ch. 17 exam review questions Flashcards
endocrine system
reacts slowly (sec or days)
effect may continue for days or longer
adapts slowly to long term stimuli
general widespread effects
nervous system
reacts quickly (Ms timescale)
stops quickly
adapts quickly to long term stimuli
targeted and specific
hormone
chemical messengers that travel in the bloodstream to stimulate physiological responses in other tissues and organs
endocrinology
study of endocrine system and the diagnosis and treatment of its disorders
endocrine gland
organs that are sources of hormones
no ducts
contain dense, fenestrated capillary networks which allow easy uptake of hormones into bloodstream
“internal secretions”
intracellular effects such as altering target cell metabolism
exocrine gland
have ducts
carry secretion to an epithelial surface or the mucosa of the digestive tract “external secretions”
extracellular effects (food digestion)
how hormones are transported in blood
hormones communicate with the body by heading towards their target cell to bring about a particular change/effect to that cell
steroid hormones
derived from cholesterol
sex steroids from gonads and corticosteroids from adrenals
monoamine hormones
made from amino acids
catecholamines, melatonin, thyroid hormone
peptide hormones
created from chains of amino acids
ex include hormones from both lobes of the pituitary, and releasing and inhibiting hormones from hypothalamus
insulin is a large peptide hormone
all hormones are made either
amino acids or cholesterol
gonadotropin releasing hormone (GnRH) stimulates release of
gonadotropins (FSH, LH)
thyrotropin releasing hormone stimulates release of
TSH
corticotropin releasing hormone stimulates release of
adrenocorticotropic hormone (ACTH, corticotropin)
prolactin inhibiting hormone inhibits release of
prolactin
growth hormone releasing hormone stimulates release of
growth hormone
somatostatin inhibits release of
GH and TSH
oxytocin stimulates
labor contraction and milk release
antidiuretic hormone stimulates
water retention by the kidneys
follicle stimulating hormone (FSH) stimulates secretion of
ovarian sex hormones
development of ovarian follicles
sperm production
luteinizing hormone (LH) stimulates
ovulation
corpus luteum secretion by progesterone and testosterone secretion by testes
thyroid stimulating hormone (TSH) stimulates secretion of
thyroid hormone from thyroid gland
adrenocorticotropic hormone (ACTH) or corticotropin stimulates
adrenal cortex to secretes glucocorticoids
prolactin after birth stimulates
mammary glands to synthesize milk
growth hormone or somatotropin stimulates
mitosis and cellular differentiation
antidiuretic hormone increases
water retention by kidneys thus reducing urine volume and preventing dehydration
oxytocin has a variety of reproductive function
released during sexual arousal
stimulates labor contractions
stimulates flow of milk during lactation
Synergistic effects of hormones
multiple hormones act together for greater effect
synergism between FSH and testosterone on sperm production
Permissive effects of hormones
one hormone enhances the target organ’s response to a second later hormone
estrogen prepares uterus for action of progesterone
Antagonistic effects of hormones
one hormone opposes the action of another
insulin lower blood glucose and glycogen raises it
upregulation of receptors
number of receptors is increased
sensitivity is increased
down regulation of receptors
number of receptors is reduced
cell less sensitive to hormone
happens with long term exposure to high hormone concentrations
pineal gland
synthesizes melatonin at night
may influence timing of puberty
thymus
involved in endocrine, lymphoid, immune
site of maturation of T cells important in immune defense
secretes hormones (thympoietin, thymosin, thymulin) that stimulate development of other lymphoid organs and activity of T lymphocytes
shrinks as we get older
thyroid gland
largest gland that is purely endocrine
made of sacs called thyroid follicles-contain protein-rich colloid surrounded by simple cuboidal epithelium of follicular cells
secrete thyroid hormone: 90% of thyroxine (T4) and 10% is triiodothyronine (T3)
TH increases metabolic rate, O2 consumption, heat production, appetite, gh secretion, alertness, reflux speed
parafollicular cells (clear cells) secrete calcitonin in reponse to rising blood calcium
parathyroid glands
increases blood Ca2+ levels
promotes synthesis of calcitriol
increases absorption of Ca2+
decreases urinary excretion
increases bone resorption
adrenal glands
adrenal medulla: inner core
adrenal cortex: thicker outer core
adrenal gland layers of glandular tissue
zona glomerulosa secretes mineralocorticoids
aldosterone released in response to falling blood pressure
zona fasciculata secretes glucocorticoids
