Cell and tissue

Cell and Tissue

1. Cell & Tissues Dr. Mrs . Deepa K. Ingawale (Mandlik) Department of Pharmacology Poona College of Pharmacy, Pune

2. Content in detail Definition of cell & cytology Different parts of cells & their functions Structure of plasma membrane Different cell organelles (Nucleus, Ribosomes, Endoplasmic reticulum, Golgi complex, Mitochondria, Lysosomes & Peroxisomes) Protein synthesis (Transcription & Translation) Cell division Movement of material across the plasma membrane

3. Learning Objectives To describe the structure & function of different parts of cells To describe the structure & functions of plasma membrane . To study different processes of drug transport across the plasma membrane . To describe the process of protein synthesis . To discuss the stages of cell division .

4. Definitions Cell: It is basic living, structural, & functional unit of the body. Cytology: It is the branch of science concerned with the study of cells.

5. Parts of Cell Two major parts: Plasma membrane Cell organelles Different parts : Plasma membrane (Cell Membrane) Cytoplasm Nucleus Nucleolus Mitochondria Golgi complex Endoplasmic reticulum

6. Diagram of Cell

7. Plasma membrane (Cell membrane) The thin barrier that separates the internal components of the cell from the external environment. It is the gate keeper that regulates the passage of substances into & out of the cell.

8. Composition of membrane It is made up of lipids & proteins . The main lipids are: Phospholipids Cholesterol Glycolipids Some carbohydrates are also involved in the membrane.

9. Membrane Lipids Phospholipids: These are the lipids that contain phosphorus (75 %) . These are arranged in lipid bilayer. These are amphipathic in nature, divided into two parts; Polar head (Hydrophilic) Hydrocarbon tails (Hydrophobic)

10. Membrane Lipids Glycolipids: These are the lipids with one or more sugar groups attached to it (5%) . These are amphipathic in nature. These are present only at one side of the membrane. Cholesterol: These are present in 20%. It is present in phospholipids in both sides of the membrane. The steroid ring of the cholesterol strengthens the membrane but decreases its flexibility.

11. Membrane proteins These proteins are embedded in a lipid bilayer. Two types of membrane proteins: Integral proteins Peripheral proteins Integral protein: The integral proteins are completely embedded in the lipid bilayer. These are also called as trans-membrane proteins.

12. Membrane proteins Integral proteins are divided into; Channel proteins: R esponsible for transfer for small water-soluble molecules across the membrane. Carrier proteins: Responsible for transfer of material across the bilayer through active transport. Receptor proteins: B ind with different neurotransmitters and produces different reactions. Pumps: Responsible for transfer of ions across the bilayer, against concentration gradient (Lower to higher concentration).

13. Membrane proteins Peripheral proteins: These are also called as extrinsic proteins. They are attached to the periphery of membrane.

14. Cell Organelles Cytoplasm It present inside the plasma membrane & external to the nucleus. The semifluid portion of cytoplasm in which cell organelles are suspended is called as cytosol . Cytosol is transparent, viscous gel like fluid containing 75 to 90% of water, suspended & dissolved components such as proteins, lipids & carbohydrate, different inorganic substances & salts. The cell organelles are bathed in the cytosol.

15. Nucleus It is spherical or oval in shape & largest structure in the cell. A double membrane which separates the nucleus from the cytoplasm is called as nuclear membrane .

16. Nucleus Both the inner & outer membrane is phospholipids bilayer. It externally continuous with the endoplasmic reticulum. It contains nuclear pores. Theses pores act as channel for transfer of ions & water soluble molecules between the nucleus & cytoplasm. Nucleus contains nucleolus a spherical structure. These are aggregations of protein, DNA & RNA.

17. Ribosomes These are tiny spheres that contain ribosomal RNA & proteins. Ribosomes are site for protein synthesis. These are made of two subunits; Smaller one: RNA of smaller size Larger one: RNA of larger size These are of two types: Those attached to endoplasmic reticulum called as rough ribosomes. Those are free in cytosol called as free ribosomes  

18. Endoplasmic reticulum These are membrane enclosed channels called as cisterns. It is an interconnected network of internal membrane. Based on the presence of ribosomes it is divided into 2 types. Rough ER Smooth ER

19. Endoplasmic reticulum Rough ER: The ribosomes are attached on the surface. It is granular in appearance & rough. It is responsible for synthesis of certain proteins. Smooth ER: The ribosomes are not attached to the surface. It is smooth in nature. It is the site of fatty acid, phospholipids & steroid synthesis.

