Q.16
The most important hormone that increases gallbladder contraction after a fatty meal is:
A. CCK
B. Gastrin
C. Secretin
D. GIP
Explanation :
Cholecystokinin (CCK) increases gallbladder contraction after a fatty meal.
Cholecystokinin (CCK): Stimulation of pancreatic enzyme secretion Q Contraction of the gallbladder Q Relaxation of the sphincter of Oddi Q Gastrin:
Produced by G cells in the antral portion of gastric mucosa Q.
It mainly stimulates the secretion of gastric acid and pepsin from stomach Q Stimulates growth of mucosa of the stomach and the small and large intestines Q Secretin:
It is produced by the S cells in the glands of the mucosa in the upper portion of the small intestine.
It mainly increases the secretion of bicarbonate Q by the ductal cells of the pancreas and biliary tract.
GIP: It is produced by K cells in the mucosa of duodenum and jejunum.
It inhibits gastric secretion and motility Q (‘gastric inhibitory peptide’).
It also stimulates insulin secretion from the pancreas Q Also termed as ‘glucose-dependent insulinotropic polypeptide’.
Cholecystokinin (CCK) Secreted by the ‘I' cells in the mucosa of the upper small intestine.
Most important actions of Cholecystokinin (CCK) Stimulation of pancreatic enzyme secretion Q Contraction of the
gallbladder Q Relaxation of the sphincter of Oddi Q CCK also augments the action of secretin in producing a secretion of an alkaline pancreatic juice Inhibits gastric emptying,
exerts a trophic effect in the pancreas, increases the synthesis of enterokinase, and may enhance the motility of the small intestine and colon.
Gastrin and CCK can also stimulate glucagon secretion.
Two CCK receptors have been identified CCK-A receptors are primarily located in the periphery Q Both CCK-A and CCK-B receptors are found in the brain Q.
Both activate PLC, causing increased production of IP3 and DAG. The secretion of CCK is increased by the contact of the intestinal mucosa with the products of digestion,
particularly peptides and amino acids, and containing more than 10 carbon atoms
Q.19
What is Intrinsic Factor related to-
A. Cobalmin absorption
B. Vitamin D
C. Folateabsorbtion
D. Vitamin C
Explanation :
Vitamin B12 (cyanocobalamine) is absorbed in the ileum Q Intrinsic factor (of the castle) is necessary for its absorpon Q .
IF is secreted by oxync cells of stomach. In the lumen of the small intesne, IF forms acomplex with vitamin B12.
Vitamin B12-IF complex binds with a specific receptor on the surface of the epithelial cells of the ileum Q .
Vitamin B12 is transported into the enterocytes leaving behing IF at the brush border,
Water and electrolytes are mainly absorbed in the jejunum. IMPORTANT FACTS ABOUT ABSORPTION
Absorption pattern of duodenum and jejunum is almost the same. Following mentioned nutrients are absorbed both in duodenum and jejunum,
however, their absorption differs quantitatively : - 3. Mainly absorbed in duodenum : - Calcium, Iron
Q . 4. Mainly absorbed in jejunum : - Amino acids, water soluble vitamins (B1, B2. B3, B5, B6, Biotin and Vitamin C),
fat soluble vitamins (A, E, D, K), Fats Q (Triglycerides, Cholesterol), Sugars (monosaccharides, disaccharides), water, NaCl (electrolytes Q ).
o Following are absorbed in the Ileum2 : - Bile & bile salts Q . Vitamin B12 Q, Na + , water.
□ Vitamin B12, (cyanocobalamine) is absorbed in the ileumQ .
Intrinsic factor (of the castle) is necessary for its absorption Q IF is secreted by oxyntic cells of the stomach. In the lumen of the small intestine, IF forms a complex with vitamin B12.
Vitamin B12-IF complex binds with a specific receptor on the surface of the epithelial cells of the ileum Q Vitamin B12 is transported into the enterocvtes leaving behing IF at the brush border.
o Following are absorbed in the colon : - Water and electrolytes Q (Na + & Cl ) Water and electrolyte absorption o Water and electrolytes need no digeson and are absorbed as such.
There is approximately 9 liters of water input: Ingested water : 2.0 litres. Saliva: 1.5 litres, gastric juice : 2.5 litres, bile 0.5 litre, pancreac juice :
1.5 litres, and smalt intesne secreons 1.0 litre. Out of these 9 litres, 7.7 litres (85%) is absorbed in small intesne and 1.0 - 1.5 litres (5-10%) is absorbed in large intesne (colon).
Total 8.8 litres of water is absorbed 2 and 0.2 litre is excreted in feces. In small intesne., most of the water is reabsorbed in the jejunum Q . o Na + and Cl are also absorbed maximally in jejunum
with some absorption in the colon.
Q.20
Liquefactive necrosis occurs in
A. Lung
B. Brain
C. Liver
D. Spleen
Explanation :
LIQUEFACTIVE (COLLIQUATIVE) NECROSIS - occurs commonly due to ischaemic injury and bacterial or fungal infections
• It occurs due to degradation of tissue by the action of the powerful hydrolytic enzyme.
• Common examples are Infarct brain and abscess cavity
• Duret haemorrhage is seen in Brain** (Duret haemorrhage is a small area in bleeding in ventral & paramedian part of the upper brain stem (midbrain & pons)
