Anatomy of the nervous system

Nervous system is the vast network of cells specialized to carry information (in the form of nerve impulses) to and from all parts of the body in order to bring about bodily activity. The brain and spinal cord together form the central nervous system. The central nervous system controls the voluntary muscles of the head, trunk, and the limbs, and IT is responsible for all movement in them and for all sensation in skin, muscles, bones and joints. The remaining nervous tissue is known as the peripheral nervous system and includes the autonomic nervous system which controls all involuntary muscles. It supplies all the internal organs, and is made up of nerve cells (neurons) supplying the glands and the muscular walls of the internal organs and the blood vessels. The autonomic nervous system is divided into the sympathetic and parasympathetic nervous systems.

Sympathetic nervous system has fibers that leave the central nervous system, via a chain of ganglia close to the spinal cord, in the thoracic and lumbar regions. Its nerves are distributed to the blood vessels, heart, lungs, intestines and other abdominal organs, sweat glands and salivary glands.

Parasympathetic nervous system has fibers that leave the central nervous system from the brain and the lower portion of the spinal cord and are distributed to blood vessels, glands, and the majority of internal organs. The system works in balance with the sympathetic nervous system, the actions of which it frequently opposes.

In human beings the nervous system has the additional ability to form cortical associations which increase the range of reactions. This function is obtained by all the human beings and formed upon signalization – the process in which the stimulus produces the same reactions as the stimulus with which it is associated. Such reflexes are called conditioned. And the stimuli producing reactions which don’t depend on surrounding conditions are called unconditioned.

POST-TEXT ASSIGNMENTS

Exercise 6. Answer the questions to the text:

1. What is the main function of the nervous system?

2. What is the central nervous system formed by?

3. What does the central nervous system control?

4. What does the peripheral nervous system include?

5. How are nerve cells called?

6. Where are the nerves of sympathetic nervous system distributed?

7. What works in balance with sympathetic nervous system?

8. What reflexes are called conditional?

Exercise 7. Translate the following word combinations into English:

клітинна сітка, діяльність організму, головний та спинний мозок, м’яз, що довільно скорочується, відповідати за рухи, тулуб і кінцівки, внутрішні органи, кровоносні судини, м’язові стінки, ланцюг нервових вузлів, грудна та поперекова ділянки, органи черевної порожнини, мимовільні рухи, додаткова здатність, умовний рефлекс.

Exercise 8. Match the terms with their definitions:

1. the enlarged and highly developed mass of nervous tissue that forms the upper end of the CNS	a) involuntary muscle
2. the part of the CNS enclosed in the vertebral column	b) ganglion
3. any structure containing a collection of nerve cell bodies	c) spinal cord
4. a cell specialized to transmit electrical nerve impulses and carry information from one part of the body to another	d) neuron
5. any agent that provokes a response in a cell or tissue	e) brain
6. muscle that is not under conscious control	f) stimulus

Exercise 9. Complete the sentences:

1. … supplies all the internal organs, and is made up of nerve cells.

2. … form the central nervous system.

3. … includes the autonomic nervous system which controls all involuntary muscles.

4. … are distributed to blood vessels, glands, and the majority of internal organs.

5. The autonomic nervous system is divided into…

6. … are distributed to the blood vessels, heart, lungs, intestines and other abdominal organs, sweat glands and salivary glands.

Exercise 10. Put questions to the underlined words:

1. Sympathetic nervous system has fibers that leave the central nervous system, via a chain of ganglia.

2. The central nervous system controls the voluntary muscles of the head, trunk, and the limbs.

3. Nervous system is specialized to carry information to and from all parts of the body.

4. Parasympathetic nervous system works in balance with the sympathetic nervous system.

5. The nervous system has the additional ability to form cortical associations.

6. The autonomic nervous system is divided into the sympathetic and parasympathetic nervous systems.

7. The remaining nervous tissue includes the autonomic nervous system.

8. This function is obtained by all the human beings and formed upon signalization.

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