Human Anatomy and physiology | B.Pharm1stYear | HAP BP101 - DRx Deepak Jatav.pptx

Human Anatomy and physiology all notes , HAP notes, Human Anatomy and physiology, DRx Learning Hub, DRx Deepak Jatav, B.Pharm 1st Year all notes, Introduction, tissue, cells, blood ect. Pharmacy Council of India , PCI , SAM GLOBAL UNIVERSITY, SAM College of Pharmacy, RGPV,

1. Human Anatomy & Physiology

2. You tube :- DRx Learning Hub Deepak Jatav Assistant Professor, M.Pharm ( SGU) [email protected]

3. HUMAN ANATOMY & PHYSIOLOGY

4. DEFINATION Human Anatomy: It is the branch of science that studies the physical structure of human body. Physiology : It is the branch of biology that deals with the internal working of living things, including functions such as metabolism, respiration and reproduction.

5. STRUCTURAL ORGANIZATION All multicellular organisms are organized at different levels, starting with the cell and ending with the entire organism. ATOM MOLECULE CELL TISSUE ORGANISM ORGAN SYSTEM ORGAN

6. LEVELS OF STRUCTURAL ORGANIZATION There are six levels of organization (from smallest to largest) The chemical level The cellular level The tissue level The organ level The organ system level The organism level

7. SYSTEMS OF THE HUMAN BODY There are 11 systems of the human body Integumentary system (hairs, nails, sweat glands, oil glands) Skeletal system Muscular system Endocrine system Cardiovascular system Lymphatic system Respiratory system Digestive system Nervous system Urinary system Reproductive system

8. BASIC LIFE PROCESSES There are 6 most important life processes of human body are : Metabolism: It is the sum of all chemical processes that occurs in the body. Catabolism: breakdown of complex chemical substance into simpler components e.g. digestion of protein into amino acids. Anabolism: building up of complex chemical substance from smaller, simpler components e.g. use of amino acids to build new proteins of the body. Responsiveness: It is the body’s ability to detect and respond to changes. Movement: It includes motion of the whole body, individual organs, single cells etc. Growth: It is an increase in body size and weight Differentiation: It is the development of a cell from an unspecialized to a specialized state. Reproduction: formation of new cells or to the production of a new individual.

9. HOMEOSTASIS Homeostasis - the self- sustaining mechanisms in organisms that tries to maintain stable internal conditions. Without homeostasis, organisms would not be able to have stable internal conditions, and therefore would not be able to survive. Homeostasis is a dynamic condition in response to changing conditions. The two body systems that largely control the body’s homeostatic state: Nervous system Endocrine system

10. Homeostasis is continually being disrupted by external stimuli intense heat, cold , and lack of oxygen internal stimuli psychological stresses exercise Disruptions are usually mild & temporary If homeostasis is not maintained, death may result

11. CONTROL OF HOMEOSTASIS Homeostatic imbalances occur because of disruptions from the external or internal environments. Homeostasis is regulated by the nervous system and endocrine system, acting together or independently. The nervous system detects changes and sends nerve impulses to counteract the disruption. The endocrine system regulates homeostasis by secreting hormones. Whereas nerve impulses cause rapid changes, hormones usually work more slowly.

12. BASIC ANATOMICAL TERMINOLOGY

13. ANATOMICAL POSITION The anatomical position is a standardized method of observing or imaging the body that allows precise and consistent anatomical references.

14. TERMINOLOGY Reclining Position If the body is lying face down, it is in the prone position. If the body is lying face up, it is in the supine position.

15. REGIONAL NAMES Head: It consist of skull and face. Neck: It supports the head. Trunk: It consist of chest, abdomen and pelvis. Upper limb: It consist of the shoulder, armpit, arm, forearm, wrist. Lower limb: It consist of thigh, ankle, and foot.

16. SECTIONS Sections are flat surfaces resulting from cuts through body structures. They are named according to the plane on which the cut is made and include Sagittal Frontal Transverse

17. DIRECTIONAL TERMS Directional terms are used to precisely locate one part of the body relative to another and to reduce length of explanations. Superior/Cephalic/Cranial Inferior/Caudal Anterior/Ventral/Rostral Posterior/Dorsal Superficial: toward surface Deep: away from surface

18. BODY C A VITIES Cranial Thoracic Abdominal Pelvic

19. CELL: Structure and function ADE PR EP SINGH, SHALU SINGH M.Sc. Medical Biochemistry HIMSR, Jamia Hamdard

20. INTRODUCTION Fundamental unit of life. Self replicating structure The first cells were observed and named by Robert Hooke in 1665 from slice of cork . Some organisms consist of a unicellular organism, others are multicellular. single cells = Diameter- 2- 120µm.

21. CELL THEORY Proposed by Matthais Schleiden and Theodor Schwann in 1839 :- - All living things are made up of cells. - Cells are the smallest working unit of all living things. - All cells come from pre- existing cells through cell division .

22. CONSTITUENTS Different substances that make a cell are collectively called Protoplasm. Protoplasm is composed of :- Water - 70- 80% Water is present in cell. 2)Carbohydrates 3)Lipids 4)Proteins 5)Electrolyte - Sodium (Na+), Potassium (K+), Magnesium (Mg2+), Calcium (Ca2+), Phosphate , Chloride (Cl- ), and Bicarbonate (HC03 - ).

23. Subcellular Structures Major Structures Present in a cell are :- Cell Membrane Cytoplasm and its Organelles Nucleus

24. Cell Membrane Thin pliable elastic outermost structure which envelops the cell. It consists of bilipid layer with embedded proteins that are- Integral Proteins ii)Peripheral proteins

25. Functions of Cell Membrane Protective :- Forms outermost boundary of the cell organelles. Digestive :- Takes in food and excretes waste products. Selective Permeability :- a)Non- Polar Molecules - Gases (like O 2 ,CO 2 , N 2 ), Lipids,Steroid Hormones, Alcohols can dissolve in the non –polar regions of the membrane and move rapidly across the membrane. b)Polar molecules :- H 2 O soluble ions , Glucose, urea etc. have much lower solubility . Therefore Penetrate the membrane much more slowly. b)Chemical and Physical Properties of membrane control the free passage of ions in and out of cell. This property helps in maintaining components in ICF and ECF.

26. Links adjacent cells together by junctional complexes to form tissues. Insulating Properties :- It acts as dielectric material of a charged condenser, thus cell membrane have very high insulating value

27. CYTOPLASM AND ITS ORGANELLES

28. CYTOPLASM Thick, gel- like semitransparent fluid that is found in both plant and animal cell. The constituent parts of cytoplasm are cytosol, cell organelles and cytoplasmic inclusions. Bounded by the plasma membrane, and contains many organelles in a eukaryotic cell (cell containing membrane bounded nucleus).

29. Cytosol The cytosol , the aqueous part of the cytoplasm outside all of the organelles, also contains its own distinctive proteins. It accounts for almost 70% of the total cell volume. Gelatinous substance consisting mainly of cytoskeleton filaments, organic molecules, salt and water. Chemically, the cytoplasmic matrix is composed of many chemical elements in the form of atoms, ions and molecules.

30. Organelles Following organelles are present in the Cytoplasm:- i)Mitochondria iii)Lysosomes v)Peroxisomes ii)Endoplasmic Reticulum iv)Golgi Appartus vi)Vacuole Each organelle is bounded by a lipid membrane, and has specific functions.

