Reproduction . Male Reproductive Physiology . The major organ involved in maintaining male reproductive function is the testis. A normal functioning testicle is required for 1)the production of mature sperm 2)and the synthesis of the major male reproductive hormone testosterone. .
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Male Reproductive Physiology
The major organ involved in maintaining male reproductive function is the testis. A normal functioning testicle is required for
1)the production of mature sperm
2)and the synthesis of the major male reproductive hormone testosterone.
The Male Reproductive System
Physiological functions of major components-
Section of human testis.
* Blood–Testis Barrier
Interaction between the Sertoli and
Hypothalamic-pituitary-gonadal axis in the male
LH and FSH
Gonadotropin Releasing Hormone (GnRH)
Change in amplitude
Change in frequency
Vesicles containing LH/FSH
Also LH and FSH synthesis
IP3 & DAG
Release of LH/FSH via exocytosis
Increased testosterone production
At the target tissues
*in the bloodstream
(5 alpha reductase)
Modulation of gene expression
Physiological Action of Testosterone and Associated Androgens.
An androgen is a substance that stimulates the growth of the male reproductive tract and development of secondary sex characteristics. It is important to realize that androgens affect most other tissues as well.
Penis and scrotum
Long bone fusion
Body Hair and
Bone size and
Some testosterone converted into estrogens
Formation of the Ejaculate and the Role of the Accessory Organs
As the sperm passes through the epididymus it matures (due to dihydrotestosterone), and becomes more concentrated (fluid reabsorption).
The sperm is then stored in the epididymus and vas deferens waiting for ejaculation.
Sperm can remain viable here for up to 60 days as nutrition is supplied and inhibitory factors decrease their energy use.
On ejaculation the sperm (and fluid) passes through the vas deferens, ejaculatory ducts and finally through the urethra. During this passage the fluid content is increased due to secretions from the accessory organs
Sperm, fructose, prostaglandins, clotting precursors
+ alkalization, semen clotters
The male sex act
•The male must have an erection and ejaculate in order to complete the sex act.
Via NO and/or ACh
This is the inability to produce or maintain an erection. In most cases it is due to problems with blood flow.
An 8 year old boy visited his pediatrician, and his mother reported that he was in good health until about two weeks ago. He describes that his initial symptoms include a mild bifrontalheadache, which has become progressively worse. During the last few days, he developed nausea and bouts of occasional projectile vomiting accompanying the headaches. Furthermore, he recently noticed that he has tremendous difficulty when walking down the stairs from his bedroom to the kitchen and reported difficulties in
sleeping. No family history of abnormal development or mental retardation exists. He has two perfectly healthy younger brothers.
This 8 year boy presents with pronounced pubic hair growth, a low pitched voice, enlarged genitalia, and acne on his forehead. Cardiac and respiratory examinations were unremarkable.
Patient is alert and oriented x 3. No receptive or expressive aphasias were noted. Pupillary light reflex was intact bilaterally. Both the left and right optic discs appeared more pale than normal. Downward gaze (while the eyes were adducted) was impaired bilaterally.