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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+
