Reproductive Physiology Flashcards
Which duct system will differentiate into the epididymis, vas deferens, ejaculatory duct and seminal vesicles?
Wolffian
Which duct system will differentiate into the uterus, ovaries and fallopian tubes?
Mullerian
Where is the SRY gene located?
Y chromosome
The SRY gene is expressed and what structure develops after?
Testes
What hormone causes the degeneration of the Mullerian ducts?
AMH (anti-mullerian hormone)
What happens in a person with androgen insensitivity?
XY, presents as female due to inability to respond to testosterone
What structures are people with androgen insensitivity missing?
The duct systems do not differentiate and degenerates completely
Which cells secrete AMH?
Sertoli cells
Which cells secrete testosterone?
Leydig cells
Where does spermatogenesis occur?
Seminiferous tubules of the testes
What is the site of sperm maturation?
Epididymis
At what point are the sperm motile?
In the vas deferens
What do the seminal vesicles do?
Secrete chemicals that promote sperm motility and fructose
What is the purpose of fructose in semen?
Food for sperm
60% of seminal fluid comes from what gland?
The seminal vesicles
What gland secretes bicarbonate?
Prostate gland
30% of seminal fluid comes from what gland?
The prostate
Why is bicarbonate secreted into the semen?
Buffers acidity in vagina
What do the bulbourethral glands do?
Buffers any residual urine and provides lubrication
How much of semen is sperm?
About 10%
What is the site of sperm storage?
Vas deferens
What moves sperm along in seminiferous tubules?
Pressure from sertoli cells secreting fluid
Which central nervous system function controls erections?
Parasympathetic
Which central nervous system function controls ejaculation?
Sympathetic drive
Viagra works by inhibiting what?
cGMP phosphodiesterase
What does cGMP do in the male reproductive system?
Promotes vasodilation and the relaxation of smooth muscle, allows for an erection
What secretes FSH and LH?
Anterior pituitary
Testosterone has a negative feedback loop on what two hormones?
LH and GnRH
What opposes estrogen action on breast growth?
Testosterone
EPO secretion by the kidney is stimulated by what hormone?
Testosterone
What does EPO do?
Increases O2 utilization
What is one concern of anabolic steroids?
Overstimulation of prostate growth
Anabolic steroids cause the shrinkage of what?
Testes, leads to low sperm count and infertility
Menstruation is on what day of the menstrual cycle?
1st day
What is the difference between the menstrual and ovarian cycle?
menstrual just refers to the uterus and ovarian just to the ovaries
What are the fingerlike projections that guide the egg into the fallopian tube?
Fimbrae
What is surrounding the oocyte?
Zona pellucida and granulosa cells
What is a follicle?
Contains the oocyte, it is full of fluid and surrounded by granulosa cells.
What leaves at ovulation?
The egg leaves surrounded by the zona pellucida and one layer of granulosa cells
What is the corpus luteum?
What remains of the follicle after ovulation - theca cells and granulosa cells. Produces progesterone
Estrogen affects what two hormones in a negative feedback loop?
LH and FSH
During what days of the ovarian cycle is the corpus luteum present?
Days 15-28
At the end of what week in the ovarian cycle does a follicle become dominant?
First week
What happens when a follicle becomes dominant?
Increased number of FSH and LH receptors, other developing follicles degenerate
What secretes estrogen during the first week?
The follicles
The decrease of FSH during days 8-14 is caused by what?
Atresia of additional developing follicles
What induces ovulation?
Massive surge in LH
How is LH stimulated before ovulation?
Estrogen has a positive feedback loop on LSH and FSH during the second week
When is the only time during the ovarian cycle that estrogen has a positive feedback loop?
Days 8-14
Thickening of the endometrium begins in what week of the menstrual cycle?
2nd week (days 8-14)
During weeks 3 and 4 of the ovarian cycle, what is the major source of hormones?
Corpus luteum
What does the corpus luteum secrete?
Estrogen, progesterone and inhibin
Why is LH inhibited in weeks 3 and 4?
Prevents new follicular development to focus energy on preparing uterus for implantation
What is present in the endometrium to serve as nutrients?
Glycogen and glycoproteins
What is the secretory phase of the menstrual cycle?
Weeks 3 and 4
If there is no pregnancy, what happens to the corpus luteum?
It degrades
What triggers a decrease in estrogen and progesterone near the end of the menstrual cycle?
Degradation of corpus luteum
What triggers menstruation?
Decrease in plasma levels of estrogen and progesterone
What does inhibin do?
Inhibits FSH secretion
How does hormonal birth control work?
Combination of estrogen and progesterone prevents follicles from developing and prevents ovulation
How long is sperm viable for in the reproductive tract?
5-7 days
What part of the egg does sperm need to bind to?
Zona pellucida
What are the major obstacles for the sperm?
Vaginal acidity and length to swim to fallopian tubes
How long does the zygote stay in the fallopian tube?
3-4 days
What causes the zygote to move toward the uterus?
Uterine contractions
At what point is the zygote totipotent?
16-32 cells
What does totipotent mean?
Ability to differentiate into any type of cell
What do the support structures (placenta and amniotic sac) differentiate from?
The trophoblast of the blastocyst
What becomes the embryo of the blastocyst?
Inner cell mass
When the zygote has reached about 100 cells, what is it referred to as?
A blastocyst
What is the long term nutritional source for the embryo?
Placenta
What does the placenta do?
Connects fetal and maternal tissues, source of fetal nutrition
When does the placenta develop?
About 5 weeks after implantation
When is pregnancy tracked from?
Date of last period
How early can pregnancy be detected?
About 1 week after missed period
What is detected during a pregnancy test?
hCG
When does the blastocyst implant?
Around day 21
Low body weight/low body fat and increased cortisol can cause what?
Amenorrhea
Why does amenorrhea happen?
Decreased GnRH, leads to no endometrium and no bleeding
What is a risk of amenorrhea if condition persists too long?
Bone degradation and muscle weakness
Where is hCG secreted from?
Trophoblast cells of the embryo
What does progesterone do in pregnancy?
Prevents uterus from contracting, keeps the embryo inside
What does estrogen do in pregnancy?
Stimulates growth of uterine muscle
What does hCG do in early pregnancy?
Keeps corpus luteum from degrading for about 2 months until the placenta grows
After 2 months, what is the main estrogen and progesterone source in pregnancy?
Placenta
How many pregnancies start with the water breaking?
About 10%
What allows for coordinated uterine contractions during birth?
Synthesis of connexin (gap junctions) between myometrial cells
What is the myometrium?
Smooth muscle of the uterus
An increase in oxytocin receptors on the myometrium causes what?
The cervix becomes soft and flexible to allow for birth
Where do contractions begin in the uterus?
Upper uterus
What hormone stimulates milk production?
Prolactin
What stimulates prolactin following birth?
Massive drop in estrogen following birth
What hormones are increased by infant suckling?
Prolactin and oxytocin
Prolactin inhibits negative feedback on what hormone?
GnRH
What is amenorrhea?
3 missed periods in a row or lack of period at all
