Male Reproduction

General Anatomy

• major outer, visible units include the penis and the testicles
• the outer scrotum of the testicles contains:
• testis - place where sperm is made
• epididymis - place where sperm matures
• vas deferens - tube that sperm is ejaculated from

• seminal vesicles
• prostate gland
• bulbourethral gland

Spermatogenesis

• The production of sperm
• main production happens in the testes (specifically the seminiferous tubules)
• Looking at a cross-section view of the seminiferous tubules, we can see different cell types involved in sperm production

• make testosterone
• Stimulated by LH

• support the regulation of sperm production
• ANALOGY: the cheerleaders or the emotional support workers ... "you got this, spermatocytes!"
• I suppose this would make the Leydig cells the practical, "all business" cells - "hey body, let me give you something materialistic and useful. Here's some testosterone."
• back to the sertoli cells... they create the blood-testes barrier
• uses tight junctions between two sertoli cells to make this barrier
• its role is to seperate later stages of sperm production from contact with the blood
• Stimulated by FSH

1. Spermatogonia cells divide by mitosis (just like all other cells of the body). One cell from each division will go on to become a sperm, the other will remain as spermatogonia so it can continue the production of more spermatogonia.
2. Primary spermatocyte goes through first meiosis and becomes a secondary spermatocyte
3. Secondary spermatocyte goes through second meiosis and becomes a spermatid
4. Spermatid becomes spermatozoa

• the typical circular cell structure we are used to seeing is now gone.
• the spermatozoa is agile and highly motile
• it has a shield on its head full of enzymes that will be released when the sperm reaches the egg.
• The entire structure is light weight and based more on speed and ability than it is on longevity
• ANALOGY: Sperm are like race cars, not a suburban... yes I just compared sperm to a race car.

Hormonal Regulation

Hypothalamus and Anterior Pituitary

• LH and FSH also inhibit GnRH release through negative feedback
• act on the gonads (specifically the testes in males)
• LH act on leydig cells and cause testosterone production
• FSH act on sertoli cells and stimulate gamete production

• testosterone - produced by leydig cells
• inhibin - hormone secreted by the sertoli cells that acts on the anterior pituitary in a negative feedback loop