Endocrine physiology Flashcards
what is homeostasis ?
maintaining the internal environment regardless of what is going on int the external environment
what kind of communication is there in the body ?
long distance and short distance
what are two examples of long distance ?
nervous and endocrine system
what are two examples of short distance ?
autocrine and paracrine
what is the type of chemical signal in endocrine system ?
hormone (cholesterol or steroid)
what signal travels where in endocrine system ?
blood
what is the speed of communication in endocrine system ?
much slower
what is a hormone ?
a chemical signal secreted into the blood to act on a distant tissue
what is a neurohormones ?
a chemical signal secreted into the blood from a neuron to act on a distant tissue
how does hormone signalling work ?
- endocrine cells release hormone
- hormones circulate throughout the body
- hormones will only bind to their specific receptors
- only target cells will express that receptor
what is released from the pineal gland ?
melatonin
what is released from the pituitary gland ?
oxytocin and ADH
what is released from the thyroid ?
thyroid hormones (T3 and T4)
what is released from the adrenal glands ?
aldosterone, epinephrin, cortisol, androgens
what is released from the pancreas ?
insulin and glucagon
what is released from the gonads ?
estrogen, progesterone, etc
what is released by the small intestine ?
cholecystokinin, secretin, GIP, and GLP-1
what is released by the stomach ?
gastrin and somatostatin
what is somatostatin ?
neuro endocrine inhibitor (inhibits pituitary secretion, memory fiction, etc)
what is cholecystokinin ?
pancreatic secretions & gallbladder contractions
what are protein hormones ?
examples : hormones from the hypothalamus and the pituitary and pacrease
precursor : amino acids
solubility : hydrophilic and dissolves in blood
location of receptor : membrane bound (receptor)
time before onset of action : fast acting and short lived
what are steroid hormones ?
examples : estrogen, testosterone, and cortisol
precursor : cholesterol
solubility : lipophilic and bound to a protein
location of receptor : intracellular
time before onset of action : slow acting and long lived
what are amine hormones ?
examples : thyroid hormone and epinephrin
precursor : tyrosine
solubility : some are lipophilic and bound to a protein while some are hydrophilic and circulate freely
where are membrane receptors found ?
outside cell near blood vessel
what does the hypothalamus do for the pituitary gland ?
regulates it
what are the two parts the pituitary gland is divided into ?
anterior and posterior
what is the posterior pituitary gland responsible for ?
ADH and oxytocin
what does the anterior pituitary gland do ?
produces and secreted its own hormones
what does ADH do ?
promotes water reabsorption in kidneys (no urine)
how do neurotransmitters differ from a hormone and neurohormone ?
short distance and long distance
how does hydrophobic hormones travel ?
binds to phospholipid plasma membrane receptors and circulates unbound
how does hydrophilic hormones travel ?
binds an intracellular receptors and circulates inside bound to a protein
what does oxytocin do ?
- promotes uterus contractions
- promotes milk excretion
- makes you feel happy/comforted (hugs)
hypothalamus hormones =
anterior pituitary hormone =
peptide neurohormones
peptide hormones
hypothalamus hormone GnRh = anterior pituitary hormone _____ (target tissues = )
LH and FSH (target tissues = gonads, ovaries, testes)
hypothalamus hormone TRH = anterior pituitary hormone _____ (target tissues = )
TSH (target tissue = thyroid gland)
hypothalamus hormone CRH = anterior pituitary hormone _____ (target tissues = )
ACTH (target tissue = adrenal glands)
hypothalamus hormone GHRH = anterior pituitary hormone _____ (target tissues = )
GH “growth hormone) (target tissue = bone, skeletal muscle, liver, etc)
hypothalamus hormone PIH/PRH = anterior pituitary hormone _____ (target tissues = )
prolactin “too much dopamine doesn’t make prolactin” (target tissue = mammary glands)
where is TRH released from ?
hypothalmus
where is TSH released from ?
pituitary gland
how is hormone release from the anterior pituitary regulated ?
hypothalamic-hypophyseal portal system
what is the precursors for thyroid hormones ?
thyroxine and iodine, come from nutrition
what happens at the colloid ?
site of T3 and T4 storage
what are two thyroid hormone diseases ?
hypothyroidism and hyperthyroidism
what is hypothyroidism ?
decrease (loss) in T3 and T4
what is hyperthyroidism ?
increase (gain) in T3 and T4
what are some symptoms of hypothyroidism ?