20. Golgi complex It is preset near the nucleus. It consists of four to six flattened sacs called as cisterns, staked upon each other like a pile of plates with expanded bulges at their ends. The stack of Golgi sacs has two regions- Cis & Trans. Golgi apparatus stores proteins & is also responsible for modifying them.

21. Mitochondria

22. Mitochondria It is called as powerhouse of cells because it generate ATP. It consist of two lipoprotein membranes. Outer mitochondrial membrane: It covers the whole structure. Inner mitochondrial membrane: It contains a series of folds called as cristae . The large central fluid-filled cavity is present called as matrix . Many oxidative enzymes causes oxidation of nutrients, carbon dioxide & water, releases energy that is utilized in formation of ATP.

23. Lysosomes These are small secretory vesicles formed from the Golgi complex . It contains 60 types of digestive & hydrolytic enzymes that can break variety of molecule. Lysosomal enzymes work at acidic pH=5 & inactivated at neutral pH. Peroxisomes Another small group of organelles called as peroxisome. They contains several oxidases enzyme for oxidation of Amino acid & fatty acid.

24. Movement of material across CM It is divided into two sub-headings: Movement of small molecules across the CM: Simple diffusion or Passive transport Facilitated diffusion Osmosis Active transport   Movement of large molecules across the CM : Endocytosis Exocytosis

25. Passive Diffusion Also known as non-ionic diffusion. It is defined as the difference in the drug concentration on either side of the membrane . Drug movement is a result of the kinetic energy of molecules. No external energy source is required. Major process for absorption of 90% of drugs. The driving force is concentration or electrochemical gradient. 25 The drugs having molecular wt. 100 to 400 D can be absorbed by passive diffusion

26. Facilitated diffusion The driving force for this mechanism is concentration gradient Occurs at much faster rate than passive diffusion No expenditure of energy (Down-hill transport) Less importance in the absorption of drugs. E.g. Entry of glucose into RBCs & intestinal absorption of vitamins B 1 & B 2, gastro-intestinal absorption of vitamin B 12 . Many lipid insoluble substances like certain vitamins, glucose, urea crosses the membrane by this process.

27. Osmosis Movement of water molecules across a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration.

28. Active transport When the drug is transported against the concentration gradient i.e. from lower concentration to higher concentration with utilization of energy called as active transport.

29. Endocytosis It involves engulfment of extracellular materials within a segment of the cell membrane to form a saccule or a vesicle. Also called as corpuscular or vesicular transport which is then removed outside. 29 Three types: A) Phagocytosis B) Pinocytosis C) Transcytosis

30. A) Phagocytosis: Cell eating (Uptake of solid particles) 30

31. B) Pinocytosis Cell drinking (Uptake of fluid solute) Small fluid molecules are engulfed by cell membrane & digested with the help of lysosome. This process requires energy in the form of (ATP ). It is important in the absorption of oil soluble vitamins & uptake of nutrients . Polio vaccine & protein molecules are absorbed by pinocytosis 31

32. C) Transcytosis It is the process in which endocytic vesicle is transferred from one extracellular compartment to another compartment. 32

33. Protein synthesis

34. Protein synthesis The proteins are responsible for determination of physical & chemical characteristics of cells . Some proteins helps in assembling cellular structures such as the plasma membrane, cytoskeleton, & other organelles . Others proteins serve as hormones, antibodies & enzymes regulating the rates of chemical reactions. Genome : All the genes in an organism Proteome: All the proteins in an organism.

35. Protein Synthesis The DNA is used as a template for synthesis of a specific protein . The protein synthesis occurs by 2 steps: Transcription: The information encoded in DNA is transcribed (copied) to produce mRNA (ribonucleic acid). Translation: The mRNA attaches to a ribosome leads to formation of new protein molecule.

36. Transcription It is the first stage of genes expression. The process occurs in the nucleus. In this process the genetic information encoded in DNA is transcribed to RNA. 3 types of RNA are made from the DNA : Messenger RNA (mRNA) Ribosomal RNA (rRNA) Transfer RNA (tRNA)

37. Translation It is the process in which ribosomes makes proteins from mRNA. It process occurs in the cytoplasm.

38. Summary of protein synthesis

39. Cell Division The eukaryotic cells divide approximately every 24 hours. The duration of cell cycle vary from organism to organism & also from cell type to cell type. The two types of cell division: Somatic cell division Reproductive cell division

40. Cell Division Somatic cell division: A cell undergoes a nuclear division called mitosis & cytoplasmic division called cytokinesis to produce two identical cells having same number of chromosomes as the original cell. Reproductive cell division: A cell undergoes a reductive cell division called as meiosis , in which the number of chromosomes in the nucleus is reduced to half.

