Repro. System Physiology

Question 1

four tasks of both repro systems

Answer 1

produce gametes
bring gametes together through copulation
combine genetic material
(gestation/parturition)

Question 2

each type of gonad (primary sex organ) produces what?

Answer 2

ovaries and testes both produce gametes and hormones

Question 3

HPG axis

Answer 3

Hypothalamic-pituitary-gonadal axis
fundamental relationship between these three structures
hypothalamus -> tropic hormone GRH -> hypophyseal portal system’s blood vessels -> anterior pituitary releases FSH & LH -> gonads release steroidal sex hormones -> systemic circulation -> target cells

negative feedback react with receptors to inhibit hypothalamus’s release of GRH, anterior pituitary’s release of FSH and LH

Question 4

HPG axis and puberty

Answer 4

prepubescent children’s circulating sex hormones are very low but still enough to exert negative feedback on hypothalamus,
as puberty approaches, hypothalamus’ cells become less sensitive, so GRH increases because they’re less inhibited
need continually larger amounts of hormone to inhibit cells in hypothalamus, so GRH continues until adult pattern achieved

Question 5

What happens during mitosis in spermatogenesis?

Answer 5

(first step), spermatozoa make 2 identical diploid copies and A stays by basal lamina while B gets pushed down to grow into a primary spermatocyte

Question 6

What happens during meiosis I of spermatogenesis?

Answer 6

primary spermatocyte divides into two different smaller haploid daughter cells aka secondary spermatocytes

Question 7

what happens during meiosis II of spermatogenesis?

Answer 7

each of the two secondary spermatocytes divides into two different smaller haploid cells called spermatids

Question 8

what does LH act on in males and what are the results?

Answer 8

interstitial cells, telling them to release testosterone, some of it will be grabbed up by Androgen Binding Protein so it can enter the testis and drive events of spermatogenesis

Question 9

What does FSH act on in males and what are the results?

Answer 9

sertoli cells, tells them to increase production of ABP so that the local concentration of testosterone can stay high for spermatogenesis

Question 10

What prevents the testes from becoming overloaded with sperm cells?

Answer 10

negative feedback - large amounts of sperm in the lumen stimulate sertoli cells to release inhibin, which acts on the anterior pituitary gland to inhibit the release of more FSH and LH

Question 11

testosterone’s effects on body other than testes

Answer 11

converted into other hormones at tissue level by local enzymes,
converted → estradiol in some brain neurons, secondary sex characteristics develop, axillary and pubic hair, sex drive in women, hypersecretion can cause super sex drive, early development of sex organs and secondary sex characteristics, females develop beard and masculine distribution of body hair, and clitoris grows

cognition, memory, sex drive, bone marrow, bone density, collagen, bone density, sperm count, prostate growth, erectile function

Question 12

erection

Answer 12

arterioles usually constricted, sexual excitement causes CNS (cerebrum) parasympathetic neurons → local release of NO → smooth muscle relaxation → filling with blood → enlargement & stiffening → veins draining penis are cut off to allow maintenance

Question 13

ejaculation

Answer 13

spinal reflex from sympathetic nerves → contraction of glands → presence of semen in urethra → bulbospongiosus series of rapid contraction → semen leaves body ~11 mph

Question 14

ED

Answer 14

erectile dysfunction affects about half of men over 40

cardiovascular disease (obesity)

too little NO, can’t fill corpora cavernosa with blood

sildenafil (Viagra) keeps NO around longer and enhances effect of existing NO

Question 15

In primary oocytes, meiosis I arrests in ___ and can resume years later if oocyte is recruited

Answer 15

prophase I

Question 16

in secondary oocytes, meiosis II arrests in ___ and only continues if fertilization occurs

Answer 16

metaphase II

Question 17

what do granulosa cells of follicles release?

Answer 17

liquor folliculi and estrogen

Question 18

when is meiosis I completed?

Answer 18

just before ovulation (release of secondary oocyte)

Question 19

corpus luteum (follicle leftover after ovulation) releases lots of which hormone?

