1. Human Reproduction
Chapter 4
Pages

2. Humans have both Primary and Secondary Sexual Characteristics
Primary Sex characteristics are present at birth.
Include body structures directly involved in reproduction such as testes, ovaries, and external genitalia.
Secondary sex characteristics refer to other visible changes that occur during puberty such as changes in height and body shape.

3. Puberty
Puberty is the maturation into an adult body capable of sexual reproduction.
In males, puberty usually begins age until around 18.

4. Puberty

5. Male Secondary Sexual Characteristics
Secondary characteristics in males help distinguish male from female but not directly involved in reproduction:
growth spurt;
Facial, underarm, and pubic hair;
deepening of voice.

6. Male Secondary Sexual Characteristics arrive during Puberty
Begins when hormones released from the pituitary gland in the brain stimulate the testes to produce more male sex hormone called testosterone.

7. Male Reproductive System
The male sex cell is a sperm cell
The whole purpose of the male reproductive system is to produce sperm AND to deliver sperm to the egg.

8. Structure of Human Sperm Cell
The Sperm Cell has three regions:
Head – contains haploid nucleus, acrosome
Middle piece – mitochondria
Tail – flagellum
List the functions of each section of sperm

9. Sperm are MUCH smaller than egg

10. Male Reproductive Structures
Two testes – outside body
Produce and nourish sperm
Produce testosterone
Scrotum – sac containing testes
Seminiferous tubules –
coiled tubes in testes
Where diploid cells undergo meiosis haploid sperm
Epididymis – where mature sperm are stored.

11. Male Reproductive Structures
Vas deferens – tube carries sperm to urethra
Urethra – tube leading to outside of body
located in the penis
Penis – specialized organ to enter female during sexual intercourse

12. Male Reproductive Structures
Accessory Glands secrete seminal fluid (sugar for energy):
Seminal vesicles
prostate gland
Cowper’s gland (Bulbourethral gland)
Semen = Sperm + seminal fluid

13. Sperm Production and Development
Sperm begin as diploid cells
Undergo meiosis  haploid
Begins in seminiferous tubules
Finish maturing in epididymis
About 74 days to mature
million sperm produced each day
Why so many?
Immature sperm = spermatozoa
Sperm cells are continually being produced by the testes, but not all areas of the seminiferous tubules produce sperm cells at the same time. Oneimmature germ cell takes as long as 74 days to reach final maturation, and during this growth process there are intermittent resting phases

14. Check your Understanding
HW: Read pages
Answer CYU p111

15. Male Reproductive System

16. Sperm Production and Development
Sperm begin as diploid cells in seminiferous tubules
Undergo mitosis to increase in number
Gradually pushed closer to center
Undergo meiosis  haploid
Finish maturing in epididymis
million sperm produced each day
Why so many?