31. Mitochondria The mitochondria were first observed by Kolliker in 1850 as granular structures in the striated muscles. Mitochondria are called the 'powerhouse of the cell'. STRUCTURE - Length- 5- 12µm Diameter- 0.5- 1µm Filamentous or globular in shape.

32. Components of Mitochondria are - Outer Membrane Inner Membrane Intermediate Space- space between outer and inner membranes Cristae - Infoldings of inner membrane Matrix- The space enclosed by inner membrane The membranes are made up of phospholipids and proteins

33. Outermost Membrane- It contains large numbers of integral membrane proteins called Porins . These porins form channels that allow molecules of 5000 daltons or less to pass. Studded with enzymes concerned with biological oxidation . Interior (Matrix) of the Mitochondria contains enzymes concerned with ‘citric acid cycle’ and ‘respiratory chain oxidation’. Major metabolic pathways involved in oxidation of carbohydrates, lipids and amino acids and part of special biosynthetic pathways involving urea and heme synthesis are located in inner matrix.

34. Inner Membrane : It contains ATPase and other enzymes concerned with synthesis and metabolism of ATP. Contains enzymes of Electron Transport Chain. The ultimate purpose of these mechanisms is oxidative phosphorylation and synthesis of ATP. Mitochondria has some protein synthesised by Mitochondrial DNA.

35. Functions Power generating units of the cells. Important to maintain proper concentration of calcium ions within the various compartments of the cell. Energy transduction through respiration. Responsible for thermogenesis.

36. Endoplasmic Reticulum Network of tubular and flat vesicular structures in the cytoplasm. An extensive network of closed, flattened membrane- bounded sacs called cisternae . Space inside the tubules is filled with Endoplasmic Matrix.

37. TWO TYPES- Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum Ribosomes absent Site of synthesis of lipid and steroid hormones. Mainly present in lipid forming cells such as adipocytes, interestitial cells of testis, glycogen storing cells of liver, adrenal cortex cells, muscle cells, leucocytes etc. Contains ribosomes Site of protein synthesis,processing and packaging. Mainly present in protein forming cells such as pancreatic acinar cells ,Goblet cells ,antibody producing plasma cells, Nissl’s granules of nerve cells etc.

38. Function Synthesis of proteins. Protein segregation. Unsaturation of fatty acid. Muscle contraction.ER is commomly known as Sarcoplasmic Reticulum in muscle fibers.

39. Golgi Bodies Golgi Bodies is a collection of membrane enclosed sacs composed of four or more stacked layers of thin, flat enclosed vessels lying near the side of the nucleus. Consist of multiple discrete compartments. Consist of four functionally distinct regions: The cis Golgi network Golgi stack –which is divided into a) The medial and b) Trans sub compartments iii)The trans Golgi network .

40. Function Wrapping and Packaging department of the cell. Produces secretion granules i.e. membrane enclosed complexes, which store hormones and enzymes in the protein secreting cells, it packages proteins. Site of formation of lysosomes i.e. large irregular structures surrounded by membrane which are present in the cytoplasm. It adds certain carbohydrates to form glycoproteins, which play an important role in the association of the cells to form tissues

41. L ysosomes Diameter - 250 -750nm These are the irregular structures surrounded by the unit membrane. More acidic than rest of the cytoplasm and external bacteria as well as worn out cell components are digested in them. The interior is kept acidic(near pH 5.0) by the action of proton pump or H + or ATPase. Lysosomes are cell hydrolases and they function best at the acidic pH.

42. Functions Acts as a form of digestive (lytic ) system or the cell, because enzymes present in it can digest essentially all macromolecules. Engulf worn out components of the cells in which they are located. Engulf exogenous substances e.g. bacteria and degrade them. When a cell dies ,lysosomal enzymes causes autolysis of the remanant . Thats why lysosomes are called as Suicidal Bags .

43. Peroxisomes Diameter - 0.5µm A lipid bilayer membrane surrounds which regulates what enters or exits the peroxisomes. Urate oxidase crystalline core. Structure is similar to that of the lysosomes but with a different composition . chemical Peroxisomes can be formed by the budding of ER, or by division

44. Contd. Contains oxidases that produces H 2 O 2. Catalases degrades hydrogen peroxide to yield water and oxygen Proteins are directed to the Peroxisomes by a unique signal sequence with the help of protein chaperones, Peroxins.

45. Function H 2 O 2 metabolism and detoxification Helps in Photorespiration in plants Biosynthesis of lipids . Cholesterol and dolichol are synthesized in animals. Synthesis of bile acids in liver. Synthesis of plasmalogens ( myelin sheath).

46. Cytoskeleton System of fibers that not only maintains the structure of the cell but also permit it to change shape and move. The cytoskeleton is made up primarily of:- i)Microtubules Intermediate Filaments Microfilaments along with protein that anchor tie them together. and

47. Microtubules- These are long hollow structures approx. 25nm in diameter. Determine shape of the cell, role in the contraction of the spindle and movement of chromosomes and centrioles as well as in ciliary and flagellar motion. Intermediate Filaments - They are 8- 14nm in diameter and are made up of various subunits. They form a flexible scaffolding or cell and help it resist external pressure. In their absence cell ruptures more easily and when they are abnormal in human, blistering in common. The proteins that makeup intermediate filament are cell types specific and are thus frequently used as cellular markers. Microfilaments - They are long solid fibers 4- 6 nm in diameter. They comprise the contractile protein actin and are responsible for the cell motion.

48. Function They are involved in the:- Movement of the chromosomes Cell movement Processes that move secretion granules in the cell Movement of proteins within the cell membrane.

49. NUCLEUS

50. The Nucleus The nucleus contains chromatin, RNAs, and nuclear proteins move freely in aqueous solution. Nucleus has an internal structure that organizes the genetic material and localizes nuclear functions. A loosely organized matrix of nuclear lamins extends from the nuclear lamina into the interior of the nucleus.

51. Contd. These lamins serve as sites of chromatin attachment and organize other proteins into functional nuclear bodies. Chromatin within the nucleus is organized into large loops of DNA, and specific regions of these loops are bound to the lamin matrix by lamin- binding proteins in the chromatin.

52. Nuclear Envelope Complex structure consisting of two nuclear membranes, an underlying nuclear lamina, and nuclear pore complexes. Two concentric membranes, called the inner and outer nuclear membranes . The outer membrane is continuous with the endoplasmic reticulum, so the space between the inner and outer nuclear membranes is directly connected with the lumen of the endoplasmic reticulum.

53. Contd. Nuclear membrane is permeable only to small nonpolar molecules. Underlying the inner nuclear membrane is the nuclear lamina, a fibrous meshwork that provides structural support to the nucleus.

54. Function Serves both as the repository of genetic information and as the cell's control center. The presence of a nucleus thus allows gene expression to be regulated by posttranscriptional mechanisms, such as alternative splicing. The nuclear envelope provides novel opportunities for the control of gene expression at the level of transcription.