Answer 19

progesterone (to maintain possible pregnancy)

fertilized egg implants in uterus and releases HcG and tells corpus luteum around

Question 20

corpus albicans

Answer 20

corpus luteum becomes a scar on ovary if no pregnancy

Question 21

atresia

Answer 21

99.9% of follicles never recruited, undergo apoptosis

Question 22

what makes a dominant follicle different?

Answer 22

follicle sensitive to even falling levels of circulating FSH that completes meiosis I and freezes in metaphase II of meiosis II

Question 23

spermatogenesis vs. oogenesis, including # of gametes per meiotic division

Answer 23

4 equal sized sperm vs. 1 lg ovum and 2-3 sm. polar bodies

Question 24

sustentocytes (sertoli) : spermatogenesis :: granulosa cells :

Answer 24

oocyte

one sertoli cell supports many sperm; many granulosa cells support one oocyte

Question 25

dominant hormone in each phase of ovarian cycle

Answer 25

follicular phase - estrogen (granulosa cells)

luteal phase (always 14 days) - progesterone (corpus luteum)

Question 26

estrogen spike during follicular development triggers anterior pituitary to release ___

Answer 26

luteinizing hormone, which triggers ovulation

Question 27

FSH and LH at ovary

Answer 27

LH stimulates thecal cells to increase production of androgens →

FSH stimulate granulosa cells to convert androgens → estrogen → negative feedback & inhibin → only dominant follicle can withstand low level of FSH

Question 28

When does ovulation occur in the uterine cycle?

Answer 28

at the end of the proliferative phase (around day 14)

Question 29

puberty onset

Answer 29

cells of the hypothalamus responsible for GnRH become less sensitive to inhibition from estrogen & testosterone, so you need increasingly higher levels of sex hormones to inhibit GnRH, leading to higher levels of sex hormones in the body and their various effects

Question 30

what is mitosis for?

Answer 30

growth and repair, which is why it makes 2 genetically identical cells (same size, same genome)

Question 31

how many chromosomes do you find in a human liver cell vs. a human sperm cell?

Answer 31

46 chromosomes in somatic (non-gamete) cells

23 chromosomes in gamete cells

Question 32

metaphase of meiosis I is significant for genetic variability because

Answer 32

tetrads, crossing over

Question 33

what else does sperm cell have besides genetic material

Answer 33

package of enzymes near nose for entering ovum, motor proteins in flagella to move (no cytoplasm)

Question 34

spermiogenesis vs spermatogenesis

Answer 34

spermiogenesis is late spermatogenesis after mitosis and meiosis I-II, whereas spermatogenesis is the whole process from spermatogonia → spermatozoa

Question 35

FSH vs LH in males

Answer 35

FSH → sertoli cells to increase ABP and get testosterone into seminiferous tubule to drive spermatogenesis

LH → interstitial cells to increase production of testosterone (some released locally, some systemic)

Question 36

influence of systemically circulating testosterone on male body

Answer 36

increased RBC production (higher hematocrit), larger and denser skeleton, positive feelings, better cognition & memory, libido, body hair and more collagen, muscle mass

Question 37

stimuli for erection (2 types)

Answer 37

top-down (cerebrum integrates 5 senses’ input) OR

direct touch stimulation

Question 38

what makes arteries of penis different from others

Answer 38

dual-innervated; parasympathetic innervation of arteries → release NO → smooth muscle relaxation

Question 39

difference between primary and secondary oocyte

Answer 39

primary is diploid, secondary is haploid (finished meiosis I)

Question 40

meiosis I completes in a ___ follicle just before ___

Answer 40

meiosis I completes in an antral follicle just before ovulation

Question 41

what hormone do follicles produce? effect regarding FSH?

Answer 41

follicles produce estrogen → negative feedback → lower FSH levels → only most sensitive follicles continue development

Question 42

estrogen has a very brief transient feedback when?

Answer 42

super high levels of estrogen briefly have a positive feedback effect and lead to FSH and LH spikes right before ovulation

Question 43

ovarian cycle (2 phases)

Answer 43

• follicular phase day 0-14
  
  • day 0-5 is menstruation
• luteal phase 14-28

Question 44

menstrual cycle (3 phases)

Answer 44

1-5 menstrual

6-14 proliferative phase (proliferating endometrium)

15-28 secretory (because high levels of secretion from endometrial glands to maintain it)