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प्रश्न
P is a cell (or group of cells) in the human body which is sensitive to a particular type of stimulus and conveys the messages to CNS through nerves Q. On the other hand, R is a part of the human body which can respond to a stimulus according to the instructions sent from the CNS through nerves S.
(a) What is P? Name five organs which contain cells (or group of cells) like P.
(b) Name the nerves Q.
(c) What is R? Give two examples of R.
(d) Name nerves S.
(e) How do messages travel through the nerves Q and S?
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उत्तर
(a) P is a receptor. The five organs which contain receptors are: eyes, ears, nose, tongue and skin.
(b) Q represents sensory nerves. Sensory nerves bring impulses from sensory organs to the CNS.
(c) R is an effector organ. Effectors are part of the human body which can respond to a stimulus according to the instructions sent from the CNS though the motor nerves. Two examples of effector organs are the muscles and glands.
(d) S represents motor nerves. Motor nerves carry impulse from the CNS to the effector organs like the muscles or glands.
(e) Messages travel in the form of electrical impulses or nerve impulses through sensory nerves (Q) and motor nerves (S).
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संबंधित प्रश्न
How are involuntary actions and reflex actions different from each other?
Give examples of unconditional reflexes
State one function each of cerebellum and pons.
What are the various sense organs in our body?
Write the names of the regions in hindbrain. Give one function of each region.
Explain the difference between of the following pair of terms :
cerebrum and cerebellum
Which of the following are cerebral reflexes?
(i) a person pulls away his hand on touching a hot object
(ii) a person spits out immediately when a fly enters his mouth while talking
(iii) A person walking bare foot lifts his foot at once on stepping on to a nail
(iv) A person's pupil contracts at once in the presence of bright light
(a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (ii) and (iv)
One of the following gives the correct sequence of the components in a reflex arc. This is:
With the help of suitable example, describe reflex action.
Complete the following statement by choosing the correct alternative from the choice given in bracker:
Reflex action is controlled by
(i) brain (ii) spinal cord
(iii) autonomic (iii) peripheral nervous system
State whether the following is simple reflex, conditioned reflex or neither of the two:
Blushing: ……………….
State whether the following is simple reflex, conditioned reflex or neither of the two:
Lifting up a book: …………………..
Mention, if the following statement is True or False
A reflex action is a spontaneous response to a stimulus.
Complete the following sentence with appropriate Word
The control of reflex action is through:
The reflex arc which is made up of one sensory and one motor neuron is ______
What kind of reflex is cycling?
The diagram given below shows the internal structure of a spinal cord depicting a phenomenon. Study the diagram and answer the following questions.
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- Name the phenomenon shown in the figure and define the same.
- Identify the parts labelled as 1 and 2. Write one functional difference between these two.
- Name the bony protective covering and the membranous protective covering of the spinal cord.
- Label the guidelines 3 and 4.
- How is the labelled part 3 different from part 4 with respect to its composition (part of neuron)?
- Give the technical term for the point of contact between the two nerve cells.
- Name the fluid filled inside the central canal of spinal cord.
- Name the term used for a small gap between two neurons.
- Give one example of a neurotransmitter.
- Draw a neat diagram of a nerve cell and label the parts: Perikaryon, Node of Ranvier, Myelin sheath and Axon terminals.
