Human Reproduction

1. Human Reproduction Male Reproduction Systems

2. Male Sexual Characteristics • At birth the male’s primary sexual characteristics are present, but it isn’t until puberty that the secondary sexual characteristics are developed. • Puberty in males develop between 11 – 13 years of age and stops around the age of 18. This is when the human male is able to sexual reproduce. • During puberty hormones are released from the pituitary gland in the brain to produce male sex hormones called testosterone. • Testosterone helps produce the secondary characteristics of the male

3. Male Sexual Characteristics • Secondary Characteristics include: growth spurts, emergence of facial, underarm and pubic hair and the deepening of the voice. • Once the secondary characteristics start to develop, the male human is potentially able and ready to reproduce. • The secondary characteristics DO NOT influence the male primary sexual characteristics. The primary sexual characteristics in males include the reproductive organs that produces sperm.

4. The Human Sperm • The structure of a human male sperm:

5. The Human Sperm • At the head of the sperm is the nucleus that contains the haploid cells with 23 chromosomes. • The capsule has chemicals in it that allows the sperm cell to enter the egg. • The mitochondria is what gives the sperm energy to move. • The flagellum is a whip-like tail that helps propel the sperm.

6. The Human Sperm • Sperm cells are created through meiosis. • Sperm cells have a short life cycle. It takes 65 – 75 days for a sperm cell to mature. • Males can produce up to 200 – 300 million sperms each day. Sperm that is not released die and within a few days are broken down by white blood cells • Only a mature sperm cell can make its way to the egg, and the older a male gets the less mature sperm cells they can create (and we are talking really old peeps)

7. Male Reproductive Structures • During puberty the males primary sexual characteristics mature and enable a male to reproduce – i.e. he does not produce sperm or the capability to reproduce prior to puberty.

8. Male Reproductive Structures • There are two testes that are in a protective sac called the scrotum. • The testes produce and nourish the developing sperm. • Each testis contains the seminiferous tubules, which contain the diploid cells that undergo meiosis to produce haploid sperm cells. • Sitting above that is the epididymis, this is where the mature sperm is stored.

9. Male Reproductive Structures • Attached to the epididymis is the the vas deferens tube. This tube carries the sperm up to the urethra. • When males get “snipped” as a form of permanent birth control method, it is the vas deferens tube that gets cut. This procedure is non-reversible. • The urethra is a little tube inside the male penis, this tube transports both the sperm and urine from the male body. • NOTE the urine and sperm cannot travel through the urethra at the same time – it is impossible.

10. Male Reproductive Structures • In order for the sperm to make its journey from the male body to the female egg, it needs to get nutrients from the male body. • The seminal vesicles, prostate gland, and Cowper’s gland are accessory glands that release seminal fluid. • Seminal fluid provides • sugar for energy (the mitochondria absorbs this); • it also protects the sperm from the acidic female reproductive tract; and • Provides the fluid for the sperm to swim/move in • The sperm and seminal fluid together make up semen

11. Assignment • Page 111 Textbook – Questions 1, 2, 3, 4, 6, 8, 11,