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Chapter 7
Introduction to the Endocrine System
40
Physiology
Undergraduate 3
09/08/2015

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Term
endocrinology
Definition
the study of hormones
Term
3 basic ways that hormones act on their target cells
Definition
1. controlling the rates of enzymatic reactions
2. controlling the transport of ions or molecules across cell membranes
3. controlling gene expression & the synthesis of proteins
Term
3 classic steps for identifying an endocrine gland once a structure is suspected of secreting hormones
Definition
1. remove the suspected gland
2. replace the hormone
3. create a state of hormone excess
Term
hormone
Definition
a chemical secreted by a cell or group of cells into the blood for transport to a distant target, where it exerts its effect at very low concentrations
Term
pheromones
Definition
specialized ectohormones that act on other organisms of the same species to elicit a physiological or behavioral response
Term
growth hormones
Definition
a large group of substances that influence cell growth & division
Term
cellular mechanism of action
Definition
the biochemical responses initiated when hormones bind to target cell receptors
Term
half-life
Definition
the amount of time required to reduce the concentration of hormone by one-half; the indicator for the rate of hormone breakdown
Term
preprohormones
Definition
contain one or more copies of a peptide hormone, a signal sequence that directs the protein into the lumen of the rough endoplasmic reticulum, & other peptide sequences that may or may not have biological activity
Term
prohormone
Definition
a small, inactive molecule created by the removal of the signal sequence from an inactive preprohormone as it moves through the endoplasmic reticulum
Term
adrenal cortex
Definition
the outer portion of the adrenal glands that makes several types of steroid hormones
Term
Where are the adrenal glands located?
Definition
one sits atop each kidney
Term
Where is cortisol produced?
Definition
adrenal cortex
Term
Steroid hormone receptors enable those steroid hormones to initiate rapid _____ in addition to their slower genomic effects
Definition
nongenomic responses
Term
What is melatonin derived from?
Definition
tryptophan
Term
catecholamines
Definition
neurohormones that bind to cell membrane receptors the way peptide hormones do
Term
What type of hormones do thyroid hormones act like?
Definition
steroid hormones
Term
parathyroid hormone
Definition
controls calcium homeostasis; an example of a hormone that uses a simple endocrine reflex
Term
pituitary gland
Definition
a lima bean-sized structure that extends downward from the brain, connected to it by a thin stalk & cradled in a protective pocket of bone
Term
Is the anterior pituitary a true endocrine gland of epithelial origin?
Definition
yes!
Term
The posterior pituitary is an extension of _____
Definition
neural tissue of the brain
Term
vasopressin
Definition
acts on the kidneys to regulate water balance in the body
Term
oxytocin
Definition
released from the posterior pituitary in women that controls the ejection of milk during breast-feeding & contractions of the uterus during labor & delivery
Term
trophic hormones
Definition
hormones that control the secretion of other hormones
Term
2 other names for "somatostatin"
Definition
1. growth hormone-inducing hormone
2. somatotropin release-inhibiting hormone
Term
prolactin
Definition
an anterior pituitary hormone that controls milk production in the female breast
Term
growth hormone
Definition
affects metabolism of many tissues in addition to stimulating hormone production by the liver
Term
gonadotropins
Definition
act on the testes & ovaries
Term
thyroid-stimulating hormone (TSH)
Definition
controls hormone synthesis & secretion in the thyroid gland
Term
adrenocorticotrophic hormone (ACTH)
Definition
acts on certain cells of the adrenal cortex to control synthesis & release of the steroid hormone cortisol
Term
In hypothalamic-pituitary pathways, the dominant form of feedback is _____, where the hormone secreted by the peripheral endocrine gland "feeds back" to suppress secretion of its anterior pituitary & hypothalamic hormones
Definition
long-loop negative feedback
Term
short-loop negative feedback
Definition
when a pituitary hormone feeds back to decrease hormone secretion by the hypothalamus
Term
synergism
Definition
the type of interaction where two (or more) hormones interact at their targets so that the combination yields a result that is greater than additive
Term
permissiveness
Definition
one hormone cannot fully exert its effects unless a second hormone is present, even though the second hormone has no apparent action
Term
Most instances of hormone excess are due to _____
Definition
hypersecretion
Term
atrophy
Definition
the loss of cell mass
Term
hyposecretion
Definition
when too little hormone is secreted; leads to symptoms of hormone deficiency
Term
hyperinsulinemia
Definition
a type of down-regulation in the endocrine system; a disorder where sustained high levels of insulin in the blood cause target cells to remove insulin receptors from the cell membrane
Term
primary pathology
Definition
a pathology (deficiency or excess) that arises in the last endocrine gland in a complex reflex pathway
Term
secondary pathology
Definition
when the dysfunction occurs in the anterior pituitary
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