Chapter 10 The Reproductive System Reproduction means being able to produce new individuals (babies) Two methods Asexual Reproduction: - one parent only and the offspring are clones of the parent. Sexual Reproduction: - two parents a male and a female - offspring are not clones of parent.

Gametes (Sex Cells) Gametes (sex cells) are needed for sexual reproduction Each parent produces a sex cell or gamete male gamete = sperm female gamete = egg Fertilisation Fertilisation is the fusion between the male and female gametes to produce a zygote

Male Reproductive System Can you identify the function of each part?

Seminal vesicles, Cowper’s gland and Prostate gland Summary of functions of main parts of male reproductive system Part Function Testis Produces sperm and testosterone Sperm duct Carries sperm from the epididymis to the urethra Seminal vesicles, Cowper’s gland and Prostate gland Produces seminal fluid which feeds the sperm and allows them to swim. Sperm and seminal fluid are collectively called semen. Urethra Allows the passage of either urine or sperm. Penis Places sperm inside the body of a female Scrotum Keeps testes at a lower temperature (35°). This is the optimum temperature for Meiosis to occur.

Urethra The urethra carries semen and urine out of the body Facts about sperm The volume of semen in a single ejaculation may vary from 1.5 to 6.0 ml. There are usually between 50 to 150 million sperm per millilitre of semen

Puberty Puberty – The age at which young people reach sexual maturity. In boys this occurs between 12-14 years. In girls this occurs between 10-13 years old.

Male Secondary Sexual characteristics Secondary sexual characteristics refer to features that distinguish males from females, apart from the sex organs themselves. The growth of pubic, facial and body hair The enlargement of larynx and ‘breaking’ of the voice Increased muscular and bone A growth spurt at puberty An increased secretion of sebum in the skin

Male Hormone - Testosterone Testosterone is the hormone responsible for Development of male sex organs: Sperm production. Development of the secondary male sexual characteristics. The primary sexual characteristics are the presence of the male and female reproductive parts

Structure of the female reproductive system

functions of main parts of female reproductive system Ovary To produce the egg (ova). To produce hormones Fallopian tube (oviduct) Catches the egg from the ovary and transports it to uterus. Site of fertilisation. Uterus Site of implantation. Holds the developing embryo. Has a lining (endometrium) enriched with blood vessels to nourish the embryo. Forms the placenta. Vagina Allows entry of sperm and exit of baby at birth.

Secondary Sexual Characteristics in Females Hormones released at puberty are responsible for: The maturing and enlargement of the breasts. The widening of the pelvis to allow for birth. The growth of pubic and underarm hair. A growth spurt.

Menstrual Cycle

Events in the menstrual cycle Days 1 – 5 1. Menstruation (period). The old lining of the uterus breaks down and leaves the body. 2. A new egg is produced in the ovary. Days 6 - 14 1. The lining of the uterus builds up again in preparation for implantation. 2. Oestrogen also prevents the development of any more eggs. Day 14 Ovulation. The release the egg into the fallopian tube. Days 14 - 28 1. The uterus lining thicken even further. If fertilisation does not take place: The egg that was released will die by day 16 if it is not fertilised. The lining of the uterus breaks down again on day 28. The menstrual cycle begins again with day 1.