1. Reproduction Source: Campbell, N. et al Biology. Fifth Edition. United States: Benjamin Cummings Publishing

2. Sexual Reproduction and Variation Important mechanism of variation Fertilization combines characteristics from both male and female producing different combinations. A cell undergoing meiosis produces 4 genetically different gametes (sex cells) Variation results from: independent assortment of chromosomes Crossing over The number of different gametes that can be produced from a cell undergoing meiosis is 2 n (where n= haploid # of chromosomes in the cell; 2 23 or 8,388,608 in humans)

3. Male Reproductive Structures Scrotum: Sac that contains testis. Located outside the body Testis: two enclosed by a tough white fibrous capsule; contain tubes that produce sperm through meiosis Seminiferous tubules: Thin highly coiled tubes in which meiosis takes place. Smooth muscles lining these tubes respond to the ANS Epididymis: Coiled tubes on the outer surface of the testis. Place where sperm undergoes maturation

4. Male Structures … Vas deferens: Muscular tube 45 cm long that ends behind the urinary bladder. Unites with the seminal vesicle Seminal vesicle: Glandular sac that secretes a variety of nutrients (fructose-energy source) and a slightly alkaline fluid that help regulate pH as the sperm cells are released to the outside. Prostate gland: Chestnut-shaped; surrounds the beginning of the urethra. Secrete a thin, milky alkaline fluid which help neutralize the acidity of the vagina and enhances sperm motility

5. Male structures… Bulbourethral glands (Cowper’s glands): two small structures located below the prostate. Composed of numerous tubes with epithelial linings that secrete a mucus-like fluid. This fluid is released in response to sexual stimulation and provides lubrication to the end of the penis.

6. Female Reproductive Structures Uterus: Receives the embryo and sustains its life during development. Located medially within the anterior portion of pelvic cavity Endometrium: inner mucosal layer that lines the uterine cavity Vagina: Conveys uterine secretions and transports the offspring during the birth process Ovaries: Place where meiosis takes place Medulla: contain blood vessels, lymphatic and nerve fibers Cortex: compact tissue with ovarian follicles