Human Development In this lesson, you will Learn About… The basic unit of life. Development before birth. The factors that affect development before birth.

Standards 1 : The student will comprehend concepts related to health promotion to enhance health.

Indictors G Explain the structures and functions of the male and female reproductive systems G Describe the scientific processes of fertilization, pregnancy, fetal development, and childbirth.

Relevance

Human Development The Vocabulary terms for this lesson are : Cell. Cell Tissue. Tissue Organ. Organ Body system. Body system Embryo. Embryo Fetus. Fetus Chromosomes. Chromosomes Genes. Genes

Building Blocks This is a cell from the lining of the stomach. cell The tissue that forms the stomach lining protects the stomach from the acid in gastric juice.tissue The stomach is an organ made up of muscle, mucous membranes, and organ other types of tissue. These tissues work together to digest food. The digestive system is an example of a body system.body system

Development After Fertilization The human body begins as a single fertilized cell. The fertilized cell then starts to divide into a number of cells. These cells are referred to as an embryo.embryo After about a week, the embryo attaches itself to the lining of the uterus. After the eighth week, the embryo is called a fetus.fetus From the moment of fertilization until birth, the cells develop into tissues, organs, and body systems.

The Developing Fetus Fertilization The union of the sperm cell with an egg cell forms an embryo 3 Months Length: 3 inches Weight: 1 ounce Behavior: begins to move 9 Months Length: 18–20 inches Weight: 7–9 pounds Behavior: eyes open, fingers can grasp, body organs and systems can work on their own 6 Months Length: 12 ½ inches Weight: 1 ½ pounds Behavior: kicks, hears sounds

Care During Pregnancy DO: Eat healthful foods. Have regular checkups. Beware of infections. DON’T: Smoke or use tobacco. Drink alcohol. Take any unnecessary drugs.

Heredity Certain traits are traits you have inherited from your parents. Structures within cells influence heredity. Chromosomes are threadlike structures that carry the codes for inherited traits. Each chromosome is divided into thousands of small parts called genes. Children inherit genes for each trait from each parent.genes

Heredity (cont’d.) Sperm cell Egg cell 23 chromosomes 46 chromosomes Sperm cell 23 chromosomes Embryo

Heredity (cont’d.) Genetic problems can cause serious disorders. Down syndrome, for example, is a genetic disorder in which a person’s cells have 47 chromosomes instead of 46. Such disorders can affect physical or mental development, or both. Genetic disorders may be mild or severe; a few are fatal.

Reviewing Terms and Facts 1.Define the term cell. A cell is the basic unit of life.

Reviewing Terms and Facts 2.Explain the difference between an embryo and a fetus. An embryo is the name of the growing organism from the first cell division until about the eighth week of development. It is then considered a fetus until birth.

3.Why should a female be under a doctor’s care while she is pregnant? Thinking Critically

Vocabulary Review A cell is the basic unit of life.

Vocabulary Review A tissue is a group of similar cells that do a particular job.

Vocabulary Review An organ is a body part made up of different tissues joined together to perform a function.

Vocabulary Review A body system is a group of organs that work together to carry out related tasks.

Vocabulary Review An embryo is the name for the developing organism from fertilization to about the eighth week of development.

Vocabulary Review A fetus is the name for the developing organism from the end of the eighth week until birth.

Vocabulary Review Chromosomes are threadlike structures that carry the codes for inherited traits.

Vocabulary Review Genes are the basic units of heredity.