CLASS 11TH BIOLOGY CHAPTER- 16 DIGESTION AND ABSORPTION NCERT QUICK REVISION NOTES FOR NEET AND CBSE EXAM

DIGESTION AND ABSORPTION

¶ Digestion: The process in alimentary canal by which the complex food is converted mechanically and biochemically into simple substances suitable for absorption and assimilation.

¶ Food: A substance which on taken and digested in the body provides material for growth, repair, energy, reproduction, resistance from disease or regulation of body processes.

¶ Thecodont: The teeth embedded in the sockets of the jaw bone, e.g., in mammals.

¶ Diphyodont: The teeth formed twice in life time e.g., in mammals.

¶ Heterodont: An adult human has 32 permanent teeth which are of four different types.

(a) Canine for tearing

(b) Incisors for cutting

(c) Premolars for grinding

(d) Molars for churning and grinding

DENTAL FORMULA OF MAN: 

(Permanent Teeth)

DENTAL FORMULA OF MAN:

(Milk Teeth)

¶ Peristalsis: The involuntary moveent of the gut by which the food bolus is pushed forward,

¶ Deglutition: The process of swallowing of food bolus. It is partly voluntary and partly involuntary.

¶ Ruminants: The herbivours animals (e.g., cow, buffalo etc.) which have symbiotic bacteria in the rumen! of their stomach which synthesize enzymes to hydrolyse cellulose into monosaccharides.

¶ Diarrhoea: The abnormal frequent discharge of semisolid or fluid faecal matter from the bowel.

¶ Vomitting: The ejection of stomach contents through the mouth, caused by antiperistalsis.

¶ Dysentery: Frequent watery stools often with blood and mucus and with pain, fever and causes dehydration.

¶ Chyme: The semifluid mass into which food is converted by gastric secretion and which passes from the stomach into the small intestine.

¶ Gastric: Anything associated with stomach is given a prefix 'gastric'.

¶ Proenzyme: The inactive forms of enzymes.

¶ Sphincter: A flap like structure at various junctions of the alimentary canal which facilities one way traffic in the alimentary canal.

¶ Bolus: The masticated food mixed with saliva.

¶ Hepatic : Anything associated with liver is given a prefix 'hepatic'. 

¶ Goblet cells: The cells of intestinal mucosal epithelium which secrete muscus.

¶ Glisson's capsule: The connective tissue sheath which covers the hepatic lobules of liver.

¶ Hepatic lobules: The structural and functional units of liver containing hepatic cells which are arranged in the form of cords.

¶ Sphincter of Oddi : The sphincter which guard the opening of common hepatopancretic duct.

¶ Villi: The small finger-like folding in the small intestine which increase the surface area for absorption of digested food. 

Crypts of Lieberkuhn-pits of intestine

Success entericus-Intestinal juices.

BASIC STEPS OF HOLOZOIC NUTRITION:

(1) Ingestion : Intake of food.

(2) Digestion: Breaking down of complex organic food materials into simpler, smaller soluble molecules.

(3) Absorption and assimilation: Absorption of digested food into blood or lymph and its use in the body cells for synthesis of complex components. 

(4) Egestion : Elimination of undigested food as faeces:

Digestive glands: 

(A) Salivary gland-3 types are

(i) Parotid (cheek)

(ii) (Below the tongue) Sublingula, 

(iii) Submaxillary or submandibular (lower jaw) Secrete saliva which contains ptyalin (Salivary Amylase)

(B) Pancreas: Secretes pancreatic juice.

Malnutrition-When a person is not getting enough food or getting unbalanced diet.

PEM-PROTEIN ENERGY MALNUTRITION

SYMPTOMS:

CURE:

Calorific Value: Amount of heat energy required to raise the temperature of 1 kg of water by 1°C.

Calorific value of Carbohydrates is 4.1 k.cal/g

Protein is 5.6 kcal/g

Fats is 9.4 kcal/g (app.)

CLASS 11TH BIOLOGY CHAPTER- 17 BREATHING AND EXCHANGEOF GASES NCERT QUICK REVISION NOTES FOR NEET AND CBSE EXAM