55. Summary COMPARTMENTS Plasma Membrane Cytosol Mitochondria Endoplasmic Reticulum Golgi apparutus Lysosomes Peroxisomes Cyotoskeleton Nucleus MAJOR FUNCTIONS Transport of ions and molecules Metab. of carbohydrate, lipids and amino acids Energy production Synthesis of proteins and lipids Modification and sorting of proteins Cellular digestion Utilisation of H 2 O 2 Cell Morphology and cell motility DNA synthesis and Repair

56. Cell to Cell Communication

57. Cell to Cell Communication Communication between cells requires: ligand : the signaling molecule receptor protein : the molecule to which the receptor binds -may be on the plasma membrane or within the cell

58. Cell to Cell Communication

59. Cell Communication There are five basic mechanisms for cellular communication: Direct contact Paracrine and Autocrine signaling Endocrine signaling Synaptic signaling

60. Cell Communication When a ligand binds to a receptor protein, the cell has a response. signal transduction : the events within the cell that occur in response to a signal Different cell types can respond differently to the same signal.

61. Cell Communication A cell’s response to a signal often involves activating or inactivating proteins. Phosphorylation is a common way to change the activity of a protein. protein kinase – an enzyme that adds a phosphate to a protein phosphatase – an enzyme that removes a phosphate from a protein

62. Three Stages of Signal Transduction • • Reception of extracellular signal by cell Transduction of signal from outside of cell to inside of cell— often multi-stepped Note not necessarily transduction of ligand Cellular Response Response is inititiated and/or occurs entirely within receiving cell •

63. Three Stages of Signal Transduction

64. Three Stages 2a. Transduction 2b. Transduction 2c. Transduction 2d. Transduction 1. Reception 3. Response Responses usually involve increasing or decreasing some Protein’s Function

65. Three Stages 2a. Transduction 2b. Transduction 1. Reception 3. Response

66. Receptor Types Receptors can be defined by their location. intracellular receptor – located within the cell cell surface receptor or membrane receptor – located on the plasma membrane to bind a ligand outside the cell

67. Receptor Types There are 3 subclasses of membrane receptors: channel linked receptors – ion channel that opens in response to a ligand enzymatic receptors – receptor is an enzyme that is activated by the ligand G protein- coupled receptor – a G- protein (bound to GTP) assists in transmitting the signal

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69. Cell- to- Cell Interactions Cells within a tissue are connected to each other by cell junctions tight junctions – create sheets of cells anchoring junctions – connect the cytoskeletons of adjacent cells communicating junctions – permit small molecules to pass between cells - gap junctions

70. INTERCELLULAR JUNCTIONS

71. The Function Cell junctions allow activities of individual cells that make up the systems to be co- ordinated Enables each system to function as an integrated whole They are fundamental to the interactions between cells. Ohh okay…

72. Plants versus Animals Major types of intercellular junctions in animals: 🞑 Tight Junctions 🞑 Gap Junctions 🞑 Desmosomes 🞑 Adherens Junctions Plants have plasmodesmata

73. Tight Junctions Multiple strands of protein form the tight junction 🞑 More strands = more impermeability 🞑 Each strand formed from proteins Claudins Occludins

74. The Function of Tight Junctions At tight junctions 🞑 Plasma membranes of neighboring cells are tightly pressed against each other Form continuous seals around the cells Prevents… leakage of extracellular fluid across a layer of epithelial cells passage of molecules and ions through the space between cells. Ex: Make us watertight Or else you might look like him…

75. Gap Junctions Also called “Communicating Junctions” 2 opposing connexons join across intercellular space. 🞑 Connexons: assembly of six proteins that create gap between two plasma membranes

76. The Function of Gap Junctions The created gap… 🞑 provides cytoplasmic channels from one cell to an adjacent cell 🞑 allows for communication through exchange of materials and transmission of electrical impulses Necessary for communication between cells in…?

77. Properties of Gap Junctions Ions/molecules are able to pass through 🞑 Some molecules too big Isolate damaged cells so damage does not spread 🞑 Damaged gap junction = bad

78. Desmosomes Also called “Anchoring Junctions” Arranged randomly on the lateral side of cells membranes The adhesion protein bridges the space between the cells

79. The Function of Desmosomes Fasten cells together into strong sheets Attach muscle cells to each other in a muscle 🞑 Muscle tears can involve rupture of desmosomes

80. Adherens Junctions They are composed of… 🞑 Cadherins bind to the catenins that are connected to the actin filaments

81. The Function of Adherens Junction Provide strong mechanical attachments between adjacent cells They serve as a bridge connecting the actin cytoskeleton of neighboring cells through direct interaction

82. Summary of Junctions in Animals

83. That wasn’t so bad!

84. TRANSPORT OF MATERIAL ACROSS THE CELL

85. PROCESS OF TRANSPORT ACROSS THE PLASMA MEMBRANE Motion of substances in and out of the cell Cell membranes are Selectively permeable Two Types of Transport Mechanisms: Passive Transport Active Transport

86. Membrane transport Passive transport is movement of molecules through the membrane in which no energy is required from the cell Active transport requires energy expenditure by the cell

87. 1. Passive Transport Passive transport is movement of molecules through the membrane in which no energy is required from the cell. Molecules move in response to a concentration gradient. - A concentration gradient is a difference between the concentration on one side of the membrane and that on the other side. Passive transport mechanisms only movement substances along the concentration gradient.

88. 1. Passive Transport Passive transport mechanisms only movement substances along the concentration gradient : - Substances move from an area of high concentration to an area of low concentration

89. 1. Passive Transport Mechanisms of Passive Transport: Diffusion movement of solute molecules from high solute concentration to low solute concentration Osmosis movement of solvent water from high solvent concentration to low solvent concentration

90. Diffusion Diffusion is movement of solute molecules from high concentration to low concentration.

91. Diffusion There are two types of diffusion Simple Diffusion Facilitated Diffusion

92. 1.Simple Diffusion Substances pass directly through the cell membrane The cell membrane has limited permeability to small polar molecules, water, and ions The motion of water across the membrane is known as osmosis

93. diffusion depends on the The rate (molecules/s) of simple degree of concentration gradient As the gradient reaches equilibrium, diffusion slows At equilibrium, substances pass in and out of the membrane at equal rates

94. 2.Facilitated Diffusion Substances must pass through transported proteins to get through the cell membrane. The cell membrane is selectively permeable. Carrier proteins bind to the molecule that they transport across the membrane.

95. 2.Facilitated Diffusion Selective permeability : integral membrane proteins allow the cell to be selective about what passes through the membrane. Channel proteins have a polar interior allowing polar molecules to pass through. Carrier proteins bind to a specific molecule to facilitate its passage.

96. ion channels

97. Carrier Proteins Carrier proteins bind to a specific molecule to facilitate its passage.

98. Osmosis Osmotic concentration is determined by the concentration of all solutes in solution.

99. 16 2. Active Transport Active transport Requires energy – ATP is used directly or indirectly to fuel active transport Able to moves substances against the concentration gradient - from low to high concentration - allows cells to store concentrated substances Requires the use of carrier proteins

100. Active transport

101. 20 Bulk Transport Bulk transport of substances is accomplished by Endocytosis – movement of substances into the cell Exocytosis – movement of materials out of the cell

102. 21 Bulk Transport Endocytosis occurs when the plasma membrane envelops food particles and liquids. phagocytosis – the cell takes in particulate matter pinocytosis – the cell takes in only fluid receptor- mediated endocytosis – specific molecules are taken in after they bind to a receptor

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107. Cell Cycle The cell cycle is a sequence of cell growth and division. The cell cycle is the period from the beginning of one division to the beginning of the next. The time it takes to complete one cell cycle is the generation time.

108. Cells divide when they reach a certain size NO (nerve, skeletal muscle and red blood cells) Cell division involves mitosis and cytokinesis. Mitosis involves division of the chromosomes. Cytokinesis involves division of the cytoplasm. Mitosis without cytokinesis results in multinucleate cells.

109. Eukaryotic cell cycle Beginning of one division to beginning of next Stages in eukaryotic cell cycle Interphase First gap phase Synthesis phase Second gap phase M phase Mitosis Cytokinesis

110. Chromosomes become duplicated during interphase Cells are very active during interphase, synthesizing biological molecules and growing the G 1 (gap) phase The S (synthesis) phase is marked by DNA replication The G 2 (gap) phase occurs between the S phase and mitosis

111. Despite differences between prokaryotes and eukaryotes, there are several common features in their cell division processes. Replication of the DNA must occur. Segregation of the "original" and its "replica" follow. Cytokinesis ends the cell division process. Whether the cell was eukaryotic or prokaryotic, these basic events must occur.

112. Hereditary material is passed on to new cells by mitosis or meiosis Cell division, growth, and reproduction Interphase Mitosis Cytokinesis Meiosis

113. Cell division Chromosomal packaging of DNA allows efficient distribution of genetic material during cell division Life cycle requires two distinct types of cell division processes: mitosis and meiosis Cell division: one cell becomes two cells during an organism’s life cycle

114. Mitosis Mitosis is nuclear division plus cytokinesis , and produces two identical daughter cells during the following steps: Prophase Metaphase Anaphase Telophase. Interphase is often included in discussions of mitosis, but interphase is technically not part of mitosis, but rather encompasses stages G1, S, and G2 of the cell cycle. 9/1/2014 12

115. A Centriole is a cylindrical cell structure composed mainly of a protein called tubulin that is found in most eukaryotic cells. Centrioles are involved in the organization of the mitotic spindle and in the completion of cytokinesis the centrosome is an organelle that serves as the main microtubule organizing center (MTOC) of the animal cell as well as a regulator of cell- cycle progression The centromere is the part of a chromosome that links sister chromatids.

116. State Description Abbv Quiescent / senescent Gap G A resting phase where the cell has left the cycle and has stopped dividing Interphase Gap 1 G 1 Cells increase in size in Gap 1. The G 1 checkpoint control mechanism ensures that everything is ready for DNA synthesis . Synthesis S DNA replication occurs during this phase. Gap 2 G 2 During the gap between DNA synthesis and mitosis, the cell will continue to grow. The G 2 checkpoint control mechanism ensures that everything is ready to enter the M (mitosis) phase and divide. Cell division Mitosis M Cell growth stops at this stage and cellular energy is focused on the orderly division into two daughter cells. A checkpoint in the middle of mitosis (Metaphase Checkpoint) ensures that the cell is ready to complete cell division.

117. Interphase The cell is engaged in metabolic activity and performing its prepare for mitosis (the next four phases that lead up to and include nuclear division). Chromosomes are not clearly discerned in the nucleus, although a dark spot called the nucleolus may be visible. The cell may contain a pair of centrioles (or microtubule organizing centers in plants) both of which are organizational sites for microtubules .

118. Prophase Chromatin in the nucleus begins to condense and becomes visible in the light microscope as chromosomes. The nucleolus disappears. Centrioles begin moving to opposite ends of the cell and fibers extend from the centromeres. Some fibers cross the cell to form the mitotic spindle.

119. Prometaphase The nuclear membrane dissolves, marking the beginning of prometaphase. Proteins attach to the centromeres creating the kinetochores. Microtubules attach at the kinetochores and the chromosomes begin moving .

120. Metaphase Spindle fibers line the chromosomes along the middle of the cell nucleus. This line is referred to as the metaphase plate. Polar microtubules extend from the pole to the equator, and typically overlap Kinetochore microtubules extend from the pole to the kinetochores This organization helps to ensure that in the next phase, when the chromosomes are separated, each new nucleus will receive one copy of each chromosome.

121. Anaphase The paired chromosomes separate at the kinetochores and move to opposite sides of the cell. The chromosomes are pulled by the kinetochore microtubules to the poles and form a "V" shape Motion results from a combination of kinetochore movement along the spindle microtubules and through the physical interaction of polar microtubules.

122. Telophase Chromatids arrive at opposite poles of cell, and new membranes form around the daughter nuclei. The chromosomes disperse and are no longer visible under the light microscope. The spindle fibers disperse, and cytokinesis will start.

123. Cytokinesis In animal cells, cytokinesis results when a fiber ring composed of a protein called actin around the center of the cell contracts pinching the cell into two daughter cells, each with one nucleus. In plant cells, synthesis of new cell wall between two daughter cells rather than cleavage furrow in cytoplasm

124. Significance of Mitosis: Restricted to Diploid Cells only Results in production of the diploid daughter cells with identical genetic compliment. Restores the Nucleo- cytoplasmic Ratio.

125. Meiosis Sexual reproduction involves fusion of two gametes, each with a complete haploid sets off chromosomes. Gametes are formed from special types of diploid cells. This specialized cell division that reduces the chromosomes no. to Half is called as meiosis

126. Key Features Involves two sequential cycles called meiosis I and meiosis II. But only a single cycle of DNA replication. Meiosis I is initiated after Parental Chromosomes have replicated to form identical sister chromatids at S Phase. Involves pairing of Homologues Chromosomes and recombination between them. 4 Haploid cells are formed at the end of the Meiosis II.

127. Mitosis vs. Meiosis

128. Tissue Prepared By: Nahid Hasan ID:1310690646 North South University Bangladesh. Prepared For: Human Physiology- I

129. Definition of Tissues Biological tissue is a collection of interconnected cells that perform a similar function within an organism. In other words, it is a group of cells working together mainly inside an organ.

130. Classification of Tissues Human body is composed of 4 basic types of tissue: Epithelial tissue Connective tissue Muscular tissue Nervous tissue

131. Origin of Tissue A fertilized egg divides to produce 3 primary germ cell layers. These layers differentiate to form the tissues of the body.

132. Epithelial Tissue Epithelial cells cover or line all body surfaces, cavities and tubes. So, These are called covering epithelia. Epithelial cells form the functional units of secretory glands. So, These are called glandular epithelia.

133. General Characteristic Closely attached to each other forming a protective barrier. Always has one free (apical) surface open to outside the body or inside (cavity) an internal organ. Always has one fixed (basal) section attached to underlying connective tissue. Has no blood vessels but can soak up nutrients from blood vessels in connective tissue underneath. Can have lots of nerves in it (innervated). Very good at regenerating (fixing itself). i.e. sunburn, skinned knee.

134. Functions To protect the tissues that lie beneath it from radiation, desiccation, toxins, invasion by pathogens, and physical trauma. The regulation and exchange of chemicals between the underlying tissues and a body cavity. The secretion of hormones into the blood vascular system, and/or the secretion of sweat, mucus, enzymes, and other products that are delivered by ducts glandular epithelium. To provide sensation. Absorbs stomach and intestinal lining (gut). Filters the kidney. Forms secretary glands.

