Anatomy and Physiology 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. Neurons are the basic working units of the brain, specialized cells designed to transmit information to other nerve cells, muscles, or gland cells.

The autonomic nervous system is divided into the sympathetic and parasympathetic nervous systems. Sympathetic nervous system has fibers that leave the central nervous system in the thoracic and lumbar regions. Sympathetic 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. The nerves are distributed to blood vessels, glands, and the majority of internal organs. The system works in balance with the sympathetic nervous system.

In human beings the nervous system has the ability to form cortical associations. All the human beings have this function which is formed upon signalization. It is a process in which the stimulus produces the same range of 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.

Exercise 6. Answer the following questions:

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 is called conditional reflexes?

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; оточуючі умови; нервові волокна; грудна та поперекова ділянки; органи черевної порожнини; мимовільні рухи; умовний рефлекс.

Exercise 8. Match the terms with their definitions:

1. involuntary muscle 2. ganglion 3. spinal cord 4. neuron 5. brain 6. stimulus

a) the enlarged and highly developed mass of nervous tissue that forms the upper end of the CNS; b) the part of the CNS enclosed in the vertebral column; c) any structure containing a collection of nerve cell bodies; d) a cell specialized to transmit electrical nerve impulses; and carry information from one part of the body to another; e) any agent that provokes a response in a cell or tissue; f) muscle that is not under conscious control.

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.

Exercise 11. Put the verbs in brackets in the correct tense and voice form:

1. The brain and the spinal cord (to form) the control center, where information (to evaluate) and decisions (to make).

2. The spinal cord (to be) a long, thin mass of neurons that (to carry) information through the vertebral cavity of the spine.

3. Neurons also (to know) as nerve cells.

4. About 100 billion neurons of the brain (to form) the main control center of the body.

5. The sensory nerves and sense organs of the peripheral nervous system (to monitor) conditions inside and outside of the body.

6. The somatic nervous system (to consist) of peripheral nerve fibers that (to pick up) sensory information from the distant organs and (to carry) them to the central nervous system.

7. The nerves of the autonomic nervous system (to innervate) the smooth involuntary muscles of the internal organs and glands and (to cause) them to secrete enzymes.

8. The sensory function of the nervous system (to involve) collecting information from sensory receptors. These signals (to pass on) to the central nervous system.

Exercise 12. Guess which term is described:

1. It consists of the brain, spinal cord, sensory organs, and all of the nerves that connect these organs with the rest of the body.

2. It is a soft, wrinkled organ located inside the cranial cavity.

3. It contains the white and grey matter.

4. It consists of the somatic and the autonomic nervous systems.

5. It is the basic unit in the nervous system, a specialized conductor cell that receives and transmits electrochemical nerve impulses.

6. It is a nerve cell cluster located in the peripheral nervous system.