What Is the Primary Function of the Pituitary Gland?

The pituitary gland, located on the ventral side of the lower thalamus, is an oval body. It is the most complicated endocrine gland in the body. The hormones produced are not only related to the growth of the body's bones and soft tissues, but also affect the activity of the endocrine glands. The pituitary gland can be divided into two parts: adenoid pituitary and neural pituitary. The pituitary gland consists of the nerve and the funnel. The pituitary gland is connected to the hypothalamus by a funnel and is oval in shape. It is located in the pituitary fossa above the middle cranial fossa and sphenoid bone, and it is surrounded by a tough dura. The anterior pituitary gland comes from the epithelium sac (Rathke sac) of the concave apex of the embryonic mouth. The pituitary gland includes the distal part, the nodule part, and the middle part; the posterior pituitary gland is smaller and is formed by the third ventricle protruding downward ( (For details, see Histology). Adult pituitary is about 1 * 1.5 * 0.5 cm in size and weighs about 0.5-0.6 grams. Women may be slightly larger during pregnancy.

Pituitary is the most important endocrine gland of the human body

The pituitary is the most important and complex endocrine gland in the body. The pituitary is oval, located in the middle cranial fossa, inside the pituitary fossa behind the anterior sulcus, and connected to the hypothalamus by a funnel. According to its occurrence and structural characteristics, it can be divided into two major parts: adenohypophysis and neural pituitary. The pituitary gland includes the anterior lobe and the middle part of the pituitary gland. It is a glandular tissue that has the function of manufacturing, storing, and secreting a variety of peptide hormones. It has a regulating effect on growth, metabolism, and sexual functions, and can affect the activities of other secretory glands. The pituitary gland includes the posterior lobe of the pituitary gland and the funnel or nerve stalk. It is the axon part of certain neurons in the hypothalamus. The hypothalamus-neurohypophysis hormone produced by hypothalamic nerve cells is stored here. The oxytocin is secreted by the posterior lobe. And vasopressin has high blood pressure, stimulates uterine contraction and anti-diuretic effect. ^[7]

Although the pituitary gland is small, many diseases occur, and the most common is pituitary tumor. Most of the pituitary tumors are benign. According to whether the tumor cells can produce hormones, they are divided into functional pituitary tumors and non-functional pituitary tumors. Functional pituitary tumors are further divided into growth hormone tumors based on the types of hormones produced by tumor cells, which present as giants or acromegaly; prolactinomas; adrenocorticotropic hormones, which appear as Cushing's syndrome; Tumor. Functional pituitary tumors produce much more hormones than normal, and symptoms of excessive hormones appear. There are also many diseases that produce insufficient pituitary hormones, such as pituitary glandularity (insufficient growth hormone), hypogonadism (insufficient gonadotropin), sometimes the entire anterior pituitary function is impaired, and insufficient secretion of multiple hormones, such as postpartum hemorrhage Caused by Sheehan Syndrome. Insufficiency of the posterior pituitary is diabetes insipidus (insufficient antidiuretic hormone).

Hypothalamic-pituitary diseases include types: diabetes insipidus, postpartum hypophyseal hypofunction, galactorrhea and amenorrhea-galactorrhea syndrome, dwarfism (too little growth hormone secretion in juveniles), and giant disease (too much growth hormone secretion in juveniles) Acromegaly (excessive growth hormone secretion in adults).

Pituitary experiment method

Pituitary: Section 53, calf pituitary, methyl blue eosin staining

Envelope: Connective tissue, stained sky blue.

Parenchyma: funnel, funnel cavity (pituitary cavity), nodule, nerve (dyed light blue), middle (dyed pink), pituitary fissure and distal (dyed purple and red) relationship.

The part connected to the lower part of the thalamus is called the funnel stalk, which is a mid-uplift downward, and the sides of the mid-uplift are nodules. The anterior part of the pituitary is called the distal part, there is a pituitary fissure behind the distal part, and there is a middle part behind the pituitary fissure. In the middle part of the bovine pituitary, a small piece of tissue from the distal part is in the shape of an oval island. The nerve is located in the posterior part of the pituitary, adjacent to the middle part.

