The organ A which is located inside the skull of our body is protected by a bony box B and it is surrounded by three membranes C. The space between the membranes is filled with a liquid D which protects the organ A from mechanical shocks. The organ A in combination with another organ E makes up the central nervous system.
(a) What is organ A ?
(b) What are (i) B (ii) C, and (iii) D ?
(c) Name the organ E.
(d) While walking barefooted, if we happen to step on a sharp piece of stone, we immediately lift our foot up. Which of the two organs, A or E, is directly involved in this action ?
(e) If we step out from a darkened room into bright sunshine, we close our eyes for a moment. Which of the two organs, A or E, is directly involved in this action ?
The organ A which is located inside the skull of our body is protected by a bony box B and it is surrounded by three membranes C. The space between the membranes is filled with a liquid D which protects the organ A from mechanical shocks. The organ A in combination with another organ E makes up the central nervous system.
(a) What is organ A ?
(b) What are (i) B (ii) C, and (iii) D ?
(c) Name the organ E.
(d) While walking barefooted, if we happen to step on a sharp piece of stone, we immediately lift our foot up. Which of the two organs, A or E, is directly involved in this action ?
(e) If we step out from a darkened room into bright sunshine, we close our eyes for a moment. Which of the two organs, A or E, is directly involved in this action ?
- The organ A is the brain. The brain is located inside the skull of our body at the top of the spinal cord.
- (i) B is the cranium. The brain is protected by a bony box in the skull called the cranium.
(ii) C are meninges. The brain is surrounded by three layers of membranes called the meninges.
(iii) D is the cerebrospinal fluid. It is present in between the meninges and protects the brain from mechanical shocks.
- The organ E is the spinal cord. The brain (organ A) and the spinal cord (organ E) together make central nervous system. -
- A person walking barefoot lifts his foot at once on stepping on the stone. organ E the spinal cord is directly invloved in this action as this is a reflex action. The stimulus here is the stone lying on the ground that was stepped upon. The pain is sensed by the receptors in the skin which triggers an impulse in the sensory neuron which transmits the impulse to the spinal cord. This is then passed on to the relay neuron, which in turn passes it on to the motor neuron. The motor neuron passes the impulse to a muscle in the feet. The muscle then contracts and pulls our feet away from the stone.
- Since the optic nerve is controlled by the brain , in this example organ A is used.
- The organ A is the brain. The brain is located inside the skull of our body at the top of the spinal cord.
- (i) B is the cranium. The brain is protected by a bony box in the skull called the cranium.
(ii) C are meninges. The brain is surrounded by three layers of membranes called the meninges.
(iii) D is the cerebrospinal fluid. It is present in between the meninges and protects the brain from mechanical shocks.
- The organ E is the spinal cord. The brain (organ A) and the spinal cord (organ E) together make central nervous system. -
- A person walking barefoot lifts his foot at once on stepping on the stone. organ E the spinal cord is directly invloved in this action as this is a reflex action. The stimulus here is the stone lying on the ground that was stepped upon. The pain is sensed by the receptors in the skin which triggers an impulse in the sensory neuron which transmits the impulse to the spinal cord. This is then passed on to the relay neuron, which in turn passes it on to the motor neuron. The motor neuron passes the impulse to a muscle in the feet. The muscle then contracts and pulls our feet away from the stone.
- Since the optic nerve is controlled by the brain , in this example organ A is used.
