Term test 2- Reproduction & Immunology Flashcards
which two hormones from the anterior pituitary, are necessary for breast milk?
PRL and GH
Describe the breast structure.
15-20 lobes divided by adipose tissue then subdivided into lobes containing alveoli that secrete milk.
Why is milk production during pregnancy prevented?
this is due to the high levels of estrogen during pregnancy. High levels of estrogen, increase secretion of PIH through positive feedback.
what are the two hormones needed for milk to be secreted from the breast, and where are they found?
prolactin from the Anterior pituitary, and oxytocin from the posterior pituitary.
what role does prolactin play in breast milk?
it stimulates production
what role does oxytocin play in breast milk?
it releases the milk.
what are some stimuli for the release of breast milk?
1) a child’s cry 2) suckling
why does oxytocin play such an important role, and why is it present in both male and females?
It is a key element in the trust factor developed by humans. it is a neuropeptide that place a key role in social attachment and affilation in non-human mammals. It causes substantial increase in trust among humans.
what determines gender?
A particular gene on the Y chromosome induces the emrbyonic gonads to become testes. females lack a Y chromosome, and the absence of this gene causes the development of ovaries.
A gene known as SRY *(sex-determining Region of the Y) is though to be important for male determination
What is special about the SRY?
it is a conserved gene, meaning it has no evolved much over the years, and development of multiple species.
it is the ultimate maleness gene, and action after 6 weeks of conceptions, it triggers fromation of the testies (from primordial gonads). These testes produce testosterone, and without the SRY gene, a fetus would develop into females. regarless of the Y chromosome’s presence.
in the fetus, sec differentiation beging with the developement of the gonad from a bipotential primordium. Explain the female development.
1) abscence fo the SRY protein-gonadal tissue develops into ovaries
2) no testosterone, so no mullerian inhibition factor (MIF) is made from sertoli cells, so wolffaian duct degenerates, and the mullerian duct presences is maintained
3) absence of MIF allows the mullerian duct to become the fallopian tube, uterus and vagina.
in the fetus, sec differentiation beging with the developement of the gonad from a bipotential primordium. Explain the male development.
1) presence of SRY protein- gonadal tissue develops into testes
2) presence of testosterone, so MIF is made from sertoli cells which causes the wolffian duct to be maintained, while the mullerian duct degenerates.
3) testosterone allows Wolffian duct to become seminal vesicle, vas deferens, and epididymis.
Which parent determines if you are a girl or boy?
this is up to the father, since mothers have two X’s, their haploids will only contain X chromosomes, but since males are XY, their haploids will produce 22 single chromasomes, and one sex chromosome being either X or Y, from the original diploid cell.
there is another factor that controls maleness in humans, what is it? (the person is SRY possitve, XY possitive, and still developed a completely female phenotype)
the insulin receptor family played a roll here. To have male anatomy there must be the presence of these 3 receptors:
1) Insulin receptor (INSR)
2) insuline-like growth factor 1 receptor (IGF1R)
3) insuline receptor-related recepetor (INSSR)
hermaphrodites is an intersex condition where individuals have what?
borth ovary and testies tissue, can be 46XX with SRY mosaicism
what is/ who are pseudohermaphrodites?
congenital condition where a person has external genitalia of one gender and internal sex organs of the other gender.
it is an endocrine disorder.
what are the conditions to be a female pseudohermaphrodite, vs. a male?
Males can have the defective enzyme 5 alpha-reductase, functional testosterone, and inadequate levels of DHT. these males have poorly developed genitalia, and were caused by inapproriate exposure to androgens during easly gestation.
Most common female case is congenital adrenal hyperplasia. (excessive secretion of androgens from the adrenal cortex).
Whats the difference between female puberty and male puberty?
Females will experience puberty before boys, and will experience their growth spurt before puberty (menarche)
boys on the other hand will go through puberty while they experience their growth spurt. The testes will develop, then the penis, then the pubic hair, as they follow a chart flow.
explain the metamorphosis of the child into the adult.
1) puberty= activation of the HPG axis resulting in gonad maturation
2) adolescence= maturation of adult social and cognitive behaviors
3) coupling of both through interactions between the nervous system and gonadal steroid hromones
if children are GnRH deficient, what can we do to help them mature sexually? and why do we use this method?
you need to treat with GnRH pulses simular to those that occur normally, the pulsaic method triggers puberty. if you treat with steady infusions of GnRH through drug-delivery pumps there is no proper development.
what are some variations that can affect puberty?
1) genetic variations in timing of onset of puberty
2) environmental factors
3) nutrition (eating disorders)
4) chronic illness (IBD, TB)
5) theoretical concern over synthetic hormones, other environmental chemicals
6) precocious puberty (very early onset)
why is Genghis Khan so influential?
You can track his lineage in mongolia history, due to men carrying a Y chromosome characteristic. he was a huge war lord in mongolia!
what cells are located at the outermost region of the seminiferous tubules, right against the basement membrane?
the stem cells caleld spermatogonia
as spermatogonia develop they move where?
towards the lumen of the seminiferous tubules
