Tag: reflex action and reflex arc

Questions Related to reflex action and reflex arc

Pavlov's pouch is

biology the nervous system the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1. An artificial stomach

  2. A bag containing digestive enzymes

  3. A bag containing food

  4. Opened stomach of a dog

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Correct Option: D
Explanation:
  • Pavlov's Pouch is an artificially created pouch for experimental purposes.
  • It was surgically created by a physiologist Ivan Petrovich Pavlov.
  • It was created to study the physiology of the digestive tract.
  • It was also used to study the principles of secretion of the fundal glands.
  • It is a small portion of the stomach which is separated from the main stomach of a dog.
  • So, the correct answer is 'Opened stomach of a dog'.

The scientist who found secretion of gastric juice to be under control of nervous system was

biology the nervous system the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1.  Ernest Starling

  2. Reamur

  3. Spallanzani

  4. Both B and C

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Correct Option: A
Explanation:

  • Secretin was the first hormone to be identified. In 1902, William Bayliss and Ernest Starling were studying how the nervous system controls the process of digestion.
  •  It was known that the pancreas secreted digestive juices in response to the passage of food (chyme) through the pyloric sphincter into the duodenum. Hence, The scientist who found secretion of gastric juice to be under control of the nervous system was Ernest Starling.
So, the correct answer is 'Ernst starling'.

A reflex arc does not involve

zoology control and co-ordination in plants and animals the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1. A receptor

  2. A sensory pathway

  3. A motor pathway

  4. The brain

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Correct Option: D
Explanation:

A reflex arc is a simple nervous pathway and consists of the sensory receptor, afferent neuron, center, efferent neuron and effector organ. 

The afferent/sensory neurons transmit the sensory information from sensory receptors to the spinal cord (sensory pathway). The interneurons of spinal cord integrate the incoming information and signal is relayed to motor/efferent neurons.  
The motor pathway transmits the signal from motor neurons to the effector organs (muscles and glands etc). Thus, reflex arc transmits the information from receptor to effector via the spinal cord. The brain is not the part of the reflex arc. 

Movement of food in the alimentary canal involves ................... movement.

zoology control and co-ordination in plants and animals the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1. Voluntary

  2. Regulatory

  3. Involuntary

  4. Digestive

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Correct Option: C
Explanation:

  • Digestion of food, contraction, and relaxation of blood vessels and many other movements are involuntary as we cannot really start or stop them simply by our will. 

Therefore, the correct answer is option C.

Spinal reflex is located in the ________

zoology control and co-ordination in plants and animals the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1. Nerves

  2. Brain

  3. Epithelial lining

  4. Spinal cord

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Correct Option: D
Explanation:

  • Spinal reflex or withdrawal reflex protects the body from the damaging stimulus. 
  • It is located in the spinal cord. In this reflex pathway, more than one relay neuron connects the sensory and motor neuron.

Therefore, the correct answer is option D.

Reflex arc is a neural pathway that involves .......... nervous system. 

zoology control and co-ordination in plants and animals the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1. Peripheral

  2. Autonomous

  3. Central

  4. Both A and C

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Correct Option: D
Explanation:

  • Reflex arc involves both peripheral and central nervous systems. As the route followed by nerve impulses in the production of a reflex act, is from the peripheral receptor organ, through the afferent nerve, to the central nervous system synapse, and then through the efferent nerve, to the effector organ. 

Therefore, the correct answer is option D.

Reflex arc located in the brain is called as___________

zoology control and co-ordination in plants and animals the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1. Somatic reflex

  2. Cerebral reflex

  3. Autonomic reflex

  4. Both A and B

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Correct Option: B
Explanation:

  • The reflex actions which involve the brain are called as the cerebral reflex. The autonomic reflex is the one that involves inner organs and the somatic reflex is one that involves the muscles. 

Therefore, the correct answer is option B.

Which of the following statements is correct about reflex arc?

(i).  Reflex arcs are efficient quick responses.
(ii). Reflex arcs are evolved for functioning in the absence of true thought processes.
(iii). A reflex arc is a neural pathway that controls reflex action.

zoology control and co-ordination in plants and animals the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1. (i), (ii) and (iii) 

  2. Only (i) 

  3. Only (ii) 

  4. Only (i) and (ii) 

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Correct Option: A
Explanation:

  • Reflex arcs have evolved in animals because the thinking process of the brain is not fast enough. 
  • Many animals do not have complex neuron networks which is needed for thinking and it is considered efficient. It is a neural pathway that controls a reflex action, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. 
  • This characteristic allows reflex actions to occur relatively quickly by activating spinal motor neurons without the delay of routing signals through the brain, although the brain will receive sensory input while the reflex is carried out. 
  • Analysis of the signal takes place after the action has been taken. 

Therefore, the correct answer is option A.

A boy running, children fighting in the ground, baby chewing food are movements caused by growth. 

zoology control and co-ordination in plants and animals the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1. True

  2. False

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Correct Option: B
Explanation:

  • The movement mentioned in the above question are regular activities done by animals and humans. 
  • They are not associated with growth, as growth does not depend on these movements. The stop and start of these activities does not regulate growth.

Therefore, option B is the correct answer.