Male Reproduction

Learner Outcome: Identify the structures in the male reproductive system and describe their functions

Male Reproductive System

The Male Reproductive Tract! See handout on anatomy

Main Curriculum Structures to know: Testes: Site of sperm production Composed of highly coiled tubules – seminiferous tubules Scrotum: muscular sac to house the testes outside the body (2-3 oC cooler temp for sperm production) Epididymis: region of testes where sperm mature & learn to swim. Vas Deferens (ductus deferens): tube that leads sperm into body for ejaculation

Ejaculatory Duct: a tubule formed at the union of the vas defens and seminal vesicle ducts and opening into the urethra Urethra: tube that transports both urine & sperm Penis: delivers sperm into the female Glans Penis: nerve endings on penis end (sensation) Prepuce: foreskin to cover penis end (before circumcision)

The seminal fluids provide a medium for the sperm. Semen: the Contributions of the 4 glands of all males: Testes, Seminal Vesicle, Prostate & Cowper’s Gland Did you know… Every time a man ejaculates, between 3 and 4 mL of fluid, containing approximately 500 million sperm cells, are released. The seminal fluids provide a medium for the sperm.

Gland I: Testes (pl. ), Testicle (sing Gland I: Testes (pl.), Testicle (sing.): male gonad (produces Sperm, Testosterone & Inhibin). Stimulated by FSH to produce sperm (Spermatogenesis) Stimulated by LH to produce Testosterone Located outside the body in the scrotum Sperm production requires a 2-3 oC lower than body core temp (thus testes are housed outside the body)

Gland II: Seminal Vesicles Base of bladder where the vas deferens enters the prostate 3 Secretions: Fructose (food source for sperm) Prostaglandins: hormone that opens the female cervix to allow sperm in Sodium Bicarbonate: a base to neutralize the acidic vagina Seminal Vesicle

Gland III: Prostate Gland Golf-ball sized, encircles the urethra Contractile & Muscular as the prostate is the “force” behind ejaculation 2 Secretions: Sodium bicarbonate to neutralize the acidic vagina Milky fluid to aid sperm motility Prostate gland

Gland IV: Cowper’s Gland (or Bulbourethral) Attached to the urethra below the prostate 1 Secretion: a clear mucous to lubricate & clean the acidic urethra (urine) Secreted before ejaculation to clean out urine that will damage the sperm Cowper’s Gland

This is what competing sperm look like: http://gawker.com/5503846/this-is-what-competing-sperm-looks-like-race-cars

Homework: Worksheet & Colouring diagrams on male anatomy Next class  Male Gametogenesis Testes anatomy Hormone feedback Sperm Anatomy

L2 Spermatogenesis – How sperm are made! http://www.olympusmicro.com/primer/anatomy/brightfieldgallery/mammaliantestes40xsmall.html

Learner Outcome: Distinguish sperm from their supporting structures (i.e., seminiferous tubules, interstitial cells, Sertoli cells)

I: Spermatogenesis - Testes function to produce sperm & testosterone 85 million sperm are produced per day per testicle (-ve feedback exists) Each sperm has 23 chromosomes BUT each human cell contains 46  Other 23 come from where? Sperm is produced in the SEMINIFEROUS TUBULES (tightly packed) within pie slice-like regions of the testes:

Testes Anatomy: Testicle Epididymis Vas deferens Rete Testes: gathers sperm Seminiferous tubules

Cross section of the Seminiferous tubules How many are shown? - Produce sperm Interstitial Cells of Leydig: - Produce testosterone Lumen - hollow to collect sperm Sertoli Cells: - Support the growing sperm

Spermatogenesis … Sertoli Cells: nurse cells within the seminiferous tubules Produce Fructose to nourish sperm Produce Inhibin (-ve feedback to FSH release from APG) Destroy mutated or damaged sperm Interstitial Cells of Leydig: make testosterone Located outside the seminiferous tubules Respond to LH & Produce testosterone

Development of sperm cells inside the seminiferous tubule (text. Pg

III: Sperm Anatomy! Flagella – for sperm motility (swim) Midpiece (mitochondria) – energy generator (consumes fructose) Nucleus – contains 23 chromosomes Acrosome –cap that contains enzymes to break down egg layers i) Many sperm required to break down the egg WHY? ii) Only 1 sperm enters the egg iii) Enzyme is called Hyalrilidase Flagella Midpiece Nucleus Acrosome

Learner Outcomes: Describe the role of hormones in the regulation of primary and secondary sex characteristics in Males Identify the principle reproductive hormones in the male and explain their interactions in the maintenance and functioning of the male reproductive system.

II: Male Endocrine Loops APG  FSH  Seminiferous tubules (testes)  Sperm Produced APG  LH  Interstitial cells of Leydig (testes)  Testosterone Produced During puberty testosterone production is a +ve feedback mechanism When too many sperm are produced the SERTOLI CELLS release INHIBIN -ve feedback to Hypothalamus which tells the APG to stop FSH release Sperm is stored in the RETE TESTES & EPIDIDYMIS. If too full, INHIBIN is released.

Feedback Loop

To do: Lab exercise 16.A (pg. 518 in the textbook) – omit c Label female anatomy diagram and define the parts using your textbook Female Anatomy Questions & Coloring Diagram (you will have a little time in class to work on this tomorrow)