MALE REPRODUCTIVE TRACT LECTURE #1 41.1

I. THE GOAL A. To produce fertile sperm that will unite with the female egg to create a new organism.

II. THE SPERM A. Parts 1. Head a. Contains nucleus which holds the DNA. b. Acrosome Cap holds enzymes that will help sperm penetrate the egg.

2. Midpiece a. Holds mitochondria which supplies energy for movement. II. THE SPERM (cont)

3. Tail a. Consists of Flagella that propel the sperm b. Whip-like motion c. Damaged or distorted tails lessen the chance of getting to the egg first. II. THE SPERM (cont)

Mitochondria Acrosome Cap II. THE SPERM (cont)

III. THE JOURNEY A. Spermato- genesis- The production of sperm.

A. Spermatogenesis (cont) 1. 4 sperm produced a. Haploid -1/2 the chromosomes 2. Takes 74 days to complete II. THE JOURNEY (cont)

B. Testis 1.Spermatoge nesis takes place here. a. Inside the seminiferous tubules II. THE JOURNEY (cont)

B. Testis (cont) 2. Scrotum- The sac that contains the testes. a. Regulates Temp. b. Spermatogenesis can only occur within 2-3°C of body temperature II. THE JOURNEY (cont)

C. Epididymis 1. “Epi” = Upon “Didymis” = Testis 2. Sperm finish maturing here a. Capable of fertilization, but don’t swim yet! II. THE JOURNEY (cont)

D. Vas Deferens- Tube that transports sperm from epididymis to the urethra. 1. The vas deferens is cut as a form of birth control (vasectomy) II. THE JOURNEY (cont)

E. Urethra-Tube that transports the sperm to the outside of the body. 1. Same tube that urine leaves the body through II. THE JOURNEY (cont)

2. Ejaculation- The process of sperm (and semen) leaving the body 3. Peristaltic (involuntary) contractions move sperm throughout the male tract a. No swimmers yet! II. THE JOURNEY (cont)

A. 3 Fluids aid in nutrition and movement of sperm 1. Seminal Vessicles- Glands that secrete a mucus-like fluid into the vas deferens a. Provides sugar for sperm for energy III. SEMEN

2. Prostate- Gland that secretes a thin, alkaline fluid into the urethra a. Allows movement b. Alkaline environment protects against female’s acidic environment. III. SEMEN (cont.)

3. Bulbourethral Glands- Glands that secrete a clear, sticky, alkaline fluid that protects sperm. a. AKA “cowpers gland” b. Located beneath the prostate III. SEMEN (cont.)

B. Fluid from the seminal vesicles, prostate and bulbourethral glands make up the semen. III. SEMEN (cont.)

A. Puberty- The onset of secondary sex characteristics that lead to sexual maturity. IV. HORMONES

B. Testosterone- Promotes secondary sex characteristics: 1. Sperm production 2. Deepening of voice 3. Increased height & muscle 4. Increased hair IV. HORMONES (cont.)

C. Follicle Stimulating Hormone (FSH)- Causes production of sperm cells 1. Released from the pituitary gland into bloodstream and carried to testes. IV. HORMONES (cont.)

D. Luteinizing Hormone (LH)- Causes production of testosterone 1. Released from the pituitary gland into bloodstream and carried to testes. IV. HORMONES (cont.)

E. Negative Feedback Mechanism 1. Similar to a thermostat 2. Ensures that hormones and sperm are not overproduced or under produced. IV. HORMONES (cont.)

Negative Feedback Mechanism