ch 5 Flashcards
1)Follicular phase (proliferative phase)
Pituitary secretes relatively high levels of FSH
Function:stimulate follicles in ovaries
At beginning of follicular phase, it signals one follicle in the ovaries to bring an egg to final stage of maturity
At same time, follicles secrete estrogen
2)ovulation
Follicle ruptures open releasing the mature egg
Estrogen has risen to a high level which inhibits FSH production
High level of estrogen stimulate hypothalamus to produce GnRH which causes pituitary to begin production of LH
Surge of LH triggers ovulation
3)luteal phase
After release of egg, the follicle, under stimulation of
LH, turns into a glandular mass of cells called corpus luteum
Corpus luteum manufactures progesterone, so progesterone levels rise during the luteal phase
High levels of progesterone also stop the pituitary secretion of LH, and as LH levels decline, corpus luteum degenerates
Degeneration comes to a sharp decline in estrogen and progesterone levels at end of luteal phase
Falling levels of estrogen stimulate the pituitary to begin production of FSH and cycle begins again
4)menstruation
Shedding of the inner lining of uterus (endometrium), which then passes out through the cervix and vagina
Estrogen and progesterone levels are low and FSH levels are rising
Menstruation is triggered by the sharp decline in estrogen and progesterone levels at the end of luteal phase
Follicular phase:
High levels of estrogen stimulate endometrium of the uterus, to grow, thicken and form glands that will eventually secrete substances to nourish embryo
Luteal phase
Progesterone secreted by corpus luteum stimulates the glands of the endometrium to start secreting the nourishing substances
If egg is fertilized, About 6 days after ovulation, the fertilized egg arrives in a uterus that is well prepared to nourish it
Corpus luteum continues to produce estrogen and progesterone for about 10-12 days
If pregnancy hasn’t occurred, its hormone output decline sharply at the end of this period
Menstrual phase
The uterine lining thus cant be maintained, and is shed, resulting in menstruation
Immediately afterward, a new lining starts forming in the next proliferative phase
Menstrual fluid is a combination of blood (from endometrium), degenerated cells, and mucus from cervix and vagina
Normal discharge for an entire period is 30-60 mL
Anovulatory cycle
Menstruation may take place without ovulating
Cervical mucus cycle
involves glands in the cervix that secrete mucus throughout the menstrual cycle
One function of the mucus is to protect the entrance to the cervix, helping to keep bacteria out
Estrogen increases at start of a new cycle- mucus is alkaline, thick and viscous
When LH production begins, just before ovulation, cervical mucus changes and becomes even more alkaline, thin, and watery
After ovulation, mucus returns to its more alkaline state
Basal body temperature
Taken with thermometer right before getting up in morning, fluctuates with phases of menstrual cycle
Temp is low during follicular phase, takes a dip on day of ovulation
Day after ovulation it rises, and continue to be higher level for rest of cycle
Progesterone raises body temp, so high temp during luteal phase is due to increases production of progesterone during that
Descent of tests and ovaries
At first, Ovaries and testes lie near top of abdominal cavity
By 10th week, they have grown and moved down to level of upper edge of pelvis
The ovaries remain there until after birth and later shift to adult position in pelvis
The testes makes a much longer journey down into scrotum via passageway called inguinal canal (ocurrs around 7 months)
Inguinal canal closes off after testes descend
2 problems can occur:
1)one or both tests failed to descend into scrotum by time of birth called cryptorchidism (undescended testes)
2)inguinal canal doesn’t close off completely
Loops of intestine can enter scrotum later in life called inguinal hernia
Homologous organs
When an organ in male and female both develop from same embryonic tissues
Analogous organ
2 organs have similar functions
8 variables of gender
1)chromosomal gender: XX in females; XY in males
2)gonadal gender: ovaries in females; testes in males
3)prenatal hormonal gender: Testerone and MIS in males but not females before birth
3b)prenatal and neonatal brain differentiation: Testosterone present for masculinization, absent for feminization
4)internal organs:fallopian tubes, uterus, and upper vagina in females; prostate, vas, and seminal vesicles in males
5)external genital appearance: clitoris, inner and outer lips, and vaginal opening in females; penis and scrotum in males
6)pubertal hormonal gender: at puberty, estrogen and progesterone in females; testosterone in males
7)assigned gender: announcement at birth
8)gender identity: the person’s private, internal sense of maleness or femaleness
What determines the age at which girl first menstruates?
1)percent body fat hypothesis:
percentage of body weight that is fat must rise to a certain level for menstruation to occur for the first time and for it to be maintained
Leptin: a hormone is related to onset of puberty in girls and in boys
Leptin levels rise as body fat increases
Leptin stimulates growth of skeletal bone and release of LH and Kisspeptin
Percent body fat hypothesis helps to explain the lack of period in people with anorexia
