Endocrine system

Adrenal cortex

80% of the gland is the cortex, which produces more than two dozen hormones called corticosteroids (steroid hormones).

Cortisone

A breakdown product of cortisol that's formed in the liver. It's used to prevent inflammation. Its side effects limit its usefulness.

Dwarfism

A condition caused by the pituitary releasing too little growth hormone during childhood.

Gigantism

A condition caused by the pituitary releasing too much growth hormone during childhood.

Glands

A gland is an organ that produces and releases a substance or a secretion.

Prostaglandins (local hormones

A hormone-like substance produced by all cells (except RBCs). They're modified fatty acids that usually affect only nearby cells and tissues.

Thirst

A signal that you should take a drink to restore lost water. You can drink as much as 1 or 2 liters of fluid. However, this volume of water added to the blood will disrupt equilibrium. So the pituitary releases less ADH, and the kidneys remove more water from the bloodstream, which restores the blood to the original concentration.

Nonsteroid hormones

Mostly can't pass through the cell membrane of their target cells. Instead it binds to receptors on the cell membrane, activating an enzyme on the inner surface of the cell membrane, which carries the message of the hormone inside the cell. The message will activate or inhibit an activity.

Cretinism

Neither the skeletal system nor the nervous system develop properly. It's prominent in parts of the world that lack the iodine in food for the thyroid to produce normal amounts of thyroxine. This leads to severe mental retardation and dwarfism.

Feedback inhibition

Occurs when an increase any substance feeds back to inhibit the process that produced the substance in the first place. (Ex: heating and cooling systems)

Calcium

One of the most important minerals in the body. If calcium levels drop below their normal range, blood cannot clot, muscles cannot contract, and transport of materials across cell membranes may fail.

Oxytocin

POSTERIOR PITUITARY, stimulates contractions of uterus during childbirth; releases milk in nursing mothers.

PTH

Parathyroid hormone, works with vitamin D. When calcium levels drop too low, it stimulates the intestine to absorb more calcium from food. It causes the kidneys to retain more calcium and stimulates bone cells to release some of the calcium stored in bone tissue into the bloodstream.

Progesterone

Prepares the uterus for a fertilized egg.

Ovary

Produce estrogen and progesterone. It's required for the development of female secondary sex characteristics and for the development of eggs.

Testis

Produce testosterone which is responsible for sperm production and the development of male secondary sex characteristics.

Pancreas

Produces insulin and glucagon, which regulate the level of glucose in the blood. By the right side, but behind the stomach.

Thyroid

Produces thyroxine, which regulates metabolism.

Cortisol

Raises the level of glucose in the blood by converting protein and fat of body tissues into glucose, used to prevent inflammation. It's released when stimulated by ACTH. ADRENAL CORTEX

Aldosterone

Regulates the reabsorption of sodium ions and the excretion of potassium ions by the kidneys. ADRENAL CORTEX

Adrenal glands

Release epinephrine and norepinephrine, which help the body deal with stress. Two pyramid structures that sit on top of the kidneys. Has an outer part called the adrenal cortex and an inner part called the adrenal medulla.

Endocrine glands

Release secretions directly into bloodstream—hypothalamus, pituitary gland, parathyroid glands, thymus, adrenal glands, pineal gland, thyroid, pancreas, ovary, testis.

Calcitonin

Released from thyroid gland. When blood calcium levels are too high, it helps to reduce the level. It signals the kidneys to retain less calcium in the bloodstream. It also reduces the amount of calcium absorbed in the intestine and stimulates calcium deposition in bones.

Pineal gland

Releases melatonin, which is involved in rhythmic activity s like daily sleep-wake cycles.

Hypothyroidism

Results in lower metabolic rates and body temperature, lack of energy, weight gain. It can be associated with goiter.

Hyperthyroidism

Results in nervousness, elevated body temperature, weight loss.

Alpha cells

Secret a glucagon

Insulin

Stimulates cells in liver and muscles to remove sugar from the food and store it as glycogen or fat.

Glucagon

Stimulates the liver to break down glycogen and release glucose back into the blood.

Adrenal medulla

The release of hormones from A.M. is regulated by the sympathetic nervous system. This produces the fight or flight response to stress. Increases rate and strength of heartbeat, stimulates respiration, dilates respiratory air passages, diverts blood away from digestive system to skeletal muscles and brain.

Parathyroid glands

These four glands release parathyroid hormone, which regulates the level of calcium in blood. These are found at the back of the thyroid gland. See PTH

Steroid hormones (first messenger

They are produced from a lipid (cholesterol). They can cross cell membranes because they are lipids. Then they bind to a steroid receptor protein to form a hormone receptor complex. That complex enters the nucleus of the cell and binds to a DNA control sequence which initiates transcription of specific genes to mRNA which moves into the cytoplasm and directs protein synthesis. It affects the genes directly so they can produce dramatic changes in cell and organism activity.

