Name: __________________________________________ Period: _________Ch 9: The Endocrine System

Objectives: Students will be able to:

Define hormone and target tissue Describe how hormones bring about their effects in the body Explain how various endocrine glands are stimulated to release their hormonal

products Describe the difference between endocrine and exocrine glands Identify the major endocrine glands and tissues List hormones produced by the endocrine glands and their general functions Describe the effect of aging on the endocrine system and body homeostasis.

The endocrine system is the ______________ messenger system of the body. The speed of the endocrine system is much slower than the fast impulse of the _____________ system. This system uses _________________ messages (_________________) that are released into the blood. Hormones control several major processes, such as:

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The Endocrine System and Hormone Function—An OverviewCompared to other organs of the body, the organs of the endocrine system are

small and lack the structural or anatomical continuity of most organ systems. However, functionally the endocrine organs are very impressive, and when their role in maintaining body homeostasis is considered, they are true giants.

The Chemistry of HormonesThe hormones produced and secreted by these organs have massive power.

Hormones are chemical substances that are produced by specialized _________. These cells _____________ hormones into extracellular fluids. ____________ transfers hormones to target sites in which these hormones ___________ the activity of other cells. Although many different hormones are produced, nearly all of them can be classified as either:

_______________________________ (proteins, peptides, and amines)1

_________________— made from cholesterol(include the sex hormones made from gonads, and hormones produced by the adrenal cortex)

___________________— made from highly active lipidsMechanisms of Hormone Action

Although blood-borne hormones circulates all the organs of the body, I given hormone affects only certain _____________ or _____________ (target cells or organs) . In order for target cells to respond to the hormone, it must have specific ____________ ________________ on its plasma membrane, or in it’s interior so with that hormone can attach. When this binding occurs, the hormone _______________ the working of the cells.

The time hormone comes from a Greek word meaning “to arouse.” Hormones are arouse or bring about their effects on the body’s cells primarily by altering cellular activity—by increasing or decreasing the rate of a normal, or usual metabolic process rather then by stimulating and new one. The changes that follow hormone binding depend on the specific hormone and the target cell type, but typically one or more of the following occurs:

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Despite a huge variety of hormones, there are two mechanisms by which hormones trigger changes in cells: steroid hormone action and nonsteroid hormone action.

Steroid Hormone ActionBeing lipid soluble molecules, the steroid hormones _____________ through the plasma membrane of target cells. The hormone enters the ____________, then binds to a specific _____________ receptor within the nucleus. The hormone receptor complex then __________ to specific sites on the cell’s ________. This in turn _________________ genes that result in synthesis of new proteins.Nonsteroid Hormone Action

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Nonteroid hormones (protein and peptide hormones) are unable to enter the target cells, they instead utilize a second-messenger system. The hormone binds to a membrane ________________. The hormone does not enter the ________. The binding sets off a series of __________________ that activates an enzyme. The enzyme _________________ a reaction that produces a ________________ __________________ molecule. The molecule oversees additional intracellular _______________ to promote a specific response.

Control of Hormone ReleaseHormones levels in the blood are maintained by _______________ feedback mechanisms. A ______________ or _______ hormone levels in the blood triggers the release of more hormone. Hormone release that’s once the appropriate level in the blood is reached. The stimuli that activate the endocrine organs fall into three major categories:

1. __________________

2. __________________

3. __________________

The most common stimulus is a ________________ stimulus, in which endocrine glands are activated by other __________________. For example, hypothalamic hormones stimulate the anterior pituitary gland secrete it’s hormones, and many into your pituitary hormones stimulate other endocrine organ to release their hormones into the blood.

Change of _________ levels of certain ions and nutrients may stimulate hormone release—these stimuli are ___________ stimuli. For example,

the release of parathyroid hormone (PTH) by cells of the parathyroid glands is prompted by decreasing blood calcium levels.

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In isolated cases, nerve fibers anyway, release and the target cells are said respond to ______________ stimuli. In example is the __________________ nervous system stimulation of the entry number below the release norepinephrine epinephrine during periods of stress.The Major Endocrine Organs

The hypothalamus is part of the nervous system, but it’s recognized as a major endocrine organ because it produces several hormones. Although the function of some hormone producing glands it’s purely endocrine, the function of others is mixed.

The _____________ gland is the size of a grape. It hangs by a stalk from the inferior surface of the ______________________. It is protected by the _____________ bone. The gland has two funtional lobes:

______________________________—glandular tissue ______________________________—nervous tissue

There are _____ anterior pituitary hormones. ______ affect none-endocrine targets—the growth hormone and prolactin. The remaining __________stimulate other endocrine glands (tropic hormones: thyrotropic, adrenocorticotropic, and two gonadotropic hormones). Tropic hormones stimulate their target organs, which also endocrine glands, to secrete there hormones, which in turn exert their effects on other body organs and tissues.

