Textbook (endocrine and reproduction) - ALL Flashcards
What does the integration centre do?
you suck :3
detects changes from the set point
What parts of the body encompass the integration centre?
- brain
- spinal cord
- endocrine glands
What are antagonistic effectors?
- “push-pull”
- increasing the activity of one effector is accompanied by decreasing the activity of an antagonistic effector
- gives a finer degree of control compared to switching one effector on and off
What is dynamic constancy?
the internal environment is never absolutely constant; homeostasis conditions are stabilized above and below the set point
Homeostasis is ultimately maintained by ____ feedback loops
negative
What are the two categories of regulatory mechanisms that homeostasis is maintained by?
- intrinsic: built into the organs being regulated (nerve fibres innervate organs)
- extrinsic: regulation by nervous/endocrine systems (chemical regulators secreted into blood)
endocrine glands lack ____ that are in exocrine glands
ducts
What are amine hormones?
- hormones derived from tyrosin and tryptophan
- secreted from adrenal medulla, thyroid, pineal glands
what are glycoprotein hormones?
protein bound to 1+ carb groups
What are steroid hormones?
- derived from cholesterol
- secreted from gonads (sex steroids)
- secreted from adreal cortex (corticosteroids + sex steroids)
How do sex and thyroid hormones compare to polypeptide and glycoprotein hormones in the way that they can be taken as medication?
- thyroid and sex can be taken in pill form
- polypeptide and glycoprotein have to be injected to avoid digestion prior to entering the blood
What is a prohormone?
- precursor for polypeptide hormones
- cut and spliced with gland cell to make hormone
What is a prehormone?
- molecule secreted by endocrine gland sometimes inactive in target cells
- target cells modify chemical structure of hormone to activate it (ie: T4 -> T3 to be active)
What is a synergistic hormone effect?
two hormones work together to produce an effect
What is a permissive hormone effect?
hormone enhances target organ responsiveness to second hormone or increases second hormone’s effect
Is there an accumulation of blood hormones? Why or why not?
- No
- hormones are removed and used by target organs or removed by liver if in excess
What are trophic hormones?
- hormones secreted by the anterior pituitary
- high concentrations cause hypertrophy of target organs
- low concentrations cause atrophy of target organs
What is the pars intermedia and what does it do?
- strip of tissue between anterior and posterior pituitary lobes in fetuses (dissapears in adults)
- produces POMC pro-hormone in fetuses
The posterior pituitary stores and releases ____ and ____ that are produced in the hypothalamus
- antidiuretic hormone: stimulates water retention by kidneys
- Oxytocin: roles in partruition and lactaction, rises during ejactulation, heightens trust and understanding of social cues
Posterior pituitary hormones that are produced in the hypothalamus are transported along axons of the ____ tract to posterior pituitary
hypothalamo-hypophyseal
Where are the adrenal glands situated?
cap the superior borders of the kidneys
The adrenal cortex secretes ____ hormones into blood in response to neural innervation
catecholamine (norepinephrine and epinephrine)
What does IGF-2 do?
supports IGF-1 with insulin-like actions
The adrenal cortex does not receive natural innervation, but is stimulated hormonally by ____hormone to secrete ____ from the zona ____ and zona ____
ACTH, cortisol, fasiculata, reticularis
Do IGF-1/2 stimulation lipolysis or decrease glucose utilization?
nah bro
What are somatomedians?
another word for Insluin-like growth factrs (IGFs)
What does parathyroid hormone (PTH) do in terms of regulation of the calcium and phosphate balance.
Kidneys:
- stimulates Ca2+ reabsorbtion and inhibits PO4^3- reabsorbtion
Intestine:
- no direct effect
Bone:
- stimulates reabsorbtion
What does 1,25-dihydroxyvitamin D3 do in terms of regulation of the calcium and phosphate balance.
no u suck. I don’t like this question >:(
Kidneys:
- stimulates reabsorbtion
Intestine:
- stimulates absorbtion
Bone:
- stimulates reabsorbtion
What does Calcitonin do in terms of regulation of the calcium and phosphate balance.
Kidneys:
- inhibits reabsorbtion
Intestine:
- no direct effect
Bone:
- stimulates deposition
What are the three response stages to stress?
