Chapter 6 - Endocrinology Flashcards
chemical regulation in animals
endocrine system acts as a means of
internal communication
coordinates activities of organ systems
endocrine glands
synthesize and secrete hormones directly into circulatory system
hormones
chemical substances synthesized by endocrine glands
secreted directly into circulatory system
exocrine glands
e.g. gall bladder
secrete substances that are transported by ducts
glands that synthesize/secrete hormones
(13)
pituitary
hypothalamus
thyroid
parathyroids
adrenals
pancreas
testes
ovaries
pineal
kidneys
gastrointestinal
heart
thymus
hormones may regulate
single type of cell or organ
or
widespread actions
specificity of hormonal action usually determined by
presence of specific receptors on or in target cells
adrenal glands
structure
location
on top of kidneys
adrenal cortex + adrenal medulla
adrenal cortex
(makes up part of adrenal glands)
in response to stress, ACTH stimulates adrenal cortex to synthesize and secrete corticosteroids
ACTH
produced by anterior pituitary
stimulates adrenal cortex to synthesize and secrete cortiocosteroids
corticosteroids
steroids hormones
synthesized and secreted by adrenal cortex
corticosteroids
(3)
glucocorticoids
mineralocorticoids
cortical sex hormones
corticosteroids derived from
cholesterol
glucocorticoids
fxn
glucose regulation
protein metabolism
glucorticoids
examples (2)
cortisol
cortisone
glucocorticoids raise blood glucose levels by
promoting:
protein breakdown
gluconegenesis
decreasing:
protein synthesis
glucocorticoids and insulin
glucocorticoids raise plasma glucose levels
and are
antagonistic to effects of insulin
gluconegenesis
metabolic pathway that results in the generation of glucose from non-carbohydrate carbon substrates such as lactate, glycerol, and glucogenic amino acids
one of the two main mechanisms humans and many other animals use to keep blood glucose levels from dropping too low
two main mechanisms humans and many other animals use to keep blood glucose levels from dropping too low
gluconegenesis
glycogenolysis
mineralocorticoids
aldosterone
fxn
regulate plasma levels of sodium, potassium
consequently, total extracellular water volume
aldosterone
(mineralocorticoids)
causes active reabsorption of sodium and passive reabsorption of water in the nephron
—> rise in blood volume + blood pressure
nephron
basic structural and functional unit of the kidney
regulate concentration of water and soluble substances (sodium salts) by filtering the blood, reabsorbing what is needed and excreting the rest as urine
eliminates wastes from the body
regulates blood volume and blood pressure
controls levels of electrolytes and metabolites
regulates blood pH
excess production of aldosterone results in
excess retention of water
resulting hypertension (high blood pressure)
cortical sex hormones
adrenal cortex secretes small quantities of adrogens
(male and female)
small physiologic effect
adrogens
male sex hormones
adrogens secreted by adrenal cortex
adrostenedione
dehydroepiandrosterone
in males, most androgens produced by
testes
in females, overproduction of adrenal androgens may
have masculinizing effects
e.g. excessive facial hair
adrenal medulla
(adrenal gland)
produces epinephrine (adrenaline)
and norepinephrine (noradrenaline)
catecholamines
amino acid-derived compounds
includes:
norepinephrine
epinephrine
epinephrine
(adrenal medulla)
increases conversion of glycogen to glucose in liver and muscle tissue
causes rise in blood glucose —> increase in basal metabolic rate
type of catecholamine
both epinephrine and norepinephrine increase
rate and strength of heartbate
dilate and constrict blood vessels to incerase blood supply to skeletal muscle, heart, brain
decrease blood supply to kidneys, skin, digestive tract
fight or flight response
description
increase rate and strength of heartbeat
dilate, constrict blood vessels to:
increase blood supply to skeletal muscle, heart, brain
decrease blood supply to kidney, skin, digestive tract
fight or flight response elicited by
sympathetic nervous stimulation in response to stress
epinephrine inhibits
“vegetative” functions e.g. digestion
not immediately important for survival
epinephrine and norepinephrine
examples of
neurotransmitters
release of adrenal corticol hormones controlled by
adrenocorticotrophic hormone (ACTH)
adrenocorticotrophic hormone (ACTH) secreted by
anterior pituitary gland
adrenocorticotrophic hormone (ACTH) stimulates production of
glucocorticoids and sex steroids
Pituitary gland
(hypophysis)
structure
small, tri-lobed gland at base of brain
lobes - anterior, posterior, intermediate
(intermediate in humans - rudimentary)
anterior pituitary
fxn
(pituitary gland)
synthesizes direct hormones and tropic hormones
direct hormones
(synthesized by anterior pituitary)
directly stimulate target organs
tropic hormones
(anterior pituitary)
stimulate other endocrine glands to release hormones
hormonal secretions of anterior pituitary regulated by
hypothalamic secretions called releasing/inhibiting hormones or factors
hypothalamic secretions which regulate hormonal secretions of anterior pituitary are called
releasing/inhibiting hormones/factors
direct hormones
types
(anterior pituitary - synthesis of hormones)
- growth hormone
- prolactin
grwoth hormones (GH, somatotropin)
fxn
(direct hormones - anterior pituitary)
promotes bone and muscle growth
dwarfism caused by
(direct hormones - anterior pituitary)
GH deficiency in children
gigantism caused by
overproduction of GH in children
acromegaly caused by..
also, definition
(direct hormone - anterior pituitary)
overproduction of GH in adults
disproportionate overgrowth of bone
localized - skull, jaw, feet, hands
prolactin
(direct hormones - anterior pituitary)
stimulates milk production and secretion in female mammary glands
tropic hormones
types
(anterior pituitary - synthesis)
- adrenocorticotropic hormone (ACTH)
- thyroid-stimulating hormone (TSH)
- luteinizing hormone (LH)
- follicle-stimulating hormone (FSH)
- melanocyte-stimulating hormone (MSH)
FLAT PiG M
FSH
LH
ACTH
TSH
Prolactin
ignore
Growth hormone
MSH
adrenocorticotropic hormone
(ACTH)
(tropic hormone - anterior pituitary)
stimulate adrenal cortex to synthesize and secrete glucocorticoids
ACTH regulated by
releasing hormone corticotrophin releasing factor (CRF)
Thyroid-stimulating hormone (TSH)
stimulates thyroid gland to synthesize and release thyroid hormone
e..g thryoxin
luteinizing hormone (LH)
females
stimulates ovulation and formation of corpus luteum
luteinizing hormone (LH)
males
stimulates interstitial cells of testes to synthesize testosterone
follicle-stimulating hormone
(FSH)
females
causes maturation of ovarian follicles which begin secreting estrogen
follicle-stimulating hormone (FSH)
males
stimulates maturation of seminiferous tubules and sperm production
melanocyte-stimulating hormone (MSH)
secreted by intermediate lobe of pituitary
fxn in mammals unclear
melanocyte-stimulating hormone (MSH)
fxn in frogs
causes darkening of the skin via
induced dispersion of molecules of pigment in melanopore cells
posterior pituitary (neurohyphosis)
fxn
does NOT synthesize hormones
stores and releases peptide hormones: oxytocin and ADH