41. Somatic Cell Division

42. Cell cycle It is an orderly sequence of events by which a somatic cell duplicates its contents & divides in to two. Human cell contains 23 pairs of chromosomes for a total of 46. Somatic cells contain two sets of chromosomes (diploid cells) denoted as 2n. It is divided into 2 phases: Interphase: when a cell is not dividing Mitotic phase: when a cell is dividing

43. Interphase During Interphase replication of DNA takes place & produces additional organelles & cytosolic components. It consists of 3 phases: G1, S, & G2. G1 phase: It is the interval between mitotic phase & S phase. During G1 phase replication of most of organelles & cytosolic components takesplace but not DNA. It lasts for 8 to 10 hours.

44. Interphase S phase: It is the interval between G1 & G2 phase & lasts for 8 hours. During the S phase, DNA replication occurs. As a result, two identical cells are formed during cell division having same genetic material. G2 phase: It is the interval between S phase & mitotic phase. It lasts 4 to 6 hours. During G2, cell growth continues, enzymes & proteins are synthesized for cell division. Once a cell completes its activities during the G1, S, & G2 phases, the mitotic phase begins.

45. Mitotic (M) Phase It is also called as equatorial division becoz contains same number of chromosomes as parent cells. It consists of a nuclear division (mitosis) & a cytoplasmic division (cytokinesis) to form two identical cells. The process results in the exact partitioning of genetic material. Divided into 4 stages: Prophase Metaphase Anaphase Telophase

46. Mitotic (M) Phase Prophase: In early prophase, the chromatin fibers shorten into chromosomes. Each chromosome consists of a pair of identical strands called chromatids . A constricted region called a centromere holds the chromatid pair together. In Late prophase, the nucleolus disappears & nuclear envelope breaks down.

47. Mitotic (M) Phase Metaphase: During metaphase, the microtubules of the mitotic spindle align the centromeres of the chromatid pairs at the exact center of the mitotic spindle called as metaphase plate.   Anaphase: During anaphase, the centromeres split separating the two members of each chromatid pair, which move toward opposite poles of the cell. Once separated, the chromatids are termed chromosomes. As the chromosomes are pulled by the microtubules of the mitotic spindle during anaphase appears V-shaped.

48. Mitotic (M) Phase Telophase: Telophase begins after chromosomal movement stops. The identical sets of chromosomes, now at opposite poles of the cell, uncoil and forms threadlike chromatin form. A nuclear envelope forms around each chromatin mass, nucleoli reappear and the mitotic spindle breaks up.  

49. Cytokinesis

50. Questions LAQ: What is cell and explain it with neat labelled diagram. (10 M) Explain the events of cell division. (7 M)   SAQ: Define and enlist different parts of cell. (3 M) Enlist the process for transfer of material across the cell membrane.(3 M) Note on transport of materials across plasma membrane (3 M, May 2010) Note on cell membrane (3 M, October 2010) Draw a neat labelled diagram of cell. (3 M, October 2011)

51. Questions Explain internal structure of human cell. (3 M, May 2012) Write a note on (5 M) Passive transport Facilitated diffusion Active transport Osmosis Endocytosis Draw a neat labelled diagram of Cell and explain Transport Mechanisms across Plasma Membrane. (5 M, October 2009) Explain in detail structure of cell membrane. (5 M, May 2009)

52. Questions Explain structure and function of plasma membrane. (5 M, May 2010) Draw a neat labelled diagram of cell and explain movement of materials across plasma membrane. (5 M, May 2011) Explain the transport of material across plasma membrane. (5 M, May 2012) Write a note on translation and transcription. (5 M)

53. Tissues Content in detail: Definition of tissue & histology Structure & function of Epithelial tissue Structure & function of Connective tissue Structure & function of Muscle tissue Structure & function of Nervous tissue

54. Tissues Learning Objectives: To understand 4 basic types of tissues. To describe the location, structure, & function of Epithelium tissue . To describe the location, structure, & function of Connective tissue. To describe the location, structure, & function of Muscle tissue. To describe the location, structure, & function of Nervous tissue.  