- alarm: sympathoadrenal system activated
- resistance: CRH secretion from hypothalamus, ACTH secretion from anterior pituitary, corticosteroid secretion from adrenal (ie: readjustment to stressor)
- exhaustion: if readjustment is not completed, sickness or death may occur
in the thyroid, follicular cells synthesize ____ and parafollicular cells secrete ____
thyroxine ; calcitonin
Androgen-binding protein is secreted into the ____ by ____ to ____
seminiferous tubule lumens ; Sertoli cells ; bind and concentrate testosterone withint the tubules
Describe the negative feedback pathway control of parathyroid hormone (calcium phosphate balance)
- a low amount of Ca2+ in plasma stimulates the parathyroid’s secretion of PTH
- the PTH secreted stimulates bone reabsorbtion
- the PTH also stimulates the kidneys to convert 25-hydroxyvitamine D3 (from the liver) to 1,25-dihydroxyvitamien D3, which results in increased intestinal absorbtion
- When Ca2+ plasma levels increase, it induces negative feedback on the parathyroid to to inhibit further PTH secretion
FSH receptors are only in the ____ in the testes
Sertoli cells
Spermatogenesis is arrested at ____ during embryonic development until puberty when testosterone rises
Prophase I
Is LH or FSH more important for spermatogenesis?
- LH - stimulates testosterone secretion
- FSH only enhances the effect of LH, w/o FSH, spermatogenesis would still occur, just later in puberty
Sexual function of the male reproduction system requires both ____ and ____ activity
sympathetic ; parasympathetic
What are the gonadotropic hormones?
FSH and LH
What is the female sex steroid(s)?
estrogen and progesterone
What is the male sex steroid(s)?
testosterone
What are kisspeptins? What do they do?
- released by neurons of the hypothalamus
- allow GnRH themselves to generate pulse secretion
____ cells in the breast contract to propel milk through the duct system
myoepithelial
In males, sex steroid secretion occurs…(constantly/cyclically)
constantly
In females, sex steroid secretion occurs…(constantly/cyclically)
cyclically
Milk secretion is controlled by ____ that is released by the hypothalamus into the hypothalamo-hypophyseal system
Prolactin-inhibiting hormone (PIH)
What is inhibitin?
- secreted by Steroli cells of seminiferous tubules in males and granulosa cells of the ovarian follciles in females
- inhibits secretion of FSH (not LH, FSH only!!)
PIH secretion is inhibited by ____ which is high during pregnancy, but counteracted by large concentrations of prolactin secretion
estrogen
sex steroids induce negative feedback on what?
gonadotropin secretion (FSH/LH)
What does luteinizing hormone released hormone (LHRH) / gonadotropin releasing hormone (GnRH) do?
stimulates release of FSH and LH
high ____ and ____ hormone levels prevent prolactin from stimulating mammary glands until after birth
estrogen ; progesterone
What’s another name for gonadotropin releasing hormone (GnRH)?
luteinizing hormone released hormone (LHRH)
What does 5α-reducatse do?
converts testostrone into dihydrotestosterone (DHT)
(testosterone derivatives)
What is colostrum?
- first milk
- provides infants with IgA antibodies as well as cytokines and lymphocytes that promote the development of a baby’s active immunity
Breastfeeding can inhibit ____ hormone secretion which inhibits ____ secretion which inhibits ovulation
GnRH ; gonadotropin
What is aromatization? Why is it important?
- testosterone can be converted into estradiol-17β by aromatase
- allows testosterone to enter the male fetal brain during development
Can LH supress FSH secretion?
no
Do X or Y chromosomes have more genes?
X
Can X and Y chromosomes recombine?
Only their tips
What are the seminiferous tubules?
- where spermatogenisis occurs
- contains Sertoli cells, which have FSH receptors, and produce inhibitin
What is genomic imprinting?
the imprinted allele (ie: maternal or paternal) is silenced and the other allele is expressed
What are interstitial (Leydig) cells?
- contain LH receptors, which stimulate testosterone secretion (i.e. they secrete testosterone)
- form a thin web of connective tissue known as interstitial tissue
- fill the spaces betwen the tubules
what is congenital adrenal hyperplasia?
type of pseudohermaphroditisim where excessive androgen secretion from the adrenal cortex without mullerian inhibition hormone production results in the formation of a uterus and tubes with partially masculinized external genetalia
lumen of the uterine tube is ____ with the uterus
continuous
what is testicular feminization syndrome?
type of pseudohermaphroditism where normally functioning testes have a lack of testosterone receptors, resulting in female genetalia without uterus or tubes due to mullerian inhibition hormone; no male accessory sex hormones
Describe the steps of oocyte and follicle development
(good luckkkk its so long lolol)
Before Puberty:
- the ovraies contain oogonia, each surrounded by a primordial follicle
- most oogiona die, however those athat live are known as primary oocytes
- primary oocytes begin meiosis, and arrest in prophase I
After Puberty:
- follicles grow, and become dark and cuboidal shaped, and are known as primary follicles
- the primary follicles secrete anti-Mullerian hormone (AMH)
- with stimulation from FSH, the follicles begin to grow granulosa cells, which fill the follicle and surround the oocyte
- neighbouring cells pass cGMP thru gap junctions to ensure cells stay arrested.