TRH

Thyroid-releasing hormone. It stimulates the anterior pituitary to secrete thyroid-stimulating hormone. When the temperature drops, there is more THR in the system. It's produced by the hypothalamus.

THS

Thyroid-stimulating hormone, ANTERIOR PITUITARY, stimulates the synthesis and release of thyroxine from the thyroid gland.

Diabetes mellitus

When the pancreas produces too little liver. The amount of glucose in the blood may rise so high that there is glucose in the urine.

Sweat

When you exercise or when you're hot, you lose water as sweat. If this continues, you become dehydrated. As you lose water, the concentration of dissolved materials in the blood rises.

Steroid receptor protein

found only in target cells. A steroid hormone binds to this after it crosses the cell membrane to form a hormone-receptor complex.

Prolactin

ANTERIOR PITUITARY, stimulates milk production in nursing mothers

ACTH

Adreno-corticotropic hormone, ANTERIOR PITUITARY, stimulates release of some hormones from the adrenal cortex. It stimulates the release of cortisol.

Type 2 diabetes

Adult-onset diabetes; usually develops after age of 40, and people produce low to normal amounts of insulin, just that the cells are unable to respond because the interaction of the insulin receptors and he insulin is inefficient.

Goiter

An enlargement of the thyroid gland.

ADH

Antidiuretic hormone, POSTERIOR PITUITARY, stimulates the kidneys to reabsorb water from the collecting tubules.

Pituitary gland

Bean sized and dangles on a stalk of tissue at the base of the skull, below the hypothalamus. Secretes nine hormones that directly regulate many body functions and controls the actions of several other endocrine glands. Has an anterior and a posterior lobe. It's the master gland of the body.

Gonads

Body's reproductive glands. Produce gametes and secrete sex hormones.

Second messenger

Calcium ions, cAMP, nucleotides, fatty acid, can all serve as second messengers for nonsteroid hormones.

Target cell

Cells that have receptors for a particular hormone.

Releasing hormones

Chemicals produced by the hypothalamus, and are carried by the circulatory system to the anterior pituitary, where they control the production and release of hormones.

Endocrine system

Controls growth, development, metabolism, metabolism, reproduction. It's regulated by feedback controls that function to maintain homeostasis.

The endocrine system contains

Hypothalamus, pituitary, thyroid, parathyroids, adrenals, pancreas, ovaries, testes—glands that release their products into the bloodstream. These products broadcast messages throughout the body (can affect almost every cell in the body).

Exocrine glands

Include glands that release sweat, tears, and digestive juices. Release their secretions through tube-like structures called ducts.

Aspirin

Inhibits the production of headache-inducing headaches and thus helps with headaches.

Hypothalamus

It's above and attached to the posterior pituitary. It controls the secretions of the pituitary gland, but its activity is influenced by the levels of hormones in the blood + by sensory information collected by the CNS. Interactions between the nervous system and the endocrine system take place here. The cell bodies of neurosecretory are in the hypothalamus so it has direct control of the p. pituitary. The a. pituitary is controlled by releasing hormones.

Type 1 diabetes

Juvenile onset. Caused by very little insulin production.

LH

Luteinizing hormone, ANTERIOR PITUITARY, stimulates ovaries and testes; prepares uterus for implantation of fertilized egg.

Posterior pituitary

Made up of axons belonging to cells called neurosecretory cells, whose cell bodies are in the hypothalamus. When the bodies are stimulated, the axons release their hormones into the bloodstream.

MSH

Melanocyte-stimulating hormone, ANTERIOR PITUITARY, stimulates the melanocytes of the skin, increasing their production of the skin pigment melanin

cAMP

Cyclic adenosine monophosphate. It can act as a secondary messenger inside the cell.

Thymus

During childhood, thymus releases thymosin, which stimulates T cell development.

FSH

Follicle-stimulating hormone, ANTERIOR PITUITARY, stimulates production of eggs and sperm.

GH

Growth hormone, ANTERIOR PITUITARY, stimulates protein synthesis and growth in cells.

Hormone-receptor complex

The bound form of a steroid hormone and a steroid receptor protein. It enters the nucleus of the cell and binds to a DNA sequence, initiating the transcription of specific genes to mRNA. Works as the regulator of gene expression (can turn on or off whole sets of genes).

Hormones

The chemicals that travel through the bloodstream and affect the activities of other cells. They do this by binding to specific chemical receptors on those cells. (The broadcasted chemical) In general, responses to hormones take much longer than to nerve impulses and last longer as well.

Anterior pituitary

The hypothalamus produces small amounts of chemicals called releasing hormones that are released into the blood vessels. They are carried to the a. pituitary and control the production and release of hormones.

Islets of Langerhans

The island-like portions of the pancreas that produce hormones. It contains alpha and beta cells, which secrete insulin and glucagon.

Thyroxine

The major hormone of the thyroid gland. Increased levels in blood cause the cells to become more active. When the hypothalamus senses the thyroxine level is low, it releases THR which causes the anterior pituitary to secrete TSH. Made of amino acid tyrosine and iodine.