Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Reproductive > Male Reproductive Physiology > Flashcards

Male Reproductive Physiology Flashcards

1
Q

What is the temperature that the testes should be kept at to maintain appropriate spree development

A

35C
- this is 2-3 degrees lower than normal body temp

Cremaster reflex, panpiniform plexus countercurrent exchange, sweat glands and scrotal skin all take part in maintaining this temp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the three accessory glands that contribute to semen secretions

A

Seminal vesicles

Prostate gland

Bulbourethral gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the thick connective tissue capsule surrounding the testies?

A

Tunica albuginea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What cells produces sperm in the testies?

A

Seminiferous tubules

  • contain spermatogenesis cells (actually make sperm)
  • also contain Sertoli cells (regulates spermatogenesis
  • sperm matures startling from the basal Lamina -> luminal surface of the seminiferous tubule

They are controlled by the leydig cells that are found adjacent to the tubules in the interstital space
- leydig produces testosterone and promotes spermatogenesis regulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why is the Sertoli cell tight junctions between Sertoli cells importaint?

A

called the blood-testies barrier

Blocks paracellular diffusion which promotes proper nutrient delivery and not too fast but not slow sperm maturation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Major functions of Sertoli cells

A

Maintains the testies-blood barrier

Phagocytosis of debris

Production of androgen binding protiens (ABPs)

Production of anti mullarian hormone

Aromatization of local testosterone to estradiol
- via P-450 aromatase enzymes

Forces sperm to move towards epididymis (no reflux)

  • *Releases inhibin in response to FSH stimulation which exert negative feedback on the HPT axis to inhibits FSH secretion
  • are a member of the TGF-B family
  • works on intracellular JAK/Stat pathway**
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

4 phases of spermatogenesis

A

1) golgi phase
- involves packing of hydrolytic enzymes and form acrosomal granule-containing acrosomal vesicles
- also begins formation of flagellar axoneme and connecting piece

2) cap phase
- acrosomal vesicle enlarges and forms the acrosome

3) acrosomal phase
- flattened spermatids and the entire cell elongates and the mitochondria conglomerate
- also forms “Manchette” which is a cylindrical collection of microtubules which elongates the spermatid
- turns into the spermatozoon
- also forms the annulus

4) maturation phase
- spermatids release excess cytoplasm which frees the spermatozoa from the syncytium
- are nonmotile until they undergo capacitation in the female reproductive tract
- Sertoli cells phagocytosis the remains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Gametogenesis in males

A

Germ cells are spermatogonia that have not progressed past mitosis until puberty

Once they hit puberty = mitosis begins and then meiosis also occurs

Spermatogonium (46 2N) -> primary spermatocyte (46 4N) -> secondary spermatocytes (23 2N) -> spermatid (23 N)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where is the primary location for storage of sperm

A

Epididymis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How much % or the semen is sperm?

A

10%

70% = seminal vesicle fluid

20% = epididymis, prostate glands and bulbourethral fluids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Ampulla of the vas deferens fluid

A

Mixes with sperm during sexual arousal

- contains citrate and fructose and helps sperm survive outside of the epididymis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Seminal vesicle fluids

A

Fluid rich in fructose, citrate, fibrinogen

Also produces prostaglandins which aid in fertilization in two ways

1) react with cervical mucus and make it more penetratable by sperm
2) induce peristaltic contractions in the female reproductive system to allow the sperm to move better

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Prostate fluid

A

Contains situate calcium and enzymes and is milky With slight alkaline pH

Increases sperm motility and aids in fertilization

Neutralizes acidic environment of vagina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the enzyme that stimulates aromatization of the A-ring of the testosterone to estradiol

A

Aromatase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Steps to testosterone production in leydig cells

A

LH binds to Gs-protein receptors
- which at the end of that cascade activates cholesterol esterases to cleave free cholesterol

Free cholesterol is sent to the mitochondria and converted into pregnenolone

Pregnenolone is sent to the smooth ER and converted to DHEA and androstenedione to ultimatelyTESTOSTERONE through a serious of steps with 17B-hydroxysteropid dehydrogenase being the main enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Two differences in testes compared to adrenal cortex in the production of testosterone

A

1) testes dont have 21B and 11B hydroxylases
- cant make glucocorticoids or Mineralcorticoids

2) testes have 17B-hydroxysteroid dehydrogenase enzymes which converts androstenedione-> testosterone
- this is why the testies always produce testosterone and never DHEA and androstenedione

