The Human BodyBY: MR. B

Changes…

• There are two periods in life when the human body changes rapidly and dramatically.

• Babies: In first year of life, babies usually triple their weight and at two and a half years they have reached half of their adult height.

• Puberty: The shape of the body changes, there are obvious signs of the development of fertility and growth spurts result in rapid height and weight gain. Even the appearance of the face is changed because of the facial bones.

Sexual Characteristics Review• Primary Sexual Characteristics:

• The development of fertility, which is the capacity to reproduce.

• Secondary Sexual Characteristics• The external changes in the body that make the appearance of each sex

distinctive.

Female Fertility

Menstruatio

n

Ovum

OvulationCervical Mucus

FertileUterus

Fallopian TubeCycle

Vagina

Not how we’ll learn about this…

• Female Fertility is usually described as a “cycle”, which means that a series of events are repeated again in the same order.

• Female Fertility Cycle begins with menstruation and ends when the next menstrual period begins.

• Most cycles last from three to five weeks, and include a short period of fertility, and a longer period of infertility.

Female Fertility

Female Fertility Cont.

• Three regular events that occur during the adult female cycle are:

• Menstruation – Shedding the lining of the uterus

• Ripening of an ovum in one of the ovaries

• Ovulation – Fully ripened ovum moves into the fallopian tube, which leads to the uterus.

Women are fertile just before and after ovulation.

Signs of Female Fertility

• As the ovum begins to ripen, the ovaries send a signal to the cervix to product mucus.

• At first the cervical mucus is quite thick.

• As ovulation approaches it becomes thinner

• The purpose of cervical mucus is:• To nourish and prolong the life of sperm cells.

• Guide and carry sperm toward the Ovum.

• Filer out abnormal or immature sperm cells.

• After ovulation the mucus thickens again and forms a barrier or plug at the opening of the uterus.

FEMALE REPRODUCTIVE SYSTEM

Female Fertility Key Terms

• Some time after girls begin to mature they experience these signs of their fertility.

• Menstruation• A sign the uterus has begun the task of building a lining.

• Cervical Mucus• A sign ovulation is occurring

Male Fertility

Testicles

Ejaculation

Semen Penis

Nocturnal Emission

Sperm

Erection

Male Fertility

• Unlike Female Fertility, it does not occur in a cycle. Physically mature males always have the ability to reproduce.

• Male fertility begins with the production and storage of sperm cells inside the testicles.

• Sperm cells must move out of the storage areas and mix with several fluids, which protect and nourish the sperm. This mixture is called Semen.

• The sperm and fluid is expelled from the body through the penis by a process called Ejaculation.

Signs of Male Fertility

• The process of producing and storing sperm cells usually begins when boys are between 12 and 16.

• Only a limited amount of sperm can be stored inside in the body. In order to make room for new sperm cells, semen is cleared out of the body periodically.

• This can happen gradually or all at once through Ejaculation.

• This often occurs during sleep, and so it is called a Nocturnal Emission.

Male Reproduction System

Secondary Sexual Characteristic StagesStage

Boy Girls

1 No physical development is evident, but internal changes have begun. There are rising levels of hormones in the blood stream; the testicles are maturing and the ovaries are enlarging

2 Age: 10-14-Gain weight and height. -Testicles and scrotum enlarge; penis remains the same size.-First signs of pubic hair are evident.

Age: 8-13-First signs of breast development. -Height and weight begin to increase.-First signs of pubic hair are evident

3 Age: 11-16-Testicles and scrotum continue to grow; penis lengthens.-Pubic Hair thickens-Height and weight increase, and shoulders broaden.-As larynx enlarges, the voice begins to deepen

Age 9-15-Breasts continue to grow.-Pubic Hair coarsens and darkens.-Cervical mucus appears and late in this stage girls may menstruate for the first time.

4 Age: 12-17-Penis length and width increases; testicles continue to enlarge.-May experience first nocturnal emission.-Voice deepens and skin becomes oilier.-Underarm hair appears and some boys may have facial hair on chin as well as upper lip

Age: 12-13-Underarm hair begins to develop.-Breasts continue to develop and menstruation is likely to begin.-Ovulation may not occur yet.-Pubic Hair is more adult in appearance.

Secondary Sexual Characteristics StagesStage

Male Female

5 Ages: 14-18-Development of genitals and pubic hair is complete.-Growth spurts slow down and body is shape of a mature male.-Boys typically begin shaving.-Depending on their genetics, some may continue to develop body hair on their upper body for several years.

Ages: 15-16-Have the body of a mature woman; full breast development.-Full adult height as been reached.-Sometime during this stage ovulation begins to occur with some regularity.