Chapter 16 endocrine Flashcards
Compare and contrast the nervous system and endocrine system
endocrine: controls body functions using chemical signals (hormones)
nervous sys: controls body functions using electrical signals (action potential)
what tissue are endocrine glands made of?
epithelial tissue
where do endocrine glands excrete hormones to?
blood stream
why are endocrine glands highly vascularized?
to be able to release hormone into blood supply
what are unicellular endocrine glands vs multicellular?
uni: a single cell is the entire gland
multi: the gland is composed of more than just a single cell
what are examples of unicellular endocrine glands?
i cells releasing CCK
m cells releasing motilin
g cells releasing gastrin
what is another name for multicellular endocrine glands?
ductless glands
what is the signaling cell?
“talker cell” makes and releases chemical signal
what is the signaling molecule?
“voice - small chemical that travels between cells
what is the target cell?
“listener cell” - cell that recognizes the sent chemical signal
what is a receptor?
“ears” protein on or inside target cells that binds to signaling molecule
what are autocrine chemical signals? example?
used by cell to signal to itself
immune cells in compliment cascade
what kind of cell signal across gap junctions?
cardiac muscle cells/ pacemaker cells
what are paracrine chemical signals? example?
signal between two different cells in the same approx location
ex: juxtaglomerular macula densa cells releasing NO and ATP to cause vasodilation/constriction
what are endocrine chemical signals? example?
signal is released into the blood to regulate other cells farther away
ex: glucagon, insulin
Describe the difference between amino acid based and steroid based hormones
amino acid: mostly water-soluble (polar)/ receptor on outside of cell/ responses are rapid and short term
steroid: lipid soluble/ receptor located inside of cell/ actions are slow and long term
why are thyroid hormones a special exception?
they are amino-acid based but are nonpolar (like steroid)
where would the TH receptor be located?
inside the cell
where do amino-acid based hormones bind to receptors?
on outside of cell
where do steroid-based hormones bind to receptors on cell?
inside the cell
because steroid based hormones cause slow, long-term changes, what period of life would they be abundant?
puberty
do lipid soluble hormones need signal transduction cascades?
no, they have the receptors on inside of cell, so no need
Compare and contrast the mechanism of water-soluble vs lipid soluble hormones
water-soluble: need second messengers for signal transduction
lipid- soluble: do not need second messenger
what are the possible effects of hormones on target cells?
change membrane potential
cause production of new enzymes/proteins
activate/deactivate enzymes
cause secretion
stimulate cellular reproduction
mechanism regulating hormone release in humoral? example?
changes in blood characteristics cause hormone release
glucose levels go up, insulin is released to allow cellular glucose uptake
glucose levels are too far down, glucagon is released to increase blood glucose levels
mechanism regulating hormone release in neural? example?
input from neurons cause hormone release
ex: epinephrine is released in response to activation of SNS
mechanism regulating hormone release in hormonal? example?
initial hormone causes the release of a second hormone
ex: “releasing hormones” from hypothalamus -> pituitary -> other endocrine glands
leptin is controlled by hormonal stimuli
Describe how hormone levels, number of receptors, and affinity affect the degree of target cell activation
hormone levels: higher hormone concentration will have strongest response “shouting”
number of receptors: cells with more receptors will have a stronger response “has more ears”
affinity: high affinity receptor will cause stronger response because they bind easily to more hormones
Describe ways two or more hormones can combine their effects on a target cell
o Permissiveness
o Synergism
o Antagonism
o Permissiveness - one hormone is required before another to fully activate cells
o Synergism - effect on target cell is stronger if two hormones are present
o Antagonism - one hormone opposes the action of another (insulin/glucagon)
where is the pituitary situated in?
in the hypophyseal fossa of the sphenoid bone
what is the posterior pituitary made of?
neurohypophysis (made of nervous tissue)
what is the anterior pituitary gland made of?
adenohypophysis (made of glandular epithelial tissue)
what is the region that connects pituitary to hypothalamus called?