55. Definitions Tissue: A group of cells, similar in origin & function unites together to form tissues. Histology: It is the science that deals with the study of tissues.

56. Types of body tissues There are 4 types of tissues: Epithelial tissue: It covers body surfaces, lines hollow organs, body cavities & ducts. Connective tissue: It protects, supports the body & its organs. It acts as energy store (reserves fat) & provides immunity. Muscle tissue: It generates physical force needed to generate body heat. Nervous tissue: It generates nerve impulses responsible for muscular contractions & glandular secretions.  

57. Epithelial Tissue Epithelial Tissue Simple Stratified Pseudo- stratified columnar epithelium Squamous Cuboidal Columnar Ciliated Squamous Cuboidal Columnar Transitional

58. Epithelial Tissue The cells are arranged in continuous sheets, in either single or multiple layers. It covers body surfaces & lines hollow organs, body cavities and ducts. It protects the underlying tissues from injury. It secrets certain chemical substances that are utilized by the body or removed outside.

59. Basement membrane & surfaces of epithelial cells

60. Simple epithelium It is made up of single layer of cells & divided into 4 types. Simple squamous epithelium Simple cuboidal epithelium Simple columnar epithelium Simple ciliated epithelium

61. Simple squamous epithelium Description: It is made up of single layer of flat cells having centrally located nucleus. Location: Lines heart, blood vessels, lymphatic vessels, lungs, glomerular capsule of kidneys. Functions: Filtration, Diffusion, Osmosis

62.   Simple cuboidal epithelium Description: It is made up of single layer of cube shaped cells having centrally located nucleus. Location: It lines the kidney tubules, ovary and pancrea Functions: Secretion & absorption

63. Simple columnar epithelium Description: It is made up of single layer of rectangular cells with nuclei at the base. Mucus secreting glands are present called as goblet cells. Location: It lines the GIT from stomach to anus, ducts of many glands & gall bladder. Functions: Secretion & absorption

64. Simple ciliated epithelium Description: It is made up of ciliated (hair like structure) rectangular cells with nuclei near base. It contains mucus secreting goblet cells. Location: It lines upper respiratory tracts, uterine (fallopian) tubes, uterus & spinal cord. Functions: Moves mucus & other substances by cliliary action. In alimentary tract propels the digestive contents forward.

65. Stratified epithelium It is made up of multiple layers of cells. It is divided into 4 types. Stratified squamous epithelium Stratified cuboidal epithelium Stratified columnar epithelium Transitional epithelium

66. Stratified squamous epithelium Description: It is composed of many layers of different shaped cells. In the deepest layer, the cells are columnar shaped, as they grow towards the surface, they become flattened. Location: Keratinized cells forms the superficial layer of skin, Non-keratinized cells lines the wet surfaces such as lining of mouth, esophagus, epiglottis, vagina & tongue. Functions: Protection

67. Stratified cuboidal epithelium Description: It is made up of two or more layers of cells. In the apical layer cube shaped cells are present. Location: Ducts of sweat, oesophageal glands and part of male urethra. Functions: Protection, limited secretion and absorption

68. Stratified columnar epithelium Description: It is made up of several layers of irregularly shaped cells. In the apical layer columnar cells are present. Location: Lines part of urethra, large excretory ducts of glands and conjunctiva of eye. Functions: Protection and secretion

69. Transitional epithelium Description: It is made up of many layers of pear shaped cells. It is variable in appearance. In relaxed state it looks like stratified cuboidal epithelium and when starched the cells become squamous shaped. Location: It is found in the lining of uterus and urinary bladder. Functions: Protects underlying structure and permits distension of organs.

70. Pseudostratified columnar epithelium Description: Not a true stratified tissue; nuclei of cells are at different levels; all cells are attached to basement membrane, but not all reach the apical surface. Location: Pseudostratified ciliated columnar epithelium lines the airways; pseudostratified non-ciliated columnar epithelium lines ducts of many glands, epididymis & part of male urethra. Function: Secretion & movement of mucus by ciliary action

71. Connective tissue It supports, connects or separates different tissues & organs of the body. It is made up of fibers, cells & ground substances. Fibers: 3 types of fibers are embedded in the ECM which strengthen & supports the CT. Collagen fibers: Very strong fibers allows tissue flexibility. Made up of protein collagen. Found in bone, cartilage, tendons & ligaments. Elastic fibers: Smaller in diameter. Made up of protein elastin that gives strength & stability to tissue. Reticular fibers: Much thinner in diameter. It consists of collagen protein that gives support & strength.

