39-3 The Reproductive System Slide 1 of 41 Sperm and eggs only have ½ the number of chromosomes than an organisms body cells. Copyright Pearson Prentice Hall 23 46

39-3 The Reproductive System Slide 2 of 41 Mitosis: process that produces 2N body cells with a full set of chromosomes The ovary and testicle cells go through a different type of cell division called meiosis. Meiosis produces 1N sex cells or cells with only ½ the number of chromosomes Copyright Pearson Prentice Hall

39-3 The Reproductive System Slide 3 of 41 Copyright Pearson Prentice Hall One ovary or testicle cell divides twice with DNA replicating only once. Four sex cells are produce each containing only ½ the number of chromosomes.

39-3 The Reproductive System Slide 4 of 41 Copyright Pearson Prentice Hall What is the true differences between males and females?????? Primary sex characteristics: Are structures directly involved in reproduction. Males: Testes and penis Females: Ovaries and uterus Sexual Development

39-3 The Reproductive System Slide 5 of 41 Copyright Pearson Prentice Hall Secondary Sex Characteristics: -Characteristics which evolve in humans through the production of hormones. -Distinguishes males from females. Examples: pubic hair, beards, distribution of fat, change in voice, breast development……..

39-3 The Reproductive System Slide 6 of 41 Copyright Pearson Prentice Hall -These traits indicate sexual maturity -They indicate sexual readiness -They are used to attract partners. Lion’s mane Deer antlers Male peacock with feathers

39-3 The Reproductive System Slide 7 of 41 Copyright Pearson Prentice Hall Sexual Development Puberty is a period of rapid growth and sexual maturation during which the reproductive system becomes fully functional. When puberty ends, reproductive organs are fully developed. Puberty usually begins between the ages of 9 and 15, and usually starts one year earlier in females than in males.

39-3 The Reproductive System Slide 8 of 41 Male Reproductive System Copyright Pearson Prentice Hall

39-3 The Reproductive System Slide 9 of 41 Copyright Pearson Prentice Hall Two main functions of the male reproductive system: 1. To make sperm (testes) 2. To deliver the sperm to the ova (penis)

39-3 The Reproductive System Slide 10 of 41 Copyright Pearson Prentice Hall Sperm production takes place in the 2 testes -produces sperm and male hormones -located in scrotum -sack outside body cavity -reduces temperature by 2 to 4 degrees for optimal temperature for healthy sperm production -each testicle is made up of 200 meters of coiled tubing called seminiferous tubules.

39-3 The Reproductive System Slide 11 of 41 Copyright Pearson Prentice Hall 120 to 200 million of sperm are produced per day

39-3 The Reproductive System Slide 12 of 41 Copyright Pearson Prentice Hall The Male Reproductive System Male Reproductive System Urinary bladder Vas deferens Pubic bone Urethra Penis Seminal vesicle Rectum Prostate gland Bulbourethral gland Scrotum Testis Epididymis

39-3 The Reproductive System Slide 13 of 41 Copyright Pearson Prentice Hall The Male Reproductive System Once sperm are produced in the seminiferous tubules they move into a sac called the epididymis, where they mature and are stored for up to 5 days

39-3 The Reproductive System Slide 14 of 41 Copyright Pearson Prentice Hall Sperm can be used/released by an ejaculation or their lysosomes will break open and digest the sperm so it can be disposed of as a waste product.

39-3 The Reproductive System Slide 15 of 41 Copyright Pearson Prentice Hall Sperm Delivery: -main organ of sperm delivery is the penis -during an sexual excitement the spongy material which makes up the penis fills with blood. -Spongy material is called glans penis

39-3 The Reproductive System Slide 16 of 41 Copyright Pearson Prentice Hall An erection is caused by this increase in blood flow~ causing the penis to swell and elongate.

39-3 The Reproductive System Slide 17 of 41 Copyright Pearson Prentice Hall The Male Reproductive System From the epididymis, sperm move into a tube called the vas deferens, which extends up from the scrotum to the penis.

39-3 The Reproductive System Slide 18 of 41 Copyright Pearson Prentice Hall The Male Reproductive System As sperm travel through the vas deferens it encounters three glands which adds fluid to the sperm creating semen: -Seminal vessicle: adds citric acid which activates the sperm. -Prostrate gland: adds fructose, a sugar used for energy by the sperm. -Cowpers gland: adds a basic fluid which neutralizes the acid in the females vagina.

39-3 The Reproductive System Slide 19 of 41 Copyright Pearson Prentice Hall The two vas deferens converge into one main tube, the urethra. The urethra travels through shaft of penis. Semen travels at a rate of 200 ft/second and exits out urethra with an ejaculation

39-3 The Reproductive System Slide 20 of 41 Copyright Pearson Prentice Hall The Male Reproductive System A sperm cell consists of: a head, which contains the 1N nucleus Acrosome: top of head which contain specialized lysosomes which release enzymes used to dissolve protective layer around egg so fertilization can take place. Head Nucleus Midpiece Mitochondria Tail Acrosome

39-3 The Reproductive System Slide 21 of 41 Copyright Pearson Prentice Hall -a tail/flagella, which propels the cell forward -a midpiece, which contains energy-releasing mitochondria Flagella/tail Midpiece with mitochondria