cortisol secreted in response to ACTH from pituitary
stimulate fat and protein catabolism, gluconeogenesis, and release of fatty acids and glucose into blood
zona reticularis secretes glucocorticoids and androgens
primary adrenal sex steroids
pancreas
contains pancreatic islets (islets of Langerhans)
alpha cells secrete glucagon
beta cells secrete insulin and amylin
Delta cells secrete somatostatin
gonads
exocrine: eggs and sperm
endocrine: mostly steroids
skin
Keratinocytes convert a cholesterol-like steroid into
cholecalciferol using UV from sun
- Ultimately converted to calcitriol by liver and kidneys
liver
- Converts cholecalciferol into calcidiol
- Secretes angiotensinogen (a prohormone), precursor of
angiotensin II (a regulator of blood pressure) - Secretes 15% of erythropoietin (E P O), which stimulates bone
marrow - Source of insulin-like growth factor I (I G F-I) that controls
action of growth hormone - Hepcidin promotes intestinal absorption of iron
kidneys
- Convert calcidiol to calcitriol (vitamin D3)
- Calcitriol increases 2
Ca absorption by intestine and
inhibits loss in the urine - Secrete renin that converts angiotensinogen to
angiotensin 1 - Angiotensin 2 created by angiotensin-converting enzyme (A C E)
in lungs - Constricts blood vessels and raises blood pressure
- Produces 85% of erythropoietin—stimulates bone marrow
to produce R B Cs
heart
- Atrial muscle secretes two natriuretic peptides in response to
an increase in blood pressure - These decrease blood volume and blood pressure by increasing
Na and H2O output by kidneys and oppose action of
angiotensin II - Lowers blood pressure
skeletal muscles
secrete myokines that mobilize fuels from
liver, adipose tissue
stomach and small intestine
secrete at least 10 enteric
hormones secreted by enteroendocrine cells
* Coordinate digestive motility and glandular secretion, some
are gut-brain peptides
* Cholecystokinin, gastrin, ghrelin, and peptide YY (P Y Y)
adipose tissue
secretes at least three hormones
including leptin
* Slows appetite
bone tissue (osseous)
Osteocalcin and lipocalin 2
* Stimulate pancreatic beta cells, promote insulin secretion
and action
placenta
- Secretes estrogen, progesterone, and others
- Hormones regulate pregnancy, stimulate development of
fetus and mammary glands
pituitary gland is called the
hypophysis
hypophyseal portal system
Primary capillaries in hypothalamus connected to secondary capillaries in
anterior pituitary by portal venules
GnRH functions
stimulates release of gonadotropins FSH and LH
TRH functions
stimulates release of TSh
crh functions
stimulates release of adrenocorticotropic hormone
pih functions
inhibits release of prolactin
ghrh functions
stimulates release of growth hormone
somatostatin function
inhibits release of GH and TSH
two hormones produced in hypothalamus but secreted in posterior pituitary gland
oxytocin
antidiuretic hormone
oxytocin function
Released during sexual arousal and orgasm; promotes feelings of
sexual satisfaction and emotional bonding between partners
* Stimulates labor contractions during childbirth
* Stimulates flow of milk during lactation, and may promote emotional
bonding between lactating mother and infant
antidiuretic hormone effects on the kidneys
what happens when someone is thirsty
increases water
retention by kidneys, thus reducing urine volume and
preventing dehydration
Also called arginine vasopressin (A VP) because it can cause
vasoconstriction, but only at unnaturally high concentrations
osmoreceptors
trigger release of ADH when they detect a rise in blood osmolarity
gonadotropins
FSH
LH
FSH funtions
stimulates:
secretion of ovarian sex hormones, development of
ovarian follicles, and sperm production
LH function
stimulates: ovulation,
corpus luteum secretion of progesterone, and
testosterone secretion by testes
TSH function
stimulates secretion of thyroid hormone (TH) from thyroid
gland
ACTH function
stimulates adrenal cortex to secrete
glucocorticoids
PRL function
after birth, stimulates mammary glands
to synthesize milk
GH function
stimulates
mitosis and cellular differentiation
diabetes mellitus
disruption of carbohydrate, fat,
and protein metabolism due to hyposecretion or inaction of
insulin
signs and symptoms: polyuria (excess urine)
polydipsia (intense thirst)
polyphagia (hunger)
revealed by hyperglycemia (elevated blood glucose)
glycosuria (glucose in urine)
ketonuria (ketones in the urine)
polyuria occurs b/c kidneys exhibit a transport maximum- limit to how fast the glucose transporters can work to reabsorb
diabetes insipidus
due to low secretion of ADH not high glucose level
type 1 diabetes mellitus
Hereditary; genetically susceptible individual generates immune
cells that destroy pancreatic beta cells
* Insulin level very low, no longer regulates glycemia, and
hyperglycemia results