72. Connective tissue Ground substance: It is gel-like substance present surrounding the cells. In the ground substance cells & fibers are suspended. It supports cells, binds them together and stores water. It is made of water, glycosaminoglycans (hyaluronan), proteoglycans, glycoproteins, hyaluronic acid, chondroitin sulfate & dermatan sulfate. Cells: It consists of fibroblasts, macrophages, plasma cells, mast cells, adipocytes & WBCs.

73. Connective tissue

74. Functions Storage of energy Protection of organs Provides structural framework to the body Connection of body tissues

75. Types of connective tissue Loose connective tissue: Areolar CT Adipose CT Reticular CT   Dense connective tissue: Dense regular CT Dense irregular CT Elastic CT Cartilage: Hyaline cartilage Fibro cartilage Elastic cartilage   Bone tissue:   Liquid connective tissue: Blood Lymph

76. Loose connective tissue These fibres are loosely woven. The fibres content is lower & cell content is higher.

77. Areolar Connective Tissue Description: It consists of collagen, elastic, reticular fibers & cells (fibroblasts, macrophages, plasma cells, adipocytes & mast cells embedded in ground substances). Location: Present below the skin, supporting blood vessels, nerves, in the alimentary canal. Functions: Strength, elasticity & support

78. Adipose Connective Tissue Description: It consists of adipocytes which stores fats as a large centrally located droplet. It prevents heat loss from body & acts as a reservoir of energy. Location: Present in SC layer deep to skin, around heart, kidneys & Yellow bone marrow Functions: Reduces heat loss from skin, serves as an energy reserve, gives shape to limbs, body & protects underlying organ from injury

79. Reticular connective tissue Description: It consists of reticular fibers & reticular cells. Location: Present in supporting framework of liver, spleen, lymph nodes, red bone marrow, blood vessels and muscles. Functions: Forms stroma of organs, filters & removes dead blood cells in the spleen & microbes in the lymph node.

80. Dense connective tissue In this fibres are densely packed, the fibres content is higher & cell content is lower as compared to loose connective tissue.

81. Dense regular connective tissue Description: It consist of bundles of collagen fibers arranged parallel manner that provides strength to tissue. Fibroblast are present in rows between the fibers. It is silvery white in colour & tough in nature. Location: It forms tendons (attaches muscle to bone) & ligaments (attaches bone to bone). Functions: Provide strong attachment to structures.

82. Dense irregular connective tissue Description: It contains collagen fibers which are irregularly arranged & few fibroblasts are appears in rows between the fibers. Location: It is present beneath the skin, bone, kidneys, liver, testes, lymph node, pericardium of heart & heart valves. Functions: Provide strength

83. Elastic connective tissue Description: It consists of elastic fibers. Fibroblasts are present between the fibres. Location: Present in lung tissues, wall of arteries, trachea, bronchial tubes & vocal cords. Functions: It allows stretching of various organs.

84. Cartilage It consists of a network of collagen fibers & elastic fibres embedded in chondroitin sulfate of ground substance. The cells of mature cartilage called as chondrocytes .

85. Hyaline Cartilage Description: It is bluish white in colour consists of collagen fibers & many chondrocytes. Most abundant cartilage in body. Location: Present at the ends of long bones, ribs, nose, part of larynx, trachea, bronchi, bronchial tubes, embryonic & fetal skeleton. Functions: It provides surfaces for movement at joints, flexibility & support.

86. Fibro cartilage Description: It is strongest form of cartilage. It consist of many chondrocytes in the bundle of collagen fibers. It is tough & slightly flexible. Location: Present in inter-vertebral disc Functions: It covers & protects bony structures of body.

87. Elastic cartilage Description: It consist of many chondrocytes in the threadlike network of elastic fibers embedded in the extracellular matrix. Location: Present in pinna of ear & top of larynx Functions: Gives support & maintains shape.