135. Classification of Epithelia According to thickness “simple” - one cell layer “stratified” – more than one layer of cells (which are named according to the shape of the cells in the apical layer) According to shape “squamous” – wider than tall “cuboidal” – as tall as wide “columnar” - taller than wide

136. Simple squamous epithelium Description: Single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm; the simplest of the epithelia. Function: Passive transport of gases and fluids. Location:Alveoli of lungs, lining body cavities (mesothelium), lining blood vessels (endothelium)

137. Simple cuboidal epithelia Description : Single layer of cubelike cells with large, spherical central nuclei. Function : Secretion and absorption. Location: Kidney tubules; ducts and secretory portions of small glands; ovary surface.

138. Simple columnar epithelia Description: Single layer of tall cells with round to oval nuclei. Types: (i)Ciliated columnar epithelia. (ii)Non- ciliated columnar epithelia. Function: Absorption; secretion of mucus, Enzymes and other substances. Location: Digestive tract, gall bladder etc.

139. Stratified squamous epithelia Description: Multilayered, surface cell are squamous, basal cells are cuboidal and divided constantly. Function: Protection. Location: Oral cavity, cervix, anal canal.

140. Stratified cuboidal epithelia Description: Generally two layers of cube- like cells. Function: Protection. Location: Large ducts of sweat glands, mammary glands, and salivary glands.

141. Stratified columnar epithelia Description: Multilayered, superficial cells elongated and columnar. Function: Protection; secretion. Location: Rare in the body; small amount in the male urethra.

142. Pseudo stratified columnar epithelia Description: Single cell layered, all cell attach to the basement membrane but not all reach the free surface. Nuclei at varying depth. Function: Secretion of mucus, propulsion of mucus by ciliary action. Location: Lines of trachea.

143. Transitional epithelia Description: Characterized by domelike cells that are neither squamous nor columnar. The form of the cells changes. Function: Stretching and protection. Location: Bladder and part of urethra.

144. Connective Tissues The tissues that connect the different parts of the body together are called connective tissues.

145. General characteristic The intercellular material is maximum where as the cellular component is minimum. Unlike the other tissues, (e.g. epithelium, muscle and nerve) which are formed mainly by cells, the major constituent of connective tissue is ECM (Extra- cellular matrix). Possess cells, fibers and ground substances.

146. Basic Functions Support and binding of other tissues Holding body fluids Defending the body against infection 🞇 macrophages, plasma cells, mast cells, WBCs Storing nutrients as fat

147. Classification of connective tissues

148. Connective tissue proper : Loose CT ; Areolar Description: Gel like matrix with all three fiber types ; cells: fibroblasts, macrophages, mast cells, and white blood cells. Function: Its macrophages phagocytize bacteria ; plays important role in inflammation ; holds and conveys tissue fluid. Location: Distributed under epithelia of body; surrounds capillaries.

149. CT proper : Loose CT ; Adipose Description: Matrix as in areolar, but very sparse; closely packed adipocytes, or fat cells , have nucleus pushed to the side by large fat droplet. Function: Provides reverse food fuel; insulates against heat loss; supports and protects organs. Location: Under skin; around kidneys and eyeballs; within abdomen; in breasts. Fat droplets Nucleus

150. CT proper: Loose CT; reticular Description: Network of reticular fibers in a typical loose ground substance; reticular cells lie on the network. Function: Fibers form a soft internal skeleton that supports other cell types including white blood cells, mast cells, and macrophages. Location: Lymphoid organs(lymph nodes, bone marrow, and macrophages.

151. CT proper: dense CT; Irregular Description: Primarily irregularly arranged collagen fibers; some elastic fibers; major cell type is the fibroblast. Function: Elasticity and structural support. Location: Dermis of the skin; submucosa of digestive tract and joints. Collagen fibers

152. CT proper: dense CT; Regular Description: Primarily parallel collagen fibers; a few elastin fibers; major cell type is the fibroblast. Function: Attaches muscles to bones and bones to bones. Location: Tendons and in most ligaments.

153. Cartilage: Hyaline Description: Amorphous but firm matrix; chondroblasts produce the matrix and when mature lie in lacunae. Function: Supports and reinforces; resists compressive stress. Location: Forms most of the embryonic skeleton; ends of long bones; cartilages of nose.

154. Cartilage: Elastic Description: Similar to hyaline cartilage, but more elastic fibers in matrix. Function: Maintains the shape and allows flexibility. Location: Supports the external ear(pinna).

155. Cartilage : Fibrocartilage Description : Collagen fibers are predominant ; matrix is as hyaline but less firm. Function: High strength, tensile absorb compressive shock. Location: Intervertebral disc; discs of knee joint.

156. Bone Description: Hard, calcified matrix containing many collagen fibers. Very well vascularized. Function: Bone supports and protects; provides levers for the muscles to act on; stores calcium and other minerals and fat; bone marrow is the site of blood cell formation. Location: Skeleton.

157. Blood Description: Liquid connective tissue, red and white blood cells in fluid matrix. Function: Transport respiratory gases, nutrients, wastes and other substances. Location: In the blood vessels.

158. Muscle Tissue 🞇 Muscle is one of our 4 tissue types and muscle tissue combined with nerves, blood vessels, and various connective tissues. 🞇 Muscles are quite complex and as we’ll find out, they are a marvel of both biology and physics.

159. General characteristics 1. Excitability 🞇 The ability to receive and respond to a stimulus 🞇 In skeletal muscle , the stimulus is a neurotransmitter (chemical signal) release by a neuron (nerve cell). 🞇 In smooth muscle , the stimulus could be a neurotransmitter, a hormone, stretch,  pH,  Pco 2 , or  Po 2 . 🞇 In cardiac muscle , the stimulus could be a neurotransmitter, a hormone, or stretch. 🞇 The response is the generation of an electrical impulse that travels along the plasma membrane of the muscle cell.

160. 2. Contractility 🞇 The ability to shorten forcibly when adequately stimulated. 🞇 This is the defining property of muscle tissue. 2. Extensibility 🞇 The ability to be stretched (Extended) 4. Elasticity 🞇 The ability to recoil and resume original length after being stretched.

161. Functions 🞇 Movement 🞇 Locomotion 🞇 Maintains posture 🞇 Produces heat 🞇 Facial expressions 🞇 Pumps blood 🞇 Peristalsis

162. 3 Types of Muscle Tissue

163. Skeletal Muscle Tissue Description: Long striated cells with multiple nuclei. Function: Contraction for voluntary movements. Location: In skeletal muscle.

164. Smooth Muscle Tissue Description: Long, spindle- shaped cells, each with a single nucleus. Function: Propulsion of substances along internal passageways. Location: In hollow organs(e.g. stomach)

165. Cardiac Muscle tissue Description: Branching, striated cells fused at plasma membranes. Function: Pumping of blood in the circulatory system. Location: Wall of heart.

166. Nerve Tissue By far the most complex tissue in the human body is nerve tissue. Formed by a network of more than 100 million nerve cells, assisted by many more glial cells. Each neuron has, on an average , at least a thousand interconnection with other neurons forming a very complex nervous system.

167. Functions Regulates & controls body functions Generates & transmits nerve impulses Supports, insulates and protects impulse generating neurons.

168. Composition of Nerve Tissue The nerve tissue is composed of two elements: The nerve cell or neuron The neuroglia

169. Neuron Description: Neurons are branching cells; cell processes that may be quite long extend from the nucleus- containing cell body. Function: Transmit electrical signals from sensory receptors and to effectors(muscles and glands) that control their activity. Location: Brain, spinal cord and nerves.

170. Glial cells Glia carry nutrients, speed repair, provide myelin for axons, support the blood- brain barrier, and may form their own communication network. They are also involved in neurogenesis.

