Reproduction Lectures 2021 - MALE REPRODUCTIVE SYSTEM Flashcards
Reproductive organs/gonads in males
Testes
- paired organ that contains gametes
Reproductive organs/gonads in females
ovaries
- paired organ that contains gametes
Gametogenesis
process by which sperm or ova are produced
Gametes have an endocrine role:
– Androgens in males
– Estrogens and progesterones in females
Reproductive tracts
house and transport gametes
What are the reproductive tracts in females?
fallopian tubes
What are the reproductive tracts in males?
vas deferens (for the most part)
Accessory sex glands in males
– Seminal vesicles
– Prostate
– Bulbourethral (Cowper’s) glands
What is the seminal vesicles a major site of?
gamate production in males
What are the Prostate & Bulbourethral (Cowper’s) glands largely responsible for?
producing fluids that aid in the survival of those gametes, but also assist in the sexual act or transmission or capacitation of sperm
Capacitation
process where sperm are not fully viable until they hit the female reproductive tract
Accessary sex glands in females
– Bartholin’s glands
– Clitoris
– Breasts
Bartholin’s glands, Clitoris & the Breasts are sex glands but also…
related to reproduction in general & associated with the Bartholin’s glands in assisting with the sexual act
Prostate gland
produce fluids that either support survival of sperm or capacitation of that sperm just prior to ejaculation; entry into the female reproductive tract
Vas deferens
- tubule structure
- comes into close association with the seminal vesicles & the prostate gland
What is the 2nd most common cancer next to lung cancer in males?
Prostate cancer
Corpora cavernosa
spongy, leaky tissue that aids in the flow of blood into the penis & essentially an erection is caused by an imbalance in blood flowing in vs. blood flowing out
Prostaglandins
a hormone found throughout the body, were 1st identified in the prostate gland
- but it turns out the seminal vesicles actually produce as much if not more prostaglandins into the sperm & the fluid surrounding the sperm & so those prostaglandins aid in the reproductive act & can promote both constriction within an ejaculation (sperm into the female reproductive tract) but also contractile forces within the female reproductive tract, promoting the advance sperm further in the female reproductive tract
Describe testes development
- testes develop from the GONADAL RIDGE during development
- descend through the INGUINAL CANAL usually complete before 7 months of gestation (within the mother’s womb)
Cryptorchidism
occurs in 1-3% of newborn males
- where the testis have failed to descend properly through inguinal canal & are essentially trapped within the body
- this has huge implications for fertility in those males (tend to be infertile)
Why do the testes lie external to the body?
- testis are ~3% lower than body core temp
- so they lie in a cooler area
- those cooler temps promote development & increase mitochondria in particular
- with increase mitochondria, that provides more energy for individual sperm & therefore better transfer for fertilization
- therefore 1 reason is b/c of the reduced temp & increased viability of the sperm at that reduced temp
What is the route in order to form an ejaculation?
Epididymis tubule –> through canal –> into vas deferens –> seminal vesicles, prostate glands –> penis for ejaculation
Head of epididymis
gathers all the seminiferous tubules within the testicle itself
Epididymis
- lots of storage
- sperm not yet fertile (infertile) at this stage (has to be capacitated)
- # of events are req. to promote fertility of that sperm
In terms of testicular mass:
the seminiferous tubules comprise of ~80% of testicular mass within each testicle
What are Leydig cells extremely imp. in?
extremely imp. in communicating gamete dev. within males & communicate with sertoli cells
Sertoli cells location
- INSIDE seminiferous tubule
- surrounded by layers of connective tissue & smooth muscle
Leydig cells location
- OUTSIDE seminiferous tubule
- produce testosterone
- communicate with the sertoli cells within the internal area of the seminiferous tubule & the dev. spermatids
Sertoli & Leydig cells…
support those dev. gametes (critical in terms of gamete dev.)
Blood Testis Barrier
- this barrier, the basal lamina that separates the internal environment of the seminiferous tubule with the external environment of the body is critical & essentially acts v. similar to a blood brain barrier as the blood testis barrier that stops the immune system from attacking what would be otherwise unknown cells (the gametes that develop within the seminiferous tubule)
- therefore, critical in gamete dev.
- blood testis barrier is by the basal lamina
Myoid cells
are found within the basal lamina
- these specific cell types are really critical for communicating b/t the leydig cells & the sertoli cells within the seminiferous tubule
- also help in movement of fluids from the external environment to the internal environment across that basal lamina
*specific cell type around the basal lamina that aid in the communication b/t sertoli & leydig cells & also production of fluids
What does the tight junction b/t sertoli cells do?
essentially separates the development of these spermatids b/t each other on either side
You get columns of spermatogonia at varying stages of dev. as you move from the…
& what will support & aid all of these?
outside (periphery of the seminiferous tubule) to the internal region of the seminiferous tubule
sertoli cells will support & aid all of these
The fluid within the seminiferous tubule, in which the mature spermatids are bathing (a water based fluid) is…
High K+ ions & high in steroids (partic. testosterone)
Why is the fluid within the seminiferous tubule high in K+ ions?
- related to motility of sperm
- with a higher K+ concen. the sperm tend to be less mobile or motile
- as a conseq. are not needlessly burning energy that would be req. once released into the female reproductive tract
- so they have a lower metabolic rate in the presence of high ECF K+ concens.
Testosterone is…
lipid soluble (won't dissolve easily within this water based fluid in the lumin of the seminiferous tubule) - so as a conseq. of that there are ABP, that is also released into the lumen of the seminiferous tubule
What is ABP & describe the importance of it
- imp. to facilitate the concen. of testosterone in the seminiferous tubule fluid
- b/c it is a water fluid environment & testosterone is a steroid so it’s lipophilic
- binds to the testosterone in the seminiferous tubules so that more testosterone can come in from the outside/is available
- total concen. of testosterone within the fluid of the seminiferous tubule is higher b/c you have a large proportion bound to the BP & a small proportion that is free
Basal lamina
barrier to prevent the immune system from attacking these unknown cells
What is within the lumen of the seminiferous tubule?
tails of spermatids within the lumen of the seminiferous tubule & diff. cell types that might support dev. of those sperm cells at diff stages
In theory, males can keep producing testosterone & sperm all their lives, but as males age things do slow down & usually through blood vessel degradation can result in:
Androgen Deficiency in Aging Males (ADAM)
Androgen Deficiency in Aging Males (ADAM)
a degradation in the blood vessels supplying the testis & as a result, an imperfect balance b/t leydig & sertoli cell communication as a conseq. of an imperfect release of antigens that can lead to a reduction in fertility in those males