88. Bone tissue

89. Bone tissue Description: It is the hardest connective tissue. It is composed of 25% of water, 30% organic material & 45% inorganic salts. It consists of Haversian canal system. Haversian canal system consists of, Central Haversian Channel: Contains blood vessels & nerves. Lamellae: Surrounding the central canal concentric plates of bone are present Lacunae: It contains oestocytes (mature bone cells) Canaliculi: It project from the lacunae (processes of oestocytes)

90. Bone tissue Location: It is present in compact & spongy bone tissue Functions: To forms supporting framework for body. To give protection to delicate organs. To form joints essential for locomotion of body. To form red blood cells in red bone marrow. To provide store of calcium salts. It gives support & maintains shape.

91. Liquid connective tissue (Blood)

92. Blood Description: Blood is a connective tissue with liquid extracellular matrix called as blood plasma. It is composed of 55% plasma and 45% of cells. Plasma is composed of, 90-92% of water, plasma proteins, mineral salts, organic waste products, nutrients material, hormones, enzymes and gaseous. Blood cells are of 3 types; Erythrocytes (RBC): Transport oxygen to body cells & remove carbon dioxide from them. Leucocytes (WBC): Involved in phagocytosis, immunity & allergic reaction. Thrombocytes (Platelets): Participate in blood clotting.

93. Blood Location: It is present within blood vessels (arteries, arterioles, capillaries, venules and veins) and within the chambers of the heart. Functions: RBCs transport oxygen to body cells & remove carbon-dioxide from them. WBCs are involved in phagocytosis, immunity & allergic reaction. These participate in blood clotting process. These are responsible for maintaining body temperature.

94. Muscular tissue It consists of elongated cells called muscle fibres that can use ATP to generate force. Three types of muscular tissues are present. Skeletal/striated/voluntary muscle tissue Cardiac muscle Smooth/non-striated/involuntary muscle tissue.

95. Skeletal muscle tissue Description: The cells are cylindrical in shape. Fibres are parallel to each other. Length is 30-40 cm. It has several nuclei located at the periphery.

96. Skeletal muscle tissue It shows alternate dark and light band i.e. striations and hence the name is striated muscle. The muscles are attached to bones hence called as skeletal muscles. The activity of fibres is within ones control (voluntary muscle). Location: It is usually attached to bone by tendons. Functions: It gives motion, posture, heat production & protection.

97. Cardiac muscle tissue

98. Cardiac muscle tissue Description: It is present in the myocardium of heart wall. It is striated but involuntary i.e. the activity of fibres is beyond ones wish (involuntary muscle tissue). Each fibers is parallel to each other, branched & multinucleated. Two cardiac muscle fibres are attached by thickened plasma membrane called as intercalated disc. Location: It is present in the heart wall. Functions: It pumps blood to all part of the body.

99. Smooth muscle tissue The fibre is very small. Thickest in the middle & tapering at each end. It contains single, centrally located nucleus. The cells are spindle shaped.

100. Smooth muscle tissue Alternate light or dark bands are absent (smooth/non-striated). Activity of theses fibers is beyond ones wish (involuntary). Location: Wall of blood vessels, wall of lymph vessels, alimentary tract, respiratory tract, urinary bladder & uterus. Functions: It gives motion (contraction of blood vessels, airways, propulsion of food through GIT, contraction of urinary bladder & gall bladder).

101. Nervous tissue

102. Nervous tissue Description: It is made up of various parts. Neurons: It is made up of cell body, axons, dendrites & axon terminals. Cell body: It contains nucleus & other organelles. Dendrites: These are input portions of neuron. Usually short & highly branched forms tree like structure. Each nerve cell contains many dendrites.

103. Nervous tissue Axon: Each nerve cell contains single axon which is thin, long & cylindrical major output portion of a neuron. Location: It is present in the nervous system. Function: Converts various types of stimuli into nerve impulses (action potentials), & conducts nerve impulses to other neurons, muscle fibers, or glands.

104. Questions LAQ: Define tissue. Enlist different types of tissues. Explain in detail epithelial tissue and connective tissue. (10 M, October 2009) SAQ: Define tissue and give its different types. (3 M) Note on nervous Tissue (3 M, October 2009) Note on Nervous tissue (3 M, May 2010) Note on nervous tissue (3 M, May 2011)

105. Questions Write a note on epithelial tissue and explain its different types. (5 M) Describe muscular tissue. (5 M) Write a note on nervous tissue.(5 M) Give types and the common locations of epithelial tissues in body. Explain Characteristics of epithelial tissues. (5 M, October 2010) Explain in detail structure and functions of epithelial tissue. (5 M, May 2011) Explain structure and function of nervous tissue. (5 M, October 2011)