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Human Physiology: Part 3
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This lesson covers Human Physiology from the Class 11 NCERT textbook in detail.

Nikhil Puranik
I'm a mechanical engineer, defence analyst and writer. I love to teach.

Unacademy user
Sir plz english mein bhi provide karwa dijiye
sir i am a zoology graduate but not well in diagram , please suggest optional for me , zoology or anthropology , i am waiting to your reply
sir please do continue the course
thanku sir ..very nicely explained..
when next lesson will be loaded,sir?
Vineet Kumar
2 years ago
This is last lesson.
  1. HUMAN PHYSIOLOGY-3 BY NIKHIL PURANIK


  2. ABOUT MIE MY NAME IS NIKHIL PURANIK PURSUING B.E IN MECHANICAL ENGINEERING FROM RNSIT LIVE IN BENGALURU PROFILE https://unacademy.com/user/nikhilrpuranik


  3. TOPICS COVERED DIGESTION OF FOOD ABSORPTION OF DIGESTED PRODUCTS DISORDERS OF DIGESTIVE SYSTEM


  4. Various types of movements are generated by the muscularis layer of the SMALLINTESTINE These movements help in a thorough mxing up of the food with various secretions in the intestine and thereby facilitate digestion. The bile, pancreaticjuice and the intestinal juice are the secretions released into the small intestine. Pancreatic juice and bile are released through the hepato-pancreatic duct. The pancreatic juice contains inactive enzymes trypsinogen, chymotrypsinogen, procarboxypeptidases, amylases, lipases and nucleases. 4


  5. Trypsinogen is activated by an enzyme, enterokinase, secreted by the intestinal mucosa into active trypsin, which in turn activates the other enzymes in the pancreatic juice. The bile released into the duodenum contains bile pigments (bilirubin and bili-verdin), bile salts, cholesterol and phospholipids but no enzymes Bile helps in emulsification of fats, i.e., breaking down of the fats into very small micelles. Bile also activates lipases. The intestinal mucosal epithelium has goblet cells which secrete mucus. The secretions of the brush border cells of the mucosa along with the secretions of the goblet cells constitute the intestinal juice or succus entericus.


  6. This juice contains a variety of enzymes like disaccharidases (e.g. maltase), dipeptidases, lipases, nucleosidases, etc. The mucus alongwith the bicarbonates from the pancreas protects the intestinal mucosa from acid as well as provide an alkaline medium (pH 7.8) for enzymatic activities. Sub-mucosal glands (Brunner's glands) also help in this. -Proteins, proteoses and peptones (partially hydrolysed proteins) in the chyme reaching the intestine are acted upon by the proteolytic enzymes of pancreatic juice as given below: Proteins Peptones Proteoses Trypsin/Chymotrypsin Dipeptides Carboxypeptidase 6


  7. Carbohydrates in the chyme are hydrolysed by pancreatic amylase into disaccharides Polysaccharides (starch) Amylase Disaccharides Fats are broken down by lipases with the help of bile into di-and monoglycerides Fats Lipases D Lipases Diglycerides Fats Diglycerides->Monoglycerides Nucleases in the pancreatic juice acts on nucleic acids to form nucleotides and nucleoside Nucleicacids NucleasesNucleotides Nucleosides 7


  8. The enzymes in the succus entericus act on the end products of the above reactions to form the respective simple absorbable forms. - These final steps in digestion occur very close to the mucosal epithelial cells of the intestine. Dipeptides Dipeptidases Dipeptidases Amino acids Maltose- Maltase Glucose + Glucose Lactose- Lactase Glucose + Galactose Sucrase Sucrose-o Glucose+ Fructose Nucleotides Nucleotidases Nucleotidases Nucleosides Sugars-Bases Nucleosides NucleosidasesSugars + Bases >Nucleosides Nucleosidases Di and Monoglycerides-pases >Fatty acids+Glycerol - Lipases Fatty acids + Glycerol


  9. The breakdown of biomacromolecules mentioned occurs in the duodenum region of the small intestine, and the simple substances thus formed are absorbed in the jejunum and ileum regions of the small intestine. The undigested and unabsorbed substances are passed on to the large intestine. No significant digestive activity occurs in the LARGE INTESTINE. The functions of large intestine are: (i) absorption of some water, minerals and certain drugs; (ii) secretion of mucus which helps in adhering the waste (undigested) particles together and lubricating it for an easy passage. The undigested, unabsorbed substances called faeces enters into the caecum of the large intestine through ileo-caecal valve, which prevents the back flow of the faecal matter. It is temporarily stored in the rectum till defaecation. 9


  10. ABSORPTION OF DIGESTED PRODUCTS Mouth Stomach Small Intestine Large Intestine Absorption of Absorption of water, some minerals and drugs takes place Principal organ for absorption Certain drugs coming in contact wat, simple of nutrients. The digestion is with the mucosa of mouth and lower side of the tongue are absorbed into the blood capillaries lining them sugars, and alcohol etc. takes place. completed here and the final products of digestion such as glucose, fructose, fatty acids, glycerol and amino acids are absorbed through the mucosa into the blood stream and lymph 10