Ncert class 11 Digestion and absorption Handwritten short and easy notes, Study notes of Biology

Download Ncert class 11 Digestion and absorption Handwritten short and easy notes and more Study notes Biology in PDF only on Docsity! Digestion & Absorption 1. Digestive System 2. Digestion of Food 3. Absorption of Digested Products 4. Disorders of Digestive System Human digestive system Alimentary Canal Anterior opening mouth ! Posteriorly opening Anus buccal cavity or oral cavity. muscular tongue ! tHecODonT Associated glands. teeth """ tooth " + jaw bone socket pancreas salivary glands liver÷ a. ¥ PhaRyNx common passage food ' Air ( Trachea (wind ) pipe) Esophagus ( food * pipe ) cartilaginous flap prevents food " entry glottis opening [ wind pipe ] f!d * Swa"owing EsoPhAGus thin, long tube extends posteriorly passing through 'J' shaped bag stomach neck, thorax diaphragm Leads to A ÷ Esophagus Gastro- esophageal sphincter Stomach 4 parts cardiac portion (esophagus opens) fundic region body (main central region) pyloric portion (small intestine) StoMAcH upper left abdominal cavity SmaLl INteStINe pyloric sphincter 3 regions ‘C' shaped long coiled middle highly coiled laRgE inTEsTinE 3 regions caecum colon rectum duodenum jejunum ileum E. ¥ smooth muscles loose connective tissues In duodenum glands also nerves blood + lymph vessels. sub-mucosal layer oblique layer (some regions) Muscularis inner circular outer longitudinal BUGBEAR B ÷ F. innermost lumen lining mucosa irregular folds stomach small finger-like foldings small intestine vi"irugae microvi"i numerous microscopic projections brush border appearanceincrease surface area Produce A ¥ Mucosal epithelium also forms large lymph vessel crypts b/w villi intestine (crypts of Lieberkuhn) stomach Mucosa forms Goblet ce!s {secrete mucus} lubrication. Intestine gastric glands Figure 16.5 A section of small intestinal mucosa showing villi : thin muscular sac Gall bladder Duct from — Ducts gall bladder from liver Common hepatic duct Pancreas - Pancreatic Duodenum duct Guard by sphincler of Oddi. Hepato-pancreatic duct The contents of these notes can not be copied or reproduced in any way B/w limbs of 'C' shaped duodenum paNcREas both exocrine & endocrine alkaline pancreatic juice (enzymes) hormones, insulin glucagon. I Oral cavity Parotid gland Mouth Pharynx Submaxillary and sublingual glands Oesophagus Liver Gall bladder Stomach Pancreas Duodenum Transverse colon Jejunum Ascending colon Descending colon lleum Sigmoid Colon Caecum Rectum Vermiform appendix Anus The contents of these notes can not be copied or reproduced in any way churning movements food + acidic gastric juice chyme pepsinogen HCL (pH 1.8) pepsin proteins proteoses & peptones (peptides). stomach stores food 4-5 hrs ↓ I ÷ . mucus & bicarbonates Rennin milk # digestion infants Small amt lipases gastric glands. also secreted by lubrication protection mucosal epithelium from HCL muscularis layer small intestine. Various movements mixing up food + secretions pancreatic juice bile Intestinal juice hepato-pancreatic duct. I → - → 1- ¥ . 3 pancreatic juice inactive enzymes chymotrypsinogen procarboxypeptidases nucleases lipases Trypsinogen activated by Enterokinase (intestinal mucosa) Trypsin Activates all 4 bile pigments (bilirubin & bili-verdin), bile salts, cholesterol phospholipids But no enzymes. Bile duodenum released fats emulsification Also Activates lipases small micelles ↓ > ↓ ¥ ↓ > ] ↓ pancreatic Succus entericus enzymes above ☝ reactions end products Act on These digestion final steps very close to mucosal epithelial cells of intestine. biomacromolecules duodenum breakdown ↓ _ It simple substances absorbed jejunum ileum large intestine some water, minerals, certain drugs; Absorption secretion mucus adhering lubricating waste (undigested) undigested, unabsorbed faces ileo-caecal valve caecum prevents back flow rectum till defaecation. stored ÷ ⇐ ¥ ' j r: → I Gastro-intestinal tract activities Neural sight smell local CNS Hormonal Digestive secretion intestinal mucosa Gastric Saliva secretion ⇒ ↓ u a. -E. Active against conc, gradient Requires energy Various nutrients like amino acids, monosaccharides like glucose, electrolytes like Na+ Fatty acids & glycerol insoluble small micelles intestinal mucosa reformed into chylomicrons fat globules lymph vessels (lacteals) villi absorbed substances Blood + stream. I ↓ ↑ ↓ ↑↓ → > Absorption Alimentary canal small intestine mouth - stomach large intestine Maximum Absorption A summary of absorption (sites of absorption &substances absorbed) is given in Table 16.1. ← ¥ → absorbed substances Assimilation digestive wastes solidif ied coherent faces initiate neural reflex Egestion Anal opening (defecation) voluntary process mass peristaltic movement. Rectum removal urge utilise for activities. Ti#ues reach ↓ ↓ ↓ faces retained within colon. Constipation bowel irregularly movements Indigestion food & not properly digested feeling of fullness food poisoning over eating / spicy 01 food & Reasons Anxiety 23 inadequate enzyme secretion i. → Protein-energy malnutrition (PEM) South-east Asia South America 4 West & Central Africa Underdeveloped countries Dietary proteins deficiencies & total food calories drought famine political turmoil. during Bangladesh 5 liberation war Ethiopia 6 severe drought mid 80s infants 7 children # produce Marasmus & Kwashiorkar PEM a$ects ↓ → v ⇒ A Marasmus Kwashiorkar proteins & calories simultaneous deficiency infants <year mother's milk $ replaced too early mother 2nd pregnancy / childbirth 1st infant " still too young extreme body emaciation limbs thinning growth impairs proteins tissue replacement skin dry thin wrinkled Growth rate body weight Decline brain 8 & mental development mother's milk $ replacement with high calorie-low protein protein deficiency unaccompanied by calorie deficiency. child > 1 year some fat still left under skin extensive edema body parts swelling unlike marasmus muscles 9 wasting limbs thinning growth & brain 8 development failure Like marasmus ⇒ ↓ I → → → → It r