Digestive Glands of Frog

In this digestive glands of frog post we have briefly explained about two enormous digestive glands of frog. The liver and pancreas.

In addition to the glands present in the frog’s stomach and small intestine, the frog has two enormous digestive glands. The liver and pancreas are two of these glands.

Digestive Glands of Frog

Liver

It is the largest reddish brown digestive glands of frog body cavity, located close to the heart and lungs. It is divided into two lobes, the right and left. These two lobes are still connected by a thin bridge of liver tissue.

The left lobe is divided into two lobes once more. The gall bladder is a thin-walled, round, large, greenish sac found between the right and left lobes. It acts as a reservoir for the bile that the liver cells constantly secrete.

Frog Digestive Glands

Digestive Glands of Frog

Bile enters the gall bladder via cystic ducts as well as directly into the bile duct via minute hepatic ducts. The hepatic and crystic ducts merge to form a common bile duct that runs through the pancreas and opens into the duodenum.

The common bile duct is also known as the hepatopancreatic duct because it receives the pancreatic fine ducts on its way to the duodenum. Bile is devoid of digestive juices. Bile only emulsifies fats; therefore, the liver is not a true digestive glands of frog.

Functions of Liver

1. The liver secretes bile, which is watery and alkaline and contains bile salts, bile pigments, cholesterol, lecithin, and water. Sodium bicarbonate, glycocholate, and taurocholate are bile salts. Sodium bicarbonate lowers the acidity of food in the intestine, whereas the other two bile salts activate pancreatic lipase and lower the surface tension of fats, allowing them to be emulsified.

2. It contains no digestive enzymes, but it adds water to food and aids in fat digestion by emulsifying it.

3. It stores excess sugar as glycogen, which is formed by the conversion of glucose (glycogenesis). It is stored as a reserve food, but when its concentration in the blood drops, it can be converted into glucose (glycogenolysis).

4. It keeps the protein concentration in the blood stable. Instead of being stored, excess amino acids are converted by the liver into ammonia, which combines with carbon dioxide and is converted into urea and other nitrogenous wastes by the action of enzymes (deamination), which are then eliminated by the kidneys as urine.

5. It also removes some excretory products that are discharged into the intestine with bile and expelled with the faeces.

6. The liver forms red blood corpuscles in an embryo, but in an adult, its Kupffer cells destroy old and worn out erythrocytes.

7. It is responsible for the storage of copper and iron as well as the formation of vitamin A.

8. It generates fibrinogen and prothrombin, which are required for blood clotting. It also produces heparin, a substance that prevents blood clotting in blood vessels.

9. It kills bacteria and removes foreign substances from the bloodstream.

10. Prussic acid is a by-product of metabolism that is harmful to the body. It is converted by the liver into the innocuous potassium sulphocyanide.

Pancreas

It is an irregular, branched, flattened, pale-colored exocrine and endocrine digestive glands of frog held by the mesentery between the stomach and duodenum. It is crossed by the common bile duct, into which the pancreatic ducts open, and is now known as the hepatopancreatic duct.

Exocrine Part

It is divided into numerous lobes and lobules that are held together by connective tissue and contain pancreatic ducts, blood vessels, lymph vessels, and nerves. There are numerous branching tubules, acini, or alveoli in the lobules. Each alveolus is made up of pyramidal glandular pancreatic cells that form a ring around a central cavity.

These alveoli communicate with one another via their ductules, which then connect to form the larger ducts and, finally, the pancreatic ducts. When the pancreas is traversed, the pancreatic ducts open into the bile duct. The nuclei of pancreatic cells are large, and the cytoplasm is non-granular.

The pancreas produces pancreatic juice which contains various enzymes which digest the proteins, carbohydrates and fats of the ingested food.

Endocrine Part

Compact groups of cells known as pancreatic islets or Langerhans islets can be found among the acini in the connective tissue. These cells are somewhat spherical, arranged in compact groups, and respond well to light staining. An islet contains three types of cells that are separated by capillaries.

Alpha Cells

The nuclei of these cells are achromatic, and the granules are large and acidophilic. These cells secrete glycogen hormone, which raises blood sugar levels. Hypoglycemia results from its deficiency.

Beta Cells

They have small, rounded nuclei that are deeply stained, as well as orange-brown granules. They produce insulin hormone.

D Cells

These cells have vesicular nuclei as well as basophilic granules. Insulin is required for carbohydrate metabolism, regulating glycogen storage in the liver and muscles, regulating blood sugar concentrations, and increasing the ability of tissues to oxidise glucose as a source of energy. Diabetes is caused by an insulin deficiency (hyperglycemia).

Further Readings

Reference