Pituitary resons and controls

How to controlling pituitary

The pituitary gland

The pituitary gland The pituitary is a powerful gland that secretes nine different hormones. Although it secretes so many hormones, it is amazingly tiny—about the size of a marble. The pituitary "marble" hangs from the underside of the brain, supported and cradled within a bony depression of the sphenoid bone. 

Controlling the pituitary: The hypothalamus

 The pituitary secretes seven major hormones from its larger front portion, or lobe, the anterior pituitary. It secretes two from its rear lobe, the posterior pituitary. The secretion of these hormones is regulated by a mass of nerve cells that lies directly above the pituitary, making up a small part of the "floor" of the brain. This regulatory nervous tissue, the hypothalamus, is connected to the pituitary by a stalk of tissue  . The hypothalamus uses information it gathers from the peripheral nerves and other parts of the brain to stimulate or inhibit the secretion of hormones from the anterior pituitary. In this way, the by pothalamus acts like a production manager, receiving in-  formation about the needs of the company's customers and regulating the production of products to satisfy those needs. The hypothalamus accomplishes its management job by producing releasing hormones that affect the secretion of specific hormones from the anterior pituitary. The hypothalmus also produces two hormones that do not regulate hormonal release in the pituitary. When they are needed by the body, the hypothalamus signals the pituitary to release them. 

The pituitary is a tiny gland that hangs from the  underside of the brain. The secretion of its many diverse hormones is controlled by a mass of nerve cells lying directly above it called the hypothalamus. The hypothalamus stimulates or inhibits the secretion of hormones from the pituitary by means of re-leasing hormones. In addition, the hypothalamus produces two hormones that it stores in the pituitary. 

The anterior pituitary

The seven hormones produced by the anterior pituitary regulate a wide range of bodily functions . Four of these hormones are called tropic hormones. The word tropic comes from a Greek word meaning "turning" and refers to the ability of tropic hormones to turn on or stimulate other endocrine glands. Of the four tropic hormones, two are gonadotropins. The gonads are the male and female sex organs, the testes and the ovaries. The gonadotropins are hormones that affect these sex organs (considered endocrine glands because they secrete sex hormones). The two gonadotropins are follicle stimulating hormone (FSH) and luteinizing hormone (LH). In females, FSH targets the ovaries and triggers the maturation of one egg each month. In addition, it stimulates cells in the ovaries to secrete female sex hormones called estrogens. In men, FSH targets the testes and triggers the production of sperm. LH stimu

lates cells in the testes to produce the male sex hormone testosterone. In females, a surge of LH near the middle of the menstrual cycle stimulates the release of an egg. In addition, LH triggers the development of cells within the ovaries that produce another female sex hormone—progesterone. (See Chapter 20 for the organs and processes of the reproductive system.)

  The two other tropic hormones are adrenocorticotropic hormone (ACTH) and thyroid-stimulating hormone (TSH). ACTH triggers the adrenal cortex to produce certain steroid hormones. The adrenal glands are located on top of the kidneys (see Figure 19-1). Each of these two glands has two distinct parts: an outer cortex and an inner medulla. ACTH stimulates the adrenal cortex to produce hormones that regulate the production of glucose from "non-carbohydrates" such as fats and proteins. Others regulate the balance of sodium and potassium ions in the blood. Still others contribute to the development of the male secondary sexual characteristics. TSH triggers the thyroid gland to produce the three thyroid hormones.. This endocrine gland is located on the front of the neck, just below the voice box (see Figure 19-1). Its hormones control normal growth and development and are essential to proper metabolism.

The front portion of the pituitary, the anterior pituitary, secretes seven hormones. Of these seven, four stimulate other endocrine glands and are called tropic hormones.

Growth hormone (GH) is produced by the anterior pituitary and works with the thyroid hormones to control normal growth. GH increases the rate of growth of the skeleton by causing cartilage cells and bone cells to reproduce and lay down their inter cellular matrix. In addition, GH stimulates the deposition of minerals within this matrix. GH also stimulates the skeletal muscles to grow in both size and number. In the past, children who did not produce enough GH did not grow to an average height; this condition is called hypo-pituitary dwarfism. However, in the past decade, scientists have been able to use the techniques of genetic engineering  to insert the human GH gene into bacteria to produce human GH. Currently.

 Sandy Allen is shown here with her mother, brother, an dog. Giantism is caused by the over secretion of growth hormone.

this laboratory-made hormone is being used successfully treating growth disorders caused by hyposecretion (UN production) of GH in children. The opposite problem also occur: during the growth years, some children pr too much GH. This hypersecretion (overproduction) cause the long bones to grow unusually long (Figure 19-and result in a condition known as giantism. In adults, h persecretion of GH causes the bones of the hands and fa to thicken, resulting in a condition known as acromegaly .