Lecture 10: Male Reproductive System Flashcards
Vas deferens pathway
Vas deferens is gonna thru other parts of the spermatic cord, leave the scrotum and go up the inguinal canal, and then it’s going posterior to the urinary bladder and tucks around the ureters.
The area on either side of the vas deferens that broadens is called…
ampulla
Lateral to the ampulla, we have..
seminal vesicles
Where the duct from the seminal vesicle connects with the end of the ampulla is…
beginning of the ejaculatory ducts
What are the functions of the vas deferens?
- connect the epididymis with the ejaculatory duct
- store sperm for up to a month w/o loss of function
Like in the epididymis, when we hit the end of the time frame, the sperm…
that are still in the vas deferens, are gonna get recycled.
One of the instructions men get after a vasectomy is no unprotected sex for a month. Why?
Everything distal to the cut can still leave the body and be ejaculated. Those sperm can still be viable for a month.
The ejaculatory duct is how long?
1 cm long
The ejaculatory duct empties into…
urethra
Why is this important?
Bc this is the point at which we start sharing urinary system structures + reproductive structures
The urethra has 3 sections. What are they?
- Prostatic Urethra
- Membranous Urethra
- Spongy Urethra
What is the Prostatic Urethra?
Region of the urethra that travels thru the prostate gland
What is the Membranous Urethra?
Point the urethra travels thru the floor of the pelvic cavity
What is the Spongy Urethra?
The longest portion that travels thru part of the penis called “corpus spongiosum’
What’s important to remember about accessory reproductive glands?
Sperm is NOT SUPPOSED TO GO thru the accessory glands
True or False.
Seminal Vesicle is part of the pathway for sperm.
FALSE
The accessory reproductive glands are:
- Seminal Vesicles
- Prostate Gland
- Bulbourethral Gland
What is the shape of the prostate gland? Why is this important?
Prostate gland is donut shaped and the hole in the middle is what the urethra travels thru.
The seminal vesicles connect their duct to the end of the vas deferens to form…
the ejaculatory duct.
Seminal vesicles produce an alkaline fluid that compared to the other fluids that are gonna be in the semen, is…
very thick and viscous.
It makes up _____ % of the semen volume.
60%
Why is it alkaline?
We generally make acidic urine and so the lining of the urethra that’s gonna be used fro sperm transport could be acidic enough to damage the sperm. So, an alkaline fluid is gonna help buffer some of that acid that was part of the urine.
That alkaline fluid is also gonna help buffer..
the slightly acidic environment of the vagina
Where does sperm travel thru?
urethra
There’s fructose in the fluid produced by seminal vesicles. What can we do with fructose?
We can convert fructose into types of carbs that can go thru glycolysis and Kreb’s cycle
Remember, the neck of the sperm that we move has a ton of…
Mitochondria
If we give them fuel, they can…
keep making ATP
What is also in the fluid of the seminal vesicles?
Prostaglandins
There’s also a coagulating enzyme called…
Vesiculase
Why do we want a coagulating enzyme?
For the sperm to have a fighting chance of swimming away to where the eggs are located, it needs to be held in the reproductive tract for a while.
What is the job of vesiculase?
to clump up for a while what was placed in the femal reproductive tract
The process of these fluids being moved out of the seminal vesicles and into the ejaculatory duct and into the urethra is called…
Emission
What’s the difference between Emission and Ejaculation?
Emission: moving fluid from seminal vesicle but NO SPERM
Ejaculation: moving sperm & all the fluids traveling with the sperm
Don’t forget, exposure to the fluid of the seminal vesicles is…
stage 1 in sperm capacitation
What is important about the prostate gland?
- Urethra passes thru it
- Contribute fluid to the ejaculate
As men age, the prostate gland enlarges. The more enlarged your prostate gets…
the more narrow the ureters are gonna become.
How does this affect urine production?
It’s going to be more difficult to get urine from the urinary bladder out into the urethra.
_____% of volume of ejaculate is prostatic fluid.
30%
Prostatic fluid is…
watery, milky, and slightly acidic
Why are we making acidic fluid?
There’s citrate is prostatic fluid.
Citrate comes from when…
you have citric acid and H+ comes off. This is another energy source. I can put citrate right in the citric acid cycle.
The fluid is a little bit acidic is not bad bc…
we get a lot more opportunity to make more ATP so the sperm can keep swimming.
Prostate Surface Antigen is found in prostatic fluid. Why do we use PSA?
High levels of PSA tend to be associated with prostate cancer.
The reason we use PSA and not say “it’s time or your annual check up. Let’s just biopsy your prostate” is bc
the biopsy goes thru the wall of the rectum and into the prostate gland.
We also have hyaluronidase which is..
an enzyme that helps to breaks down things like mucus.
The last set of accessory glands are Bulbourethral glands which are also called…
Cowper’s glands
The Bulbourethral glands are a size of a pea and have a duct that empties into…
spongy urethra
Bulbourethral glands also produce an alkaline fluid. But the fluid from the Bulbourethral glands have mucus in it.
have mucus in it.
What do we need mucus for?
Protecting against friction damage to the sperm?
Typical ejaculate is typically…
2 -5 ml of fluid
It should also contain how much sperm?
20 million - 100 million of sperm
Everything else is…
Fluid
The seminiferous tubules in the testes and the epididymis contributes…
< 5% of the 2-5 mL
The seminal vesicles combined make up about
~ 60%
Prostate is
~ 30%
Cowper’s gland is
< 5%
Sperm is
2%
We also have protease in the fluid component of sperm. Those protease helps…
break down cervical mucus
Cervical mucus is the…
the main barrier to fertilization when a woman is about to ovulate or hasn’t just ovulate.
We also have an enzyme that is called…
Seminalplasmin
Seminalplasmin is an…
antibacterial enzyme
They also help…
to protect against bacteria that might be in the vagina
We have an enzyme called Fibrinolysin. This does what?
Breaking down proteins that form the clump to hold the sperm in the male reproductive tract.
So 15 - 30 minutes after intercourse, what does fibrinolysin do?
Break down the clump
The essential organ of the male reproductive tract is…
testes
The penis is made up of…
3 cylindrical masses of erectile tissue.
The 2 superior structures of the penis is…
Corpra cavernosa
Sitting below is the…
Corpus spongiosum
The Corpus spongiosum are going expand at its distal end and cover the Corpra cavernosa. This area is called…
Glans penis
How does erectile tissue work?
We have central arteries. The one in the corpus spongiosum is smaller but we increase blood flow into the erectile tissue and blood gets trapped there. We have vasoconstriction that keeps the blood from leaving.
If you have trouble with an erection, how can this happen?
Circulatory problems decrease enough blood getting into erectile tissue to allow an erection.
Examples of medications for erectile dysfunction medication are:
- Viagra
- Cialis
What does it mean for an erection that lasts for 4 hours?
There’s not any O2 getting into the erectile tissues. No new blood getting out = no new blood coming in.
In order to get the blood back, you need to…
have the erection end or you have to take the blood out to end the erection.
What is the function of the Penis?
-Intro. of sperm into the female reproductive tract
- Urinating
- Ejaculation
Start at the hypothalamus and it releases the hormone:
GnRH ( Gonadotropin-releasing hormone)
GnRh stimulates the release of 2 anterior pituitary hormones. They are:
FSH (Follicle stimulating Hormone) and LH (leuteinizing hormone)
FSH stimulates…
Spermatogenesis / Meiosis
The more sperm we produce, the more sperm that sertoli cells have to support. This increases…
Inhibin
What does Inhibin do?
inhibits release of FSH
In a male, LH is going to stimulate…
testosterone production
Testosterone is going to stimulate…
Spermiogenesis
Testosterone inhibits…
GnRH release
If i have a lot of developing sperm that are being nurtured by sertoli cells, …
I need a lot of testosterone to finish spermiogenesis.
The way this is set up is if i have high Inhibin levels, …
I shut off FSH. I DON’T shut off GnRH.
Which means I’m only shutting off this branch about Spermatogenesis. I leave the GnRH levels high> meaning…
LH levels are high > getting testosterone I need for Spermiogenesis.
When testosterone levels are high enough, …
I shut the whole thing off.
I need to have the ability of testosterone being produced so I can…
do the spermiogensis and gradually drop that inhibin so I can go back to making sperm.
If i don’t finish the spermiogenesis,…
I can’t let go of those developing sperm that are being anchored to the seminiferous tubule and inhibin levels will stay high .
What is the difference between Spermiogenesis and Spermatogenesis?
Spermatogenesis: overall process.
- Meiosis (getting diploid to haploid)
- basic development that happens before it’s time to change the shape
Spermiogenesis: have something haploid and have to make it the shape of a functional sperm
-growing the tail, etc.
What are the functions of Testosterone?
- maintain the organs of the male reproductive tract & accessory glands
- stimulates libido
- promotes “maleness” a.k.a male secondary sexual characters ( more muscle mass mass than woman, male body hair distribution)
- involved in regulation metabolism
- stimulates bone growth & closure of epiphyses
- mild stimulater of H2O and Na reabsorption in the kidney. It’s a mild stimulator of K secretion
Anabolic steroids…
stimulate building of muscle
The other hormone is men is…
Estrogen. Males have a low level but measurable level of estrogen. We don’t know role of estrogen.
Some estrogen can be made by…
Leydig cells
In males, what is the main producer of estrogen?
Liver
What else can produce estrogen?
Adipose tissue
What are the POSSIBLE function of estrogen in males?
- might be regulating spermatogenisis
- might be involved in regulating FSH and LH
- might be involved in “normal sexual behavior”
- might be involved in partner preference (like ppl with curly/straight hair, blond/brunette)
