus, hence referred to as Monocytes. Lymphocytes They play a vital role in producing antibodies. Their size ranges from 8 to 10 micrometres . They are commonly known as natural killer cells. They play an important role in body defence . On average, a human body contains about 10 to 12 lymphocytes cells. These white blood cells are colourless cells formed in lymphoid tissue, hence referred to as lymphocytes. There are two main types of lymphocytes – B lymphocytes and T lymphocytes.

59. Platelets Also called thrombocytes, are cell fragments produced from megakaryocytes (special cells in the bone marrow). Non nucleated,round or oval, biconvex disc like bodies. Life span of 8 days to 1 week. Blood normally contains 1,500,00-3,500,00 platelets mm–3. Platelets can release a variety of substances most of which are involved in the coagulation or clotting of blood. Low count is known as THROMBOCYTOPENIA and high count is thrombocytosis. A reduction in their number can lead to clotting disorders which will lead to excessive loss of blood from the body.

60. LYMPH It is a colourless fluid containing specialised lymphocytes which are responsible for the immune responses of the body. Lymph is also an important carrier for nutrients, hormones, etc. Fats are absorbed through lymph in the lacteals present in the intestinal villi. Exchange of nutrients, gases, etc., between the blood and the cells always occur through this fluid. An elaborate network of vessels called the lymphatic system collects this fluid and drains it back to the major veins. CIRCULATORY SYSTEM Open circulatory system is present in arthropods and molluscs in which blood pumped by the heart passes through large vessels into open spaces or body cavities called sinuses. Closed circulatory system in which the blood pumped by the heart is always circulated through a closed network of blood vessels found in annelids and chordates. All vertebrates possess a muscular chambered heart. Fishes have a 2-chambered heart with an atrium and a ventricle . Amphibians and the reptiles (except crocodiles) have a 3-chambered heart with two atria and a single ventricle. Crocodiles, birds and mammals possess a 4-chambered heart with two atria and two ventricles.

61. HUMAN CIRCULATORY SYSTEM Human circulatory system, also called the blood vascular system consists of a muscular chambered heart, a network of closed branching blood vessels and blood, the fluid which is circulated. HEART LOCATION : the mesodermally derived organ, is situated in the thoracic cavity, in between the two lungs, slightly tilted to the left. SIZE : size of a clenched fist. STRUCTURE : It is protected by a double walled membranous bag, pericardium, enclosing the pericardial fluid. Heart has four chambers, two relatively small upper chambers called atria and two larger lower chambers called ventricles. A thin, muscular wall called the interatrial septum separates the right and the left atria , whereas a thick-walled, the inter-ventricular septum , separates the left and the right ventricles.

62. The atrium and the ventricle of the same side are also separated by a thick fibrous tissue called the atrio -ventricular septum. Each of these septa are provided with an opening through which the two chambers of the same side are connected. The right atrium and the right ventricle is guarded by a valve formed of three muscular flaps or cusps, the tricuspid valve , whereas a bicuspid or mitral valve guards the opening between the left atrium and the left ventricle. The openings of the right and the left ventricles into the pulmonary artery and the aorta respectively are provided with the semilunar valves. The valves in the heart allows the flow of blood only in one direction, i.e., from the atria to the ventricles and from the ventricles to the pulmonary artery or aorta. These valves prevent any backward flow.

63. HISTOLOGY OF HEART: The entire heart is made of cardiac muscles. The walls of ventricles are much thicker than that of the atria. A specialised cardiac musculature called the nodal tissue is also distributed in the heart . A patch of this tissue is present in the right upper corner of the right atrium called the sino -atrial node (SAN). Mass of this tissue is seen in the lower left corner of the right atrium close to the atrio -ventricular septum called the atrio -ventricular node (AVN). A bundle of nodal fibres , atrioventricular bundle (AV bundle) continues from the AVN which passes through the atrio -ventricular septa to emerge on the top of the interventricular septum and immediately divides into a right and left bundle. These branches give rise to minute fibres throughout the ventricular musculature of the respective sides and are called purkinje fibres . These fibres alongwith right and left bundles are known as bundle of His. The nodal musculature has the ability to generate action potentials without any external stimuli, i.e., it is autoexcitable . SAN can generate the maximum number of action potentials, i.e., 70-75 min–1 , and is responsible for initiating and maintaining the rhythmic contractile activity of the heart. Therefore, it is called the pacemaker. Our heart normally beats 70-75 times in a minute.

