Anatomy & Physiology Exam 3 (MSU VMT) #1

primary function is to produce hormones to maintain homeostasis

endocrine system

__________ act on specific target cells to produce specific effects

hormones

chemical messengers produced by endocrine glands and secreted directly into blood vessels

hormones

_______ produce effects when they find their specific receptors in or on cells

hormones

a cell that has receptors for a hormone is referred to as a _________ of that hormone

target

direct stimulation from the nervous system

hormone secretion

secretion of some hormones is stimulated by ___________ nerve impulses when an animal feels threatened

sympathetic

The control of hormone secretion is related to an animals _____ ___ ____ response

fight or flight

Negative feedback systems are when the level of specific hormone does what?

drops below needed levels, the appropriate endocrine gland is stimulated to produce more hormone.

In negative feedback systems- once the proper hormone level is present in the bloodstream stimulation of that endocrine gland is?

reduced and production of that hormone is reduced.

what are the major endocrine glands

anterior pituitary, posterior pituitary, thyroid, parathyroid, adrenal cortex, adrenal medulla, pancreas, testis, ovary

controls activities of the pituitary gland

hypothalamus

_________ of blood vessels links hypothalamus with anterior portions of pituitary gland

portal system

_____________ in the hypothalamus secrete releasing and inhibiting factors into portal blood vessels

modified neurons

two separate gland with different structures, functions, and embryological origins

pituitary gland

the anterior pituitary is the __________:_______ portion

adenohypophysis; rostral portion

stimulated by hypothalamus and direct feedback from target organs and tissues to produce in hormones

anterior pituitary

The posterior pituitary is the _______;______ portion

neurohypophysis; caudal portion

stores and releases hormones produced in hypothalamus

posterior pituitary

What are the anterior pituitary hormones?

growth hormone, prolactin, thyroid stimulating, adrenocorticotropic, follicle-stimulating, luteinizing hormone, melanocyte-stimulating

promotes body growth in young animals; helps regulate metabolism of proteins, carbohydrates, and lipids in all the body's cells

growth hormone

helps trigger and maintain lactation

prolactin

how is prolactin stimulated?

nursing

When prolactin stimulation stops what happens?

milk production stops, and the mammary gland shrinks back to its nonlactating size.

stimulates release thyroid hormones

thyroid stimulating hormone

secretion of TSH is regulated by feedback from the __________ gland

thyroid

stimulates growth and development of the adrenal cortex and release of some of its hormones

adrenocorticotropic hormone

can also be released quickly as a result of stimulation of the hypothalamus by other parts of the brain

ACTH

______ sends a burst of ACTH-releasing factor to the anterior pituitary through the portal system causing ACTH to be released quickly

hypothalamus

stimulates growth and development of ovarian follicles- oogenesis

follicle stimulating hormone

What does follicle stimulating hormone stimulate?

spermatogenesis

complete process of follicle development in ovary

luteinizing hormone

increasing amounts of estrogens feedback to the anterior pituitary and cause reduced production of ______ and increased production of _____

FSH and LH

___ levels reach a peak when follicle is fully mature: usually causes ovulation

LH

after ____________, LH stimulates cells in the empty follicle to multiply and develop into the corpus luteum

ovulation

produces progestin hormones necessary for the maintenance of pregnancy

corpus luteum

in the _______, LH stimulates interstitial cells to develop and produce testosterone

male

stores two hormones produced in the hypothalamus

posterior pituitary

what are the two hormones of posterior pituitary?

antidiuretic hormone and oxytocin

The antidiuretic hormone and oxytocin are transported from hypothalmus to

posterior pituitary and stored in nerve endings

Antidiuretic hormone and oxytocin are periodically released into the bloodstream in response to

t nerve impulses from hypothalmus

helps prevent diuresis

antidiuretic hormone (ADH)

How does the antidiuretic hormone help prevent diuresis?

