Question

D. Differentiate between the following.
1. Cerebrum and cerebellum
2. Gray matter and white matter
3. Sensory and motor nerve
4. Voluntary and reflex action​

Answer 1

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Ans #1.

Cerebrum is a major part of the brain as well as the fore brain. It decides intelligence, analytical mind, logical thinking and stores short and long term memory.

Cerebellum is a part of the hind brain and is connected to the spinal cord. It is responsible for muscular control and coordination.

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Ans #2.

Gray matter are the neurons (nerve cells) that have either less or no myelin sheaths at all.

White matter are the neurons or nerve cells whose axon is well covered with myelin sheaths and helps in faster transmission of nerve impulse.

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Ans #3.

Sensory neurons are present in our receptor or sensory organs. These receptors receive various stimuli such as pressure, heat, smell, taste etc. There are 5 receptors in humans. They are:

1. Thigmo-receptors for touch
2. Photo-receptors for light
3. Phono-receptors for sound
4. Gustatory receptors for taste
5. Olfactory receptors for smell

The main function of the sensory neuron is to receive the stimulus from environment and pass it on to the CNS for processing.

Once the data is processed, messages are sent to the effector organ via the motor neuron. The effector organ can be muscles or glands.

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Ans #4.

Voluntary actions are controlled by the brain and the brain is aware of them. Eg:- Peristalsis, Beating of heart etc.

Reflex actions are rapid, spontaneous actions that are controlled by the spinal cord and the brain is not aware about it. However, once the action is performed, the brain is informed about it. Eg:- Coughing when dust enters out nose etc.

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