Questions

1. What is the function of the muscular system?

2. What are characteristics of muscular tissue? Define each of them.

3. Describe the inner structure of muscle tissue.

4. What is the outer structure of muscle?

5. What attaches muscles to bones? Describe these structures.

6. What main classifications of muscles do you know?

7. Why is striated muscular tissue called like this?

8. What are other definitions for striated muscular tissue?

9. What does it mean “voluntary” and ‘involuntary”?

10. What is the function of skeletal muscle? What skeletal muscles do you know?

11. Why is smooth muscular tissue called like this?

12. What are other definitions for smooth muscular tissue?

13. What is the function of visceral muscles? What visceral muscles do you know?

14. What kind of muscle is heart?

15. What are special features of cardiac muscle?

16. What names do muscles bear in English anatomical nomenclature? Give examples.

17. What is muscle tone? What is it due to? What for is it needed?

18. When is muscle tone minimal?

Additional Questions. Something to Think about

1. What is the origin of the word “muscle”? (clues: the Latin word “musculus”, meaning, a little mouse)

2. How many muscles are there in the human body?

3. Give the examples of muscular movements.

4. Can muscle cells contract? What causes the muscle cell to contract?

5. What is given off during muscle contraction as work and heat?

6. What acid is normally produced by contracting muscles? (clue: lactic acid)

7. What is muscle bundle?

8. When do muscles totally relax?

9. What may affect the tone of muscles?

10. What is myoglobin? What for is it needed? (clues: red-colored protein, to supply oxygen to the muscle cells)

11. What hormone is needed for muscle growth? (clue: testosterone)

12. Why do not women and girls have to worry about developing large, bulding muscles? (clues: a male hormone, to need)

Text 3. The Cardiovascular System

Part 1. Blood Vessels

There are three major types of blood vessels in the body. These are called arteries, veins, and capillaries.

Arteries are the large blood vessels which lead blood away from the heart. Their walls are made of connective tissue, elastic fibers, and an innermost layer of epithelial cells. Arteries are strong enough to withstand the high pressure of the pumping action of the heart. Their elastic walls allow them to expand as the heartbeat forces blood into the arterial system throughout the body. Smaller and thinner branches of arteries are called arterioles. They carry the blood to the tiniest of blood vessels, the capillaries.

Capillaries are delicate, microscopic vessels with only one epithelial cell in thickness. They carry nutrient-rich, oxygenated blood from the arteries and arterioles to the body cells. Their walls are thin enough to allow passage of oxygen and nutrients out of the bloodstream and into the tissue fluid surrounding the cells. At the same time, waste products such as carbon dioxide and water pass out of the cells and into the thin-walled capillaries. The waste-filled blood then flows back to the heart in small veins called venules which branch to form larger vessels called veins.

Veins are thinner-walled than arteries. They conduct waste-filled blood toward the heart from the tissues. Veins have little elastic tissue and less connective tissue than arteries, and the blood pressure in veins is low. In order to keep blood moving back toward the heart, veins have valves which prevent the backflow of blood. Muscular action also helps the movement of blood in veins.