•eceptors in hypothalamus detect changes in osmotic pressure of blood that result from dehydration/hemoconcentration

what causes the release of ADH?

generates nerve impulses

travels to the kidney- causes kidneys to reabsorb more water from the urine and return it to the bloodstream

ADH

effect on uterus- causes contraction of the myometrium at the time of breeding and at parturition

oxytocin

induced uterine contractions that aid transport of spermatozoa to the oviducts and stimulates uterine contractions that aid in the delivery of the fetus and placenta

oxytocin

effect on mammary gland- causes movement of milk down to the lower parts of the gland

oxytocin

Stimulation by nursing or milking causes ________ to be released

oxytocin

consists of two lobes on either side of larynx

thyroid gland

thyroid hormones is produced in _______

follicles

What are the thyroid hormones?

thyroxine (T4) and triiodothyronine (T3)

When are thyroid hormones produced?

when TSH from anterior pituitary reaches the thyroid gland

T4 is produced in greater abundance than T3 but is mostly converted to T3 before producing effects on target cells

true

1 multiple choice option

influences development and maturation of CNS; growth and development of muscles and bones, regulates the metabolic rate of all the body, and allows animals to generate heat and maintain internal body temperature

thyroid hormones

produced by C cells located between thyroid follicles; helps maintain blood calcium levels

calcitonin

calcitonin prevents _______ by encouraging excess calcium to be deposited in the bones

hypercalcemia

involved in muscle contraction, blood clotting, milk secretion, and formation and maintenance of skeleton

calcium

produced by parathyroid glands; helps maintain blood calcium levels

parathyroid hormone

how does parathyroid hormone prevents hypocalcemia?

it causes kidneys to retain calcium and intestine to absorb calcium from food; withdraws calcium from bones

located near the cranial end of the kidneys

adrenal glands

what are the two glands of the adrenal glands?

adrenal medulla and adrenal cortex

produces numerous steroid hormones

adrenal cortex

what are the 3 main groups of steroid hormones that the adrenal cortex produces?

glucocorticoids, mineralocorticoids, and sex hormones

help maintain blood pressure and help the body resist the effects of stress

glucocorticoids

what is a glucocorticoids?

cortisol. cortisone, and corticosterone

regulate the levels of important electrolytes in the Body

mineralocorticoids

what is a mineralocorticoids?

aldosterone

what are sex hormones?

androgens and estrogens

Produces Epinephrine & norepinephrine

adrenal medulla

Secretion is controlled by the sympathetic portion of the ______ _____ ______ which is the animals fight or flight response

autonomic nervous system

increases heart rate and output, increase blood pressure, dilates air passageways in the lungs, and decreases GI function

adrenal medulla

located near the duodenum, has both exocrine and endocrine functions

pancreas

small percentage of the total volume of the pancreas

endocrine component

group of cells scattered throughout the pancreas

islets of langerhans

produce glucagon

alpha cells of pancreas

produce insulin

beta cells of pancreas

produce somatostatin

delta cells of pancreas

lowers blood glucose levels by causing glucose, amino acids, and fatty acids to be absorbed into body cells

insulin

lowers blood glucose levels by stimulating liver cells to convert glycogen to glucose and by stimulating gluconeogenesis

glucagen

inhibits secretion of insulin, glucagon, and GH; diminishes GI activity

somatostatin

clumps of endocrine cells in testes

interstitial cells

produce androgens when stimulated by LH

testes

primary androgen of testes

testosterone

provides development of male secondary sex characteristics and accessory sex glands and autonomic nervous system

testosterone

produce ova and hormones in cycles

ovaries

what are the ovaries controlled by?

FSH and LH

hormone groups produced in the ovaries

estrogens and progestins

FSH stimulates ovarian follicles to develop

estrogen

Cells of follicles produce and release ?

estrogens

Amount of estrogen produced ____________ as follicle grows

increases

1 multiple choice option

increasing estrogen levels accelerate _________ and _______ changes

physical and behavioral

Estrogens Feedback to anterior pituitary causes?

anterior pituitary gland to reduce the production of FSH and increase the production of LH

When follicle is fully mature, LH level peaks. In most animal species ovulation occurs when

LH level peaks

group of hormones produces by corpus luteum

progestins

High LH level stimulates cells of empty follicle to

multiply and develop into corpus luteum

principal progestin

progesterone

helps prepare uterus to receive the fertilized ovum; needed to maintain pregnancy

progesterone

Prpgestins-- In pregnant female, hormone signal is sent from uterus, and corpus luteum is

maintained

if no pregnancy occurs, lack of hormone signal causes corpus luteum to

shrink and disappear