18. THE NERVOUS SYSTEM
EXERCISE 1 Fill each gap with a suitable word.
The nervous system is responsible 1) _______________ sending, receiving, and
interpreting information from all parts of the body. The nervous system monitors and
coordinates internal organ function and responds 2) _______________ changes in the
external environment. The nervous system includes 3) ________________ the central
nervous system (CNS) and peripheral nervous system (PNS).
The central nervous system (CNS) is the processing center for the nervous system.
It receives information 4) _______________ and sends information to the peripheral
nervous system. The central nervous system is made 5) _______________ of the brain and
spinal cord.
The brain processes and interprets sensory information sent from the spinal cord. It
has nerve cells called the neurons and supporting cells called the glia. There are two
6) _______________ of matter in the brain: grey matter and white matter. Grey matter is
the outer layer of brain tissue and it contains neurons. White matter is beneath the grey
matter and it contains only myelinated axons. The brain consists 7) _______________ four
principal parts:
·ð The cerebrum forms the biggest region of the brain. It is divided
8) _________________ two hemispheres. Each hemisphere controls the
activities of the side of the body opposite that hemisphere.
·ð The cerebellum is the other large region of the brain that is located behind
and below the cerebrum.
·ð The diencephalon is also 9) ________________ as the fore brain stem and
contains the thalamus, the hypothalamus, the pituitary gland and the pineal
gland.
·ð The brainstem has three parts: the midbrain, the pons and the medulla
oblongata.
The spinal cord is a long tube-like structure which originates at the brain and
extends about two-thirds of the way down the spine, as far as the first lumbar vertebra. It
rests 10) _______________ the spine. The spinal cord is 11) _______________ of 31 pairs of
spinal nerves which branch off to various parts of the body. Both motor and sensory nerves
are located in the spinal cord. Spinal cord nerves transmit information from body organs
and external stimuli to the brain and send information from the brain to other areas of the
body.
The neuron is the basic unit in the nervous system. It has three parts:
·ð The cell body  it is like any other cell 12) ________________ a nucleus or
control center.
·ð The dendrites  they receive messages from other neurons and send these
messages to the cell body.
·ð The axon  it carries impulses away from the cell body to another neuron or
tissue.
EXERCISE 2 Complete the test with suitable words from the box.
connect carry network stimuli antagonistic
referred involuntary respond
The peripheral nervous system (PNS) consists of nerves that 1)
_____________________ impulses towards as well as away from the CNS, allowing the
brain to detect sensations within as well as 2) ____________________ to sensations outside
the body. It is made up of the somatic and the autonomic nervous systems.
The somatic nervous system is responsible for carrying motor and sensory
information both to and from the central nervous system. This system is made up of nerves
that 3) ____________________ to the skin, sensory organs and all skeletal muscles. The
system is responsible for nearly all voluntary muscle movements as well as for processing
sensory information that arrives via external 4) _____________________ including hearing,
touch and sight.
The autonomic nervous system has three parts: the sympathetic nervous system,
the parasympathetic nervous system, and the enteric nervous system. The autonomic
nervous system regulates 5) ____________________ body functions, such as heartbeat,
blood flow, breathing and digestion. The sympathetic and parasympathetic systems often
function in 6) _____________________ ways, e.g. the sympathetic nervous system
accelerates the heart rate while the parasympathetic nervous system slows it down. The
enteric nervous system is the third part of the autonomic nervous system. It is a 7)
____________________ of neurons, neurotransmitters, and special proteins located
throughout the gastrointestinal system. It is sometimes 8) ____________________ to as the
nervous system of the gut, or the "brain" or "mind" of the gut.
EXERCISE 3 Label the picture with the following terms:
axon, cell body, dendrite, nucleus
EXERCISE 4 Label the picture with the following terms:
cerebellum cerebrum hypothalamus medulla midbrain
pituitary gland pons spinal cord thalamus