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
what is responsible for inhibiting ACTH? what is this an example of?
cortisol released from adrenal cortex
negative feedback
when does CRH get released?
- in the mornings due to circadian rhythm
- stress
what can too much ACTH cause?
symptoms associated with stress such as high blood pressure, low immune function
what does TSH stand for?
what cell type in the anterior pituitary releases TSH?
thyroid-stimulating hormone
thyrotropic cells
describe how TSH is regulated. what causes it to be released? what does it do when it is released?
thyroid releasing hormone (TRH) in the hypothalamus causes TSH to be released which then goes to thyroid and causes the thyroid to release thyroid hormone
hypothalamus -> TRH -> pituitary gland -> TSH -> thyroid -> thyroid hormone
what cell type makes FSH and LH in the anterior pituitary?
gonadotropic cells
what does FSH and LH stand for?
follicle stimulating hormone
luteinizing hormone
what hypothalamus releasing hormone causes FSH and LH to be released?
gonadotropin-releasing hormone (GnRH)
what does it mean when we say that the release of GnRH by the hypothalamus is pulsatile?
it is released in bursts (levels go up and down)
constant high levels of GnRH causes what to happen?
gonadotropic cells to become unresponsive and no longer produce FSH and LH (chemical castration)
what cell type produces and releases PRL in anterior pituitary?
prolactin cells
what makes prolactin release different that the other anterior pituitary?
does not need releasing hormone from hypothalamus but instead requires drop in dopamine initiated by the hypothalamus
what does PRL cause to happen?
triggers production of breast milk in females (no clear function in males)
what gland is the largest pure endocrine gland in the body?
thyroid
what is the small piece of tissue that connects both lateral lobes of the thyroid called?
isthmus
what is the structure of thyroid follicles made of?
hollow spheres with outer edges made of epithelial cells and inner hollow center is colloid which contains thyroglobulin (protein used to make TH)
what is found in the space between each of the hollow spheres of the thyroid follicles?
parafollicular cells (c cells) which produce calcitonin
what is the protein that makes thyroid hormone?
what are the two types of thyroid hormone?
thyroglobulin
T3 and T4
what is the name for T3 and T4?
which is potent?
which is most common?
T3: triiodothyronine (potent)
T4: thyroxine (most common)
what is the effect of TH?
increased basal metabolic rate - makes all cells burn more energy which is important for neuronal development and prepubescent growth
what causes TH to be released?
TSH from the pituitary which is released in response to TRH from the hypothalamus
what inhibits TRH release? what is this called?
thyroid hormone circles back to inhibit TRH release
negative feedback
what factors besides prepubescent growing would cause the release of TH?
other conditions that require increase energy requirements
(pregnancy/ cold temps)
what is hypothyroidism in adults?
caused by low function of thyroid gland causing myxedema
what are symptoms of myxedema?
swelling of mucus membranes
low metabolism (lethargic, chilled, mentally slow, constipated)
what can hypothyroidism in children cause?
cretinism
what is cretinism? what is it caused by?
hypothyroidism in children which results in permanent mental retardation and stunted growth
due to lack of iodine in food or soil (common in developing countries)
where do most Americans get their iodine?
salt
what is hyperthyroidism?
excessive function of thyroid gland resulting in wasting, nervousness, tremors
what condition can cause hyperthyroidism? what would that look like?
Graves’ disease - autoimmune disease where antibodies mimic TSH
bug eyes (exophthalmos)
what is a goiter?
noncancerous overgrowth of thyroid due to colloid build up
what cell type releases calcitonin?
parafollicular cells (c cells)
when is calcitonin released? what does calcitonin do?
is released in response to high blood calcium levels
lowers blood calcium levels by decreasing osteoclast activity so that more calcium ends up in the bones
what is the location of the parathyroid gland? how many of them are there?
somewhere posterior of the thyroid
most have 4
some people have 8
when is parathyroid hormone released? what is the effect of parathyroid hormone?
is released when blood calcium levels are too low
functions to bring blood calcium levels up by either increasing osteoclast activity/ tells DCT to save more calcium/ tells gut to absorb more calcium
what type of regulation is parathyroid hormone?
humoral
what is the function of the adrenal cortex?
produces 3 types of corticosteroids
what is the function of the adrenal medulla?
part of ANS
produces epinephrine/norepinephrine
what are the three layers of the adrenal cortex in order of superficial to deep?
zona glomerulosa
zona fasciculata
zona reticularis
what hormone does the zona glomerulosa produce?
what are those responsible for?
ex?
mineralocorticoids
regulates sodium reabsorption and potassium secretion in DCT
ex: aldosterone
what would the release of aldosterone cause?
kidneys to save sodium and water which increases blood pressure
what is aldosterone released in response to?
low blood sodium
high blood potassium
low blood volume/pressure
what can hypersecretion of aldosterone cause?
water retention (edema)
hypertension
weakness (due to low potassium)
what hormone does the zona fasciculata secrete?
