Pancreas

Definition:

Pancreas is a soft fleshy gland that is mixed in nature. It generates enzymes that aid in digestion and are released into the small intestine. Islets, which are collections of cells, are also present. 

Location: 

The abdomen is home to the pancreas. Its portion is positioned between the spine and the stomach. The opposite piece is placed in the duodenum, which is the first segment of the small intestine.

Structure: 

Pancreas is an elongated, flattened pinkish-gray soft fleshy gland of mixed nature. It looks like a pepper or a leaf. It is about 12-15cm in length and about 5 cm in width. Pancreas consists of three parts namely body, body, and tail. the head part. wide and is attached to the duodenum. The lower part is narrow and extends to the spleen. The part between the head and the tail is called the body. Small ducts emerge from the pancreatic enzyme-secreting glands and unite to form the main pancreatic duct or duct of Wirsung, which runs along the length of the pancreas to the bile duct. Enters the duodenum through the ampulla of the vater. Pancreas is called a mixed gland as it consists of both exocrine and endocrine glands.

Different types of glands--

(a) Exocrine gland: 

Pancreas consists of numerous lobules or acinus. Each lobule consists of a central tubular lumen and concentrically arranged cells surrounding the lumen. Pancreatic juice is secreted from the cells of the lobules. The lumen or small pancreatic ducts unite to form the main pancreatic duct or Wirsang duct. Lobules are ductal glands, so they may be called ductal glands and their secretion is external, that is, the secretory juice is carried thru ducts, so they're called exocrine glands. Pancreatic gland cells are arranged like clusters of grapes at the ends of small ducts. They are composed of sap-secreting serous cells, which act as exocrine glands that secrete enzymes that aid in food digestion. 90% of the pancreas is part of the exocrine gland.

(B) Endocrine gland: 

Outside of the pancreatic juice-secreting sacs, small polygonal cell clusters unite to form islets of Langerhans or Langerhans islands. Islets of Langerhans consist of a cluster of about 1 million cells. Each cluster or cluster contains four types of cells.

Namely-

(1) alpha cell  - Glucagon (glucagon) hormone secretion which increases the amount of glucose in the blood.

(ii) Beta cell - secretes insulin hormone which lowers blood glucose level.

(iii) Delta cell - secretes somatostatin hormone which is secreted by alpha and beta cells i.e. blood glucagon and Insulin secretion regulates and

(iv) gamma cell or pancreatic polypeptide cell: (pancreatic polypeptide cell = PP cell) - Secretes pancreatic polypeptide which will increase pancreatic secretion and stimulates the pancreas to secrete pancreatic juice. Because the islets of Langerhans do not have ducts, they are called ductless glands. Their secretion of Alpha or beta cells. Delta cells are pancreatic endogenous i.e. secreted hormones are called endocrine glands as they circulate through the blood to different parts of the body. 10% of the pancreas is part of the endocrine gland. 

Functions: Pancreatic enzymes play an important role in the digestion of meals (carbohydrates, carbohydrates, and fats). And its hormones play a function in regulating diverse physiological capabilities.

The function of the Pancreas as an Exocrine Gland:

As an exocrine gland, the function of the pancreas mainly refers to the digestive function. Apart from digestion, the pancreas performs several important functions. The juice secreted by the exocrine glands of the pancreas is called pancreatic juice. This juice is made up of digestive enzymes and an alkaline fluid.

(a) Digestive function:

Carbohydrate digestion:

Pancreatic juice secretes an expansion of enzymes for the digestion of sugars, carbohydrates, and fats, which input the duodenum through the pancreatic duct and take part in meals digestion.

1. Amylase enzyme breaks down starch and glycogen into maltose

2. Maltase enzyme breaks down maltose into 2 molecules of glucose.

Protein digestion:

 1. Trypsin is secreted into an inactive form called trypsinogen. This inactive enzyme is called zymogen. With the help of the enterokinase enzyme secreted by duodenal mucosa, it becomes active trypsin and breaks down protease and peptone into polypeptides.

2. Chymotrypsin enzyme breaks down protease and peptone into polypeptides.

3. The enzyme carboxypeptidase breaks down the terminal linkages of polypeptides (peptones) into simple amino acids.

4. Aminopeptidase enzymes break down polypeptides into amino acids.

5. Tripeptidase enzyme breaks down tripeptides into amino acids.

6. Dipeptidase enzyme converts dipeptides into amino acids.

7. The enzyme collagenase breaks down collagen-like proteins into simple peptides (i.e. peptones and protease).

8. The enzyme elastase breaks down the connective tissue protein elastin into simple peptides (protease). ( i.e. peptone is digestible)

Lipid digestion:

1. Lipase breaks down fat into fatty acids and glycerol.

2. Cholesterol esterase. It converts 02 esters of dietary cholesterol into final cholesterol and fatty acids in the presence of bile.

(b) Indigestible Function:

1. Acid-base balance Pancreatic juice maintains acid-base balance.

2. Acid mitigation: As pancreatic juice is alkaline in nature, it helps in the action of intestinal juice from the stomach. The acidity of incoming chyme is mitigated.

3. Hydration Control: It helps in maintaining the hydration of the body.

4. Body temperature regulation: The pancreas regulates body temperature by secreting pancreatic juice.

5. Excretion of some heavy metals, antidotes, alkaloids, etc. through pancreatic juice in the alimentary canal come and go out with the stool.

6. Lubrication: With the help of pancreatic mucin, food material slides from one place to another in the small intestine.

7. Inhibition of trypsin action: Trypsin inhibitor of pancreatic juice inhibits the action of trypsin.

Pancreatic Juices:

The juice secreted from the pancreatic ductal gland is called pancreatic juice. It is alkaline (pH

8.0-8.3) in nature. Relative importance 1.010-1.030.

Components of pancreatic juice:

1. Water 97.6%

2. Solids: 2.4%

a. Inorganic material: 0.6%, Na K Ca Zn,. CF, HCO, PO ion, etc.

b. Organic ingredients: 1.8%, various enzymes, viz.

i.. Carbohydrate Digesters: Enzymes like amylase, montage, sucrase, lactase, etc.

ii. Protein digesters: trypsinogen, chymotrypsinogen, carboxypeptidase, elastase, collagenase, nuclease, nucleotidase, etc.

iii. Digestive: Pancreatic lipase.

The function of pancreatic juice:

1. As it is alkaline in nature, it also soothes gastric juices.

2. Amylase, maltase, sucrase, and lactase enzymes present in pancreatic juice digest sugars.

3. Trypsinogen, chymotrypsinogen, nuclease, and carboxypeptidase digest non-vegetarian food.

Frequently ask questions:

(i) Explain the structure of the liver and function of the liver.

(ii) State the role of the liver in digestion.

(iii) How does the pancreas play a role in protein digestion – explain.

(iv) Write the role of a leaf-like gland in regulating blood glucose levels.

(v) Which of the liver and pancreas plays a greater role in digestion? Comment analytically.

(vi)  Stomach, Analyze what happens if the gallbladder and pancreas do not work together.

(vii) Explain the role of exocrine glands in digestion.