- some of the follicles will continue to grow, and develop vesicles, where they are then called secondary follciles
- vesicles fuse to form a singular antrum, and the follicle is know as a mature/graafian follicle
- LH begins to lower cGMP levels, which allows meiosis to continue, which produces a secondary oocyte and a polar body
- meiosis begins again, but arrests in metaphase II
- the follicle forms a cumulus radiata to support the oocyte
- the granulosa cells forms a corona radiata ring
- oocyte and corona radiata are seperated by a zona pellucida
(ovulation is then set to begin!)
What is capacitation? What causes it?
- a sperms ability to fertilize an egg
- caused by alkalinity of the female reproductive tract causeing in increase in sperm pH (activates sperms flagellum, i.e. its ability to swim)
- progesterone within the follicular fluid activates Ca2+ channels, aka CatSper, which causes sperm hyperactivation
- sperm are drawn to ovum vias chemotaxis (chemical attraction) and termotaxts (high temperature attraction)
what happens to the sperm when deposited into the female? (focus on acrosome)
- progesterone activates CatSper channels
- acrosome reaction occurs, resulting in fusion of the acrosomal membrane with the plasma membrane – forming pores in which acrosomal enzymes exit through (exocytosis)
- enzymes then allow the sperm to digest the zona pellucida and get to the oocyte
What is polyspermy?
when >1 sperm fertilize 1 egg
What is phospholipase C? What does it do?
- enzyme released by the oocyte once sperm fuses
- produces the second messnger inositol triphosphate, which triggers endoplasmic reticulum release of Ca2+ – producing a Ca2+ wave
- this wave protects against polyspermy, and allows fertilized oocyte to resume meiosis to produce a mature ovum and a polar body
What is considere an embryo?
zygote ➡ 8 weeks
What is considered a fetus?
8 weeks ➡ parturition
what is a blastocyte?
a hollow structure consisting of an inner cell mass (which will become the fetus) and a chronion (which will bome the placenta)
describe the conversion from zygote to implantd blastocyte (just do the names of things)
- zygote
- (after cleavage 1) 2-cell stage
- (after cleavage 2) 4-cell stage
- (after cleavage 3) 8-cell stage
- (after cleavage 4) 4-cell stage
- (after cleavage 5) mordula
- blastocyte
- implanted blastocyte
what is chorionic gonadotropin (hCG)? What secretes it, and what does it do?
- chorionic cells / placenta
- works similarly to LH, and preserves the corpus luteum after implantation
- prevents immunological rejection of implanted embryo
What is chorion frondosum?
maternal tissue
What is decidual basalis?
fetal tissue
the placenta is made up of what?
chorion frondosum and decidual basalis
What is amniotic fluid made of?
isotonic secretions, as well as fetal urine and sloughed off cells
What do umbilical arteries do? How many are there?
- 1
- transport blood from the fetus to the vessels in chorionic villi
What do umbilical veins do? How many are there?
- 1
- transport blood from vessels in the chorionic villi to the fetus
What happens to the mother cardiovascular system during pregnancy?
- overall increase in blood volume
- decrease in peripheral resistance
What does chorionic somatomammotropin (hCS) do? What secretes it?
- the placenta
- suppliments the activity of placental growth hormone (PGH) and acts alongside the mothers GH to promote lipolysis and gluco-sparing by matrna tissue and polyurea
What does placental growth hromone (PGH) / Growth hormone variant (hGH-V) do? What secretes it?
- the placenta
- acts alongside the mothers GH to promote lipolysis and gluco-sparing by matrna tissue and polyurea
What hormones stimulate uterine contractions, and what produces them?
- oxytocin (hypothalamus)
- prostaglandins (uterus)
How does the fetal adrenal cortex contribute to the induction of labour in mammals?
Corticosteroids secreted by the fetus stimulate placental conversion of progesterone to estrogen
Describe the induction of labour in primates
- something we don’t understand interferes with progesterone receptors
- the placenta produces corticotropin-releasing hromone (CRH) which stimulates ACTH release from the anterior pituitary
- ACTH stimulates release of cortisol from the adrenal cortex of the mother and baby, when then stimulates relased of more CRH
- the fetal adrenal zone secretes dehydroepiandrosterone sulfate (DHEAS), which travels to the placenta for the conversion of estrogens (to estriol)
- the estriol then travels to the uterus to increase sensitivity to hormones by producing more receptors
