Chapter 11 Study guideA&P: Endocrine System

How does negative feedback control the release of these hormones?

CRH from the hypothalamus causes the pituitary to release ACTH. ACTH in turn stimulates release of glucocorticoids. When a high level of glucocorticoids is present, they inhibit further release of CRH, and slow down or stop their own synthetic pathway.

What do Lutenizing Hormones do?

Causes ovulation and formation of corpus luteum in the ovary

How many parathyroid glands are there and where are they found?

Four: located on the back of the thyroid gland

Thyroxine (T4): How many iodine atoms does it contain? Triiodothyronine (T3): How many iodine atoms does it contain?

Four; Three

____ hormones combine with receptors on target cell ______; the receptors have a ______ site and a/an ______ site. The hormone-receptor complex (as first messenger) triggers a cascade of biological activity.

Non-Steroid; membranes; binding; activity

What factors influence growth besides GH?

Nutritional status, genetics

Explain in general how negative feedback works.

When the concentration of a regulated substance reaches a certain level, the gland is inhibited from secreting more hormone.

How do they affect the release of TSH?

When these hormones reach a high level, the release of TSH is inhibited

What effects do epinephrine and norepinephrine have on the body?

Similar effects to those of the sympathetic division of the autonomic nervous system: increase in heart rate & breathing rate, decrease in digestive activities

How many hormones does it secrete?

Six

_______ hormones are lipid-soluble and can pass through cell membranes. Their receptors are located in the target cell's ______.

Steroid; nucleus

How causes the need of PTH?

Stimulates osteoclasts in bone which break down bone tissue and release calcium into the blood; it also influences the kidneys to conserve calcium

What effect does it have on males? On females?

Stimulates sperm production in the testes; Stimulates development of ovarian follicles, secretion of estrogens

What else can trigger glucocorticoid release? Name an important Glucocorticoid. Which zone secretes these hormones?

Stress , injury, or disease; cortisol; middle zone

What are epinephrine and norepinephrine secreted in response to?

Stress and "fight or flight" situations

The hormones secreted are the same as neurotransmitters of this system, but are called hormones because they are secreted into the _______.

blood

The endocrine system is made up of what?

cells, tissues, and organs that secrete hormones into body fluids such as the blood stream

Insulin __________ the blood levels of glucose by stimulating the liver to form __________, increasing __________ synthesis, and stimulating adipose cells to store _____.

decreases; glycogen; protein; fat

The pancreas secretes hormones as an _________ gland, and digestive juices into the digestive tract as an __________ gland. Where is the pancreas located? Behind and beneath the stomach

endocrine; exocrine

The adrenal cortex makes up most of the adrenal glands and consists of _______ cells in three layers— an outer, middle, and an inner zone.

epithelial

The anterior pituitary consists mostly of ________ tissue arranged around blood vessels and enclosed in a capsule of collagenous _______ tissue.

epithelial; connective

The thyroid consists of secretory parts called _______, filled with hormone-storing ________.

follicles; colloid

The digestive glands secrete hormones associated with the processes of digestion. The _________ secretes atrial natriuretic peptide, which affects sodium excretion, and the kidneys secrete ___________ for red blood cell production.

heart; erythropoietin

Factors that serve as stressors to the body produce stress and threaten ___________

homeostasis

The posterior pituitary releases hormones into the bloodstream in response to nerve impulses from the ______.

hypothalamus

Responses to stress are designed to maintain homeostasis. The __________ controls the general stress syndrome, which involves increased sympathetic activity and increased secretion of which hormones?

hypothalamus; Epinephrine, cortisol, glucagon, growth hormone, and antidiuretic hormone.

The brain controls the activity of the pituitary gland in two ways: Releasing hormones from the _______ control the secretions of the anterior pituitary and are carried in the bloodstream by ________ veins.

hypothalamus; hypophyseal portal

Glucagon _______ the blood levels of glucose by stimulating the breakdown of ________ and the conversion of noncarbohydrates into ________.

increases; glycogen; glucose

Other glands respond directly to changes in the composition of the _____ environment.

internal

The pancreas' endocrine portions are the pancreatic ______ that include two cell types--______cells that secrete glucagon, and ______ cells that secrete insulin.

islets; alpha; beta

The adrenal glands sit atop the _____, enclosed in a layer of _______.

kidneys; fat

The hormone aldosterone controls the levels of _sodium__ ions by conserving them in the _____. It also causes the excretion of _____ ions.

kidneys; potassium

The thyroid gland is located below the ______ and consists of two broad _______ connected by an ________.

larynx; lobes; isthmus

Transcription of a specific gene results in the synthesis of a molecule of ____, which in turn, directs the synthesis of a specific _____.

mRNA; Protein

The pineal gland, near the upper portion of the thalamus, secretes _________, which is involved in the regulation of __________ rhythms of the body.

melatonin; circadian

There are several ways in which hormone release is very closely regulated. All of these mechanisms use ______ ________.

negative feedback

The posterior lobe consists of ______ fibers and supporting ______ cells arising in the hypothalamus.

nerve; neuroglial

The adrenal medulla is made up of modified _________ that are connected to the _______ nervous system.

post-ganglionic neurons; sympathetic

The thymus gland, lying between the lungs under the ___________, secretes _________, which affect production and differentiation of T lymphocytes that are important in ________.

sternum; thymosins; immunity

Glucocorticoids influence the metabolism of glucose, protein, and fat in response to conditions that ______ the body and require a greater supply of ______ in the bloodstream.

stress; glucose

Sex hormones, produced in the ________, are mostly of the ____ ______, called _androgens_, but can be converted to __________ hormones, called _________, in the skin, liver, and adipose tissues. ** These hormones supplement those released by the gonads, and may stimulate early development of reproductive organs.

