1. Male Reproductive System
6.6 & 11.4

2. Essential Idea: Sexual reproduction involves the development and fusion of haploid gametes
11.4
Sexual Reproduction
Understandings:
Spermatogenesis and oogenesis both involve mitosis, cell growth, two divisions of meiosis, and differentiation
Processes in spermatogenesis and oogenesis result in different numbers of gametes with different amounts of cytoplasm
Fertilization in animals can be internal or external
Fertilization involves mechanisms that prevent polyspermy
Implantation of the blastocyst in the endometrium is essential for the continuation of pregnancy
HCG stimulates the ovary to secrete progesterone during early pregnancy
The placenta facilitates the exchange of materials between mother and fetus
Birth is mediated by positive feedback involving estrogen and oxytocin
Applications:
The average 38 week pregnancy in humans can be positioned on a graph showing the correlation between animal size and the development of the young at birth for other mammals
Skills:
Annotate a diagram of seminiferous tubule and ovary to show the stages of gametogenesis
Annotate a diagram of a mature sperm and egg to indicate functions

3. Embryonic development into male/female
A. Embryos identical until about 8 weeks - The same embryonic structures give rise to ovaries and testes, clitoris and penis
B. Females – genes on 2 X chromosomes interact to produce high estrogen and progesterone levels -> female reproductive structures
C. Males – genes on Y chromosome responsible for testosterone production and testes development

4. II. Male Reproductive System

6. A. Spermatogenesis – starts at puberty and continues for life
Seminiferous tubules of testes

7. Arise from spermatogonia (germinal epithelial cells) near outer edge of seminiferous tubules
a. Undergo mitosis to replenish supply of spermatogonia
b. Undergo meiosis to produce spermatozoa (millions/day) – stimulated by follicle stimulating hormone (produced by pituitary)

8. Daughter cells must mature into fully motile spermatozoa
a. Sertoli cells – provide nutrients for developing sperm
b. Leydig cells – leutinizing hormone from pituitary stimulates production of testosterone
c. Move closer to
the center of the
seminiferous tubule
as they develop
d. Move to
epididymis to finish
maturation

9. Mature sperm
a. Acrosome – contains hydrolytic enzymes to help get into egg
b. Mitochondria – produce ATP for swimming
c. Flagellum – tail for swimming

10. Production of semen
a. Mature sperm moves from epididymis to vas deferens
b. As it moves through vas deferens, fluid is added
i. Seminal vesicle adds 70% of fluid - high in fructose (sugar) to provide energy
ii. Prostate adds alkaline fluid – to help neutralize low pH in vagina

11. Hormones involved
Leutinizing hormone (LH) - stimulates Leydig cells in testes to produce testosterone
Follicle Stimulating Hormone (FSH) - along with testosterone, stimulates meiosis of spermatogonia