Characteristics of all anterior pituitary hormones inclide: ____________________ __________________________________________ ____________________________________________________

________________ _________________ (GH) is a general metabolic hormone. It’s major effects are directed to growth _____________ muscles and _______ bones. It is a protein sparing and anabolic hormone that causes of amino acids to be built into _____________. It also causes _________ to be broken down for a source of ___________ while it spares glucose, helping to maintain a blood sugar homeostasis (Homeostatic Imbalance p. 305).

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_________________ (PRL) stimulates and maintains ___________ production following childbirth. It’s function in ___________ of unknown.

_____________________________ hormone (ACTH) regulates endocrine activity of the adrenal cortex.

_________________- ____________________ hormone (TSH) influences ___________and activity of the thyroid.

_________________________ hormones regulate hormonal activity of the gonads. ___________________-____________________ hormone (FSH) stimulates _____________ development in ______________. It also stimulates __________ development in __________. __________________ hormone (LH) triggers ________________, causes ruptured follicles to become the corpus luteum (progersterone and some estrogen). In males, it’s simulates ___________________—referred to as interstitial cell-stimulating hormone (ICSH) (Homeostaic Imbalance p. 305).

The anterior pituitary gland controls the activity of so many other endocrine glands that it is often been called the “master endocrine gland.” The removal or destruction has a dramatic effect on the body. The adrenal and thyroid glands atrophy. The release of hormones is controlled by _________________ and ________________ hormones produced by the ____________________. The hypothalamus produces ____ hormones (oxytocin and antidiuretic hormone) that are transported by _______________________ cells of the posterior pituitrary. The posterior pituitary id not strictly an endocrine glans, but does release hormones. The posterior pituitary is more of a storage facilty until a nerve impluse is receid from the hypothalmus.

The psoterior pituitary is not strictly an endocrine gland because it does not make hormones, but does release hormones. ________________ is released in large amounts only during child birth, thus _____________________ contractions of the uterus

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during labor. It also causes _______ ejection. Forms of oxytocin (i.e. Pitocin) are used to induce labor. It is also used to stop postpartum bleeding.

Diuresis is urine production. __________________ hormone (ADH) can _____________ urine production. ADH causes the kidneys to reabsorb more water from the forming urine; as a result, urine volume decreaes and blood volume increases. In large amounts, it causes ___________________________________________ leading to increased blood pressure, for this it is sometimes called ____________________. Drinking alcoholic beverages inhibits ADH secretion and results in the output of large amounts of urine. The dry mouth and intense thirst experienced “hangover” reflect this dehydrating effect of alcohol (Homeostatic Imbalance . 307).

The thyroid gland is a hormone-producing gland that is familiar to most people primarily because many ibese individuals blame their overweight condition on their glands. The effect of the thyroid hormones on body weighr is not as great as many believe it to be. The thyroid is found at the base of the ____________, just inferior to the Adam’s apple. It consists of ____ lobes and a connecting isthmus (or central mass). The thyroid produces ____ hormones:

__________________________

__________________________

The thyroid gland is composedc of hollow structures called follicles, which store sticky colloidal material.

Thyroid hormone is often referred to as the body’s major ________________ hormone. It is composed of ___ active ___________-containing hormones:

________________ (T4)—secreted by thyroid follicles _________________________(T3)—conversion of T4 at target

tissuesThyroid hormone controls the rate at which glucose is “burned,” or oxidized, and converted to body heat and chemical energy. All body cells are a target (Homeostatic Imbalance p. 309).

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Calcitonin, also called thyrocalcitonin, _______________ blood calcium levels by causing its deposition on bone. It is ____________________ to parathyroid hormone (PTH). It is produced by c (parafollicular) cells found in the connective tissue between the follicles. It is released directly into the blood in repsonse to increasing levels of blood calcium.

_________________________ glands are tiny masses of glandular tissue most often found on the _______________ surface of the thyroid. There are a totalof ____ glands, usually found two on each lobe of the thyroid. The parathyroid secretes PTH which is the most important regulator of calcium ion homeostasis of te=he blood. PTH is repsonsible for:

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Adrenal GlandsThe adrenal glands are ____ bean-shaped glands that curve over the top of the

_______________. Although the adrenal glands look like a single organ, it is structually and functionally _____ endocrine glands in one:

_______________—outer glandular region in three layers _______________—inner neural tissue region

The adrenal cortex produces ____ major groups of steroid horones collectvely called corticosteroids:

1. _____________________________2. _____________________________3. _____________________________Mineralcorticoid (mainly _______________) is produced in the ____________ adrenal

cortex. It regulates ____________ (sodium and potasiium ions specifically) content in the blood, __________, and ___________________ balance. Their target organ is the kidney tubules that selectively reabsorb the minerals or let them be flushed out with urine. When blood levels of aldosterone rise, the kidney tubule cells reclaim increasing amounts of Na2+ and secrete more K+ into the urine. When sodium is reabsorbed, water follows. Release of aldosterone is stimulated by humoral factors (too few sodium ions, too many potassium ions). Production is stimulated by __________ and angiotensin II. Production is inhibited by atrial natriuretic peptide.

