Human Reproduction UPCO Chapter 21 Puberty Human reproduction

Human Reproduction UPCO: Chapter 21

Puberty � Human reproduction is controlled by hormones � Hormones are chemicals secreted by glands in the endocrine system � Testes secrete testosterone � Ovaries secrete estrogen � Puberty is the time when hormones produce physical changes in the body that enable us to produce gametes � These changes are called secondary sex characteristics � Males reach puberty at around 12 -14 years of age � Females reach puberty at around 10 -14 years of age

Secondary Sex Characteristics Male �Growth of beard or facial hair Female �Development of breasts (Mammary glands) �Changes in body shape �Lowering of voice �Growth of body hair

Do Now…. Answer questions # 1 -5 on page 355.

Male Reproductive System • Performs 2 major functions: − Production of sperm − Deposit of sperm inside the female reproductive tract • Sperm production takes place in gonads called Testes • Testes are held in a sac called the scrotum • This keeps the temperature of the sperm lower than the body • Sperm passes out of the body thru the penis through tubes called the urethra • As the sperm passes out of the body fluid is added to it: − − − Makes it more alkaline Supplies glucose for energy Provides a liquid medium Called semen Ejaculation- when sperm is passed out of the body

Male Reproductive System

Do Now… Answer questions # 1 -5 on page 356.

Female Reproductive System � Main function is to produce eggs � Site of fertilization ( Fallopian Tubes) and embryonic development � Production of eggs takes place in the follicles of the ovaries � Release of the egg from the follicle is called ovulation � After ovulation the egg passes through the oviduct (fallopian tube) � From the fallopian tube the egg moves into the uterus. � If it is not fertilized it will be sloughed off through the cervix into the vagina and out of the body � If it is fertilized it will implant itself into the wall of the uterus and begin to grow

Female Reproductive System

Do Now… Answer questions # 1, 2 on page 357.

Fertilization � During intercourse the penis becomes erect for better transfer of sperm into the vagina � After intercourse the sperm travel through the female reproductive tract to the oviducts � Sperm and egg may unite and a zygote is formed � Fertilization takes place in the oviduct (fallopian tube) � Cleavage begins while the zygote is still in the oviduct � 6 -10 days later it may become implanted into the wall of the uterus � If more than one egg is released then multiple births may occur § Identical twins- one zygote separates into 2 cells § Fraternal twins- 2 eggs are released and each is fertilized by a different sperm

Fertilization

Do Now… Answer questions # 1 -6 on page 358.