Distal: Three types of cell-forming cells with sinusoids can be seen. The cell cord is often lumpy. There are three types of cells: a. Eosinophils: The cytoplasm contains eosinophilic granules, the nucleus is round, the number is large, and most are located around the distal part. b. Basophils: The cytoplasm contains gray-blue or purple-blue basophil particles, which are larger in volume and most in the middle of the distal part. C. Suspicious cells: The cytoplasm is very lightly stained, and the boundaries of the cells are unclear, mostly in the center of the cell mass. ^{[3] [2] [1] [4] [6]}

Clinical manifestations of pituitary

The pituitary gland is an important endocrine organ. It contains several endocrine cells and secretes a variety of endocrine hormones. If an endocrine cell grows an adenoma, special clinical manifestations can occur. The details are described as follows: ^{[3] [1] [2] [4-5]}

Performance of different pituitary adenomas

Endocrine manifestation

(1) Growth hormone cell adenoma: The early tumor is only a few millimeters in size, which is mainly manifested by excessive secretion of growth hormone. Underage patients can grow too fast and even develop into giants. Adults later show acromegaly. If your face changes, your forehead gets bigger

Anterior pituitary

, Jaw protrusion, thick nose and thick lips, thickened fingers, tight shoes and hats, change the larger model several times, and even have to make it specially. Some patients have increased meals, rough hair skin, hyperpigmentation, and numb fingers. Wait. In severe cases, they feel general weakness, headache, arthralgia, sexual decline, amenorrhea and infertility, and even diabetes.

(2) Prolactin cell adenoma: Mainly manifested as amenorrhea, galactorrhea, infertility, severe axillary hair loss, pale and delicate skin, increased subcutaneous fat, as well as fatigue, fatigue, lethargy, headache, and decreased sexual function. Males showed decreased libido, impotence, breast hyperplasia, scarce beards, severe reproductive organ atrophy, decreased sperm count, infertility, etc. Men and women did not change much.

(3) Adrenocorticotrophic adenoma: clinical manifestations are concentric body obesity, full moon face, buffalo back, multiple blood quality, purple skin on the thighs of the abdomen, and increased coat hair. Severe amenorrhea, loss of libido, general weakness, and even bedridden. Some patients do not have hypertension or diabetes.

(4) Thyroid stimulating hormone cell tumor: Rare, due to excessive secretion of pituitary thyroid stimulating hormone, causing hyperthyroidism symptoms, hyperthyroidism symptoms disappear after pituitary tumor removal. In addition, the feedback of hypothyroidism causes focal hyperplasia of the pituitary gland, which gradually develops into a pituitary adenoma. When it grows up, it can also cause the symptoms of the enlarged saddle and the compression of nearby tissues.

(5) Follicle-stimulating cell adenoma: very rare, only individual reports of clinical sexual dysfunction, amenorrhea, infertility, reduced sperm count, etc.

(6) Melanin-stimulating cell adenoma: Very rare, and only a few patients have reported dark skin without cortisol increase.

(7) Endocrine inactive adenomas: Early patients with no special sensory tumors grow up, which can compress the clinical manifestations of pituitary insufficiency caused by the pituitary.

(8) Malignant pituitary tumor: short history and rapid progression of the disease, not only the tumor grows and oppresses the pituitary tissue, but also invades the surrounding area, causing bone damage to the saddle bottom or immersion in the cavernous sinus, causing oculomotor nerve paralysis or abductor nerve paralysis. Sometimes the tumor penetrates the base of the saddle and reaches the sphenoid sinus, and neurological symptoms are not obvious for a short period of time.

Visual field disturbance

Early pituitary adenomas often have no visual field of vision. If the tumor grows up, stretches upwards, and oppresses the optic cross, a visual field defect occurs, the outer upper quadrant is affected first, and the red visual field appears first. Later, when the lesions increase and the compression is severe, the white field of vision is also affected. Gradually the defect can expand to double temporal hemianopia. If it is not treated in time, the visual field defect can be enlarged again, and the vision is also reduced, so that it is completely blind. Because pituitary tumors are mostly benign, the initial lesions can last for a considerable period of time. When the disease is severe, the visual field of vision can suddenly increase. If the tumor is to one side, it can cause blindness or blindness in one eye.

Other neurological symptoms and signs

If the pituitary tumor grows backward and compresses the pituitary stem or hypothalamus, it can cause polydipsia and polyuria; if the tumor grows laterally and invades the cavernous sinus wall, oculomotor nerve or abductor nerve paralysis occurs; if the tumor passes through the saddle septum, If the tumor grows upward, the ventral part of the frontal lobe may cause psychiatric symptoms. If the tumor grows upward and obstructs the anterior part of the third ventricle and the interventricular foramen, symptoms of increased intracranial pressure such as headache and vomiting may appear. Cause coma, paralysis, or rigidity. ^{[3] [2] [1] [4-6]}