Control and Coordination: CBSE Class 10 Biology practice questions
Practise 50 questions on Control and Coordination, free, with an explanation for each answer.
Sample questions
You pull your hand away from a hot flame before you have time to think. Why is this response so quick?
- The brain is able to think faster when there is danger
- A reflex arc in the spinal cord acts without waiting for the brain
- The muscles of the hand decide on their own without any nerves
- Pain receptors are present only inside muscles
Show the answer
B. A reflex arc in the spinal cord acts without waiting for the brain
A reflex arc joins the input (sensory) nerve and the output (motor) nerve at the point where they first meet, the spinal cord. The information still reaches the brain later, but the response does not wait for the slow, complicated thinking process. Muscles cannot act without a nerve impulse, and heat receptors are in the skin, not in muscles.
What happens at the synapse between two neurons?
- The axon of one neuron fuses with the cell body of the next
- An electrical impulse jumps across the gap as a spark
- Chemicals released at the axon end cross the gap and start an electrical impulse in the dendrite of the next neuron
- The impulse stops and the signal is lost
Show the answer
C. Chemicals released at the axon end cross the gap and start an electrical impulse in the dendrite of the next neuron
The electrical impulse reaching the axon end triggers the release of chemicals. They diffuse across the gap (synapse) and start a similar electrical impulse in the next neuron. The neurons do not fuse and the signal is not lost. A similar synapse passes impulses on to muscle or gland cells.
A person has an injury that cuts the spinal cord in the middle of the back. Which signals are affected?
- Only the signals from the brain to the legs
- Impulses between the brain and the body below the injury, in both directions
- Only the sensations from the legs to the brain
- None, since the brain controls the whole body directly
Show the answer
B. Impulses between the brain and the body below the injury, in both directions
The spinal cord carries sensory impulses up to the brain and motor commands down from the brain. A cut blocks both ways below the injury. The brain cannot reach muscles directly; it needs the cord and nerves, so the other options are incomplete or wrong.
Topics covered
- Reflex action
- Neuron
- Synapse
- Nerve impulse
- Receptors
- Human brain
- Nervous system
- Protection
- Muscle action
- Reflex arc
- Spinal cord
- Plant movement
- Tropic movements
- Phototropism
- Plant hormones
- Tropism
- Speed of response
- Hormones
- Nervous vs hormonal
- Adrenaline
- Endocrine system
- Hormone disorders
- Thyroid
- Growth hormone
- Feedback