Digestive Gland and Their Role in Digestion

Biomacromolecules in food  (carbohydrates, proteins, and so on) cannot be used by human bodies in their natural state.

In the digestive system, they must be broken down and turned into simple compounds (glucose, amino acids, etc.).

Biomacromolecules such as carbohydrates are broken down into simple sugars like glucose, lipids into fatty acids and glycerol, and proteins into amino acids during digestion.

Digestion is the process of converting complex dietary molecules into simple absorbable forms.

Layers of Alimentary Canal 

From the oesophagus to the rectum, the alimentary canal wall has four layers: serosa, muscularis, submucosa, and mucosa.

1.The outermost layer, the serosa, is made up of a thin mesothelium (visceral organ epithelium) and connective tissues.

Smooth muscles make up the muscularis.

2.The loose connective tissues that make up the submucosal layer contain nerves, blood arteries, and lymph vessels. Glands can also be seen in the submucosa of the duodenum.

3.The mucosa is the deepest layer that lines the alimentary canal’s lumen. In the stomach, this layer creates uneven folds called rugae, and in the small intestine, it creates little finger-like folds called villi. Goblet cells in the mucosal epithelium release mucus that aids in lubrication. In the stomach, mucosa forms glands (gastric glands).

Digestive Glands 

The salivary glands, liver, and pancreas are digestive glands connected with the alimentary canal.

Salivary Glands

1.The parotids (cheek), the submaxillary (lower jaw), and the sublinguals (lips) are the salivary glands that produce the most saliva (below the tongue).

2.Salivary juice is secreted into the buccal cavity by these glands, which are located just outside the cavity.

3.The starch is broken down into sugars by saliva.

Liver

The liver is a reddish brown gland located in the upper right side of the belly.

1.It is the body’s biggest gland.

2.It secretes bile juice, which is then stored in the gallbladder.

3.The bile serves a crucial role in fat digestion.

4.It is divided into two lobes. The structural and functional elements of the liver that contain hepatic cells are known as hepatic lobules.

5.The bile released by the hepatic cells travels through the hepatic ducts before being deposited and concentrated in the gallbladder, a thin muscular sac.

6.The common bile duct is made up of the cystic duct from the gallbladder and the hepatic duct from the liver.

7.The common hepato-pancreatic duct, which is guarded by the sphincter of Oddi, connects the bile and pancreatic ducts and opens into the duodenum.

Pancreas

1.The pancreas is a big cream-colored gland that sits beneath the stomach.

2 Carbohydrates and proteins are broken down by pancreatic juice into simpler forms.

3.The partially digested food now makes its way to the lower region of the small intestine, where the intestinal juice [succus entericus] completes the digestion of all of the food’s components.

4.The pancreas is an extended complex (both exocrine and endocrine) organ located between the limbs of the duodenum’s ‘U’ shape.

5.The exocrine component produces an alkaline pancreatic juice with enzymes, whereas the endocrine portion produces hormones, insulin, and glucagon.

Action Of Enzymes In Stomach

1.Food is stored in the stomach for 4-5 hours. The chyme is made up of food that has been fully mixed with the stomach’s acidic gastric liquid by the churning movements of its muscular wall.

2.When exposed to hydrochloric acid, the proenzyme [inactive precursor of an enzyme] pepsinogen is transformed into the active enzyme PEPSIN, the proteolytic (breakdown of proteins or peptides into amino acids) enzyme of the stomach.

3.Pepsin is a digestive enzyme that breaks down proteins into proteoses and peptones (peptides).

4.The mucus and bicarbonates in the gastric juice help to lubricate and prevent the mucosal epithelium from being excoriated by the very concentrated hydrochloric acid. The acidic pH (pH 1.8) that pepsins prefer is provided by HCl.

5.Rennin is a proteolytic enzyme found in newborns’ stomach juice that aids in milk protein breakdown

Conclusion 

This gland secretes digestive fluids that comprise HCL, Pepsin, and additional mucus. Gastric glands secrete hydrochloric acid, which destroys microorganisms consumed with food. The acidic PH aids the function of pepsin enzymes, which break down proteins in diet.