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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
Briefly explain the following terms : Reflex action
Which of the following is not a natural reflex action?
A. Knee-jerk
B. Blinking of eyes due to strong light
C. Salivation at the sight of food
D. Sneezing when any irritant enters the nose
Name the most important part of the human brain.
Which part of the eye contains cells which are sensitive to light?
When you smell a favourite food your mouth begins to water (that is, you secrete saliva). Write down what is the example of the gland which is stimulated to secrete saliva.
Which of the following helps in maintaining posture and balance of the human body?
All the voluntary actions of our body are controlled by :
(a) cerebrum
(b) cerebellum
(c) pons
(d) medulla
The olfactory receptors in humans are located in :
(a) eyes
(b) tongue
(c) ears
(d) nose
A cylindrical structure P in our body begins in continuation with medulla and extends downwards. It is enclosed in a bony cage Q and surrounded by membranes R. As many as x pairs of nerves arise from the structure P. The structure P is involved in the reflex actions of our body and conduction of nerve impulses to and from another organ S of our body with which it forms CNS.
(a) Name the structure P.
(b) Name (i) bony cage Q, and (ii) membranes R.
(c) How much is x?
(d) Name the organs S.
(e) What are the reflexes involving structure P only known as?
Your are driving your bicycle at a fast speed. Suddenly, a small boy comes in front of your cycle and, without wasting any time in thinking, you immediately apply the brakes and accident is avoided. What name is given to such an action?
Define voluntary and reflex actions. Give examples of each.
What is a reflex action?
State whether the following is
Constriction of pupil
Give Technical Term:
Response to a stimulus without the intervention of the will of an animal.
Complete the following sentence with appropriate Word
The control of reflex action is through:
Give an example for conditioned reflexes.
If after cutting through dorsal root of a spinal nerve of a mammal, the associated receptor in skin was stimulated the animal would ______.
Which sensory organ is involved in vertigo (sensation of oneself or objects spinning around)?
