Repro Physl 3 Flashcards
Where are the testes?
In the scrotum
What comprises the internal genitalia of males?
- Ducts for sperm storage and transport
* Prostate gland, bulbourethral gland, seminal vesicles
What is the male external genitalia comprised of?
Penis and scrotum
Where is the prostate gland located?
Below the bladder and encircles the urethra
What is the urethra?
A common passageway for urine and semen
Which part of the shaft of the penis is the urethra?
The ventral aspect
What is the Urethra encircled by?
The corpus spongiosum
What does the corpus spongiosum contribute to?
The erectile tissue and erection
What makes up the erectile tissue?
The corpus spongiosum and the corpora cavernosa
What is the scrotum an extension of?
The abdominal wall
Where are the testes initially located?
In the abdomen during the early part of fetal development
When do the testes descend into the scrotum?
During the 7th month of development
Why do the testes descend into the scrotum?
Rising testosterone
What is Cryptorchidism?
When the testes don’t descend into the scrotum but testosterone production is intact but spermatogenesis is temperature sensitive and sperm may not be produced
When must Cryptorchidism be corrected?
Before puberty, so spermatogenesis can still occur
What helps to cool the testes?
The fact that they’re outside of the body and the countercurrent exchange system
What is the spermatic cord comprised of?
- The blood vessels that either drain or supply the testes
- Nervous input
- Vas deferens
Why is the position of arterial blood supply and venous drainage of the testes important?
Because the warm blood entering the arterial supply will be cooled as it approaches the testes by dissipating into the venous drainage
What structures are located within the testes?
The seminiferous tubules
What makes up the majority of testicular mass?
The seminiferous tubules
Where do the seminiferous tubules converge?
Into the rete testis
What does the rete testis converge into?
The efferent ductules
What do the efferent Ductules coalesce into?
The epididymis
Where does sperm go from the epididymis?
The urethra
What is the path of sperm from the seminiferous tubules?
Seminiferous tubules ➡️ Rete testis ➡️ efferent ductules ➡️ epididymis ➡️ vas deferens
What is the Inguinal canal?
The space where the spermatic cord passes down the testis
What is the tissue that surrounds seminiferous tubules?
Interstitial tissue
Where does the vas deferens go once it leaves the testis?
It passes behind the bladder and each one will join a seminal vesicle
What is the ejaculatory duct?
The junction where each vas deferens joins a seminal vesicle
What does the ejaculatory duct enter?
The prostate gland and joins the urethra
What is interesting about the prostate gland?
It doesn’t have its own separate duct its secretions just come from the wall and directly into the urethra
Where does the bulbourethral gland drain?
Into the urethra at its junction with the prostate gland
What secretes a significant amount of fluid in the male reproductive system?
The prostate and the seminal vesicles
What secretes the fluid in which sperm is suspended?
The seminal vesicles and prostate
What are the chemicals released from the male accessory gland?
- Nutrients
- Protective buffers
- Prostaglandins
- Mucoid secretion
What is the purpose of the nutrients released from accessory glands?
To nourish sperm
What is the purpose of the buffers released from accessory glands?
Neutralizing the environment of the vagina
What do seminal-vesicle derived chemicals do?
Promote increased sperm motility
What is the source of prostaglandins in the male reproductive system?
The seminal vesicles and not the prostate
What is the purpose of mucoid secretions in the male reproductive system?
Lubrication
Where do mucoid secretion from the male reproductive system come from?
bulbourethral glands
What is low levels of zinc associated with?
Infertility
Where is spermatogenesis occuring?
In the seminiferous tubules
What is the final phase of spermatogenesis?
Differentiation of spermatids into spermatozoa (sperm) where there is extensive cell remodelling and elongation
What is each seminiferous tubule surrounded by?
A basement membrane
What types of cells is the seminiferous tubule comprised of?
- Developing sperm
* Sertoli cells
What are leydig cells directed by?
LH
What are sertoli cells directed by?
FSH
What kinds of cells are at the basement membrane of the seminiferous tubules?
The immature/germ cells
What kinds of cells are at the lumen of the seminiferous tubules?
There are higher stages of development of sperm
What does the basement membrane of the seminiferous tubules have?
Interstitial leydig cells and a vascular supply
What is the fluid in the lumen of the seminiferous tubules produced by?
Sertoli cells
What do Leydig cells do?
Synthesize and release testosterone
What do Sertoli cells require?
Testosterone in order to mediate their functions
What is the partnership between leydig cells and sertoli cells?
Leydig cells will produce testosterone which can act on Sertoli cells and help support the Sertoli cells functions in spermatogenesis
What makes up the wall of the seminiferous tubule?
The Sertoli cells because they extend from the basement membrane to the lumen
What are sertoli cells joined together by?
Tight junctions
What do the sertoli cells tight junctions allow for?
It allows them to for a ring around the outer circumference of each seminiferous tubule
What is the sertoli cell barrier or the blood testes barrier?
The unbroken ring that Sertoli cells form around the seminiferous tubule
What do sertoli cells do for spermatogonia?
The provide nourishment for developing spermatogonia
What do sertoli cells secrete?
Inhibin, growth factors, enzymes and androgen binding protein
Where are the leydig cells located?
Outside the seminiferous tubules in the interstitial tissue between connective tissue
What is the purpose of Leydig cells?
They synthesize and release testosterone
When are leydig cells active?
They are active in the fetus but not after birth then are reactivated at puberty
What do leydig cells convert testosterone into?
Estradiol
How do Gonadotropins released from the pituitary affect leydig cells?
They stimulate Leydig cells to produce testosterone
What is the testosterone produced by leydig cells required for?
The function of sertoli cells
How do Gonadotropins from pituitary affect sertoli cells?
They cause increased activity of sertoli cells which nourish developing sperm cells to form mature sperm
Where in the seminiferous tubule does mitosis occur?
In the basal compartment away from the lumen
What does GnRH act on what does it do?
The anterior pituitary and causes it to release gonadotropins (FSH and LH)
What does LH primarily act on?
Leydig cells
What effects does LH have on leydig cells?
It stimulates the release of testosterone
What can the testosterone released by leydig cells do?
- It can enter the systemic circulation and act on androgen receptors causing secondary effects
- Can bind to androgen receptors on Sertoli cells to support their function
What cells does FSH act primarily on?
Sertoli cells
What does FSH cause sertoli cells to do?
Create cell products that will nourish developing sperm most important androgen binding protein
What cells produce androgen binding protein?
Sertoli cells
What does Androgen binding protein do?
Binds to androgens and prevents testosterone from diffusing back into leydig cells and increases local concentration in the seminiferous tubules
What does inhibin produced by sertoli cells do?
It has a negative feedback at the anterior pituitary to regulate production of FSH
What suppresses LH and GnRH release?
Negative feedback of testosterone on the anterior pituitary
What do the luminal secretions of the Sertoli cells contain?
Androgen binding protein
What do the chemical messengers released by sertoli cells do?
Produces paracrine agents that stimulate proliferation and differentiation of germ cells and modulate Leydig function and inhibin
What ensures that there are normal healthy sperm cells?
Sertoli cells phagocytizing defective sperm
When do sperm cells unbind from sertoli cells?
When their transformation is complete
Where is the final maturation of sperm cells?
The epididymis
What happens to sperm in the epididymis?
They lose cytoplasm and develop a tail
What does the Acrosome contain?
Many different proteins and enzymes for fertilization
Which part of sperm are the mitochondria found?
The midpiece
What stores sperm until ejaculation?
The vas deferens and the epididymis
What concentrates the sperm dramatically?
The fluid absorbed from the epididymis lumen
What causes the movement of sperm into the epididymis?
The Sertoli cells secretions that increase pressure in the seminiferous tubules (the sperm are non-motile and do not move by themselves at this stage)
What occurs in a vasectomy?
A portion of each vas deferens is surgically removed blocking the passage of sperm from the epididymis and into the urethra
