Reproduction Flashcards
What is a person’s biological sex based on differences in gonads or the organs that make gametes?
can have testes or ovaries
What is a person’s biological sex based on differences in chromosomes?
have 1 pair of sex chromosomes which can be XX or XY
What is a person’s biological sex based on differences in steroid hormones?
steroids like androgens and estrogen, inhibin, or activin
What is a person’s biological sex based on differences in reproductive anatomy?
internal reproductive anatomy and sex specific external genitalia used for assignment of sex at birth
In regards to gender what is the social definition of gender?
the social and societal constructs of norms behaviors roles associated with being a woman man girl and boy
In regards to gender what is the personal definition?
personal deeply felt identification of ones gender based on self awareness
What is the relationship between reproduction and homeostasis?
reproduction is the antagonist to homeostasis for an individual and is rather in regards to the species which means it may or may not be beneficial to individual
Why is the evolutionary compromise made in the male reproductive anatomy in which the testes are outside of the body?
the testes develop in the inner cavity where the ovaries in women develop and in males they come down from the abdomen pushing the intestines out of the way and they are pulled by a ligament which is attached to the abdomen wall and pull the testes down there is a hole called the inguinal canal which the testes fall down to near the scrotum
What is the vas deferens and what does it do?
is a duct which conveys the gametes made in the testes to the outside and it trails begind the desceding testes and is snagged behind the ureter
What does the urethra go right through?
the prostate gland
What does the prostate gland do?
the main organ that contributes secretions to the semen
What is the prostate gland highly sensitive to and what condition can this cause?
highly testosterone sensitive and it grows and hypertrophies and squeezes down on the urethra so in older men they have problems with urination and have to go more often and this is called benign prostatic hyperplasia BPH
What disease can the prostate gland’s sensitivity to testosterone cause?
can cause cancer because it is stimulated by testosterone
Why are the testes external to the abdomen while the ovaries are not?
production of sperm in the testes cannot happen at body temp so the sperm must be held outside the body in the scrotum which is 1-2 degrees C lower
What muscle wraps around the scrotum and is controlled by heat and cold sensitive nerves in the skin of the scrotum?
the cremaster muscle - in response to cold the muscle contracts and pulls up the testes into the abdomen and heat causes the muscle to relax so the testes tend to hang lower
What is the counter current heat exchanged which helps maintain testicular temperature?
maintenance of a cooler temp in the scrotum is hard if the artery brings body temp blood from the core of the abdomen so there is a venous drainage and they form a mesh with the arteries so the cool blood in the veins can exchange with the heated blood in the arteries so the blood in the veins is warm as it goes back ot the abdomen and the blood in the arteries is cold as it goes back down to the scrotum - this is well developed in marine mammals
What are the two main functions of the testes?
to produce gametes or sperm and secrete testosterone
What is the term for the tightly coiled tubules that have a gradient and are found in the testes and have different cell types?
seminiferous tubules
What is found in the outer basement membrane of semniferous tubules?
capillaries and leydig cells which are both outside the tubule
What do leydig cells do?
secrete testosterone at high levels in men even in old age; they also secrete a testosterone binding protein which keeps the concentration of testosterone inside the tubules really high compared to the outside so testosterone leaves
Damage to a boys germ cells due to the stress of starvation increases the rick of heart disease and cancer and fertility in who?
the grandchildren of that boy
What can environmental and chemical stressful damage cause in men?
can cause damage to the precursors of the spermatogonia and this can have long term effects in life
How do you get from spermatogonium (2n) to a spermatozoa?
spermatogonium (2n)—> primary spermatocyte (2n) – meiosis I—–> secondary spermatocyte (n) –Meiosis II–> spermatids (n) ——-> spermatozoa
What happens to the spermatids (n) generated by meiosis ii?
they get pushed into the epididymis which is continuous with the seminiferous tubules and get produced with the sperm - one day one hundred million sperm will enter the epididymis
What causes ejaculation?
the smooth muscle from the epididymis and the semniferous tubules contract
What makes up semen?
sperm and other fluids
How many sperm are in an ejaculate of a couple mL?
100 million sperm/mL - if you do not consistently ejaculate a few 100 million are attacked and the sperm get old
What is the endocrine control of testicular function?
the hypothalamus secretes GnRH ——> anterior pituitary gonadotropes ——-> FSH and LH; FSH——> sertoli cells and they cause spermatogenesis and secrete inhibin and activin
LH —–> leydig cell —–> testosterone—-> spermatogenesis
What cell type makes sperm in the seminiferous tubules?
Sertoli cells
What does kisspeptin a hypothalamic hormones do?
turns on GnRH secretion during puberty because prior to puberty it is off
What does neurokinin b a hypothalamic hormone do?
a peptide that stimulates LH secretion more than FSH
What does the hypothalamic hormone LPXRFa do?
inhibits GnRH
What does the hypothalamic neuron spexin do?
stimulates GnRH secretion and promotes satiety
What does the inhibin secreted by sertoli cells do?
go back and inhibit FSH