**adrenal sex hormones inner zone; male type; androgens; female; estrogens

What is a goiter and what may cause one?

A goiter is an enlarged thyroid gland that is usually caused by lack of iodine. Without iodine, the thyroid cannot make T3 and T4, and thus nothing inhibits the release of TSH. The excess TSH continues to over- stimulate the thyroid, causing it to grow abnormally and produce a goiter.

What controls the levels of glucagon in the blood?

A negative feedback system; low blood glucose level stimulates glucagon secretion

What is the target organ for ACTH?

Adrenal Cortex

How are these hormones from the hypothalamus regulated?

As the level of circulating thyroid hormones fall, the hypothalamus secretes TRH. When the levels of circulating thyroid hormones are at a rising level, the hypothalamus stops secreting TRH.

What is the name of the hormone from the hypothalamus that controls the release of ACTH?

Corticotropin- releasing Hormone (CRH)

What hormone does it affect the release of?

Cortisol

The hormone-receptor complex binds with the _____ and activates specific ______.

DNA; GENES

What disorder may result if ADH is not secreted in sufficient quantities?

Diabetes insipidus

What is the difference between an endocrine gland and an exocrine gland?

Endocrine glands secret hormones into the body fluids; exocrine glands secrete hormones outside of the body

The ovaries produce what two hormones? What hormones does the placenta produce? The testes produce __________.

Estrogen and progesterone; Estrogen, progesterone, and gonadotropin; testosterone

The hormone receptor complex activates a protein in the cell membrane, called a _____.

G-protein

Which hormones from the hypothalamus control the levels of GH?

GH-Releasing Hormone and GH_Release-Inhibiting Hormone

Which hormone from the hypothalamus affects its release?

Gonadotropin-Releasing Hormone

What is the controlling hormone for LH from the hypothalamus called?

Gonadotropin-releasing hormone

What are the target organs for FSH?

Gonads (testes or ovaries)

What controls the blood level of insulin?

High blood glucose level

Why are mineralocorticoids important? Which zone secretes mineralocorticoids?

Important in homeostasis of the body, maintaining electrolyte and water balance, and maintaining normal blood volume and pressure; Outer zone

How is LH different in males than in females?

In males it stimulates the testes to release testosterone

What are the functions of this hormone ?

It causes contraction of the uterine walls during childbirth, and milk letdown during breast feeding

What is the function of ADH?

It causes the kidneys to conserve water

What part of the thyroid secretes calcitonin?

It is secreted by the extrafollicular cells of the thyroid

What is the function of calcitonin?

It lowers blood levels of calcium and phosphate ions

What is the function of GH?

It stimulates body cells to grow and reproduce

The ________ system influences certain endocrine glands directly with impulses.

Nervous

How is it related to calcitonin from the thyroid?

PTH and Calcitonin have opposite effects and work together to maintain the correct levels of calcium ions in the blood

What function do most of them have in common?

Several stimulate other endocrine glands

Which hormones of the hypothalamus control the secretion of PRL?

Prolactin release-inhibiting hormone, and prolactin releasing factor

What is the function of PRL?

Promotes milk production in lactating women

What does psychological stress result from?

Real or perceived dangers, anger, fear, anxiety, personal loss

Prostaglandins are locally-produced lipids that affect the organ in which they are produced, with a variety of effects. What are some of these effects?

Relax or contract smooth muscle, stimulate secretion, influence blood pressure, affect reproductive physiology

Out of T3 and T4, which is more potent?

T3

Each hormone acts only on specific cells in the body called?

Target Cells

What is its target tissue?

The breasts

What structure actually produces the hormones released by the posterior pituitary?

The hypothalamus

What is the name of a common second messenger?

The most common second messenger is cAMP

What is its target organ?

The thyroid gland

What is the function of T3 and T4?

They increase metabolic rate in many cells

Stress may be physical, psychological, or some combination of the two. What effects does physical stress have on the body?

Threatens the survival of tissues and life

What hypothalamic hormones affect its release?

Thyrotropin-Releasing Hormone (TRH)

What is the function of the endocrine system?

To control certain physiological activities and help maintain homeostasis

What is the function of PTH?

To increase blood calcium levels

What is the function of TSH?

To stimulate the thyroid gland to secrete thyroid hormones

What disorders may result from a lack of or too much GH?

Too little: pituitary dwarfism. Too much: gigantism, acromegaly

The hypothalamus regulates the _____ ________ gland's release of hormones.

anterior pituitary

The pituitary gland is attached to the base of the brain and has a front lobe called the ______ ______ and a rear lobe called the ____ ______.

anterior pituitary; posterior pituitary