Animal A&P quiz 7 exam 3

what does the endocrine system do?

work with the nervous system to maintain homeostasis

what are hormones

chemical messengers produced by the endocrine glands and secreted directly into the bloodstream

when do hormones produce effects?

when they find their specific receptors in or on cells

a cell that has receptors for a particular hormone is called a ____

target

what 3 things control hormone secretion?

1. Feedback systems

2. Direct stimulation from nervous system

3. Levels of certain chemicals in the blood

Explain negative feedback

increase of plasma hormones causes the hypothalamus to decrease releasing factors which decrease trophic hormone from the pituitary gland which causes target organ activity and decrease of plasma hormones

what is an example of positive feedback?

oxytocin

What are the major endocrine glands?

hypothalamus, pituitary, thyroid, parathyroid, adrenal, pancreas, testis, and ovaries

what does the hypothalamus control?

appetite control, body temperature regulation, wake-sleep cycles

what is the hypothalamus a bridge between?

the nervous and endocrine system

explain the portal system

modified neurons in the hypothalamus which secrete releasing and inhibiting factors into tiny blood vessels

what does the portal system communicate with?

the anterior pituitary

what do modified neurons in the hypothalamus also produce?

antidiuretic hormones and oxytocin

ADH and Oxytocin are transported to the ____ pituitary and stored

posterior

the master endocrine gland is composed of 2 separate glands which are:

the anterior pituitary and the posterior pituitary

what is the hypothalamic pituitary axis

communicates with the pituitary gland in response to environmental stimuli, changes in homeostasis, and stress, and this neuroendocrine communication is referred to as that

what are the hormones produced from the anterior pituitary

Growth Hormone, Prolactin, TSH, ACTH, FSH, LH

what is prolactin

helps and maintains lactation. release continues as long as the teat is stimulated by nursing/milking

what is the thyroid-stimulated hormone?

stimulates growth and development of the thyroid gland and causes it to produce hormones. regulated by negative feedback from the thyroid gland.

what is the ACTH hormone

stimulates growth and development of the cortex of the adrenal gland and releases some of its hormones. regulated by the negative feedback of the adrenal cortex. can also be released quickly as a result of stimulation of the hypothalamus by other parts of the brain.

what is the follicle-stimulating hormone in females?

stimulates the growth and development of follicles in the ovary. stimulates the lining cells of the follicles to produce and secrete estrogens

what does the follicle-stimulating hormone do in males?

stimulate spermatogenesis

what is the luteinizing hormone in females?

completes the process of follicle development in the ovary. estrogen from the follicle feedbacks on the pituitary and FSH decreases (neg. feedback) and LH increases (pos feedback)

LH peaks resulting in ovulation. After ovulation, LH stimulates cells in the empty follicle to multiple and develop into the corpus luteum.

What is the corpus luteum

produces progesterone which is necessary to maintain pregnancy

What does the luteinizing hormone do in males?

LH stimulates cells in the testes (interstitial cells) to develop and produce testosterone.

What is the posterior pituitary?

-no production of hormones

-stores antidiuretic hormone and oxytocin produced by the hypothalamus

-hormones are released when the posterior pituitary receives nerve impulses from the hypothalamus

what are antidiuretic hormones?

helps prevent the loss of large amounts of water in urine.

antidiuretic hormones cause what?

kidneys to reabsorb more water from the urine- conserves water and concentrates urine

when is antidiuretic hormone released

when the hypothamus detects a water shortage

Deficiency of ADH causes what?

diabetes insipidus

What is oxytocin

causes the uterus to contract at the time of breeding and at partuition. also causes milk let down

where is the thyroid gland located

on either sides of the trachea

what 2 hormones does the thyroid gland produce?

the thyroid hormone and calcitonin

what is the function of calcitonin?

helps lower blood calcium levels

what is the thyroid gland a collection of?

follicles that are lined by simple cuboidal or columnar epithelium

what are the follicles filled with?

cuboidal, gel-like substance that consists of protein/ iodine complex

Thyroid hormone is produced when stimulated by _____ from the ______ pituitary

the thyroid stimulating hormone

from the anterior pituitary gland

calcitonin inhibits what

the action of osteoclasts and works opposit of the parathyroid hormone

what is the parathyroid hormone

helps prevent hypocalcemia. causes kidneys to retain calcium and the intestines to absorb calcium from food. and withdraws calcium from the bones

what are adrenal glands

small glands located near the cranial ends of the kidneys. consists of the adrenal cortex and the adrenal medulla

what is the adrenal cortex?

develops from glandular tissue.

The adrenal cortex Production stimulated by ____ from the ________ pituitary

by the ACTH

from the anterior

what is glucocorticoid hormones

includes cortisol and corticosterone

-hyperglycemic effect

-helps maintain blood pressure and helps body resist the effects of stress

deficiency of insulin results in

diabetes mellitus

majority of each testis is composed of

coiled seminiferous tubules

glucagon opposed what

insulin

increases blood glucose levels by acting on the liver to convert glycogen to glucose

what is the overall effect of insulin

to lower blood glucose levels

true or false the pancreas has both endocrine and exocrine functions

true

the adrenal medulla produces what?

epinephrine and norepinephrine

what is addisons disease

deficiency of aldosterone

results in dehydration, sodium depletion, and potassium excess