64. CARDIC CYCLE: It can be explained in 3 phases : JOINT DIASTOLE : (time taken : 0.4sec) All the four chambers of heart are in a relaxed state. So deoxygenated blood carried by vena cava is poured into right atrium and at the same time oxygenated blood from lungs carried by pulmonary vein is poured into left atria. ATRIAL SYSTOLE:(time taken 0.1 sec) The SAN now generates an action potential which stimulates both the atria to undergo a simultaneous contraction – the atrial systole. The tricuspid and bicuspid valves are open, blood from the pulmonary veins and vena cava flows into the left and the right ventricle respectively through the left and right atria. VENTRICULAR SYSTOLE : (time taken 0.3 sec) The action potential is conducted to the ventricular side and causes the ventricular muscles to contract, (ventricular systole), the atria undergoes relaxation (diastole). Ventricular systole increases the ventricular pressure causing the closure of tricuspid and bicuspid valves due to attempted backflow of blood into the atria. As the ventricular pressure increases further, the semilunar valves guarding the pulmonary artery (right side) and the aorta (left side) are forced open, allowing the blood in the ventricles to flow through these vessels into the circulatory pathways. This sequential event in the heart which is cyclically repeated is called the cardiac cycle and it consists of systole and diastole of both the atria and ventricles .

65. DOUBLE CIRCULATION : PULMONARY CIRCULATION HEART(DEOXYGENATED BLOOD) LUNGS(OXYGENATION) HEART (OXYGENATED BLOOD) SYSTEMIC CIRCULATION HEART(OXYGENATED BLOOD) BODY PARTS HEART (DEOXYGENATED)

66. EVALUATION OF CARDIAC OUTPUT: Heart beat 72 times in 1 minute So 1 cardiac cycle = 60/72 = 0.8 seconds 1 CARDIAC CYCLE : 0.8 SECONDS IN EACH CARDIAC CYCLE BLOOD PUMPED = 70 ml(stroke volume) The stroke volume multiplied by the heart rate (no. of beats per min.) gives the cardiac output So in 1min amount of blood pumped = 70*72 = 5040ml or 5.4L Therefore, the cardiac output can be defined as the volume of blood pumped out by each ventricle per minute and averages 5000 mL or 5 litres in a healthy individual

67. NOTE : During each cardiac cycle two prominent sounds are produced which can be easily heard through a stethoscope. The first heart sound ( lub ) is associated with the closure of the tricuspid and bicuspid valves whereas the second heart sound (dub) is associated with the closure of the semilunar valves. Electrocardiograph (ECG) ECG is a graphical representation of the electrical activity of the heart during a cardiac cycle. Administration : A patient is connected to the machine with three electrical leads (one to each wrist and to the left ankle) that continuously monitor the heart activity. For a detailed evaluation of the heart’s function, multiple leads are attached to the chest region. Each peak in the ECG is identified with a letter from P to T that corresponds to a specific electrical activity of the heart. The P-wave represents the electrical excitation (or depolarisation ) of the atria, which leads to the contraction of both the atria. The QRS complex represents the depolarisation of the ventricles, which initiates the ventricular contraction. The contraction starts shortly after Q and marks the beginning of the systole. The T-wave represents the return of the ventricles from excited to normal state ( repolarisation ). The end of the T-wave marks the end of systole. By counting the number of QRS complexes that occur in a given time period, one can determine the heart beat rate of an individual.

68. BLOOD PRESSURE The heart supplies the organs and tissues of the body with blood. With every beat, it pumps blood into the large blood vessels of the circulatory system. As the blood moves around the body, it puts pressure on the walls of the vessels. Blood pressure readings are made up of two values: Systolic blood pressure  is the pressure when the heart beats – while the heart muscle is contracting (squeezing) and pumping oxygen-rich blood into the blood vessels. Diastolic blood pressure  is the pressure on the blood vessels when the heart muscle relaxes. The diastolic pressure is always lower than the systolic pressure. Blood pressure is measured in units of millimeters of mercury (mmHg). The readings are always given in pairs, with the upper (systolic) value first, followed by the lower (diastolic) value. Blood pressure is measured with a sphygmomanometer 120mmHg systolic pressure and 80mmHg diastolic pressure (for healthy individual)

69. DISORDERS OF CIRCULATORY SYSTEM High Blood Pressure (Hypertension): Hypertension is the term for blood pressure that is higher than normal (120/80). If repeated checks of blood pressure of an individual is 140/90 (140 over 90) or higher, it shows hypertension. High blood pressure leads to heart diseases and also affects vital organs like brain and kidney Coronary Artery Disease (CAD): Coronary Artery Disease, often referred to as atherosclerosis, affects the vessels that supply blood to the heart muscle. It is caused by deposits of calcium, fat, cholesterol and fibrous tissues, which makes the lumen of arteries narrower. Angina : It is also called ‘angina pectoris’. A symptom of acute chest pain appears when no enough oxygen is reaching the heart muscle. Heart Failure: Heart failure means the state of heart when it is not pumping blood effectively enough to meet the needs of the body. Congestion of the lungs is one of the main symptoms of this disease. Cardiac Arrest - It is triggered by an electrical malfunction in the heart that causes an irregular heartbeat ( arrhythmia ). With its pumping action disrupted, the heart cannot pump blood to the brain, lungs and other organs. Seconds later, a person loses consciousness and has no pulse. Death occurs within minutes if not treated. Heart Attack : A heart attack occurs when a blocked artery prevents oxygen-rich blood from reaching a section of the heart.

