Lecture 6 Endocrine Part 1 Flashcards
what structure is the ANS controlled by
medulla oblongata
explain how the ANS is controlled by higher brain centers
sensory information from periphery –> main parts of the brain including hypothalamus –> send information to medulla oblongata –> synapses with preganglionic ANS neurons and modifies behavior
give an example of how higher brain centers regulate the ANS
seeing something scary –> increased heart rate
listening calming music –> decreased heart rate
explain how chemoreceptors and baroreceptors are autonomic reflexes (where are they found, what they respond to and how)
chemoreceptors in aorta –> detect rise in CO2 and fall in O2 –> information sent to medulla oblongata –> heart rate and breathing increased, blood vessel constriction
baroreceptors in aorta detect fall in blood pressure –> information sent to medulla oblongata –> increased heart rate to raise blood pressure
2 parts of pituitary gland and alternate name
anterior pituitary = adenohyophysis
posterior = neurohypophysis
posterior pituitary hormones released
ADH and oxytocin
name of tract that transports posterior pituitary hormones
hypothalamo-hypohyseal tract (axon bundle)
name of part that produces posterior pituitary hormones
paraventricular and supraoptic nucleus (cell bodies) make and package ADH and oxytocin in vesicles –> sent down hypothalamo-hypohyseal tract to posterior pituitary
neurohormones
made in brain but secreted as hormones in the blood
ADH - when is it released and what are the three effects
high blood osmolality, low blood volume and blood pressure –> 1) kidneys reabsorb water and excretet K+, 2) sense of thirst created 3) sweat glands inhibited to conserve water
why ADH is called vasopressin
- at high concentration directly causes vasoconstriction and increase blood pressure
- at low concentration indirectly increases blood pressure
oxytocin 3 main functions (just list them)
1) milk ejection
2) labor
3) bonding
oxytocin role in labor
oxytocin –> uterine contraction –> sensory information sent to brain –> more oxytocin
- after birth no more sensory information sent and positive feedback stops
oxytocin role in milk ejection
- stimulates milk ejection in mammary glands
oxytocin role in bonding
physical contact between adults, caregivers and babies, humans and animals releases oxytocin aka love hormone and helps with bonding
portal meaning
portal = vessel that goes from primary to secondary capillary system
hepatic portal vein
goes from capillaries in GI to capillaries in liver
anterior pituitary transports system name and why
hypothalamo-hypophyseal portal system
- goes from primary capillaries in hypothalamus to secondary capillaries in anterior pituitary and brings inhibiting/releasing hormones
what are anterior pituitary releasing and inhibiting hormones
- created by hypothalamus and sent to anterior pituitary, causes release or inhibition of release of trophic hormones from anterior pituitary
list the 6 releasing/inhibitory hormones
- TRH - thyrotropin releasing hormone
- GHRH - growth hormone releasing hormone
- somatostatin
- PIH - prolactin inhibiting hormone
- GnRH - gonadotropin releasing hormone
- CRH - corticotropin releasing hormone
explain hypothalamo-pituitary-ovarian axis
- GnRH from hypothalamus –> FSH and LH from anterior pituitary –> ovaries that release estrogen and progesterone
FSH effects
- women: follicles grow, estrogen production
- men: sperm production
LH effects
- women: ovulation
- men: testosterone production from interstitial cells of Leydig
hypothalamo-pituitary-thyroid axis
hypothalamus and TRH thyrotropin releasing hormone –> anterior pituitary releases TSH thyroid stimulating hormone –> T3/T4 released from thyroid
hypothalamo-pituitary-adrenal axis
stress –> higher brain centers –> hypothalamus secretes CRH –> anterior pituitary secretes ACTH t–> adrenal cortex releases cortisol
trophic hormone meaning and result of too little / too much
trophic = nourishes a gland
- too much = hypertrophy (increase in size) and hyperplasia (increase in number of cells)
- too little = atrophy of gland
list 6 trophic hormones
- FSH
- LH
- prolactin
- growth hormone
- ACTH
- TSH
which 2 trophic hormones dont use negative feedback?
growth hormone and prolactin
explain generally how negative feedback works
hormones produced at the end of the axis inhibit hypothalamus and anterior pituitary hormones from being released
effect of taking birth control / hormone replacements drugs
exogenous estrogen and progesterone –> negative feedback –> less FSH, LH (and GnRH)
affect of menopause
menopause –> no more follicle creating estrogen –> increase in FSH and LH (and GnRH)
prolactin pathway
hypothalamus releases PIH –> inhibition of prolactin release from anterior pituitary –> inhibition of milk production in mammary glands
prolactin secreting adenoma effects
cancer in anterior pituitary that secretes lots of prolactin –> inappropriate milk production in men, women and kids called galactorrhea
iodine deficiency effect on thyroid axis
iodine deficiency –> thyroid cannot produce T3 and T4 = primary hypothyroidism
primary hypothyroidism
problem in the thyroid gland
primary hyperthyroidism - alternate name, cause, and effect
- TSI!
autoimmune disease, antibodies that are TSH agonist are created called thyroid stimulating immunoglobins (TSI) –> mimic TSH –> lots of T3/T4 released and thyroid gets larger –> less TSH and TRH
TSH secreting adenoma of the anterior pituitary - effect and type of hyperthyroidism
increased TSH –> thyroid produces lots of T3/T4 and grow
- secondary because problem with pituitary
- list adrenal and ovarian axis
- why can they effect each other
CRH –> ACTH –> cortisol
GnRH –> FSH and LH –> estrogen and progesterone
- cortisol, estrogen, and progesterone are all steroids and at high concentrations can bind each others receptors
stress in serious athletes and name of 2 resulting diseases
cortisol binds mimics estrogen and progesterone –> inhibits FSH and LH secretion –> oligomenorrhea (irregular period) and amenorrhea (no period)
2 parts of adrenal gland
- adrenal medulla, releases epi and norepi as part of sympathoadrenal gland
- adrenal cortex
what does zona glomerulosa produce
cholesterol –> aldosterone a mineralcorticoid
what does zona fasciculata produce
cholesterol –> glucocorticoid (cortisol and corticosterone)
what does zona reticularis produce
cholesterol –> DHEA –> androgens
mineralocorticoid meaning
oid = steroid, cortico = from adrenal cortex, mineral = role in electrolyte balance
aldosterone effect adn comparison to ADH
aldosterone = Na+ and water reabsorption and K+ excretion, no change in blood osmolality –> increase blood volume and pressure
- stimulate by hyperkalemia
glucocorticoid meaning
- stimulates production of glucose in blood
- look at info about cortisol
explain hypothalamo-pituitary-adrenal axis
stress –> higher brain centers –> hypothalamus – CRH –> ACTH –> cortisol
cortisol effects (lots of them!
- gluconeogensis and glyogenlysis
- insulin resistance in skeletal muscle and fat cells (insulin receptors removed so glucose utilization in the periphery is decreased)
- fat accumulation in abdominal region
- muscle break down
- immune system and inflammation decreased
- suppresses bone formation leading to osteoporosis
ptocin
exogenous oxytocin, given when cervical dilation but no uterine contraction
explain how breast feeding a twin born first helps the delivery of the second one
breast feeding –> increased oxytocin –> uterine contraction –> second baby delivered
