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प्रश्न
How are involuntary actions and reflex actions different from each other?
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उत्तर १
Involuntary action is a set of muscle movements that do not require thinking. However, it is controlled by the brain, for example, the beating of the heart. On the other hand, reflex action is rapid and spontaneous in response to any stimulus. For example, closing one's eyes immediately when a bright light is focused.
उत्तर २
| Involuntary actions | Reflex actions |
| These are normal involuntary actions of internal or external organs of the body. | These are sudden involuntary responses to external stimuli. |
| They occur in reaction to internal cues. | They operate in opposition to damaging stimuli, most of which are external. |
| They are related to how interior body parts work | They are related to emergencies, that is, reactions to external stimuli. |
| It occurs without the organism's volition. Heart rate, breathing, etc., as examples. | The brain, not the spinal cord, is involved in several reflexes. |
| These actions are controlled by the brain. | These actions are controlled by the spinal cord. |
संबंधित प्रश्न
How do we detect the smell of an agarbatti (incense stick)?
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
Give the functions of medulla.
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.
Cerbellum, medulla and pons are the parts of :
(a) mid-brain
(b) hind-brain
(c) forebrain
(d) spinal cord
All the voluntary actions of our body are controlled by :
(a) cerebrum
(b) cerebellum
(c) pons
(d) medulla
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?
When we touch a hot plate unknowingly, then this heat is sensed by a receptor P present in our fingers. The receptor triggers and impulse in neuron Q which transmits the message to an organ R which is a part of the central nervous system. Here the impulse is passed on to a neuron S which in turn passes it to a yet another neuron T. The neuron T passes the impulse to a tissue U in our arm. The tissue U then contracts and pulls our hand away from the hot plate.
(a) What is the name of (i) receptor P (ii) neuron Q, and (iii) organ R?
(b) What is (i) neuron S, and (ii) neuron T?
(c) Name the tissue U.
(d) What name is given to the phenomenon in which hand is pulled away quickly from the hot plate?
(e) Name the effector in this whole process.
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?
Write down the following activities in the correct order for a simple reflex arc:
(a) impulse travels in the motor fibre
(b) impulse travels in the sensory fibre
(c) effector organ stimulated
(d) impulse crosses the synapse
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.
Contraction of eye pupil
State whether the following is simple reflex, conditioned reflex or neither of the two.
Sudden application of brakes of the cycle on sighting an obstacle in front
State whether the following is
Sneezing
State whether the following is
Cleaning
Give Technical Term:
The scientist, who conducted experiment on a dog to show conditioned reflex
The given diagrammatic representation of reflex action shows knee jerk reflex.
Identify the parts labeled as A to E and select the correct option.
