Endocrine and Nervous Systems Flashcards
What are the key things the endocrine system regulates?
metabolism and fluid retention
tropic hormones
cause other hormones to be released
allows for careful control of a system
hypothalamus and location
bridges the nervous system’s signals to the endocrine system’s hormones
located below the thamalus and above the pituitary gland
anterior pituitary
receives hormonal signals from hypothalamus
posterior pituitary
receives neuronal signals from hypothalamus
releases ADH to regulate fluid balance and oxytocin for labor contractions
thyroid
releases thyroid hormones which affect metabolism and behavior
Where are the adrenal glands located?
kidneys
two regions of adrenal glands and what they secrete
adrenal cortex: cortisol (long-term stress)
adrenal medulla: epinephrine and norepinephrine (acute stress)
GnRH
tropic hormone released from hypothalamus
eventually affects reproduction
when can testosterone increase?
after winning a competition
oxytocin
promotes uterine contractions during labor
great example of positive feedback
more oxytocin means more contractions which means more oxytocin
has psychological effects for bonding - “cuddle” hormone
what releases oxytocin?
posterior pituitary
what psychological effects does oxytocin have?
bonding and affection
considered the “cuddle” hormone
prolactin
promotes lactation and moderates stress and anxiety
secreted by anterior pituitary
what can low levels of prolactin lead to psychologically?
PPD
melatonin
induces sleep with circadian rhythms
leptin
reduces hunger
released by adipose cells
ghrelin
promotes hunger
released by stomach cells
stomach “growling” is ghrelin
Where do leptin and ghrelin act?
on the hypothalamus
NPY
stimulates appetite and increases food intake
cortisol
secreted by the adrenal cortex
increases blood sugar levels
thyroid hormones
promote metabolism
what can hypothyroidism lead to?
fatigue
where are neurotransmitters recieved?
at dendrites of neurons
where are neurotransmitters stored and released from?
axon terminal of neurons
what is the resting potential and polarization needed to fire a neuron?
resting potential: -70mV
firing threshold: -55 mV
Neuromuscular junction
synapse between motor neuron and muscle
used in reflexes
acetylcholine
tells muscles to contract
sent across neuromuscular junction
excitatory neurotransmitters
depolarize the electric potential of target neuron
less negative, and more likely to send signal
does a neuron fire if it gets more polarized or depolarized?
depolarized (less negative) will fire
inhibitory neurotransmitters
hyper-polarize the electric potential of target neuron
more negative, and less likely to send signal
what else does acetylcholine do besides muscle contraction?
communicates between central nervous system and autonomic nervous system
sends signals in parasympathetic system
glutamate and GABA
glutamate: excitatory neurotransmitter
GABA: inhibitory neurotransmitter
dopamine
involved in reward pathways (can lead to drug addiction)
mediates motor function
seratonin
regulates mood, appetite, sleep, and intestinal movement
SSRIs
keep serotonin in synapses longer
used to treat depression
do not create more serotonin
endorphins
suppress pain and produce euphoria
runner’s high generates endorphins
agonist
compound that activates a certain receptor, causing a response
might not be the primary ligand of a receptor
antagonist
bind a receptor but not not cause a response
blocks agonists
central nervous system
brain and spinal cord
peripheral nervous system
nerves that send and receives signals to and from central nervous system
somatic nervous system
controls voluntary activities and skeletal movement
subdivision of PNS
autonomic nervous system
controls unconscious, automatic activities
subdivision of PNS
parasympathetic nervous system
rest and digest system
vasodilation of GI tract
vasoconstriction of skeletal muscles
pupils constrict
vasodilation
increases blood flow to an area
vasoconstriction
decreases blood flow to an area
sympathetic nervous system
flight or fight response
vasodilation of skeletal muscles (can run or fight)
vasoconstriction of GI tract
pupils dillate
epinephrine increases blood glucose levels
heart rate increases
epinephrine
released from adrenal medulla on kidney
increases blood glucose levels
part of sympathetic nervous system and acute stress response
enteric nervous system
regulates gut
subdivision of autonomic nervous system
what do efferent neurons secrete?
acetylcholine at neuromuscular junctions to effect the muscle and cause contraction
nociceptors
also known as pain receptors
are found in abundance in the skin
What types of hormones do the pituitary glands release?
peptide hormones
Thyroid hormone pathway
TRH from hypothalamus
TSH from anterior pituitary
T3 and T4 from thyroid
Reproductive hormone pathway
GnRH from hypothalamus
LH + FSH from anterior pituitary
Reproductive organs respond
Corticosteroid hormone pathway
CRH from hypothalamus
ACTH from anterior pituitary
Corticosterioids are produced from adrenal cortex
Growth hormone pathway
GHRH from hypothalamus
GH - growth hormone
What hormones does anterior pituitary produce independently of hypothalamus?
prolactin and endorphins
What do the parathyroid glands release?
parathyroid hormone (PTH) which raises calcium levels in the blood
What hormones does the thyroid release?
T3 and T4
calcitonin
What does the adrenal cortex secrete?
1) cortisol
2) aldosterone
3) sex hormones
What does aldosterone do?
promotes fluid retention by increasing Na+ uptake in collecting duct and distal convoluted tubule
What does adrenal medulla secrete?
secretes epinephrine and norepinephrine
What type of hormones are epinephrine and norepinehpine?
amino acid derived hormones
specifically, catecholamines
Where is insulin secreted?
from the beta cells of the pancreas
Where is glucagon secreted?
from the alpha cells of the pancreas
Where is somatostatin secreted?
the delta cells of the pancreas
Somatostatin
slows down digestion
pineal gland
secretes melatonin
found in the brain
ANP
produced by cardiac muscles
decreases BP by promoting fluid loss
Hormones secreted by the digestive system
1) gastin
2) secretin
3) CCK
secretin
small intestine tells pancreas to secrete bicarbonate to neutralize the acidic chyme
CCK
stimulates the release of hydrolytic enzymes from pancreas and bile from liver
What does parathyroid hormone do?
raises Ca2+ levels
tells osteoclasts to break down bone
What does calcitonin do?
lowers calcium levels
What does vitamin D do?
helps increase Ca2+ levels
ACE inhibitors
medication that stop aldosterone production to help lower high BP
hypertension medication
How does aldosterone specifically work?
Increases Na+ concentration in nephron’s collecting duct and distal conducting tube
Water follows by osmosis into blood
Na+ concentration is raises by increasing K+ secreted
What does ADH do? How?
increases BP/blood volume
places more aquaporins in collecting duct
How does ANP work?
does the opposite of aldosterone and increases fluid loss
lowers BP
