25.3 Male Reproductive Flashcards
What is the spermatgonesesis pathway?
- Primordial germ cells
- Spermatogonia: in testes, mitotic at puberty
- Primary spermatocytes: complete 2nd half of mitosis
- Secondary spermatocytes: finish 2md half of mitosis
- Spermatids:undergo differentiation to become mature sperm
Where are Sertoli cells and what are their functions?
- Surround primary spermatocytes and help with spermatgonesesis.
- Form estrogens from testosterone
What role do the Sertoli cells have in the spermatgonesesis pathway?
- Surround primary spermatocytes.
2. Help regulate the rate and coordinating the process of spermatgonesesis
Where are the mitochondria located in the mature sperm?
- Spirally wrapped around the neck and body
What is the purpose of multiple mitochondria linked in the neck and body of the sperm?
Provide energy for the movement of microtbulules
What does the proacrosomal vesicle develop into and what is contained in this region?
- Acrosome
2. Contain hyaluronidase and proteolytic enzymes
What happens to the head of the sperm during spermatogenesis?
- Nucleus condenses and is capped by the acrosome
- Distal centrioles organize flagellum
- Mitochondria move to base around flagellum
- Excess cytoplasm is sloughed off
What begins to organize the flagellum?
- The distal centrioles that are on opposite side of acrosome
How long must sperm remain in the epididymis before they gain motility?
18-24 hours
Where are cells of leydig found?
Interstitial space of testes
What is the function of the leydig cells?
Secrete testosterone
What activates the cells of leydig to secrete testosterone?
- Leutinizing hormone (LH)
What signals are required for spermatogenesis?
LH, FSH, testosterone
What are the male accessory glands?
- Seminal vesicles
2. Prostate gland
Where are the seminal vesicles and what do they do?
- Behind prostate
2. secretory epithelium, releasing secretions at ejaculation
What is the mucoid material that is secreted from the seminal vesicles?
- Fructose
- Citric acid
- Prostaglandin
Fibrinogen
Where do the seminal vesicles empty?
Into ejaculatory ducts
How much of the content of semen is produced by the seminal vesicles?
60% total semen content
What is the action of prostaglandins being contained in high amounts in the semen?
- Promote sperm movement in cervical area
2. Induce retro-peristaltic contraction of uterus and Fallopian tubes
Why would prostaglandins inducing retro-peristaltic contraction of the uterus and Fallopian tubes be beneficial?
- Helps the sperm to migrate to the egg, for fertilization
How much of the semen content comes from the prostate gland?
30% of semen content
What does the prostate gland secrete during ejaculation?
- Calcium, citrate, phosphate ions.
2. Clotting enzyme, profibrinolysin
Where does the alkaline fluid in the semen come from?
The prostate gland. To neutralize the seminal fluids
What is an androgen?
Steroid hormone with masculinizing effect
What hormones are androgens?
- Testosterone
- Dihydrotestosterone
- Androstenedione
What is testosterone?
And androgen steroid that has a masculinizing effect
What is dihydrotestosterone?
Androgen steroid that has a masculinizing effect
What is androstenedione?
Androgen steroid that has a masculinizing effect
What are androgens synthesized from?
Cholesterol and acetyl-CoA formed in testes and adrenal glands
Where are androgens synthesized?
Testes and adrenal glands.
Specifically from the cholesterol and acetyl-CoA
Where is testosterone formed by?
Cells of leydig.
When are cells of leydig most prevalent and least prevalent?
- Numerous in newborn and male after puberty
2. Nonexistent in testes during childhood.
What protein does testosterone loosely bind to?
- Albumin
What protein is tightly bound with testosterone after the hormone is secreted?
Beta-globulin tightly binds with testosterone
What is the majority of testosterone that enters tissue?
Dihydrotestosterone. Highly present in external genitalia and fetal external genitalia
Where is circulating testosterone converted to androsterone and dehydroepiandrosterone?
In the liver
What does the liver convert circulating testosterone into?
Androsterone and dehydroepiandrosterone
How can circulating testosterone be excreted form the body?
- Into the GI via bile
2. Urine through kidney
What can circulating testosterone be conjugated into?
- Glucuronides and sulfates
What are different functions that testosterone can be contributed to ?
- Hair pattern growth
- Larynx hypertrophy
- Increase skin thickness
- enlarge external genitalia
What effect with testosterone have on BMR?
Increase BMR
What effect will testosterone have on hematocrit?
Increase
What will testosterone do to the distal kidney tubule’s?
Increase sodium reabsorption
What is the function of gonadotropin-releasing hormone?
Similar to LH hormone,
- Stimulate anterior pituitary to release LH and FSH
- From arcuate nuclei of hypothalamus
What is the function of leutinizing hormone?
- Glycoprotein
- Activates cAMP
- Activate Sertoli cells to secrete testosterone
What effect does testosterone have on the hypothalamus?
Negative feedback, which inhibits the release of GRH which reduces the amount of LH and FSH released
What is inhibin?
Hormone from the Sertoli cells
1. Prevents FSH secretion from the anterior pituitary
Which hormone does inhibin act the strongest on?
FSH
Which hormone does inhibin have a relatively weak effect on inhibiting?
Gonadotropin releasing hormone
Describe the pathway of a sperm from seminiferous tubule’s to the vas deferens?
- Semiferous tubules
- Rete testis
- Efferent ductus
- Tail of epididymis
- vas deferens