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Glucocorticoids (including _______________ and _______________) are produced in the __________ layer of the adrenal cortex. Gluccocorticoids promote normal cell _____________ and help the body resist __________-__________ _______________ by increasing blood glucose levels. Due to their anti-inflammatory properties, gluccocorticoids are often prescribed as drugs to supress inflammation for patients with rhematoid arthritis. They are released in response toincreased blood levels of ___________.

Regardless of one’s gender, both male and female _______ ________________ are produced by the adrenal cortex throughout life in relatively small amounts. Although the bluk of sex hormones are prouced by the adrenal cortex layer are _____________ (male sex hormones), some ______________ (female sex hormones) are also formed (Homeostatic Imbalance p. 311).

The adrenal medulla, like the posterior pituitary, develops from nervous tissue. When the medulla is stmulated by the sympathetic nervous system neruons, its cells will release ___ similar hormones (catecholamines) into the bloodstream:

______________________ (adrenaline)

_______________________ (noradrenaline)

These hormones prepare the body to deal with _________-________ stress (Homeostatic Imbalance p. 313-14). Catecholamines increase:

____________________________

____________________________

____________________________

____________________________

Pancreatic IsletsThe ____________ is loocated in close proximity to the stomach, and is a _________

gland. The islets of the pancreas produce hormones. Two important hormones produced by the islet cells are:

_______________—allows gluclose to cross plasma membranes into cells from beta cells of the islets (hypoglycemic hormone), it targets all body cells.

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_______________—allows glucose to enter the blood from alpha cells (hyperglycemic hormone, along with gluccocorticoids, and epinephrine), its main target is the liver, causing it to break down stored glycogen to glucose.

These hormones are antagonists that maintain blood sugar homeostasis (Homesostatic Imbalance p. 315).

Pineal GlandThe pineal gland is found in the __________ ventricle of the brain. It secretes

___________________, which is important for making one drowsy at night. It helps establish the body’s _________ and ___________ cycles—found to secrete more melatonin at night, and much less during the day. It may have other as-yet-unsubstantiated functions.

Thymus GlandThe thymus gland is located _____________ to the ___________. It is largest in

___________ and _________________, and decreased in size throughout adulthood. It produces ______________, which is important for maturing some types of ___________ ____________ _________. It is important in developing the ______________ system.

GonadsThe males and female gonads produces sex hormones that are identical to those

produced by the adrenal cortex cells. The femae gonads, or ___________, are paired, almond-sized organs located in the pelvic cavity. Besides producing female sex cells (ova), the ovaries produce ____ groups of steroid hormones:

__________________ __________________

The ovaries do not really begin to function until puberty, when the nanterior pituitary gonadotropic hormones stimulate them into activity.

Estrogens (primarily esterone) is produced by _____________ follicles or the _____________, stimulates the development of _______________ female characteristics (growth and maturation of the reproductive organs and the appearance of hair in th epubic and axillary regions). Estrogens work with progesterone to prepare the uterus to receive a _________________ egg (producing cyclic changes in the uterine lining—

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menstrual cycle). Estrogens also help ________________ pregnancy, and prepares the breasts to produce ___________ (lactation).

Progesterone quiets the muscles of the uterus during pregnancy so the implanted embryo will not be aborted. It is alsoproduced by the corpus luteum.

The paired oval testes of the male are suspended in a sac, the scrotum, outside the pelvic cavity. In addition t making the male sex cells, sperm, the testes also produce male sex hormones , or ______________, of which, ____________________ is the most importnant. Testosterone is made by ______________________ cells of the testes. It is responsible for adult male secondary characteristics (growth of facial hair, developmennt of heavy bones and muscles, lowering of the voice, and stimulates male sex drive). It promotes growth and maturation of male reproductive system. It is required for sperm cell production.

PlacentaThe placenta is a remarkable oran formed temporatily in the uterus of pregnant

women. In addition to its roles as the repiratory, excretory, and nutrition-delivery systems for the fetus, it also produces hormones that maintain the _________________. During very early pregnancy, a hormone callled human chorionic gonadotropic (hCG) is produced by the developing embryo and then by the fetal part of the placenta. hCG stimulates the corpus luteum of the ovary to continue to produce estrogen and progesterone so that the lining of the uterus is not sloughed off in menses.

Developmental Aspects p. 323

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