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1., , The serosa is the, , outermost, , layer, , which, , 1s, , composed of, , simple squamous cpithelium., 2. The muscnlaris consists of two layers, the outer layer is, composed of longitudinal muscle fibres, while the inner layer is, , composed of circular muscle fibres., 3. The muscle fibres in both the layers are arranged in, bundles which are bound together by connective tissue., 4. The submucosa is made up of connective tissue containing, blood vessels, nerves and lymph vessels., 5. Muscularis mucosae is a thin layer and its fibres are arranged in two layers., 6. The mucosa is the thickest layer. It consists of, simple, columnar epithelium and tubular or, gastric glands., T. The gastric glands are, very long and are arranged parallel, to each other., 8., , They are simple or simple branched tubular type., 9. The gastric glands, composed of two types of cells namely, peptie celts and oxyntic cells., 10. The peptic cells are found at the, base of gastric glands., 11. These are, polygonal and granular and secrete digestive, enzymes., 12. The oxyntic cells, (parietal cells) are found towards the, luminal, of, , part, , 13., , These, , gastric glands., are, , HC1., 58., , circular, , T. S. of, , Comments, , or, , oval,, , duodenum of a, , Transverse section of duodenum of a, , histological struclures:, 1., , non-granulated, , Outermost layer is, simple squamous epithelium., , serosa, , and secretee, , mammal, , mammal shows the, , following, , which is usually consists of, , a, , 2., , The muscularis consists of, muscle fibres to the, outside and circular muscle fibres to longitudinal, the inside., 3. The submucosa consists, of, , connective tissue, holding blood, lymphatic vessels., The, 4, muscularis mucosae is thin and, double layered, ing of outcr layer of, consist, longitudinal fibres and inner, fibres., of, layer, circular, 5. The mucosa Is, into numerous, finger-like folds called villi thrown, large and small, which are all, covered, by simple columnar, epithelium with scattered goblet cells,, vessels,, , nerves and
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6., , Each villus contains blood vessels,, , lymphocytes and a, , lacteal., 7., , At the base between the villi, , are, , present crypts of Lieber, , kuhn. These are lined by columnar epithelium which contains, goblet cells., , simple squamous epithelium., longitudinal, , -, , serosa, , muscle fibres, circular muscle ., , 2-muscularis, , fibres, , blood vessel, -3-submucosa, , muscularis(long.layer), , mucosae (circ.layer), crypts of, , 4, , Lieberkuhn, , -mucosa, , goblet cells, lacteal, simple columnar-, , 2, , epithelium, , lymphocytes, , 3, Villi, , 4, , 8., , 9., , Fig. 310. T. S. of duodenum of a mammal., The crypts of Lieberkuhn lead into Bruner's glands., The secretions of the crypts of Lieberkuhn and Bruner's, , glands form the, , intestinal juices., , T. S. of liver of, , 59., , a, , mammal, , Comments:, , Transverse section of liver ot a mammal shows the following, , histological structures, , The liver is composed of polygonal lobules containing a, in the centre and portal canals at, central vein (intra-lobular vein), 1., , the corners., , strand and, contains a branch of portal vein (inter-lobular vein), hepatic artery,, , 2., , Each portal, , bile duct and, , lymph, , canal consists of connective tissue, , vessel.
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3, The liver cells are polyhedral or rectangular and arranged, in single celled long chains cxtending radially from the central vein, to the periphery of the lobule., bile duct, , hepatic, O, , artery, , J, , portal vein, (interlobular vein), , hepatic, cords, central vein, , ( intra-, , Icbular vein), , sinusoids, , liver jcells, , Fig. 311., , 4., , T. S. of liver of a mammal., , Each liver cell has granular cytoplasm and a prominert, , nucleus., , 5. The sinusoids are formed from branches of the hepatic, portal veins and empty into central veins., 6. Liver has several functions which ae as follows, () It produces bile which plays an important role. in the, digestion of food., (ii) It stores the soluble products of digestion and metabolize them for assimilation., (ii) Oxidation of sugar takes place in it., (iv) Toxic substances are detoxicated in the liver.
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62., , T. S. of, , lung of, , a, , mammal, , respíratory, bronchlole, ciliated, epidemis, , -alveoll, , blood, , S, , yessels, , branch of, , pulmonary, , artery, , X, alveolar duct, , Fig. 314., , T. S. of lung of a mammal, , Comments :, , Transverse section of lung of a manmmal shows the following, structures, , 1. Histologically it consists of numerous alveoli., 2., 2. The alveoli communicate with one another by apertures in, their walls, 3., , Around each alveolus is a network of capillary blood vessels, , in connection with pulmonary artery or vein of the lung., which open in, 4. Numerous alveoli form clusters, , duct., , a, , alveolar, , it enters the lungs, divides and subthe bronchioles., divides into finer and finer branches,, are subdivided into respiratory bronchioles., 6. The bronchioles, , 5., , Each bronchus, , as
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7, , The respiratory bronchiole gives rise to several alveolar, , ducts wlhich open into alvcoli or air-sac., 8. The alveoli which are richly supplied with blood vessels, form the seat of respiration., 9, The air is taken into the alveoli by the respiratory bronchioles through alveolar ducts which get it from bronchioles which, in their turn get it from the bronchus., air, bronchioles, bronchus, respiratory, trachea, bronchioles > alveolar ducts > alveoli, gaseous exchange takes, place and CO, is then taken out., , »
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78., , Elastic cartilage, chondrocytes, A, , yellow fibres, , NO, , lacunac, , O, Fig. 331., , Elastic cartilage., , Comments:, 1., , cartilage., 2., , Elastic cartilage is, , fundamentally, , similar to hyaline, , Numerous yellow fibres are present which run through the, , matrix in all directions., 3. Chondrocytes are somewhat rounded in shape and lie within the lacunae. These cells are scattered in the matrix in groups of, two or singly., 4 It is yellowish in colour and more flexible and elastic., 5. It is found in mammals in the pinna of ear, the ends of, nose, in the epiglottis and certain other regions.
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Comments:, Transverse section of bone exhibits the following important, , characters:, 1., , Haversian system, , ), , Each consisting of a central Haversian canal surrounded by, rings of osteocytes lying each in a lacuna., (ii) The lacunae are connected together by five canaliculi, (iii) Among the rings of lacunae lie very thin concentric, layers of bone lamellae which compose the matrix of, , tissue., 2. Some bone lamellae, bone lacunae atnd canaliculi are, present among the Haversian system but are not arranged arround, Haversian canals. These are called interstial lamellae or, , non, , Haversian system., 3., , Haversian canals are about 22-110 microns in diameter., , 81., , L.S. of bone, Haversiañ cana, connecting, canal, , bone lametlae, bone lacunae, , canaliculi,, , Fig. 334., , L. S. of bone., , Comments:, , Longitudinal section of bone reveals the following details:, 1. Hayersian canals are connected with each other, by connec, ting canals., , 2., 2. Osteocytes, bone lacunae, bone canaliculi and bone lamellae, are arranged lengthwise.
