Main Functions:
(A) Fore-brain: (i) It has regions which receives sensory impulses from various receptors. Based upon information and information stored in the brain, it make a decision how to respond. The information is passed on to motor areas which control movement of voluntary muscles such as our leg muscles.
(ii) It is the site of intelligence and judgement.
(iii) It controls intellect, speech, language, hunger and the spinal senses.
(B) Mid-brain:
(i) It controls the reflex action of right, such as change in the size of pupil, hearing and of balance. Thus, it controls such involuntary action.
(C) Hind-brain:
(i) It controls involuntary actions such as blood pressure, salvation, and vomitting.
(ii) It regulates the voluntary movement of skeletal muscles (motor activities) to maintain the posture and balance of the body. This controlled cerebellum, a part hind-brain. It controls activities such as walking in a straight line, riding a bicycle, picking up a pencil etc.
(iii) Medulla oblongata controls life activities such as respiration and circulation.
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Voluntary actions |
Involuntary/Reflex actions |
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1. |
The actions are under the will or conscious of the individual. |
1. |
Actions occur without consulting the will. |
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2. |
They may or may not involve information from receptors or sense organs. |
2. |
Involuntary actions always occur in response to stimuli picked up by receptors. |
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3. |
Impulses originate in the brain. |
3. |
Impulses originate in the region of receptors. |
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4. |
Every voluntary action occurs under conscious directions from brain. |
4. |
Brain is seldom consulted consciously though an involuntary action always involves spinal cord or brain for transfer of information from afferent neurons to efferent neurons. |
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5. |
The actions employ voluntary muscles. |
5. |
The actions employ involuntary muscles but occasionally voluntary muscles also get involved. |
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6. |
Voluntary actions do not occur in the form of an arc. Mainly three parts are involved— brain (CNS), efferent neuron and effector organ. |
6. |
They occur in the form of a reflex arc. A reflex arc consists of five parts—receptors, afferent neuron, interneuron in CNS, efferent neuron and effector organ. |
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