Anatomy

ENDOCRINE SYSTEM

A gland is an organ whose function is to produce and secrete chemical substances.
There are two types of glands:
Exocrine glands and endocrine glands.

The exocrine gland:
It pours its secretions outside, through an excretory canal. The gland is called "external secretion or open gland.

The main exocrine glands are:
salivary glands present in the mouth, which secrete saliva
-the sebaceous glands of the skin that secrete sebum
-the mammary glands that secrete milk
-the sweat glands of the skin that excrete sweat

• all the digestive glands of the pancreas, intestine and stomach.

The endocrine gland:
It pours its secretion, called hormone, directly into the blood.
The gland is called "internal secretion"

Endocrine glands include:
-thyroid
-the parathyroids
-l'hypophyse
-l'épiphyse
-the pancreas (cells of the islets of langerhans)
the adrenal glands (cortico- and adrenal medulla)
the gonads (ovaries and testicles)
-the thymus

SALIVARY GLANDS

2 parotid glands,
2 submaxillary glands
2 sublingual glands

They secrete saliva (about 1 L per day) composed of:
99.5% water, mineral salts, an enzyme (amylase)
saliva permeates food, the first chemical step in digestion.
it protects against caries by neutralizing acids.

GASTRIC GLANDS:

lining the wall of the stomach, secrete a digestive juice:
gastric juice, 2nd chemical step of digestion.

THE PANCREAS :

exocrine function:
by the secretion of the pancreatic juice dumped into the duodenum.

the pancreatic juice contains:

• electrolytes: the role of which is to neutralize the acidity of the stomach chyme
• enzymes: which act on proteins, lipids, starch, nucleic acids.

the secretion of pancreatic juice depends on:

• the nervous system (neurovegetative)
• Hormones: the secretin released by the duodenum at the arrival of the acidic stomach chyme.

endocrine function:
secretes 2 types of hormones that regulate the blood glucose level:

• insulin: hormone that lowers blood sugar (hypoglycemic)
• glucagon: hormone that raises glucose levels (hyperglycemic)

LIVER :
the largest of the glands (1.5 kg)
it secretes bile, intervenes in the metabolism of carbohydrates, lipids, proteins and iron.

• the bile flows through the hepatic ducts and accumulates in the gallbladder, before being excreted in the duodenum by the common bile duct.
  bile facilitates the digestion of lipids.
• the liver synthesizes proteins whose role is essential when blood clotting (fibrinogen, prothrombin)
• under the action of insulin, the liver stores excess glucose in the form of glucogen.

many diseases cause impaired liver functions:

• cirrhosis
• hepatic colic
• hepatitis (A.B.C.D.E.F.G)
• jaundice or jaundice

ENDOCRINE GLANDS

THYROID :
the largest of the endocrine glands, located on the anterior aspect of the neck, below the larynx and directly applied against the trachea.
it consists of 2 side lobes united by a narrowed part called the isthmus.

a) thyroid hormones:

• Di-iodo thyronine = T2
• Tri-ioda thyronine = T3
• Tetra-iodo-thyronine = T4 (75% of circulating hormones)
• Thyrocalcitonin (calcium metabolism)

the essential fact is the iodine richness of the thyroid hormones.

b) physiology:

• the thyroid activates the combustion processes at the cell level. it acts on:
  the use by the cells of carbohydrates, proteins, lipids,
• on thermal regulation and in the metabolism of iodine.
  she has an action on:
• the growth,
• causes thyroid dwarfism, if ablation or insufflation.
• on the cartilages, prepares the ossification.
• on the genital system: stimulates the appearance of puberty