Term
True or False
Gonads are undifferentiated during early fetal life |
|
Definition
|
|
Term
| Describe the general concept of embryonic differentiation of sex |
|
Definition
-primordial germ cells form
-circulate in vasculature & migrate through tissues
-colonize genital ridge to form indifferent gonads
Cortex differentiates into ovary, or medulla differentiates into testis based on transient expression of genes:
-Testes Differentiation Factor (TDF) from the Sex-Determinining Region Y |
|
|
Term
| Describe the pathway taken if an embryo will become male |
|
Definition
Testes Differentiation Factor (TDF) present
1. testes develop
2. Leydig cells & Sertoli cells develop
3. Leydig prod. testosterone, sertoli prod. MIF
4. MIF causes mullerian duct to degenerate
5. Testosterone causes Wolffian duct to develop epidydimis, ductus deferens, ejaculatory ducts
6. Testosterone causes development of prostate, penis & scrotum from other embryonic structures |
|
|
Term
| Describe the pathway taken if an embryo will become female |
|
Definition
No TDF present
1. Ovaries develop...lack of tesosterone & MIF
2. Mullerian duct develops uterus, uterine tubules
3. Wullfian duct degenerates
4. Other embryonic structures develop into vagina, labia & clitoris develop |
|
|
Term
| Describe the structure of the hypothalamus as it relates to sex differentiation of the brain |
|
Definition
-2 centers with GnRH neurons
Tonic center: basal secretion
Surge center: ovulatory cysts & female behaviour |
|
|
Term
| Describe the sex differentiation of the brain |
|
Definition
-occurs during perinatal period
-placenta & embryonic adrenals releases estradiol
-estradiol binds to carrier in blood (doesnt enter brain)
-testosterone released by testes diffuses into brain, is converted to estradiol
-estradiol in brain activates surge center, creating a ''male' brain |
|
|
Term
| What is the primary goal of male repro organs |
|
Definition
| successfully produce spermatozoa & deliver to female |
|
|
Term
| Describe the general cycle of spermatozoa production & delivery (5 steps) |
|
Definition
1. Testes manufacture spermatozoa
2. Epidydimis head & body - fluid is absorbed, membrane of spermatozoa changes, nucleus & flagella stabilize (gain motility)
3. Epidydimis tail stores spermatozoa, smooth muscle will contract when sexuall stimulated
4. Accessory sex glands add metabolic substrates, surface coatings
5. Penis erects, ejaculates to deliver sperm in vagina |
|
|
Term
| At what temperature must testes be kept? How is this achieved? |
|
Definition
4-6 below the temperature required for spermatogenesis
-testes decend via inguinal canal, so they are outside the body cavity
-veins in spermatic cord act as a heat exchanger |
|
|
Term
| Describe the outer structure of the testes (4 points) |
|
Definition
Scrotum: skin sac from abdominal cavity with a layer of smooth muscle
-scortal fascia & parietal vaginal tunic are layers of connective tissue lining the scrotum
-tunica albugine + visceral vaginal tunic covers the testes
-smooth muscle covers the septa (helps to move immature sperm) |
|
|
Term
| Describe the inner structure of the testes |
|
Definition
Seminiferous Tubules
-sperm production
-ducts collect sperm to rete testis in center, bringing sperm to epidydimis
Interstition
-between the seminiferous tubules
-composed of connective tissue, nerve, blood vessels & leydig cells |
|
|
Term
| Which cells produce testosterone? |
|
Definition
|
|
Term
| Describe some of the characteristics of the boar reproductive tract |
|
Definition
-more pronounced intersitium = leydig cells produce estrogens and more androgens
-location = reduced efficiency of heat exchange
-large seminal vesicles = large volume of semen
-large bulbo-urethral glands = produce gel fraction
These contribute to a prolonged ejaculation with a large volume of semen, and therefore fewer sperm 'reserves'. (can't ejaculate as frequently) |
|
|
