ANATB - Endocrine Glands I

why is the anterior pituitary gland considered the master endocrine gland?

because it controls the activity of so many other glands

pituitary gland is split into

anterior pituitary and the posterior pituitary

how does the hypothalamus control the release of hormones from the anterior pituitary gland?

by releasing/inhibiting hormones from the hypothalamus b/c their blood supplies are connected

what is the relationship between the posterior pituitary gland and the hypothalamus, why is the posterior pituitary not considered a gland

the posterior pituitary is not an endocrine gland because it doesn’t make the hormones it releases, it is a storage area for hormones from the hypothalamus

released only during childbirth and nursing from the posterior pituitary gland, stimulates powerful contractions of the uterus

oxytocin

released by the posterior pituitary gland, inhibits or prevents urine production, controls kidneys

antidiuretic hormone (or vasopressin)

how does antidiuretic effect urine and blood pressure?

causes the kidneys to reabsorb water from forming urine, preventing it, and increasing blood volume

what kind of effect does alcohol have on antidiuretic hormone

it inhibits antidiuretic secretion and results in large outputs of urine

what are diuretics, what are they used for?

a type of drug, used to clear extra fluid out and bring down blood pressure

6 anterior pituitary hormones and what they effect

1. growth (GH, bone and muscle)

2. prolactin (PRL, mammary glands)

3. follicle-stimulating (FSH, testes or ovaries)

4. luteinizing (LH, testes or ovaries)

5. thyrotropic (TH, thyroid)

6. adrenocorticotropic (ACTH, adrenal cortex)

which pituitary hormones exert effects on non-endocrine targets?

growth hormones and prolactin hormones

which pituitary hormones are topic hormones (stimulate other endocrine glands)

1. follicle-stimulating

2. luteinizing

3. thyrotropic

4. adrenocorticotropic

a general metabolic hormone, major effects are directed to growing skeletal muscles and bones, stimulates target cells to grow and divide, breaks down fats

growth hormone (GH)

what are some potential uses of GH and the pros/cons of these uses

pros: body fat decreases, bone density + muscle mass increase, boosts immune system, may reverse some effects of aging.

cons: edema, high blood sugar, hypertension, diabetes, cancer

structurally similar to growth hormone, only target is the breasts, stimulates and maintains milk production

prolactin (PRL)

in women, stimulates follicle development in the ovaries, which produce estrogen. in men, stimulates sperm development

follicle-stimulating hormone (FSH)

in women, triggers ovulation of an egg, produces progesterone and some estrogen. in men, stimulates testosterone production

luteinizing hormone (LH)

stimulates growth and activity of the thyroid gland

thyrotropic hormone (TH), also called thyroid-stimulating hormone (TSH)

regulates endocrine activity of the cortex portion of the adrenal gland

adrenocorticotropic hormone (ACTH)

hyposecretion of FSH or LH leads to

sterility

when hypersecretion of GH occurs after bone growth has ended, causing bones in face and hands to enlarge, usually caused by tumors in the effected endocrine gland

acromegaly

hypersecretion of GH causes

gigantism

hyposecretion of GH causes

pituitary dwarfism

hyposecretion of ADH leading to excessive urine output, drinking huge amounts of water, and continuous thirst

diabetes insipidus

small, cone shaped gland that hangs from the roof of the third ventricle of the brain, secretes melatonin

pineal gland

rises and falls during the day and night, highest at night making us drowsy, lowest at noon, establishes sleep-wake cycle, can inhibit reproductive system

melatonin

located at the base of the throat, 2 lobes, makes thyroid hormone and calcitonin, composed of hollow structures called follicles

thyroid gland

the body’s major metabolic hormone (actually 2 hormones. T3 and T4), made from iodine, controls how fast glucose is oxidized and converted to body heat or chemical energy (ATP). targets every cell in the body

thyroid hormone

an enlargement of the thyroid gland that results when a diet is deficient in iodine

goiter

hyposecertion of thyroxine from the thyroid gland in children can lead to ___ this may be fixed in children with hormone replacements

cretinism

hypothyroidism in adults, causes physical and mental slugishness, fatigue, poor muscle tone and low body temp, usually results for a tumor in the thyroid gland

myzedema

second important hormone of the thyroid gland, decreases blood calcium ion by depositing calcium in bones

calcitonin

tiny masses of glandular tissue often found on the posterior surface of the thyroid gland, secrete PTH

parathyroid glands

the most important regulator of calcium ion homeostasis of the blood, stimulates bone destruction cells to break down bone matrices to release blood

parathyroid hormone (PTH)

how does parathyroid hormone contrast with calcitonin

PTH is hypercalcemic, it increases blood level of calcium ions, calcitonin is hypocalcemic, it decreases blood level of calcium ions

what happens when blood calcium ion level falls too low? what is this called?

neurons become extremely irritable and overactive, muscles go into uncontrollable spasms that can be fatal, causes massive bone destruction. hyperparathyroidism