171. By iTutor.com T- 1- 855- 694- 8886 Email- [email protected]

172. The integument as an organ, nd is an alternative name for skin. a The integumentary system includes the skin and the skin derivatives hair , nails , and glands . The integument as an organ:

173. The Integument Is the largest system of the body 16% of body weight, 1.5 to 2m 2 in area, The integument is made up of two parts: Cutaneous membrane Epidermis– Superficial epithelium Dermis – underlying CT with blood supply Accessory structures Hair Nails Exocrine Glands

174. Protection First line of defense against Bacteria Viruses Protects underlying structures from Ultraviolet (UV) radiation Dehydration Vitamin D production Needed for calcium absorption Sensation Sensory receptors

175. Body temperature regulation If too hot Dermal blood vessels dilate Vessels carry more blood to surface so heat can escape If too cold Dermal blood vessels constrict Prevents heat from escaping Excretion Small amounts of waste products are lost through perspiration

176. Understanding how the skin can function in these many ways starts with understanding the structure of the 3 layers of skin The Epidermis Epithelial tissue Dermis Dense connective tissue proper – irregular Hypodermis Subcutaneous tissue- loose connective tissue proper and adipose tissue

177. Epidermis Dermis Hypodermis or subcutaneous layer

178. The Epidermis Is a vascular stratified squamous epithelium Nutrients and oxygen diffuse from capillaries in the dermis Cells of the Epidermis Keratinocytes Contain large amounts of keratin Are the most abundant cells in the epidermis

179. Epiderm is Epidermal ridge Dermal papilla Dermis The structural relationship and interface between the epidermis and underlying dermis. The proportions of the various layers differ with the location sampled.

180. Thin Skin Covers most of the body Has four layers of keratinocytes Thick Skin Covers the palms of the hands and soles of the feet Has five layers of keratinocytes

181. Structures of the Epidermis The five strata of keratinocytes in thick skin From basal lamina to free surface Stratum basale Stratum spinosum Stratum granulosum Stratum lucidum Stratum corneum

182. Thick skin LM  210 Surface Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale Basement membrane Dermis Papillary layer of dermis E P I D E R M I S

183. Stratum Basale Is attached to basement membrane by hemidesmosomes Forms a strong bond between epidermis and dermis Forms epidermal ridges (e.g., fingerprints) Dermal papillae (tiny mounds) Increase the area of basement membrane Strengthen attachment between epidermis and dermis Has many basal cells or germinative cells

184. Thick skin SEM  25 Pores of sweat gland ducts Epidermal ridge Epidermal ridges

185. Stratum Spinosum — the ―spiny layer‖ Produced by division of stratum basale Eight to ten layers of keratinocytes bound by desmosomes Cells shrink until cytoskeletons stick out (spiny) Continue to divide, increasing thickness of epithelium Contain dendritic (Langerhans) cells , active in immune response

186. Stratum Granulosum — the ―grainy layer‖ Stops dividing, starts producing Keratin A tough, fibrous protein Makes up hair and nails Keratohyalin Dense granules Cross- link keratin fibers

187. Stratum Lucidum — the ―clear layer ‖ Found only in thick skin Covers stratum granulosum Stratum Corneum — the ―horn layer‖ Exposed surface of skin 15 to 30 layers of keratinized cells Water resistant Shed and replaced every 2 weeks

188. The Dermis Located between epidermis and subcutaneous layer Anchors epidermal accessory structures (hair follicles, sweat glands) Two components Outer papillary layer Deep reticular layer Dermis

189. The Papillary Layer Consists of areolar tissue Contains smaller capillaries, lymphatics, and sensory neurons Has dermal papillae projecting between epidermal ridges The Reticular Layer Consists of dense irregular connective tissue Contains larger blood vessels, lymphatic vessels, and nerve fibers Contains collagen and elastic fibers Contains connective tissue proper

190. An inflammation of the papillary layer Caused by infection, radiation, mechanical irritation, or chemicals ( e.g., poison ivy) Characterized by itch or pain Characteristics Strong, due to collagen fibers Elastic, due to elastic fibers Flexible

191. Hair Papillary layer Reticular layer Cutaneous plexus Papillary plexus Epidermal ridges Dermal papillae Capillary loop of papillary plexus

192. The Hypodermis (Subcutaneous Layer) Lies below the integument Stabilizes the skin Allows separate movement Made of elastic areolar and adipose tissues Connected to the reticular layer of integument by connective tissue fibers Deposits of Subcutaneous Fat Distribution patterns determined by hormones Reduced by cosmetic liposuction ( lipoplasty )

193. The Hair Follicle Hair follicles are the organs that form the hairs. Hair follicles are the organs that form the hairs. Located deep in dermis. Produces nonliving hairs. Wrapped in a dense connective tissue sheath. Base is surrounded by sensory nerves ( root hair plexus ). Control bacteria

194. Exposed shaft of hair Sebaceous gland Arrector pili muscle Connective tissue sheath Root hair plexus Accessory Structures of Hair Arrector pili Involuntary smooth muscle Causes hairs to stand up Produces ―goose bumps‖ Sebaceous glands Lubricate the hair

195. Regions of the Hair Hair root Lower part of the hair Attached to the integument Hair shaft Upper part of the hair Not attached to the integument Boundary between hair shaft and hair root Arrector pili muscle Hair shaft Sebaceous gland Hair root Connective tissue sheath Hair bulb Hair matrix Hair papilla

196. Hair Shaft Structure Medulla Core, dead cells contain soft keratin and air to provide flexible Cortex Middle layer, dead cells contain hard keratin to provide stiffness C uticle Outermost, overlapping dead keratinized cells form shiny surface

197. Head: UV protection Cushion from trauma Insulation Nostrils, Ear canals, Eyelashes: Prevent entry of foreign material Body Hair: sensory detection Root hair plexus: Sensory nerves at base of hair follicle that detect slight movement of hair Arrector pili muscle: Attached to every hair follicle Contract to stand hair perpendicular to skin surface

198. Nails Protect fingers and toes Made of dead cells packed with keratin Metabolic disorders can change nail structure Nail Production Occurs in a deep epidermal fold near the bone called the nail root Free edge of Nail Body of Nail Laternal Nail fold Lunula Eponychium (cuticle)

199. Structure of a Nail Nail body The visible portion of the nail Covers the nail bed Lunula The pale crescent at the base of the nail Sides of nails Lie in lateral nail grooves Surrounded by lateral nail folds

200. A cross-sectional view Lateral nail fold Nail body Lateral nail groove Nail bed Phalanx (bone of fingertip)

201. Eponychium Proximal nail fold Nail root Lunula Nail body Epidermis Dermis A longitudinal section Phalanx Hyponychium

202. T h e Sk el e t a l Sys te m : Structure, Function, and Diseases of the bones and joints

203. The Skeletal System Parts of the skeletal system Bones (skeleton) Joints Cartilages Ligaments (bone to bone)(tendon=bone to muscle) Divided into two divisions Axial skeleton Appendicular skeleton – limbs and girdle

204. Functions of Bones Support of the body Protection of soft organs Movement due to attached skeletal muscles Storage of minerals and fats Blood cell formation

205. Bones of the Human Body The skeleton has 206 bones Two basic types of bone tissue Compact bone Homogeneous Spongy bone Small needle- like pieces of bone Many open spaces

