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Terms in this set (14)

The pituitary gland, also called the hypophysis, is about 1 cm in diameter and is located beneath the brain in a bony receptacle called the sella turcica. It is attached to the underside of the brain by a stalk called the infundibulum.

The circle of Willis surrounds the pituitary gland and provides it with blood exchange. The pituitary gland is actually composed of two distinct masses of tissue: anterior lobe and posterior lobe.

The anterior lobe is derived from the top of the pharynx and is the glandular portion. The posterior lobe is derived from the nervous system. They both fuse together to form a single organ.

The pituitary gland is often referred to as the master gland because it is responsible for the regulation of so many body activities. The release of hormones from the pituitary gland is controlled by the brain, specifically the hypothalamus.

Eight important hormones are secreted by the pituitary, six via the anterior lobe and two via the posterior lobe. These hormones are:

•Growth hormone (GH). This regulates the growth of all body tissue and is very active during adolescence.

•Thyroid stimulating hormone (TSH). This regulates the activity of the thyroid gland.

•Adrenocorticotropic hormone (ACTH). This assures normal function of the adrenal cortex. It also works on all cells to help break down fats.

•Follicle stimulating hormone (FSH). In the male this stimulates the testes to produce sperm; in the female it stimulates the production of estrogen.

•Luteinizing hormone (LH). This works in conjunction with FSH to induce ovulation and produce progesterone. In the male, this is called interstitial cell stimulating hormone (ICSH) and stimulates the testes to produce testosterone.

•Prolactin. This hormone works with other hormones to initiate the secretion of milk by the mammary glands.

•Oxytocin. This causes the uterus to contract during labor, as well as stimulates the mammary glands to let down milk. This is generated by the hypothalamus through the posterior lobe.

•Vasopressin. This has two separate functions: to constrict the blood vessels causing increased blood pressure, and to permit the kidneys to reabsorb water. This is also a posterior lobe hormone.
The pancreas is a flat, tongue-shaped fleshy organ lying against the abdominal wall in the left upper quadrant. It is 12-15 cm in length, 5-6 cm in greatest width, and functions as both an exocrine and endocrine gland.

The endocrine portion of the pancreas consists of scattered clusters of cells called the islets of Langerhans. Two types of cells make up these clusters: alpha cells and beta cells. The hormones produced by them are taken up in the blood and do not enter the duct system of the pancreas.

The alpha cells produce a hormone called glucagon. This converts glycogen into glucose and regulates the level of glucose in the blood. The beta cells produce a hormone called insulin that increases the cellular utilization of glucose. Together these hormones are essential for the metabolism of carbohydrates. There are two rare cell types as well: Delta cells that secrete somatostatin, and F (PP) cells that secrete pancreatic polypeptide (a hormone that may inhibit pancreatic exocrine activity).

Triangular-shaped adrenal glands sit atop each kidney. Each one has an outer cortex and an inner medulla that individually function as separate glands. The inner medulla produces two hormones, epinephrine and norepinephrine. These two hormones, often called adrenalin, increase cardiac output and heart rate, dilate coronary vessels, increase mental alertness, increase respiratory rate, and elevate the overall metabolic rate. The outer cortex produces a variety of hormones, including cortisol to regulate carbohydrate and protein metabolism, aldosterone to control fluid and electrolyte balance, and androgen (male hormones) that affect the growth of body and facial hair.

In all, approximately 30 hormones are produced by the adrenal glands, and modern medicine does not fully understand the interplay and effects of all of them.
exocrine - Secretes fluids that are transported via "ducts" to their appropriate destinations and function within a particular body system.

endocrine - Secretes chemicals, called hormones, directly into the blood.

pituitary - Referred to as the master gland because it is responsible for the regulation of so many body activities.

thyroid - Secretes hormones that regulate normal growth and development, including mental processes and sexual maturity.

parathyroids - Hormone secreted by the parathyroids is called parathormone (PTH). This hormone regulates the ratio of calcium and phosphorus in the blood and bone tissues.

pancreas - Functions as both an exocrine and endocrine gland.

adrenals - Triangular-shaped glands that sit atop of each kidney. Each one has an outer cortex and an inner medulla that individually function as separate glands.

gonads - Male and female sex glands. They produce both sex hormones and sex cells.

pineal - Releases a hormone called melatonin that plays a role in sexual maturation and in maintaining daily body rhythms.

hypophysis - Another name for the pituitary gland.

sella turcica - Bony receptacle located beneath the brain which contains the pituitary gland.

infundibulum - A stalk which attaches the pituitary gland to the underside of the brain.

circle of Willis - Surrounds the pituitary gland and provides it with blood exchange.

hypothalamus - Controls the release of hormones from the pituitary gland.

adrenocorticotropic - Hormone that assures normal function of the adrenal cortex. It also works on all cells to help break down fats.

luteinizing - Works in conjunction with FSH to induce ovulation and produce progesterone.
acromegaly - Disease characterized by large, coarse features, particularly of the face and hands. This results from overproduction of the growth hormone.

Addison's disease - A chronic type of adrenocortical insufficiency, characterized by hypotension, weight loss, anorexia, weakness, and a bronze-like hyperpigmentation of the skin.

cachexia - A profound and marked state of constitutional disorder; general ill health and malnutrition.

Cushing syndrome - A condition resulting from an excess of the adrenocorticotropin hormone.

cystic fibrosis - Widespread dysfunction of the exocrine glands occurring in infants, children, and young adults.

de Quervain thyroiditis - A condition characterized by fever and painful enlargement of the thyroid gland, often following a viral infection.

diabetes insipidus - A temporary or chronic disorder of the posterior lobe of the pituitary gland involving a deficiency of the vasopressin hormone.

diabetes mellitus - A syndrome characterized by hyperglycemia resulting from impaired insulin secretion or effectiveness. It is classified into two main categories, noninsulin dependent and insulin dependent.

Diabetes Mellitus Type 1 - also called insulin-dependent diabetes mellitus (IDDM). Type 1 diabetes mellitus is also referred to as juvenile diabetes. It is characterized by an abrupt onset of symptoms, usually in early adolescence, in persons who suffer from an insufficient amount of insulin being produced by the pancreas.

Diabetes Mellitus Type 2 - may be either non-insulin-dependent diabetes mellitus (NIDDM) or insulin-dependent diabetes mellitus (IDDM). This is also referred to as adult-onset diabetes, because it is usually found in adults over 45 who have a family history of diabetes, are overweight, do not exercise, and/or have high cholesterol levels.

(Note on formatting: The latest word from the American Diabetes Association is that roman numerals are no longer to be used to designate diabetes types. The preferred usage is now type 1 and type 2. Not all codebooks and dictionaries reflect this change, but some medical records may.)

dwarfism - The congenital underdevelopment of the body.

endemic - Present or prevalent in a population or geographic area at all times; said of a disease or agent.