Pancreatic Secretions

PANCREATIC SECRETIONS

Q. 1

Best stimuli for pancreatic secretion rich in electrolytes ?

 A

Ach

 B

CCK

 C

Secretin

 D

Gastrin

Q. 1

Best stimuli for pancreatic secretion rich in electrolytes ?

 A

Ach

 B

CCK

 C

Secretin

 D

Gastrin

Ans. C

Explanation:

Secretin increases the secretion of bicarbonate by the duct cells of the pancreas and biliary tract. It thus causes the secretion of a watery, alkaline pancreatic juice. Its action on pancreatic duct cells is mediated via cAMP. It also augments the action of CCK in producing pancreatic secretion of digestive enzymes. It decreases gastric acid secretion and may cause contraction of the pyloric sphincter.

Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 25. Overview of Gastrointestinal Function & Regulation. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong’s Review of Medical Physiology, 24e.

Q. 2

Which among the following secretions has the highest HC03 content?

 A

Saliva

 B

Bile

 C

Succus entericus

 D

Pancreatic secretions

Q. 2

Which among the following secretions has the highest HC03 content?

 A

Saliva

 B

Bile

 C

Succus entericus

 D

Pancreatic secretions

Ans. D

Explanation:

The pancreatic juice is alkaline and has a high HCO3– content (approximately 113 mEq/L vs 24 mEq/L in plasma).
 
Composition of Normal Human Pancreatic Juice:
  • Cations: Na+, K+, Ca2+, Mg2+ (pH approximately 8.0)
  • Anions: HCO3–, Cl–, SO42–, HPO42–
  • Digestive enzymes
  • Other proteins
Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 25. Overview of Gastrointestinal Function & Regulation. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong’s Review of Medical Physiology, 24e.

Q. 3

Pancreatic secretion contain –

 A

Trypsin

 B

Lipase

 C

Enteropeptidase

 D

A & B

Q. 3

Pancreatic secretion contain –

 A

Trypsin

 B

Lipase

 C

Enteropeptidase

 D

A & B

Ans. D

Explanation:

A i.e. Trypsin; B i.e Lipase


Q. 4

All of the following are secreted proenzyme form except :

 A

Trypsin

 B

Chymotrypsin

 C

Pepsin

 D

Ribonuclease

Q. 4

All of the following are secreted proenzyme form except :

 A

Trypsin

 B

Chymotrypsin

 C

Pepsin

 D

Ribonuclease

Ans. D

Explanation:

D i.e. Ribonuclease


Q. 5

Pancreatic juice rich in water and electrolytes poor in enzymes is secreted in response to :

 A

Pancreatozymin

 B

Cholecystokinin

 C

Secretin

 D

Proteins

Q. 5

Pancreatic juice rich in water and electrolytes poor in enzymes is secreted in response to :

 A

Pancreatozymin

 B

Cholecystokinin

 C

Secretin

 D

Proteins

Ans. C

Explanation:

C i.e. Secretin


Q. 6

True about iron absorption are all, except ‑

 A

Major site of absorption is duodenum

 B

Stored as Ferritin

 C

Absorbed in ferrous form

 D

Pancreatic secretions improves the absorption

Q. 6

True about iron absorption are all, except ‑

 A

Major site of absorption is duodenum

 B

Stored as Ferritin

 C

Absorbed in ferrous form

 D

Pancreatic secretions improves the absorption

Ans. D

Explanation:

Ans. is ‘d’ i.e., Pancreatic secretions improves the absorption

Iron absorption

  • Iron is absorbed from upper small intestine mainly duodenum.
  • In diet iron occurs in two forms, haeme iron and inorganic (non-haeme) iron.
  • Haem iron is better absorbed than inorganic iron, but the major fraction of diet is inorganic iron.
  • Inorganic iron is mostly in ferric form; needs to be reduced to ferrous form because iron is absorbed in ferrous form.
  • After absorption ferrous form is once again oxidized to ferric form inside enterocytes.
  • A fraction of absorbed iron is rapidly delivered to plasma transferrin.
  • However, most of the iron is deposited in the enterocytes as ferritin, some to be transferred more slowly to plasma transferrin, and some to be lost when senescent mucosal cells (enterocytes) are sloughed into the intestine.
  • Iron absorption is regulated according to the demand, e.g., when there is iron deficiency, absorption increases.
  • This regulation is mediated by “iron metabolism regulatory hormone”, i.e., hepcidin that inhibit iron absorption.
  • When there is iron deficiency, concentration of hepacidin falls and there is increase iron absorption.
  • Hepacidin also decreases release of iron from storage sites.

Transport and storage of iron

  • Iron is transported is blood in combination with a glycoprotein transferrin.
  • Iron is transported into cells through attachment of transferrin to specific membrane bound receptors.
  • Iron is stored as ferritin (major storage form) or haemosiderin.
  • Ferritin is a complex of iron and apoferritin (iron + apoferritin ferritin).
  • Iron is mainly stored in reticulo-endothelial cells monocytes/macrophages of liver, spleen, bonemarrow.
  • It is also stored in hepatocytes (parenchymal cells of liver) and myocytes of skeletal muscles. Note :
  • Iron is stored in ferritin in ferric form.

Q. 7

Pancreatic lipase that digests lipids requires ‑

 A

Vit B 12

 B

Pyridoxine

 C

Tocopherol

 D

Colipase

Q. 7

Pancreatic lipase that digests lipids requires ‑

 A

Vit B 12

 B

Pyridoxine

 C

Tocopherol

 D

Colipase

Ans. D

Explanation:

Ans. is ‘d’ i.e., Colipase

  • Lipase requires colipase which prevents inactivation of lipase by bile salts.
  • For fat digestion, following are required :- Pancreatic lipase, colipase, bile-salts activated lipase, cholesterol ester hydrolase, and phospholipase A2. Trypsin is also involved indirectly as it activates inactive procolipase to active colipase.
  • Lingual lipase and gastric lipase are of very little significance in fat digestion.
  • Bile salts help in fat digestion by : (i) Emulsification of fat and (ii) activating bile salt activated lipase.

Q. 8

Centroacinar cells are present in ‑

 A

Pancreas

 B

Parotid gland

 C

Prostate

 D

None

Q. 8

Centroacinar cells are present in ‑

 A

Pancreas

 B

Parotid gland

 C

Prostate

 D

None

Ans. A

Explanation:

Ans. is ‘a’ i.e., Pancreas

Pancreas

  • It is a mixed exocrine and endocrine gland.

 A . Exocrine part

  • The exocrine portion is a compound acinar gland, consists of pancreatic acini.
  • The acini of pancreas consist of a group of pyramid-shaped acinar cells’ (pancreatic parenchymal cells) arranged around a small lumen.
  • The centroacinar-cells are seen at the centre of acini where the duct system begins. These cells are an extension of the intercalated duct cells into the acinus. They add bicarbonate ions to pancreatic juce.
  • Individual acini are drained by intercalated ducts (interalobular ducts), which drain into larger interlobular ducts, found in connective tissue septa.

 B.  Endocrine part

  • Islets of Langerhans constitute the endocrine part and are scattered throughout the exocrine part, most abundandly in tail region.


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