WHAT IS THE BODY MADE OF?

The human body has many parts, doesn’t it?

Can you name them from the smallest parts through the largest ones?

WHAT IS THE BODY MADE OF?

Like all things (living or not living) the human body consists of atoms of chemical elements. The most common chemical elements in the body are carbon, nitrogen, and oxygen. The body also contains smaller amounts of many other elements including calcium, iron, phosphorus, potassium, and sodium.

Atoms of chemical elements combine and form microscope structures called molecules. The most common molecule in the human body is water. Water makes about 65% of the body. Most of the chemical reactions that occur in the body require water. Except for water, all the chief molecules in the body contain carbon. The most important of these molecules are large, complicated structures called macromolecules. There are four main kinds of macromolecules: carbohydrates, lipids, proteins, and nucleic acids.

The cell is the basic unit of all living things. The cell of the human body consists chiefly of water, proteins, and nucleic acids. The molecules that make up the cell are not alive, but the cells themselves are living things. Each of the body’s cells is able to take in food, get rid of wastes, and grow. Most of the cells can also reproduce. A thin covering consisting of lipid molecules encloses each cell. This lipid envelope permits only certain substances to enter or leave the cell. The body has many types of cells, such as blood cells, muscle cells, and nerve cells.

Cells of the same type form tissues. The body has four chief kinds of tissues. Connective tissue helps support and join together various parts of body. Most connective tissue is strong and elastic. Epithelial tissue covers the body surface and so forms the skin. It also lines such body openings as the mouth and the throat. Epithelial tissue prevents harmful substances from entering the body. Muscle tissue makes it possible for the body to move. It consists of threadlike fibers that can contract (shorten). Nervous tissue carries signals. It permits various parts of body to communicate with one another.

An organ consists of two or more kinds of tissues joined into one structure that has a certain task. Groups of organs form organ system. Each organ system carries out a major activity in the body.

VOCABULARY

I. Read the following words aloud. Guess their meaning. Check yourself using a dictionary.

II. Complete the definitions. Use glossary if necessary:

1. Molecules are microscopic structures formed of _______________.

2. Macromolecules are _______________.

3. The cell is _______________.

4. Tissue is a group of _______________.

COMPREHENSION. SKIMMING

I. Find the best answer to complete the sentence. Write the letter of your answer on the line.

II. Arrange in proper order from the smallest part through the largest one (number 1 through 6):

------tissues
------molecules
------organ systems
--1--chemical elements
------organs
------cells

SCANNING

I. One world in each sentence is not correct. Find it out. Write the correct world.

1. The most common chemical cells in the body are carbon, hydrogen, nitrogen, and oxygen.
2. The most common tissue in the human body is water.
3. Carbohydrates provide water.
4. Proteins have similar duties.
5. Tissue is the basic unit of all living things.
6. Each of the body’s cells is able to take in wastes.
7. The basic cells are blood cells, muscle cells, and digestive cells.
8. The body has three chief kinds of tissues.
9. Muscle tissue makes it possible for the body to grow.
10. Groups of tissues form organ systems.

II. Circle T if the sentence is true. Circle F if the sentence is false:

ACTIVITY

I. Answer the following questions:

1. Which are the most common chemical elements in the body?
2. Which other elements does the body contain?
3. What do atoms of chemical elements form?
4. What is the most common molecule in the human body?
5. Why is water of great importance for the human body?
6. Which other element do all of the chief molecules of the human body contain?
7. What macromolecules does the human body contain?
8. What is the basic unit of all living things?
9. What is each of the body’s cells able to do?
10. What types of cells does the body have?
11. What do cells of the same type have?
12. What are the four chief types of tissues?
13. What does an organ consist of?
14. What forms organ systems?
15. What is the role of each organ system?

II. Compose sox sentence on the text. Some of them may be right, some may be wrong. Ask your classmates to approve or disapprove these sentences. Work in pairs or groups.

III. Describe the structure of human heart. Use the support bellow:

IV. Fill in the table. Ask your classmates questions about the role of macromolecules:

WRITING

I. Complete the sentences:

1. Connective tissue helps ___________.
2. Epithelial tissue covers ____________.
3. Muscle tissue makes _____________.
4. Nervous tissue _________________.

RESEARCH*

I. Find out:

1. The story of functional organ systems worked out by P.K. Anokhin.
2. What is its idea?