70. TRANSPORTATION IN PLANTS INTRODUCTION The plants have low energy needs, as they use relatively slow transport systems. Plant transport systems move energy from leaves and raw materials from roots to all their parts. The xylem (tissue) moves water and minerals obtained from the soil to all other parts of the plants. The phloem (tissue) transports products of photosynthesis from the leaves (where they are synthesized) to other parts of the plant

71. CONDUCTION OF WATER & MINERAL IONS

72. TRANSPORTATION OF FOOD Phloem transports soluble products of photosynthesis, amino acids, and other substances. The transport of soluble products of photosynthesis is called  translocation . The substances are transported to the storage organs of roots, fruits and seeds. The translocation takes place in the sieve tubes with the help of adjacent companion cells. The movement of substances is bidirectional i.e both upward and downward. Energy from ATP is utilized for translocation.

73. EXCRETION Ammonia, urea and uric acid are the major forms of nitrogenous wastes excreted by the animals. Ammonia is the most toxic form and requires large amount of water for its elimination, whereas uric acid, being the least toxic, can be removed with a minimum loss of water. 1)The process of excreting ammonia is Ammonotelism : Many bony fishes, aquatic amphibians and aquatic insects are ammonotelic in nature. 2)Ureotelic : Mammals, many terrestrial amphibians and marine fishes mainly excrete urea. 3)Uricotelic : Reptiles, birds, land snails and insects excrete nitrogenous wastes as uric acid in the form of pellet or paste with a minimum loss of water . DIFFERENT TYPES OF EXCRETORY SYSTEM Protonephridia or flame cells are the excretory structures in Platyhelminthes (Flatworms, e.g., Planaria), rotifers, some annelids and the cephalochordate – Amphioxus. Nephridia are the tubular excretory structures of earthworms and other annelids. Malpighian tubules are the excretory structures of most of the insects including cockroaches. Antennal glands or green glands perform the excretory function in crustaceans like prawns. Vertebrates have complex tubular organs called kidneys.

74. HUMAN EXCRETORY SYSTEM In humans, the excretory system consists of a pair of kidneys, one pair of ureters, a urinary bladder and a urethra . KIDNEY : Kidneys are reddish brown, bean shaped structures situated between the levels of last thoracic and third lumbar vertebra close to the dorsal inner wall of the abdominal cavity. Each kidney of an adult human measures 10-12 cm in length, 5-7 cm in width, 2-3 cm in thickness with an average weight of 120- 170 g. Towards the centre of the inner concave surface of the kidney is a notch called hilum through which ureter, blood vessels and nerves enter. Inner to the hilum is a broad funnel shaped space called the renal pelvis with projections called calyces. The outer layer of kidney is a tough capsule. Inside the kidney, there are two zones, an outer cortex and an inner medulla. The medulla is divided into a few conical masses (medullary pyramids) projecting into the calyces (sing.: calyx). The cortex extends in between the medullary pyramids as renal columns called Columns of Bertini

75. Ureters There is one ureter that comes out of each kidney as an extension of the renal pelvis. It is a thin muscular tube that carries urine from the kidneys to the bladder. Urinary Bladder The bladder is a sac-like structure. And a smooth muscle layer lines it. It stores the urine until micturition. Furthermore,  Micturition  is the act of expelling urine from the body. The bladder receives urine from the ureters, one from each kidney.  Urethra The urethra is a tube that arises from the urinary bladder. Its function is to expel the urine outside by micturition. In addition, it is shorter in females and longer in males. Furthermore, in males, it functions as a common path for sperms and urine. Also, sphincter guards the opening of the urethra.

76. NEPHRON : Each kidney has nearly one million complex tubular structures called nephrons ,which are the functional units. STRUCTURE : Each nephron has two parts – the glomerulus and the Renal tubule. Glomerulus : It is a tuft of capillaries formed by the afferent arteriole – a fine branch of renal artery. Blood from the glomerulus is carried away by an efferent arteriole. Renal tubule : It begins with a double walled cup-like structure called Bowman’s capsule , which encloses the glomerulus. Glomerulus alongwith Bowman’s capsule, is called the malpighian body or renal corpuscle . Proximal convoluted tubule : a highly coiled network of renal tubule. Henle’s loop : A hairpin shaped structure of the tubule which has a descending and an ascending limb. Distal convoluted tubule : The ascending limb continues as another highly coiled tubular region called distal convoluted tubule (DCT). The DCTs of many nephrons open into a straight tube called collecting duct, many of which converge and open into the renal pelvis through medullary. The Malpighian corpuscle, PCT and DCT of the nephron are situated in the cortical region of the kidney whereas the loop of Henle dips into the medulla .