206. Microscopic Anatomy of Bone

207. Bones are classified by their shape : long short flat irregular

208. Classification of Bones on the Basis of Shape

209. Classification of Bones Long bones Typically longer than wide Have a shaft with heads at both ends Contain mostly compact bone Examples: Femur, humerus

210. Gross Anatomy of a Long Bone Diaphysis Shaft Composed of compact bone Epiphysis Ends of the bone Composed mostly of spongy bone

211. Structures of a Long Bone Periosteum Outside covering of the diaphysis Fibrous connective tissue membrane Sharpey’s fibers Secure periosteum to underlying bone Arteries Supply bone cells with nutrients

212. Classification of Bones Short bones Generally cube-shape Contain mostly spongy bone Examples: Carpals, tarsals

213. Classification of Bones Flat bones Thin and flattened Usually curved Thin layers of compact bone around a layer of spongy bone Examples: Skull, ribs, sternum

214. Classification of Bones Irregular bones Irregular shape Do not fit into other bone classification categories Example: Vertebrae and hip

215. Surface features of bones Sites of attachments for muscles, tendons, and ligaments Passages for nerves and blood vessels Categories of bone markings Projections and processes – grow out from the bone surface Depressions or cavities – indentations

216. Types of Bone Cells Osteocytes Mature bone cells Osteoblasts Bone- forming cells Osteoclasts Bone- destroying cells Break down bone matrix for remodeling and release of calcium Bone remodeling is a process by both osteoblasts and osteoclasts

217. Axial skeleton supports and protects organs of head, neck and trunk Axial skeleton: skull (cranium and facial bones) hyoid bone (anchors tongue and muscles associated with swallowing) vertebral column (vertebrae and disks) bony thorax (ribs and sternum) Appendicular skeleton includes bones of limbs and bones that anchor them to the axial skeleton Appendicular skeleton: pectoral girdle (clavicles and scapulae) upper limbs (arms) pelvic girdle (sacrum, coccyx) lower limbs (legs)

218. 22 bones in skull 6 in middle ears 1 hyoid bone 26 in vertebral column 25 in thoracic cage 4 in pectoral girdle 60 in upper limbs 60 in lower limbs 2 in pelvic girdle 206 bones in all

219. The Axial Skeleton Forms the longitudinal part of the body Divided into three parts Skull Vertebral column Bony thorax

220. The Axial Skeleton

221. The skull 8 sutured bones in cranium Facial bones: 13 sutured bones, 1 mandible Cranium encases brain attachments for muscles sinuses

222. Bones of the Skull

223. The Hyoid Bone The only bone that does not articulate with another bone Serves as a moveable base for the tongue

224. The Vertebral Column Vertebrae separated by intervertebral discs The spine has a normal curvature Each vertebrae is given a name according to its location

225. Vertebral column 7 cervial vertebrae 12 thoracic 5 lumbar 1 sacrum (5 fused 1 coccyx (4 fused) Vertebrae vary in size and morphology

226. Thoracic cage ribs thoracic vertebrae sternum costal cartilages True ribs are directly attached to the sternum (first seven pairs) Three false ribs are joined to the 7 th rib Two pairs of floating ribs

227. Joints Fibrous - Fibrous joints connect bones without allowing any movement. The bones of your skull and pelvis are held together by fibrous joints. Cartilaginous - Cartilaginous joints are joints in which the bones are attached by cartilage. These joints allow for only a little movement, such as in the spine or ribs. Synovial - Synovial joints allow for much more movement than cartilaginous joints. Cavities between bones in synovial joints are filled with synovial fluid. This fluid helps lubricate and protect the bones. Bursa sacks contain the synovial fluid.

228. A joint, or articulation, is the place where two bones come together. There are three types of joints classified by the amount of movement they allow:    Immovable slightly movable freely movable

229. Types of Joints Hinge- A hinge joint allows extension and retraction of an appendage. (Elbow, Knee)

230. Ball and Socket- A ball and socket joint allows for radial movement in almost any direction. They are found in the hips and shoulders. (Hip, Shoulder)

231. Gliding- In a gliding or plane joint bones slide past each other. Mid- carpal and mid- tarsal joints are gliding joints. (Hands, Feet)

232. Saddle- This type of joint occurs when the touching surfaces of two bones have both concave and convex regions with the shapes of the two bones complementing one other and allowing a wide range of movement. (Thumb)

233. The Synovial Joint

234. Types of Synovial Joints Based on Shape

235. Types of Synovial Joints Based on Shape

236. ORGANIZATION OF SKELETAL MUSCLE

237. ORGANIZATION OF SKELETAL MUSCLE All activities that involve movement depend on muscles 650 muscles in the human body Various purposes for muscles for: Locomotion Upright posture Balancing on two legs Support of internal organs Controlling valves and body openings Production of heat Movement of materials along internal tubes Three types of muscles in the human body Skeletal Cardiac Smooth

238. ORGANIZATION OF SKELETAL MUSCLE Skeletal muscles are muscles which are attached to the skeleton. 40% of human body mass Skeletal muscles are mainly locomotion , and voluntary relaxation . responsible for contraction and

239. ORGANIZATION OF SKELETAL MUSCLE Muscle ( whole organ ) Fascicle ( portion of muscle ) Muscle Fiber ( single muscle cell ) Myofibril ( muscle cell organelle ) Sarcomere ( portion of myofibril ) Myofilament ( part of sarcomere )

240. STRUCTURE OF SKELETAL MUSCLE Skeletal muscles are composed of clusters of muscle cells. Muscle fibers Myofibers Myocytes A muscle consists of packages of muscle cells called fascicles A muscle cell is long and spindle shaped

241. STRUCTURE OF SKELETAL MUSCLE Cell structure Muscles cells contain many nuclei The plasma membrane→ sarcolemma The cytoplasm→ sarcoplasm Length ranges from 0.1cm to more the 30cm in length Diameter ranges from 0.001cm to 0.01cm in diameter Myofibrils→ elongated protein molecules aligned in parallel arrangements extend the full length of the cell.

242. STRUCTURE OF SKELETAL MUSCLE

243. STRUCTURE OF SKELETAL MUSCLE

244. STRUCTURE OF SKELETAL MUSCLE The myofibril consists of protein chains called myofilaments. Myofilaments have a symmetrical, alternating pattern of thick and thin elements .

245. STRUCTURE OF SKELETAL MUSCLE Thick myofilament consists of a large number of bundled myosin molecules aligned in overlapping arrays. hexameric proteins with two identical heavy chains and two pairs of different light chains. regulatory light chain (RLC) essential light chain (ELC)

246. STRUCTURE OF SKELETAL MUSCLE The thin myofilament (F- actin, filamentous actin) made up of two helically intertwined chains of G- actin (globular actin) units. Other proteins that bind to the actin molecules: Tropomyosin The Troponin complex→ made up of three members

247. PHYSIOLOGY OF MUSCLE CONTRACTION SLIDING FILAMENT MECHANISM : The length of skeletal muscle shortens during contraction because the thick and thin filaments slide over one another. The process is known as the sliding filament mechanism. The thick filament contains 300 myosin molecules. It contain two parts: Myosin tail Myosin heads Myosin tail forms the shaft of the thick filament and heads projects towards the thin filament. Thin filament contain actin, troponin and tropomyosin.