17
Q

How does LH stimulate steroidogenesis

A

1) phosphorylation of cholesterol esterase (activates it)
- generates cholesterol molecule from cholesterol ester

2) activation of CYP11A1 (cholesterol desmolase via Gs protein stimulation
- promotes cholesterol -> pregnenolone

18
Q

Testosterone levels in the blood

A

An adult male produces 6-7 mg a day

  • diffuses into blood immediately after being synthesized in leydig cells
  • this amount slowly declines starting at age 50 and reaches about 4 mg per day in 70s

2-3% of hormone is actually free

30-40% is bound to albumin

60% is bound to SHBG that binds both estradiol and testosterone (higher affinity for testosterone though)

  • this binding both inactivates testosterone and estradiol as well AA’s increases its half life
  • liver damage decreases SHBG which can casue free levels of testosterone and estrodiol to increase
19
Q

Fate of testosterone in blood

A

Varies, but primarily functions as a pro hormone and is converted to biologically active DHT by 5-a reductase or into estradiol by aromatase enzymes

DHT is produced because it has higher binding affinity for the androgen receptor and is 2-3x more potent than testosterone
- **is the most potent natural androgen

20
Q

Affects of testosterone vs DHT

A

Testosterone

  • internal male genitalia differentiation
  • increases muscle mass
  • aids in growth spurts
  • undergoes all “puberty aspects”

DHT

  • external male genitalia differentiation
  • male hair pattern and baldness
  • prostate growth
  • sebaceous glands
21
Q

How do finasteride and dutasteride work to treat benign prostatic hyperplasia

A

They inhibit 5a-reductase which is required to peripherally convert testerosterone to DHT
- one of DHT’s effects are to increase hyperplasia fo the prostate

22
Q

How does estrogen work in males?

A

Unknown completely, but there is a known effect on bone maturation and biology since aromatase deficency in males results in excessively tall stature and delayed closure of the epiphyseal plates

23
Q

Kallmann syndrome and HPT axis

A

These patients have a tertiary hypogondotropic hypogonadism dysfunction

This is casued by a mutation in the KAL gene which results in GnRH neuronal precursors to inproperly move to the cribiform plate instead of the hypothalamus
- this also results in loss of smell (anosmia)

24
Q

What is follistatin

A

A protein hormone made by the serotoli cells with several isoforms that binds and deactivates activin and also induces paracrine signaling onto leydig cells to develop sperm better
- activin has unknown effects

25
Q

How is GnRH released

A

In a pulsitile fashion
- also causes FSH and LH to be secreted in a pulsitile fashion as well

** this is important since a continuous secretion of GnRH results in sensitization and down regulation of the GnRH receptor, but a pulsitile does NOT DO THIS**

26
Q

How does GnRH, FSH and LH levels change with respect to age

A

Fetus and infancy

  • high levels of FSH
  • moderate levels of LH
  • generally no GnRH

Puberty

  • GnRH now takes over and starts secreting in a pulsitile fashion
  • LH and FSH release in pulsitile fashion with LH being higher than FSH

Menopause/senescence
- FSH and LH levels get really high chronically and inhibit GnRH release as well as induce desensitization to FSH/LH receptors

27
Q

Corticosteroids affects on inhbitng GnRH based on age

A

Lower doses are needed in infancy

Higher doses are needed to achieve the same effect in once puberty kicks in-right before senescence

This is due to the age dependent feedback sensitivity to the

28
Q

What is the earliest detectable secondary sexual characteristics in girls and boys

A

Breasts = girls

Testicular enlargement = boys

29
Q

Effects of anabolic steroids they in males on LH/FSH and sex steroids

A

Increases testosterone and DHT in blood but low in the testicles

Decreases LH and FSH

  • *this causes a decrease in spermatogenesis since the rates of intratesticular testosterone is decreased due to negative feedback on anterior pituitary from testosterone and DHT levels**
  • in order to maintain spermatogenesis, intratesticular testosterone must be 100x higher than blood levels
30
Q

Erection in males

A

Is a neuro vascular event that is parasympathetic induced from sexual arousal

  • the parasympathetic cavernous nerves induce vascular smooth muscle dilation in the helicine arteries via Nitric Oxide release
  • Nitric Oxide induces GCMP which induces relaxation and GMP levels in smooth muscles and arteries

Sperm release pathway = “SEVEN UP”

  • Seminiferous tubules
  • Epididymis
  • Vas Deferens
  • Ejaculatory ducts
  • Nothing
  • Urethra
  • Penis

Reproductive (66 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions