Renal Physiology Flashcards
How is the testis connected to the prostate gland?
Epididymis, vas deferens
What is connected to the prostate gland?
Vas deferens, urinary bladder, ampulla and seminal vesicles
Why is the testis housed inside the scrotum?
To maintain the core temperature; the change in temperature can damage the production of sperm
How is the descent of the testes (include timeline)?
3 months: above the inguinal canal (inside the body)
7 months: below the inguinal canal (inside the body)
Birth: outside the body
What tubules is contained in the testes?
Seminiferous tubules (produce sperm)
When does spermatogenesis begins?
Puberty
What’s the difference between a normal seminiferous tubules and someone affected by mumps?
The person affected by mumps have lower spermatogenic cells and are more hollow (seminiferous tubule)
What are the 3 cells in the testis and their function?
Leydig cells (interstitial cells)- secrete testosterone Sertoli cells (epithelial cells)- support sperm development Myoid cells (smooth muscle)- peristalsis to propel sperm
What is the importance of blood-testis barrier and what is involved (junction and compartments)?
To protect the sperm from chemicals.
- Tight junctions
- Luminal compartment
- Basal compartment
What are the 8 functions of Sertoli cells?
- Support sperm development: “trophic role”
- Secrete luminal fluid in for sperm housing
- Secrete androgen-binding protein
- androgen buffer
- helps maintain steady [androgens] in lumen
- Act as target cells for testosterone and FSH
- secrete paracrine factors that stimulate spermatogenesis
- Secrete inhibin
- hormone of negative feedback loop for FSH
- Secrete paracrine factors that affect Leydig cell function
- Phagocytosis of old and damaged sperm
- Site of immunosuppression (blood testis barrier)
How does Sertoli cells know when to secrete inhibin?
When the hormone-producing cell in the anterior pituitary secrete hormone to Sertoli cells, it secretes inhibin
What is the function of epididymis?
Maturation of sperm, storage site of sperm
What is the function of vas deferens?
Conduit, storage site for sperm
What does childhood to onset of adolescence mean?
The inability to reproduce hormones
When puberty starts, what happens in males?
- Sexual maturation
- Reproductive organs mature
- Secondary sexual characteristics develop
How does the production of male hormone occur in the Leydig cells?
Cholesterol > Pregnenolone > Progesterone > Androgens (testosterone)
What are the 4 products that the testosterone can be converted to?
- Testosterone
- Di hydro testosterone
- Estrogen
- Inactive molecules
How does the release of testosterone occur?
Higher centres stimulates the hypothalamus to release Gonadotropin-releasing hormone (GnRH) to the anterior pituitary. Anterior pituitary releases LH to Leydig and FSH to sertoli. Leydig cells releases testosterone. Testosterone sends a negative feedback to the hypothalamus and anterior pituitary.
What are the key secondary sexual characteristics in males?
Pubic hair grows and genitals develop; increased body hair on limbs and torso; beard grows; voice breaks; growth spurt
What are the 6 effects of androgens in males?
- Stimulate spermatogenesis
- Promote development of secondary sex characteristics
- Increase sex drive
- Promote protein synthesis in skeletal muscle (anabolic effect)
- Stimulate growth hormone secretion
- Promote development of male reproductive structures during embryonic life
What’s the difference between mitosis and meiosis?
Mitosis ensures the continuous supply of spermatogonia while in meiosis the chromosome number becomes half
Where does spermatogenesis occur?
Inside the seminiferous tubules in the space in between adjacent Sertoli cells (from basement membrane to lumen)
What are the 4 main cells in the spermatid?
- nucleus
- mitochondria
- Golgi apparatus
- acrosomal vesicle
How long does it take for spermatid to form a spermatozoa?
Approximately 24 days
What does the acrosomal vesicle develops into?
It develops into an acrosomal cap that is initially above the nucleus and then wraps the nucleus
What are the 3 sections of the sperm and what do they contain?
- Head
-Nucleus: chromosomes
-Acrosome: enzymes necessary for fertilization - Midpiece
-Mitochondria: source of energy - Tail
Whiplike movements propel sperm
After spermatogenesis, what occurs?
The spermatozoa is released into lumen of seminiferous tubules and remains immobile for about 20 days
How does the sperm move to the epididymis?
Pressure generated by the fluid secreted from Sertoli cells pushes the sperm and fluid to the epididymis
What occurs in the epipdymis?
The sperm acquires motility and is concentrated. The sperm resides for about 6-12 days.
What does the gonadotripins stimulate?
- release the FSH (stimulate gametogenesis)
- LH (stimulate androgen secretion)
How does the pulse generator work?
The pulse generator is at the onset of puberty; under the influence of higher brain centres (eg exercise, nutrition)
What’s the difference between the negative feedback of Sertoli cells and leydig cells?
The negative feedback of Sertoli cells only act on the anterior pituitary while the leydig cells act on both anterior pituitary and hypothalamus
What is the function of seminal fluid (in the seminal vesicle)?
- Dilution of sperm
- Provision of energy (fructose)
- Formation of semen “clot”
Why is the seminal fluid alkaline?
To protect the sperm; fructose provide energy, enzymes also protect the sperm
What is the function of the prostate gland?
Secrete citrate and enzymes
What happens when there’s a hypertrophy in the prostate gland?
Bio marker for cancer
What is the function of PSA?
Act as an anti-clotting factor; breaks down semen clot such that the sperm can be freed and allowed to move
What is the function of bulbourethral gland?
Secrete viscous fluid with mucus
What are the 3 phases in the neural control of males and how are they controlled?
- Erection - parasympathetic nervous system
- Emission - sympathetic nervous system
- Ejaculation
What are they key points of the parasympathetic control of erection?
Arteries supplying blood to erectile tissues > relaxation of smooth muscle > increase blood flow
What is the mechanism of vasodilation in erectile response?
Activation of parasympathetic nerve > increased nitric oxide > increase cGMP > vasodilation / inactive breakdown product > increase blood flow
What enzyme breaks down cGMP to lower its level?
Phosphodiesterase
What is the main function of viagra?
It inhibits phosphodiesterase so that cGMP levels cannot be lowered
What accounts for the low number of sperm to reach the site of fertilization?
- pH of female tract is acidic
- sperm do not have enough energy
What is capacitation?
Sperm maturation in the female tract
What occurs during capacitation?
The sperm head goes through destabilization. The multiple fusion points fuse with the membrane of the acrosome. The acrosomal enzymes then are released.
Whiplashing of the tails occurs.
What are the 3 phases of the female reproductive activity?
- Menarche - onset of puberty
- Menstruation - female reproductive system cycles
- Menopause - loses the ability to reproduce around 45-50
What is the function of the uterine tubes?
Transports ova form ovaries to uterus
What is the function of infundibulum and fimbraie?
Picks up released ovum
What is ectopic pregnancy?
The development of embryo in the uterine tube
What is the outer layer of the wall of the uterus and what is it made up of?
Perimetrium; epithelial cells and connective tissue
What is the middle layer of the uterus and what is it made up of?
Myometrium; smooth muscle
What is the inner layer of the wall of the uterus and what is it made up of?
Endometrium; epithelial cells, connective tissue and numerous glands
How is the egg developed in the ovary?
Immature follicles > maturing follicles > graafain follicle > release of egg