248. PHYSIOLOGY OF MUSCLE CONTRACTION Myosin tail forms the shaft of the thick filament and heads projects towards the thin filament. Thin filament contain actin, troponin and tropomyosin. At the onset of contraction, the sarcoplasmic reticulum release calcium ions into cytosol There they bind to troponin and cause troponin-tropomyosin complexes to move away from binding site on actin. Once the binding sites are free, the repeating sequence of events of the contraction cycle occurs that causes the filaments to slide on each other.

249. PHYSIOLOGY OF MUSCLE CONTRACTION The contraction cycle consists of 4 steps ATP hydrolysis. Attachment of myosin to actin to form cross- bridges. Power stroke. Detachment of myosin from actin.

250. PHYSIOLOGY OF MUSCLE CONTRACTION ATP hydrolysis : The myosin head includes an ATP- binding site and an ATPase, an enzyme that hydrolyses ATP into ADP and phosphate group. This hydrolysis gives energy to myosin head. ADP and a phosphate group remain attached to the myosin head.

251. PHYSIOLOGY OF MUSCLE CONTRACTION Attachment of myosin to actin to form cross- bridges: The energized myosin head attaches to the myosin binding site on actin and releases the previously hydrolyzed phosphate group. When the myosin head attach to actin during contraction, they are referred to as cross-bridges.

252. PHYSIOLOGY OF MUSCLE CONTRACTION Power stroke : Once the cross bridges are formed, the power stroke occurs. The cross- bridge rotate towards the center of the sarcomere and release the ADP molecule. The cross- bridge generates a force which slides the thin filament over the thick filament.

253. PHYSIOLOGY OF MUSCLE CONTRACTION Detachment of myosin from actin: At the end of power stroke, the cross-bridge remains firmly attached to actin until it binds another molecule of ATP. As ATP binds to the ATP binding site on the myosin head, the myosin head detaches from actin.

254. The Cardiovascular system & Physiology of Heart

255. Contents Components of the cardiovascular system (CVS) The systemic and pulmonary circulation Basic functions of the various parts of the CVS. General function of the CVS. Physiological anatomy of the heart. Blood vessels Heart sounds Characteristics of blood

256. Cardiovascular system In order to pump blood through the body, the heart is connect to the vascular system of the body. It is the closed system. It is designed to transport oxygen and nutrients to the cells of the body and remove carbon dioxide and metabolic waste products from the body.

257. Components of CVS Heart: It is a pump composed of 4 chambers (2 atria & 2 ventricles. The heart provides the driving force for the cardiovascular system. Blood Vessels: The blood vessels are systems of tubes including : Arteries and arterioles which carry the blood from the heart to all parts of the body. The arteries serve as distribution channels to the organs .

258. Components of CVS Venules and veins which carry the blood back from the tissues to the heart. The veins serve as blood reservoirs and collect the blood to return it to the heart. Blood capillaries which form a network of fine vessels connecting the arterioles with the Venules. The blood capillaries are the sites of exchange of gases (O2 & CO2), nutrients and waste products between blood and tissues.

259. PHYSIOLOGICAL ANATOMY of the HEART The HEART is the great central pump of the CVS. It lies in the left side of the thoracic cavity partly behind the sternum and between the right and left lungs. It is covered by a fibrous sac called the pericardium. GENERAL STRUCTURE OF THE HEART The heart is a hollow muscular organ. Its walls are composed of a muscle called the cardiac muscle or the myocardium .

260. Cardiac Chambers & their functions The human HEART is consist of four chambers : Two atria (right and left) which are separated from each other by the interatrial septum. Two ventricles (right and left) which are separated from each other by the interventricular septum. The wall of the left ventricle is about 3 times thicker than the wall of the right ventricle. The ventricular myocardium (wall) is much thicker and stronger than the atrial myocardium (wall). The atrial muscle (of both atria) is completely separated from the ventricular muscle (of both ventricles) by a fibrous ring called AV ring (atrioventricular ring).

261. The atria have 2 main functions: They act as blood reservoir for the blood returning back to the heart. They act as pumps ( primer pumps ). Atrial contraction pushes about 25% of the blood filling the ventricles during ventricular diastole and about 75% of the blood that ventricles during their diastole pass passively i.e. by its own weight. The ventricles , on the other hand , are the powerful cardiac pumps filling the arteries with blood. The right ventricle (pulmonary pumps) pushes blood into the pulmonary arteries and the left ventricle (systemic pump) pushes blood into the aorta during ventricular systole. .

262. Cardiac Valves and their functions The human heart contains four valves Two atrioventricular valves (AV valves) between the atria and the ventricles: Tricuspid valve between the right atrium and the right ventricle. Mitral or tricuspid valve between the left atrium and there left ventricle. Two semi lunar valves: Aortic valve between the left ventricle and the aorta. Pulmonary valve between the right ventricle and the pulmonary trunk.

263. Functions of the cardiac valves The cardiac valves allow for the blood to pass only in one direction i.e. The AV valves allow for the blood to pass from the atria into the ventricles during ventricular diastole. During ventricular systole, the AV valves close to prevent back flow of blood from the ventricles into the atria. The semi lunar valves allow for the blood to pass from the ventricles into the arteries during ventricular systole. During ventricular diastole, these valves prevent back flow of blood from the arteries into the ventricles (as these valves become closed during ventricular diastole).

264. The right ventricle pumps relatively large volumes of blood at a low pressure through the pulmonary circulation (the right ventricle is essentially flow generator). The normal cross- section of the right ventricle is crescent- shaped. If the right ventricle must eject blood against a high pressure for prolonged periods (as seen in certain pulmonary diseases), it assumes a much more cylindrical appearance and there is a thickening of the right ventricular free wall (right ventricular hypertrophy). The right ventricle

265. The left ventricle pumps blood through the systemic circulation. It is cylindrical in shape and normally has a thicker wall than does the right ventricle. The left ventricle works much harder than the right ventricle because of the higher pressure in the systemic circulation (the left ventricle is essentially pressure generator). Consequently, the left ventricle is more commonly affected by disease processes than is the right ventricle. The left ventricle

266. During ventricular systole, blood is pumped into the circulation. During diastole, the pumping of blood stops and the ventricles get filled with blood. In this way, the flow of blood from the ventricles into the systemic and pulmonary circulations is an intermittent pulsatile flow. Blood flow from the heart

267. Blood flow from the heart

268. Blood vessels

269. Heart Sounds Heart sounds are the noises generated by the beating heart and the resultant flow of blood through it. Specifically, the sounds reflect the turbulence created when the heart valves snap shut. In cardiac auscultation, an examiner may use a stethoscope to listen for these unique and distinct sounds that provide important auditory data regarding the condition of the heart. In healthy adults, there are two normal heart sounds often described as a lub and a dub (or dup ), that occur in sequence with each heartbeat. These are the first heart sound (S 1 ) and second heart sound (S 2 ), produced by the closing of the AV valves and semilunar valves , respectively.

270. Functions and Characteristics of the Blood Blood is the only liquid tissue in the body. It is a connective tissue. Consists of formed elements (cells and cell fragments) in a liquid intercellular matrix (plasma) Average adult blood volume is around 5 liters (8% of body weight)

271. Blood Functions Transportation : Blood transports oxygen and nutrients to cells, CO 2 and waste away from cells, hormones to target tissues Regulation : Helps maintain stable body temperature, pH, water and electrolyte levels Protection : Clotting prevents fluid loss, white blood cells protect body against disease