Unit 11
The Nervous System
Question: Define the nervous system and explain its functions.
Answer:
The nervous system is the control and communication system of the human body. It is made up of the brain, spinal cord and nerves. The nervous system sends messages, or electrical signals, between the brain and all other parts of the body. These signals help the body to perform different activities such as breathing, moving, speaking and seeing. The nervous system also keeps track of what is happening inside and outside the body and helps the body respond to different situations.
The nervous system works with the help of special nerve cells called neurons. These neurons carry messages between the brain, spinal cord, muscles, organs and sense organs. There are three types of neurons:
> Sensory neurons carry information from the sense organs to the brain.
> Motor neurons carry messages from the brain and spinal cord to the muscles.
>Interneurons connect sensory and motor neurons and help in thinking, learning and remembering.
The nervous system performs many important functions. It controls thoughts, memory, learning and feelings. It helps in movement, balance and coordination of the body. It controls the senses such as seeing, hearing, tasting, touching and smelling. The nervous system also regulates breathing, heartbeat, digestion and sleep. It helps the body respond to stress and danger by controlling actions like sweating and blinking. It also controls body processes such as puberty, growth and aging.
Thus, the nervous system plays a very important role in controlling and coordinating all the activities of the body.
Question: What are the parts of the nervous system? Explain their functions.
Answer:
The nervous system is divided into two main parts: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).
The Central Nervous System consists of the brain and spinal cord. The brain is the control center of the body. It receives signals from the nerves and controls thinking, memory, feelings, movement and other body activities. The spinal cord connects the brain to the rest of the body and carries messages to and from the brain.
The Peripheral Nervous System is made up of a network of nerves that branch out from the spinal cord to different parts of the body such as the organs, arms, legs, fingers and toes. It carries information between the brain, spinal cord and the body.
The Peripheral Nervous System has two parts:
Somatic nervous system – It controls voluntary movements such as walking, writing and speaking.
Autonomic nervous system – It controls involuntary activities such as breathing, heartbeat and digestion.
Thus, the nervous system helps in controlling and coordinating all the activities of the body.
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