77. STRUCTURE OF NEPHRO N

78. Mechanism of Excretion in Humans The process of excretion in humans takes place in the following steps: Urine Formation The urine is formed in the nephrons and involves the following steps: Glomerular Filtration Tubular Reabsorption Secretion Glomerular Filtration It is the primary step in urine formation. In this process, the excess fluid and waste products from the kidney are filtered out of the blood into the urine collection tubules of the kidney and eliminated out of the body. On an average, 1100-1200 ml of blood is filtered by the kidneys per minute . The glomerular capillary blood pressure causes filtration of blood through 3 layers, i.e., the endothelium of glomerular blood vessels, the epithelium of Bowman’s capsule and a basement membrane between these two layers. Blood is filtered so finely through these membranes, that almost all the constituents of the plasma except the proteins pass onto the lumen of the Bowman’s capsule. Therefore, it is considered as a process of ultra filtration . The amount of filtrate produced by the kidneys every minute is known as Glomerular Filtration Rate. GFR in a healthy individual is approximately 125 ml/minute, i.e., 180 litres per day .

79. The functions of the various tubules involved in the process are: Proximal Convoluted Tubule (PCT) : PCT is lined by simple cuboidal brush border epithelium which increases the surface area for reabsorption. Nearly all of the essential nutrients, and 70-80 per cent of electrolytes and water are reabsorbed by this segment. PCT also helps to maintain the pH and ionic balance of the body fluids by selective secretion of hydrogen ions, ammonia and potassium ions into the filtrate and by absorption of HCO3 – from it. Henle’s Loop: Reabsorption is minimum in its ascending limb. The descending limb of loop of Henle is permeable to water but almost impermeable to electrolytes. This concentrates the filtrate as it moves down. The ascending limb is impermeable to water but allows transport of electrolytes actively or passively. Distal Convoluted Tubule (DCT): Conditional reabsorption of Na+ and water takes place in this segment. DCT is also capable of reabsorption of HCO3 – and selective secretion of hydrogen and potassium ions and NH3 to maintain the pH and sodium-potassium balance in blood. Collecting Duct: This long duct extends from the cortex of the kidney to the inner parts of the medulla. Large amounts of water could be reabsorbed from this region to produce a concentrated urine. It also plays a role in the maintenance of pH and ionic balance of blood by the selective secretion of H+ and K+ ions .

80. MICTURITION Urine formed by the nephrons is ultimately carried to the urinary bladder where it is stored till a voluntary signal is given by the central nervous system (CNS). This signal is initiated by the stretching of the urinary bladder as it gets filled with urine. In response, the stretch receptors on the walls of the bladder send signals to the CNS. The CNS passes on motor messages to initiate the contraction of smooth muscles of the bladder and simultaneous relaxation of the urethral sphincter causing the release of urine. The process of release of urine is called micturition and the neural mechanisms causing it is called the micturition reflex. An adult human excretes, on an average, 1 to 1.5 litres of urine per day. The urine formed is a light yellow coloured watery fluid which is slightly acidic (pH-6.0) and has a characteristic odour . On an average, 25-30 gm of urea is excreted out per day.

81. DISORDERS OF THE EXCRETORY SYSTEM Malfunctioning of kidneys can lead to accumulation of urea in blood, a condition called uremia, which is highly harmful and may lead to kidney failure. In such patients, urea can be removed by a process called hemodialysis. Blood drained from a convenient artery is pumped into a dialysing unit after adding an anticoagulant like heparin. The unit contains a coiled cellophane tube surrounded by a fluid ( dialysing fluid) having the same composition as that of plasma except the nitrogenous wastes. The porous cellophane membrane of the tube allows the passage of molecules based on concentration gradient. As nitrogenous wastes are absent in the dialysing fluid, these substances freely move out, thereby clearing the blood. The cleared blood is pumped back to the body through a vein after adding anti-heparin to it. This method is a boon for thousands of uremic patients all over the world. Kidney transplantation is the ultimate method in the correction of acute renal failures (kidney failure). A functioning kidney is used in transplantation from a donor, preferably a close relative, to minimise its chances of rejection by the immune system of the host Renal calculi : Stone or insoluble mass of crystallised salts (oxalates, etc.) formed within the kidney. Glomerulonephritis: Inflammation of glomeruli of kidney.