Stomach :
- J shaped organ
- Present in the abdominal cavity just below the Diaphragm on the left side.
- Divided into 4 parts:-
1. Fundus
2. Corpus/Body
3. Pylorus
- Fundus has gastric gland.
1. G-cells :- Release gastrain
2. D-cells :- Release somatostation
3. Argentaffin cells :- Secrete serotin
- The 2 surface of stomach are :
(i)Lesser curvature/omentum
(ii)Greater curvature/omentum
Function of stomach :
Acts as reservior of food. holds food for 4 to 5 hours.
NOTE :-
Regurgition :- Failure of closer of cardiac sphinter due to its incomplete devlopment in infants.
Acid reflux or heart burn :- Failure of closer of cardiac sphincter leading to backflow of acidic enzyme.
Gastric gland :
- Present in stomach.
- Present in the mucosal layer of the fundic part of stomach.
- Type of simple branched tubular glands.
- 30 crores in number.
- also called oxyntic tubular gland.
Consists of three types of cells -
1.) Chief cells / peptic cells /zymogenic :-
Release enzyme(a) pepsinogen(b) Prorennin (c)gastric lipase
2.) Oxyntic (parietal) cells :-
Secret HCl and intrinsic factor of Castle( which help in absorption of vitamin B12 ).
3.) Goblet cells :-
Which release mucus.
Note :-
- vitamin b12 helps in maturation of RBC.
Gastric juice :
- Normal volume = 2-2.5 litre per day
- pH of gastric juice =1.5-2
- gastric juice increase by :
(i) parasympathetic nervous system (PNS)
(ii) alcohol
(iii) Caffeine
(iv) Aspirin / Disprin
(v) Histamine
(vi) Protein diet / spicy food
(vii) Gastrin (local hormone)
Zollinger-ellison syndrome :
It is a pancreatic tumor in which gastrin release is increase forming peptic ulcers.
Phases of gastric juice secretion :
1.) Cephalic phase -
Increase gastric juice secretion by seeing, smelling, testing food or hearing and thinking about food.
2.) Gastric phase -
Increase in gastric juice secretion by food entering into stomach.
3.) Intestinal phase -
Decrease in gastric juice secretion by the food leaving the stomach and entering intestine.
Function of HCl :
- Activate pepsinogen to pepsin.
- Inactivate salivary amylase.
- Provide ideal pH for gastric enzyme.
- Kill microbes.
- Soften the protein and cellulose fibre.
- Help in absorption of iron.
Note :-
-Deficiency of iron leads to Hypochromic anaemia.