infundibulum
is the pituitary gland the “boss” of the endocrine system?
no, the hypothalamus is the actual boss, but we used to believe the pituitary gland was
where does the infundibulum of the pituitary gland connect to?
the hypothalamus
Compare and contrast how the neurohypophysis and adenohypophysis are connected to the hypothalamus
anterior: is connected via the hypophyseal portal system (several types of blood vessels)
posterior: neurons start in hypothalamus and end in pituitary gland where they can release their hormones (neuroendocrine cells)
where is oxytocin synthesized?
where does it go?
synthesized by paraventricular nucleus in hypothalamus -> posterior pituitary -> uterus/ breast tissue/ brain
what effect does oxytocin have once it has been delivered to uterus/ breast tissue/ brain?
uterus: stim smooth muscle to cause birth
breast: stim smooth muscle to cause milk ejection
brain: feeds back to brain as a neurotransmitter to increase sexual and affectionate behavior
what triggers the release of oxytocin? what kind of stimuli are each?
hormonal stimuli: increased estrogen (like in late pregnancy)
neural stimuli: mechanical stimulation (suckling) of breast tissue
stretching of uterus
sight, smell, sound of baby
what is the synthetic drug to replace oxytocin? what is its use?
Pitocin - speeds up labor
what decreases/slows oxytocin?
stress reduces
alcohol and THC slows responses
where is ADH (antidiuretic hormone) made and released?
supraoptic nucleus of hypothalamus -> posterior pituitary -> kidneys (V2 receptors)/ arteries (V1 receptors)
what do the V2 receptors in the kidneys cause to happen when ADH binds to them?
causes aquaporin insertion in collecting duct in order to promote water reabsorption, increase blood volume, and decrease urine output
What do the V1 receptors in the arteries cause to happen when ADH binds to them?
causes vasoconstriction to increase blood pressure
knowing what ADH does, when would it need to be released?
- high blood osmolarity = dehydration
- low blood volume
- nicotine (bad side effect causes vasodilation b/c it increases ADH release)
what does a lack of ADH release cause? what can cause this?
diabetes insipidus - causes dilute urine because ADH no longer promotes water reabsorption
can be caused by head trauma damaging supraoptic nucleus in hypothalamus
the neurons go straight to posterior pituitary from the hypothalamus
these neurons are what directly carry the signal
what cell type in the anterior pituitary releases growth hormone?
somatotropic cells
what does GH stimulate?
tissue building (physical anabolic growth)
triggers release of energy stores that power growth (metabolic)
what tells somatotropic cells to release GH? what tells them to inhibits GH?
GHRH (growth hormone releasing hormone) released by hypothalamus
Somatostatin (GHIH) released by hypothalamus inhibits release
what effects does direct effects of GH cause?
increases blood sugar
increases metabolism of fats
what effects does indirect effects of GH cause? what does indirect mean?
indirect means that GH goes to liver and activated IGFs (insulin-like growth factors) to then go and tell skeletal muscle and bone
causes: nutrient uptake and actual cell growth
what is the difference between direct and indirect GH effects?
direct: GH facilitates energy to be able to be used
indirect: GH uses IGFs to actually tell cells to grow
what is gigantism? cause by?
excessive overall growth due to too much GH before puberty
caused by pituitary tumor
what is acromegaly?
enlarged hands, feet, face caused by too much GH after puberty
caused by pituitary tumors
what is pituitary dwarfism? caused by?
overall small growth due to too little GH before puberty
caused by genetic mutations
what does ACTH stand for?
what cell type within the anterior pituitary releases ACTH?
adrenocorticotropic hormone
corticotropic cells
what hypothalamus hormone triggers ACTH release in anterior pituitary?
where does ACTH get released to?
what form of regulation is this?
- corticotropin-releasing hormone (CRH)
- released to adrenal cortex where then triggers release of corticosteroids
- hormonal regulation