Physiology of digestion, Biology

Assignment Help:

PHYSIOLOGY OF DIGESTION

Food - omnivorous.
Digestion - Intercellular.

(i) Mechanical - by chewing, deglutinationm, churnning, peristalais. Under control of medulla oblongeta. (ii) Chemical - by hydrolases enzymes.

It can be studied in following steps -

DIGESTION IN BUCCAL CAVITY

  1. Digestion starts in buccal cavity.
  2. In buccal cavity food is masticated and mixed well with saliva.
  3. About 30% starch of food is converted into maltose in buccal cavity.
  4. Digestion of fats and carbohydrates do not take place in buccal cavity.
  5. Saliva contains - mucus, lysozymes, ptyalin or salivary amylase and electrolytes such as Na+, K+, Cl- and HCO .
  6. In buccal cavity pH is slightly acidic (6.8 pH).
  7. Starch sali var y amylase fi Maltose +lim it dextrins

DIGESTION IN OESOPHAGUS

  1. No digestive juice is secreted in the oesoophagus, onlymucus is secreted. Action of salivary amylase continues.

DIGESTION IN STOMACH

  1. Fundic glands of stomach secrete digestive enzymes, HCl and mucus.
  2. In stomach mainly digestion of proteins takes place.
  3. Protein digesting enzymes are secreted in proenzyme form.
  4. No carbohydrate splitting enzyme is secreted in stomach.
  5. Gastric glands of stomach secrete gastric juice.
  6. Gastric juice contain HCl & digestive enzymes.
  7. In stomach pH is highly acidic (1.3 to 2.3 pH).
  8. 2316_digestion in stomach].png
  9. HCl in stomach kills bacteria present in food and activates pepsinogen.
  10. HCl present in stomach inactivates salivary amylase and stops action on carbohydrates.
  11. Gastrin hormone secreted from G-cells of gastric epithelium stimulates secretion of HCl.
  12. Enterogastrone secreted from epithelium of duodenum inhibits secretion of gastric juice.

DIGESTION IN SMALL INTESTINE

  1. It receives bile juice and pencreatic juice.
  2. Hepatocrine stimulates bile juice for synthesis.
  3. CCK stimulates contraction of gall bladder.
  4. Secretin (discovered by Beylis & Sturling) & pancreozymine stimulate pancreatic juice.
  5. First bile juice reacts on food.
  6. In bile juice -  89% H O,  11% Others [Mucous, Incorganic, Bile juice (Sodium or Potassium taurocholate and glycholate), Bile pigment, Cholesterol, Lecithin, pH 7.7 - 8.6]
  7. Total amount 500 - 1000 ml / 24 Hr.
  8. Bile salts are helpful in imulsification particles of imulsified lipid are micellus or chitomicellus (.1 - .5m)
  9. The reaction is known as saponification.
  10. Bile salts are helpful in absorption of Vit. A, D, E & K.
  11. Bile pigment, cholesterol & lecithin are excretory.

PANCREATIC JUICE - COMPLETE JUICE

  1. 98.5% H O,  1.5% Others [Inorganic salts, Mucous, Chemotrypsinogen, Carboxypeptidase, Aminopeptidase, Trypsinogen,  Amylase, Maltase, Isomaltase, Limit Dextrinase, Lipase or steapsine, Cholesterol esterase, Polynucleotidase, pH 8.0]
  2. Total amount - 500 - 800 ml / 24 hrs.
  3. 2068_pancreatic juice.png
  4. Now food is termed as chyle.
  5. Endopeptidase react with peptide bond.
  6. Glycosidase for Carb. digestion.
  7. Here food gets succus entericus stimulated by enterokrinine harmone.
  8. It's consists of - 98.5% H O, 1.5% Others [Mucous, Inorganic salts, Erapsin, Maltase, Isomaltase, Limit Dextrinase, Sucrase, Lectase, Lipase, Polynucleotidase, Phasphotase, Nucleosidase]
  9. 831_pancreatic juice.png1.png

DIGESTION OF CELLULOSE

  1. No vertebrate secretes any enzyme for digestion of cellulose.
  2. In all herbivores digestion of cellulose takes place with the help of symbiotic bacteria and protozoans present in the alimentary canal.
  3. In ruminants like cow, buffalo, goat, camel etc. symbiotic bacteria and protozoans are found in compound stomach.
  4. In ruminants digestion of cellulose takes place in the compound stomach.
  5. In other herbivores like rabbit and horse, digestion of cellulose takes place in caecum.
  6. After digestion cellulose is converted into sugars. 

Related Discussions:- Physiology of digestion

Coelom - metazoa, Coelom - Metazoa True coelom is a body cavity which ...

Coelom - Metazoa True coelom is a body cavity which arises within the embryonic mesoderm so that the cavity lies between the body wall (integument; ectoderm) and guts (endoder

Tertiary prevention -community mental health programme, Tertiary Prevention...

Tertiary Prevention: In tertiary prevention, emphasis is placed on reducing disability resulting from illness. Tertiary prevention often means long term care. Disability may r

Syngamy - patterns of sexual reproduction, Syngamy - Patterns of Sexual Rep...

Syngamy - Patterns of Sexual Reproduction Sperm fuses with the egg. This results in both the union of the paternal nucleus with the maternal one (karyogamy), as well as the fu

Write the meaning of hyperglycemia, Q. Write the meaning of Hyperglycemia? ...

Q. Write the meaning of Hyperglycemia? Hyperglycemia is a Greek term: hyper -meaning excessive; glyc - meaning sweet; and emia- means "of the blood". It is a condition in whic

Coronary vascular resistance reflexly, Baroreceptor activity affects corona...

Baroreceptor activity affects coronary vascular resistance reflexly. With carotid occlusion, baroreceptor hypotension leads to reflex adrenergic stimulation, increased metabolic ac

Netlike membranous complex of superposed flat saccules, Q. A netlike membra...

Q. A netlike membranous complex of superposed flat saccules with vesicles detaching from the extremities seen in electronic microscopy. What is the observed structure? What is its

How does immune process that causes the hemolytic disease, How does the imm...

How does the immune process that causes the hemolytic disease of the newborn take place? In a hemolytic disease of the newborn the mother has Rh- blood and this mother when gen

Explain entecavir, Explain Entecavir  Entecavir  (Baraclude) taken ora...

Explain Entecavir  Entecavir  (Baraclude) taken orally once a day as monotherapy appears to be superior to lamivudine for patients with chronic HBV infection, but susceptibili

Define classification of fats and fatty acids, Define Classification of Fat...

Define Classification of Fats and Fatty Acids? You must be wondering in this unit on lipids why we are talking about fats and oils and not using the term lipids. Definitely whe

Explain diffusion and osmosis in cell structure, Explain Diffusion and Osmo...

Explain Diffusion and Osmosis in cell structure? Diffusion and Osmosis :  Diffusion through a cell membrane occurs as it does elsewhere, from an area of high concentration of

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd