growth and development chapter 8. lesson 1 adolescence: a time of change

GROWTH AND DEVELOPMENT

Chapter 8

Lesson 1

Adolescence: A Time of Change

adolescence The period between childhood and

adulthood

Changes During Adolescence

Differences in how younger or older teens may look are caused by adolescence.

Mood swings are a normal part of adolescence.

Changes During Adolescence

Hormones are produced in the endocrine system.

endocrine system A body system containing glands that regulate growth and other important activities

Changes During Adolescence

These glands make up the endocrine system:

PituitaryPituitary ThyroidThyroid AdrenalAdrenal PancreasPancreas Ovaries /Testes

Ovaries /Testes

Physical Changes

Physical changes that occur during puberty include the growth of body hair and increased sweating, or perspiration.

puberty The time when you start developing the physical characteristics of adults of your gender

Female

Hips wider Menstruation Acne Increase sweating Increased levels of hormones Underarm / pubic hair Development of breasts Formation of mature eggs Increase in body fat

Male

Facial / pubic hair / underarm hair Deepened voice Acne Increased sweating Increased hormones Production of sperm Shoulders broadened Muscle development

Mental/Emotional Changes

Changes in hormones can affect your feelings as well as your thoughts.

You may experience mood swings.

Lesson 2

Human Reproduction

Human Reproduction

The male reproductive system is different than the female reproductive system.

reproductive system The body system that makes it possible to create offspring

The Female Reproductive System

The two main functions of the female reproductive system are:

egg cell The female reproductive cell

Storing egg cells

To reproduce

The Female Reproductive System

The process of reproduction begins when the egg cell joins with a male reproductive cell (sperm cell).

The ovaries are the two female reproductive glands that store the egg cells.

The Female Reproductive System

After fertilization, an egg will travel to the uterus, the organ in which the baby will develop.

fertilization The joining of a female egg with a male

reproductive cell

The Female Reproductive System

Menstruation is often referred to as a “period.”

menstruation Blood, tissue, and the unfertilized egg flow out of the body

The Male Reproductive System

Sperm cells are made inside the testes.

sperm The male reproductive cells

The testes begin making sperm cells during puberty.

Lesson 3

Heredity and the Life Cycle

Heredity

Heredity is the process by which parents pass certain traits to their children.

Hair color and body build are examples of inherited traits.

Heredity

Traits are passed along by chromosomes.

chromosomes Tiny strands of matter that carry the

codes for inherited traits

Chromosomes are made up of genes.

genes The basic units of heredity

Chromosomes and Fertilization

Among each sperm’s 23 chromosomes, one alone determines the gender of the fertilized egg cell.

An egg caries only an X chromosome. Sperm carry either an X or Y chromosome.

If a sperm carries an X chromosome, a female will result. If a sperm carries a Y chromosome, a male will result.

Data and Observation

Inherited Trait Yes No

Dimples

Earlobe attached

“Widow’s peak”

Left handed

Right handed

Tongue rolling

“Vulcan” sign

Blue eyes

Inherited Trait

Yes No

Brown eyes

Green eyes

Curly hair

Straight hair

Straight thumb“Hitchhiker’s thumb”

Left hand claspRight hand clasp

Development Before Birth

The newly fertilized

egg travels down

the fallopian tube

to the uterus.

The newly fertilized

egg travels down

the fallopian tube

to the uterus.

The egg attaches itself to the wall of the uterus.

The egg attaches itself to the wall of the uterus.

The egg begins to be divided

millions of times.

The egg begins to be divided

millions of times.

The tissues, organs, and

body systems are eventually

formed.

The tissues, organs, and

body systems are eventually

formed.

The Developing BabyTime Size Features Development

fertilization microscopic arms, legs, fingers, toes, eyes, ears

heart is beating; nervous system is forming; cannot survive outside uterus

6 months after fertilization

about 14 inches long; weighs about 2 pounds

hair, eyebrows, fingernails, toenails

can move and kick; sucks thumb; can hear sounds; might survive outside uterus

9 months after fertilization

18–20 inches long; weighs 7–9 pounds

smooth skin, fully developed organs

eyes open and close; fingers can grasp; body organs and systems can now work on their own; ready for birth

The Developing Baby

In the uterus, the fetus receives oxygen and nutrients through a tube called the umbilical cord.

fetus What the developing unborn baby is known as from the eighth week until birth

The Developing Baby

Throughout pregnancy, an expectant mother needs prenatal care.

prenatal care Special care to ensure that the expectant mother and the baby remain healthy

Prenatal care includes eating healthy foods, getting enough rest, and seeing the doctor regularly.

The Life Cycle

The life cycle is divided into six major stages.

InfancyInfancy ChildhoodChildhood AdolescenceAdolescence EarlyAdulthood

EarlyAdulthood

MiddleAdulthood

MiddleAdulthood

LateAdulthood

LateAdulthood

Age 1 Ages1–11

Ages12–18

Ages19–30

Ages30–60

Ages60+