Chapter 20 - Reproduction Flashcards
The germ cells or [] are made in the testes and ovaries by [] and contain 23 chromosomes
The [] is formed after fusion of sperm cell and ovum and contains [] chromosomes.
- Gametes, meiosis
- Zygote, 46 chromosomes
Cells that give rsie to sperm - []
Cells that give rise to ova - []
Spermatogonia
Oogonia
What is the gene that codes for TDF (testis-determing factor)?
SRY
The early-appearing Leydig cells in embryonic testes secretes large amounts of androgens - which androgen primarily?
Testosterone
What are the embryonic, reproductive accessory sex organs ducts for males and females?
- Male - wolffian (meonephric) ducts
- Female - mullerian (paramesonephric) ducts.
In males - Sertoli Cells secrete [] [] factor, that causes regression of the mullerian ducts.
Mullerian inhibition Factor
The secretion of testosterone, from the [] cells, causes growth of wolffian ducts ultimately leading to the male reproductive accessory organs: [] , [], [] , []
- Leydig Cells
- Epididymis, Ductus (vas) deferens, seminal vesicles, ejaculatory duct
FSH and LH are produced and secreted from where?
- Anterior Pituitary
What is the hormone produced in the hypothalamus that stimulates the secretion of FSH and LH from the anterior pituitary?
GnRH - gonadotropin-releasing hormone
What are the 3 primary effects on the gonads from the gonadatropic hormones (FSH and LH)?
- stimulation of spermatogenesis or oogenesis
- stimulation of gonadal hormone secretion
- maintenance of the structure of the gonads.
Whats the first flow (menstrual cycle) of a woman called?
Menarche
What are the 2 components of the testes and what does each component do?
- Seminiferous Tubules
- this is where spermatogenesis occurs
- Interstial Tissue
- Contains Leydig Cells - secrete testosterone
In Males -
FSH acts upon the [] [], specifically [] cells, stimulating [] in the seminiferous tubules
LH acts upon the [] [], stimulating the secretion of []
- Seminiferous Tubules, Sertoli Cells, Spermatogenesis
- Leydig Cells, testosterone
Does inhibin act as a negative feedback mechanism for LH?
- No, testosterone acts as the negative feedback component towards LH
- Inhibin acts as negative feedback on the secretion of FSH from the anterior pituitary
Where are spermatogonia found in the seminiferous tubule?
Are they diploid or haploid?
- They are found at the outermost region of the seminiferious tubule, right against the basal lamina.
- These are diploid. (they will become haploid though)
How do Sertoli cells aid in the transformation of spermatids to spermatozoa?
Sertoli cells phagocytize the “residual bodies” of cytoplasm surrounding the spermatids.
What are the 2 tissue layers of the penis that fill with blood during erection?
- Corpora Cavernosa - dorsal
- Corpus Spngiosum - ventral
Which enzyme is activated by NO in the penis to convert GTP into cGMP.
What does cGMP indirectly do to create an erection?
- Guanylate Cyclase
- cGMP closes Ca2+ channels.
- Fall in intracellular Ca2+ causes smooth muscles to relax and corpora cavernosa to relax and blood vessles to dilate = erection!
What enzyme breaks down cGMP, specifically in the penis to cause erectile dysfunction?
What are 2 medications that inhibit this enzyme?
- Phosphodiesterase (PDE)
- Viagra, Cialis
What are the 3 layers of the uterus?
- Perimetrium - outer layer of connective tissue
- Myometrium - smooth muscle layer
- Endometrium - inner epithelial layer
- Stratum basale
- Stratum functionale - grows and sheds during menstruation
What is a follicle called once it is mature, it’ll have a single fluid- filled cavity?
Graafian Follicle
The theca of the ovary produces [] in response to LH stimulation.
[] is convereted to estradiol by the enzyme aromatase located in the [] cells of the follicle.
- Testosterone
- Testosterone, granulosa
What does FSH do to the follicle?
- Stimulates increased amounts of aromatase in the granulosa cells.
- This will increase the amount of estradiol in the blood as follicles grow under FSH stimulation.
- Testosterone is converted to estradiol by aromatase
If a follicle stops growing it will become [] - regression term the applies the follicle did not rupture.
This is a type of apoptosis
Atresia
What is the corpus albicans?
- It is a corpus lutuem from a previous non-fertile cycle that regresses to a nonfunctional state.
Unlike the ovarian follicle, the corpus luteum secretes two sex steroid hormones: [] and []
Estradiol and progesterone
The cyclic changes in the endometrium are called [], [], and [] phases…
Menstrual
Proliferative
secretory
How long does the follicular phase last?
What is happening with the follicles during this phase?
What are the level of ovarian hormones during this phase? What stimulates these hormones release?
- Day 1 of the cycle to Day 13 (Highly variable)
- 1 follicle will reach maturity and become a graafian follicle
- other primary follicles can grow into secondary follicles
- Ganulosa cells secrete an increasing amount of estradiol
- estradiol levles are at their highest concentration in the blood 2 days before ovulation (Day 12ish)
The rapid increase in what hormone causes the LH surge?
What does this LH surge due to the follicle?
- Estradiol
- Causes the wall of teh graafian follicle to rupture
LH causes the empty follicle to become what “new” structure?
What does this structure secrete?
Corpus Luteum
estradiol and progesterone
High levels of progesterone (and a little estradiol) have what “type” of effect on the release of FSH and LH?
Negative Feedback affect.
During what Ovarian stage does the “Proliferative phase” of the endometrium take place?
Follicular
During the proliferative phase [] secreted by the developing follicles promotes growth of the []
estradiol
Stratum Functionale of the endometrium
During the secretory phase, the increased secretion of [] from the [] stimulates the development of the uterine gland.
What happens to the endometrium during this phase?
- progesterone, corpus luteum
- The endometrium becomes thick, vasuclar and spongy.
- The uterine gland becomes engorged with glycogen so it will be well prepared if fertilization occurs.
[] [] occurs as a result of a fall in ovarian hormone secretion during the late luteal phase.
Menstrual phase.
T/F
Progesterone level increase and Estrogen levels decrease at the end of the secretory phase/beginning of menstruation?
False.
Estrogen levels increase and progesterone levels decrease
What hormones can actually inhibit lactation?
Estrogen and Progesterone
What are the 3 main functions of estrogen during the female “cycle?”
- Growth of ductile tissue, fatty deposits in breasts
- Promotes Prolactin - acts on breast tissue growth preparing mamary gland for lactation
- Growth and contractile responsiveness of uterine muscle to Oxytocin
- Does not stimulate the muscle to contract though!
What are the main functions of Progesterone during female “cycle?”
- Growth glandular portion of the breast
- Suppresses contractile activity in uterine smooth muscle
- Maintains the secretory phase of the uterus
