Handout #2 of 2Be sure to also print out Handout #1

Male Sexual Anatomy,

Physiology, & Response

• Male Gonads – testes

• External Genitalia– Penis– Testes

Penis• The organ through which both sperm

and urine pass.• The shaft of the penis contains two

corpora cavernosa and a corpus spongiosum, which fill with blood during arousal, causing an erection.

• The head is called the glans penis.

Male Circumcision

• The removal of some or all of the foreskin (prepuce) from the penis

• 80% of US boys; 15% boys around the world• “ no absolute medical indication”, “has

potential medial benefits and advantages as well as disadvantages and risks” -American Academy on Pediatrics

– Recent development - Circumcision and HIV risk

Testicles• The paired testes or testicles have two

major functions: – Sperm production– Hormone production

• Point of origin– Back wall of the abdomen– Descent into scrotum (7 months)

• Undescended testicles

Seminiferous Tubules

• Found within each testicle

• Site of spermatogenesis– production of sperm

• about 60 days

• Two tiny glands called bulbourethral (Cowper) Glands secrete a thick, clear mucus shortly before ejaculation

Epididymis

• A crescent-shaped structure consisting of a long coiled tube. This is where the sperm mature.

Ductus (Vas) Deferens

• An 18 inch long tube that joins the ejaculatory duct with the prostate gland.

• 1st path taken by sperm during ejaculation.

• Seminiferous Tubules• Epididymis• Ductus (vas) Deferens –

– 1st path taken by sperm during ejaculation

• Seminal Vesicles– Contributes fluid (most of the seminal fluid)

• Prostate Gland– Contributes fluid (15 – 30%)

• Ejaculatory Duct• Cowper’s Gland

– Contributes fluid

• Urethra

Sperm

Acrosome: Contains enzymes that help penetrate the egg.

Head: Contains nucleus/genetic material

Middle piece: Energy

Tail: Movements

Semen• Ejaculated liquid that contains sperm. • Function is to nourish sperm and provide them

with a hospitable environment and means of transport when they are deposited within the vagina.

• Mainly made up of secretions from the prostate gland.

• The semen from a single ejaculation generally contains between 100 million and 600 million sperm.

Male Sexual Physiology• The reproductive processes

of the male body include the production of hormones and the production and delivery of sperm.

• Although men do not have a monthly reproductive cycle comparable to that of women, they do experience regular fluctuations of hormone levels.

Hormones• Testosterone

– The most important male hormone which triggers sperm production and regulates the sex drive.

• FSH– Maintains sperm production– Acts on male cells: Sertoli Cells

• LH– Stimulates production of testosterone– Acts on male cells: Leydig cells

Capacitation

• Maturation of sperm in the female tract.

• One time explosion of energy that signals a cascade of events, including boosting the motion of the sperm and triggering the actions of the acrosome.

The Path of the Sperm

2. Some (~400) enter uterus through cervix2. Some (~400) enter uterus through cervix

3. Approx. 40 enter fallopian tube 3. Approx. 40 enter fallopian tube4. Move up fallopian tube, undergocapacitation, and contact egg4. Move up fallopian tube, undergocapacitation, and contact egg

1. Hundreds of millions of sperm deposited in vagina1. Hundreds of millions of sperm deposited in vagina

Prep for In-Class Assignment

• Separate sheet of paper– Write your Name, Date and In-class Assignment #– Write legibly– Use blue or black ink

• Questions will be asked in class• Must turn in your assignment to the instructor• In-class assignments are open book and worth

10 points. Only given in-class.