what does it do?
example?
glucosteroids
increase blood sugar
ex: cortisol (stress hormone)
what are the effects of cortisol on the body?
increased blood sugar
increased blood pressure
suppression of immune system
inhibits CRH release (negative feedback)
what hormone does the zona reticularis make and secrete?
what does it do?
example?
gonadocorticoids
weak sex hormones
ex: androstenedione
when is androstenendione present in the body?
during early puberty (preteen) before strong sex hormones of the gonads are made
what are the effects of androstenedione?
hair growth in puberty
is the only source of estrogen after menopause
what age is androstenedione released?
between age 7-13
what can too much androstenedione cause?
in females: adrenogenital syndrome - push secondary male sexual characteristics in females
in males: promotes early onset puberty
what is the type of regulation of release is for aldosterone?
humoral (sodium levels)
what is the type of regulation of release is for cortisol?
hormonal (ACTH)
what is the type of regulation of release is for androsteindione?
neural (aging)
what type of cells is the adrenal medulla made of? what is this similar to?
neuroendocrine cells
similar to posterior pituitary
what hormone do the neuroendocrine cells in the adrenal medulla secrete?
epinephrine and norepinephrine
thyroid hormones are tyrosine derived, what other hormones are like this? what does that mean for the receptor?
epinephrine and norepinephrine
receptors would be located inside the cells
what is the ratio that epinephrine and norepinephrine is released?
80% epinephrine
20% norepinephrine
what are the effects of epi/norepinephrine?
increase blood sugar
increase heart rate
increase blood pressure
increase metabolic rate
diverts blood from skin and gut to muscles and vital organs
when is epinephrine/norepinephrine released? what kind of regulation is this?
short-term stressors
neural regulation
which endocrine organ also acts as an exocrine organ?
pancreas
how does the pancreas act as an exocrine gland?
excrete digestive enzymes
how does the pancreas act as an endocrine gland?
endocrine cells in the Islets of Langerhans called alpha cells and beta cells
what type of hormone do alpha cells secrete in the Islets of Langerhans of the pancreas?
make glucagon (peptide hormone)
where does glucagon target when it is released? why?
liver
to increase blood sugar by glycogenolysis and gluconeogenesis
what are the other hormones that increase blood sugar besides glucagon?
cortisol
epinephrine/norepinephrine
growth hormone
what is glycogenolysis?
breakdown of glycogen to glucose
what two instances would glucagon be released? what type of regulation?
in response to low blood glucose (humoral)
in response to SNS (neural)
what type of hormone do beta cells secrete in the Islets of Langerhans of the pancreas?
secrete insulin
what effect does insulin have on the body
decreases blood sugar by activating insulin dependent glucose transport channels (GLUTs) in skeletal muscle and adipose tissue
which is more common of the islet of langerhan cell types?
beta cells are most common
which organs have insulin-independent GLUTs?
brain
liver
kidney
when is insulin released?
in response to high blood sugar levels
in response to PNS
what is diabetes mellitus?
occurs when blood glucose levels are too high
there is plenty of glucose in the blood but cells are not up-taking it so the body metabolizes proteins and fats instead
what are symptoms of diabetes mellitus?
polyuria (excessive urination)
polydipsia (excessive thirst)
polyphagia (excessive hunger)
what causes type 1 diabetes mellitus?
beta cells are killed by an autoimmune response so there is no insulin production
what is type 1 diabetes treatment?
insulin injections
pancreatic islet cell transplants
what causes type 2 diabetes mellitus?
due to chronic high blood sugar levels
which causes cells to become insulin resistant so they no longer uptake glucose into the cell (cell then starves)
what is type 2 diabetes mellitus treatment?
diet and exercise
insulin injections (amplify signal)
medication to inhibit glucose absorption in intestines and glucose release by liver
should decrease amount of sugar entering the blood so it should decrease blood sugar levels
what is the correct term for sperm/eggs?
spermatocytes
oocytes
what is copulation?
sex - delivery of male gametes into female reproductive tract
during sex, what shape is the penis? how was this determined? who was wrong about their idea of what shape it was?
boomerang shape
MRI analysis determined its correct shape
Leonardo Da Vinci was wrong
what is fertilization?
where does this occur usually?
when sperm and egg cells unite
in the ampulla of the uterine tube
what is conceptus?
product of fertilization
what is a conceptus called when it is 1-8 weeks old?
what is called after that?
embryo
then called fetus until birth
where does implantation occur?
embryo attaches to uterine lining (endometrium)
what is the difference between monozygotic and dizygotic twins?
mono: 1 fertilization event leads to two identical embryos
di: 2 separate fertilization events lead to non-identical embryos
what is gestation?
support of embryonic and fetal development (occurs inside uterus)
what is parturition? when does it occur?
birth
approx. 280 days from last menstrual cycle
what happens to homologous chromosomes in meiosis 1?
homologous chromosomes separate
what happens to sister chromatids in meiosis 2?
sister chromatids separate
