Male reproductive Physiology Flashcards
What is the function of the testes
Production of male gametes and male sex hormone testosterone
Where does spermatogenesis and spermatogenesis take place
Convoluted seminiferous tubules
Where does testosterone production take place
In interstitial cells of Leydig , in between seminiferous tubule coils
What glands create the fluid medium that transports the spermatozoa
1- Seminal vesicles
2- Prostate gland
3- Cow[ers Bulbourethral gland
Where do the testes develop in fetus
In Abdomen and descends down inguinal canal and then lie at scrotum
What is the condition in which the testes don’t descend and what can it lead to
Cryptorchidism can lead to infertility and increased risk of testicular cancer
How is cryptorchidism corrected
Via surgery before birth , because testes can’t survive in the abdomen due to its temperature
Why are the testes in an external location of body
Testes need to be 2-3 degrees below core temperature so spermatogenesis can occur.
What alters the distance that the scrotal sac hangs from the abdomen depending if there is a need to conserve heat or ventilate
The cremaster muscle
What helps remove heat from testes in countercurrent exchange mechanisms and how
Spermatic arteries and Pampiniform plexus of veins. Cool blood flowing out from the veins cools the blood in the spermatic arteries as the veins and arteries are parallel to each other
What can reduce fertility in men
Hot baths and insulated athletic supporters
What are the 4 stages of sperm formation
1- Spermatogenesis
2- Spermiogenesis
3- Spermiation
4- Capacitation (Spermatocytes become capable to fertilize ovum)
Explain Spermatogenesis
Production of haploid gametes from diploid precursors
1- Spermatogonia become spermatozoa through dividing by mitosis
2- once divided , one cells matures to become spermatozoa and other forms permanent reserve
3- Daughter cell ( 2n + 2n ) then undergoes meiosis to develop 4 secondary spermatocytes ( haploids)
4- now called spermatids
Explain Spermiogenesis & Spermaition
Gametes become motile
1- Sertoli cell nourished developing sperm cell , phagocytosis old cells and protects sperm from toxins
2- tight junctions between Sertoli cells forms a blood testicle barrier to stop substances from passing through
3- Spermiation : Sertoli cells secrete sperm into lumen along with with seminiferous tubule fluid
What makes up the seminiferous tubule fluid
Fluid high in potassium , androgens , estrogen , inositol and glutamic acids
Explain the structure of the Spermatozoon
1- Head : nuclear material + ayrosomal cap ( enzymatic )
2- Mid section : centrioles for cell division in fetus , mitochondria , micro tubular tail
What is the purpose of the mitochondria in the midsection of the sperm
Necessary to provide energy for flagellum to rotate and make sperm motile
What forms the micro tubular core of spermatozoon
Centrioles
Where does capacitation occur
In epididymis and female genital tract
Explain the Hormonal Control of Male reproductive tract
1- Daily release of GNRH ( usually at night )
2– Influences release of FSH and LH
3- FSH influences Sertoli cells to promote spermatogenesis & Sertoli secrete inhibit that acts as a negative feedback on FSH
3- LH acts on Leydig cells to release testosterone which negatively feedbacks to LH and GNRH
What is the function of testosterone ( Hint: 6 )
1- Essential in spermiogenesis.
2- Gives male phenotype ( characteristics) in utero and prenatal structure changes that create male external genitalia
3- develops and maintains male reproductive system , responsible for changes at puberty
4- promotes adolescent growth spurt
5- anabolic hormone promoting muscle deposition and increased metabolic rate
6- behavioural effects on male libido and aggression
Explain physiology of an erection
Dilation of penile arterioles fill erectile tissue of penis with blood. Corpus cavernosa and spongiosum then becomes turgor and more rigid in order to penetrate female.
Activation of parasympathetic dilator nerves and inactivation of sympathetic constrictor nerves
What stimulates an erection
1- erotic cognitive stimuli and stimulation of sensory receptors on glans and anterior penis.
2- veins draining penis are compressed reinforced erection
What drugs are used for erectile disfunction
Drugs increasing Nitric oxide production ( viagra ) and vasodilators (cGMP ) are used to treat erectile dysfunction
Explain the phases of ejaculation ( Hint: 2 )
1- emission : sympathetic reflex stimulated nerves in smooth muscle of epididymis, vas deferens and accessory glands causes mix of sperm and secretion to mix to form semen that’s deposited in urethra
2- Expulsion : somatic reflex of skeletal muscles around base of penis ( bulbocavernosa ) expel semen with force out of the penis
What is semen composed of
1- 60% of fluid from seminal vesicle : fructose for nourishment , prostaglandins and clotting agents
2- 25% from prostate glands containing citrate and protease to break down clotted semen
3- mucoid secretion of bulbourethral gland that lubricates the urethra and clears way before ejaculation
What is PSA
Prostate specific antigen that is used as clinical marker for prostate cancer