- low metabolic rate
- sensitive to cold room temperatures
- weight gain due to decreased fat breakdown and increased fat storage
- depression, easily fatigued
- low blood pressure
what are some symptoms of hyperthyroidism ?
- high metabolic rate
- sensitive to warm room temperatures
- weight loss due to increase fat breakdown and decreased fat storage
- hyperactive or “nervous” activity
- rapid heart rate
what is a goiter ?
enlarged thyroigland
what causes a goiter ?
hypothyroidism, high / massive buildup of TSH (low T3 and T4)
how to treat a goiter ?
one pill, once a day
what is graves’ disease ?
autoimmune disorder that causes hyperthyroidism
what causes hypothyroidism ?
too little / access T3 and T4
how to treat graves’ disease ?
anti-thyroid medicine that reduces the amount of T3 and T4 produced in the thyroid
how are thyroid hormones produces and what stimulates their synthesis and release ?
produced using thymine and iodine, taken into the colloid, and synthesized and released when stimulated by TSH
what are the differences between active thyroid hormones and its precursors ?
T4 is inactive and T3 is active
what are the four layers of the adrenal glands ?
- zona glomerulosa
- zona fasciculata
- zona reticularis
- adrenal medula
what’s an acronym for layers of the adrenal glands ?
GFRM
class of hormone and example for zona glomerulosa
mineralocorticoids and aldosterone
class of hormone and example for zona fasciculata
glucocorticoids and cortisol, corticosterone
class of hormone and example for zona reticularis
androgens and dehydroepiandrosterone
class of hormone and example for adrenal medulla
stress hormones and epinephrin and norepinephrine
way to remember class of hormones for each layer of the adrenal glands ?
SALT
SUGAR
SEX
STRESS
what does cortisol do ?
increase of glucose in blood
where is cortisol released from ?
the adrenal glands
describe the feedback pathway modulating levels of cortisol
CRH -> ACTH -> Cortisol
what can you compare thyroid hormone function symptoms to ?
to what exercise does to the body
cortisol once released in the body activates other hormones; ____ and ____
muscle and adipose
muscle from cortisol allows for _____
protein catabolism
what are proteins broken down into ?
amino acids
what are triglycerides broken down into ?
glycerol fatty acids
adipose from cortisol allows for ______
lipolysis (breakdown of lipids)
what organ and system does cortisol affect ?
immune system and the liver
cortisol’s affect on the immune system leads to _______
immune suppression (more vulnerable)
cortisol’s affect on the liver leads to ______
gluconeogenesis (impacts blood glucose)
what is Cushing’s disease ?
hyper secretion of cortisol (too much cortisol being secreted)
what is hyperglycemia ?
high blood glucose level
what are symptoms of Cushing’s disease ?
- muscle atrophy and weakness
- thinning skin, stretch marks with tearing
- easily bruised and abdominal weight gain
- stunted growth
- round face and hump on back
what is epinephrine ?
a fight or flight hormone
what type of hormone is epinephrine ?
hydrophilic amine
what are the two “divisions” of cells in pancrease ?
exocrine and endocrine
glucagon is composed of what cells ?
alpha cells
insulin is composed of what cells ?
beta cells
in what state is glucagon found ?
fasted (break molecules into glucose)
in what state is insulin found ?
fed state
islet of langerhans in the pancreas =
glucagon and insulin
endocrine pancreas =
islets of langerhans
exocrine pancreas =
acinar and duct tissue
what hormones are released by the hypothalamus ?
hormones that control the puituitary
what hormones are released by the parathyroid gland ?
parathyroid hormones
what hormones are released by the thyroid glands ?
thyroid hormones (T3 & T4), calcitonin
what hormones are released by the adrenal glands ?
aldosterone, epinephrine, cortisol and androgens