* Treatments: insulin injections, insulin pump, or dry insulin inhaler
* Monitoring blood glucose levels and controlled diet also important
type 2 diabetes mellitus
Problem is insulin resistance—unresponsiveness of target cells to
insulin
* Risk factors are heredity, age (40+), obesity, and ethnicity (Native
American, Latin American, and Asian descent)
* Treated with weight-loss program and exercise since:
* Loss of muscle mass causes difficulty with regulation of glycemia
* Adipose signals interfere with glucose uptake into most cells
* If necessary, also use glycemia-lowering oral medications and, if still not
enough, use insulin
diabetes mellitus pathogenesis
- Cells cannot absorb glucose, must rely on fat and proteins
for energy needs, thus weight loss and weakness - Fat catabolism increases free fatty acids and ketones in
blood - Ketonuria promotes osmotic diuresis, loss of Na and K irregular
heartbeat, and neurological issues - Ketoacidosis occurs as ketones decrease blood pH
- Deep, gasping breathing (Kussmaul respiration) and diabetic
coma are terminal result
Chronic pathology (chronic hyperglycemia) leads to
neuropathy and cardiovascular damage from
atherosclerosis and microvascular disease - Arterial damage in retina and kidneys (common in type 1),
atherosclerosis leads to heart failure (common in type 2) - Diabetic neuropathy—nerve damage from impoverished blood flow
can lead to erectile dysfunction, incontinence, poor wound healing,
and loss of sensation from area
what is on a target organ that makes it respond to a hormone
receptor
corticosteroids include
mineralocorticoids
glucocorticoids
sex steroids
cortisol is a
glucocorticoid secreted by the zona fasciculata and reticularis,
and helps the body adapt to stress
mineralocorticoids
from the zona glomerulosa: electrolyte balance
Know glucocorticoids from the zona fasciculata and reticularis:
glucose balance
aldosterone
secreted by the zona glomerulosa of the
adrenal cortex and the effects on blood pressure and volume by water retention and
sodium retention
Cushing syndrome
due to high level of cortisol due to several causes
related to ACTH or adrenal cortex
hormones secreted by adrenal medulla
catecholamines have multiple effects
* Increase alertness and prepare body for physical activity
* Mobilize high-energy fuels, lactate, fatty acids, and glucose
* Glycogenolysis (breakdown of glycogen to glucose) and
gluconeogenesis (convert fats, amino acids, other carbs to
glucose) by liver boost glucose levels
* Epinephrine inhibits insulin secretion and so has a glucose-
sparing effect—muscles use fatty acids, saving glucose for
brain
* Increase blood pressure, heart rate, blood flow to muscles,
pulmonary airflow, and metabolic rate
* Decrease digestion and urine production
epinephrine function
inhibits insulin secretion and so has a glucose-
sparing effect—muscles use fatty acids, saving glucose for
brain
norepinephrine function
released due to stress
cause glycogen hydrolysis in liver
glycogen
glycogenolysis
breakdown of glycogen to glucose
glucose
sugar
gluconeogenesis
converts fats, amino acids, other carbs to glucose
glucagon
when blood glucose concentration falls
thyroid gland
main function to promote metabolic rate
largest adult gland that is PURELY endocrine
follicular cells
secrete thyroid hormone (t3 and t4)
parafollicular cells
secrete calcitonin in response to rising blood calcium
(mainly in children)
calcitonin decreases blood calcium level and increases calcium decomposition in bones
90% of thyroid hormone is
t4
function of thyroid hormone is to
increases metabolic rate
promotes alertness
stimulates fetal nervous system
10% of thyroid hormone is
T3
main functions of parathyroid hormone
regulate blood calcium levels by raising the calcium level in the blood and not under control of the pituitary glans
reabsorbs calcium from bone as one takes money from savings to checking account (blood)
The pancreas is both
endocrine and exocrine gland
Know the functions of alpha cell or A cells:
ecrete glucagon
Glucagon acts on the liver for
lycogenolysis and gluconeogenesis
Glycogenolysis
breakdown of glycogen into glucose
Gluconeogenesis
synthesis of glucose from fats and proteins
Know that diabetes mellitus is manifested by
polyuria (urinate too much), polyphagia
(feeling hungry) polydipsia (feeling thirsty), glycosuria (sugar in urine)
Monoamine hormones include
dopamine, epinephrine, norepinephrine, melatonin, and
thyroid hormone (T3 and T4
Peptide hormones include
the two hormones from the posterior pituitary, glucagon
(from the pancreas), hormone from the hypothalamus are mostly peptide
Peptide hormones are proteins therefore are produced in the
Rough ER just like other
protein
oxytocin and insulin are
peptide hormones
steroid hormones enters the cell’s
nucleus because they are lipids (hydrophobic)
