Tag: reflex action

Questions Related to reflex action

Who among the following discovered the conditioned reflexes?

biology control and coordination in living organisms reflex action innate and learned behaviour coordination in human beings- chemical control

  1. Sherington

  2. Hill

  3. Pavlov

  4. Berstain

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Correct Option: C
Explanation:

Conditioned reflex is automatic responses to certain stimuli learnt during lifetime/training. It was studied by Russian physiologist Ivan Pavlov during his experiment on induction of salivation in dogs. Thus, the correct answer is option C.

Which one does not involve brain ?

biology nervous system of man reflex action innate and learned behaviour coordination in human beings- chemical control

  1. Spinal reflex

  2. Cerebral reflex

  3. Cranial reflex

  4. Voluntary action

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Correct Option: A
Explanation:

Reflex is an involuntary and instantaneous action in response to a stimulus.

  1. A spinal reflex is a reflex action is controlled by spinal cord and related sensory afferent and an efferent muscle without the influence of brain like we remove our hand when we touch hot object.
  2. Cerebral reflex is an involuntary controlled action that involves brain like a closing of eyes in an exposure of light.
  3. Cranial nerve is mediated by the pathway that includes cranial nerves and brain includes the peripheral and central nervous system.
  4. Voluntary actions are those which depends on our will like eating, bathing etc. and controlled by the cerebellum.
The correct option is "Spinal reflex".

Which biologist first noticed that the muscles of disected frog legs twitched wildly when a spark from an electric machine struck them?

biology nervous system of man reflex action innate and learned behaviour coordination in human beings- chemical control

  1. Georges Cuvier

  2. Franz Joseph Gall

  3. Kaspar Friedrich Wolf

  4. Luigi Galvani

Show answer
Correct Option: D
Explanation:

Luigi Galvani was an Italian physician who demonstrated what we now understand to be the electrical basis of nerve impulses when he made frog muscles twitch by jolting them with a spark from an electrostatic machine. So, the correct option is "D" (Luigi Galvani).

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 barefoot 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.

biology nervous system of man reflex action innate and learned behaviour coordination in human beings- chemical control

  1. (i) and (ii)

  2. (ii) and (iii)

  3. (iii) and (iv)

  4. (ii) and (iv)

Show answer
Correct Option: D

Which of the following is not a reflex action?

biology nervous system of man reflex action innate and learned behaviour coordination in human beings- chemical control

  1. Salivation

  2. Sweating

  3. Withdrawal of hand when pinched by needle

  4. Blinking of eyes

Show answer
Correct Option: B
Explanation:

Reflex action is induced by the motor nerves. It is an involuntary and instant movement in response to a stimulus. A reflex action is done by neural pathway of reflex arc. In this, the action is done before the impulse reaches the brain. Out of the given options, sweating is not a reflex action. Salivation is a reflex action in which smell of food activate neural pathway and activates muscles and glands. This releases salivary juices. When someone is pinched by a needle, it activates neural pathway to evoke a response. The skin receptors quickly send nerve impulses to the spinal cord and response is relayed back. Apart from these, coughing, sneezing and blinking of eyes are also reflex actions.

Thus, the correct answer is 'Sweating.'

The kneejerk reflex in response to a mallet tap over the patellar ligament

biology nervous system of man reflex action innate and learned behaviour coordination in human beings- chemical control

  1. is a conditioned reflex

  2. is a monosynaptic reflex

  3. has its reflex centre in the spinal cord

  4. is mediated by a three neuron reflex are

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Correct Option: B
Explanation:

Monosynaptic Reflex is a simple reflex that involves the transmission of an impulse from a sensory neuron to a motor neuron across a single synapse in the spinal cord. The knee-jerk reflex action is an example of such type of reflex.

So, the correct option is 'is a monosynaptic reflex'.

What is the advantage of reflex action ?

biology nervous system of man reflex action innate and learned behaviour coordination in human beings- chemical control

  1. It has to be learned

  2. It happens differently each time

  3. It does not have to be learned

  4. None of them

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Correct Option: A

The reflex action was discovered by

biology nervous system of man reflex action innate and learned behaviour coordination in human beings- chemical control

  1. Marshall

  2. Best

  3. Taylor

  4. Pavlov

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Correct Option: A
Explanation:
  • Involuntary actions in response to external or internal stimuli are termed as reflex actions. Peripheral nervous system and the spinal cord are involved in controlling the reflex actions. Here, the brain is not involved.
  • The reflex action was discovered by Marshall. He proposed the theory explaining the body's reflex, or involuntary, actions.
  • So, the correct answer is 'Marshall'.

Which of the following best characterize the simple response to simple stimuli?

biology nervous system of man reflex action innate and learned behaviour coordination in human beings- chemical control

  1. Simple reflex

  2. Complex reflex

  3. Fixed action patterns

  4. Behavioral cycles

  5. Environmental rhythms

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Correct Option: A
Explanation:

  • A stimulus is anything that can be perceived by a given organism including sight, sound, touch, smell, taste, etc.
  •  A response is generally characterized as the behaviour proximal to the stimulus. So if a bell rings and a person jumps the stimulus is the bell and the response is the jump. 
  • The ability of an organism or organ to respond to external stimuli is called sensitivity. When a stimulus is applied to a sensory receptor, it normally influences by a simple reflex. Hence, Simple reflex is best to characterize the simple response to simple stimuli. 
So, the correct answer is 'Simple reflex'.

In reflex action, the reflex is formed by

biology nervous system of man reflex action innate and learned behaviour coordination in human beings- chemical control

  1. Brain- spinal cord- muscles

  2. Receptor- spinal cord- muscles

  3. Muscles- receptors- brain

  4. Muscles- spinal cord- receptor

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Correct Option: B