A person entering an empty room suddenly finds a snake right in front on opening the door. Which one of the following is likely to happen in his neuro-hormonal control system?

  • Option 1)

    Sympathetic nervous system is activated releasing epinephrin and norepinephrin from adrenal medulla.

  • Option 2)

    Neurotransmitters diffuse rapidly across the cleft and transmit a nerve impulse.

  • Option 3)

    Hypothalamus activates the parasympathetic division of brain.

  • Option 4)

    Sympathetic nervous system is activated releasing epinephrin and norepinephrin from adrenal cortex.

 

Answers (1)
P Plabita

As we discussed in concepts

Factors affecting Cardiac Output -

A special neural centre in the medulla oblangata can moderate the cardiac function through autonomic nervous system (ANS).

- wherein

Neural signals through the sympathetic nerves (part of ANS) can increase the rate of heart beat, the strength of ventricular contraction and thereby the cardiac output.

 

 and

Adrenaline and noradrenaline -

Adrenaline and noradrenaline are rapidly secreted in response to stress of any kind and during emergency situations and are called emergency hormones or hormones of Fight or Flight

- wherein

These hormones increase alertness, pupilary dilation, piloerection (raising of hairs), sweating etc. Both the hormones increase the heart beat, the strength of heart contraction and the rate of respiration. Catecholamines also stimulate the breakdown of glycogen resulting in an increased concentration of glucose in blood. In addition, they also stimulate the breakdown of lipids and proteins

 

 In emergency situation, ANS acts quickly & release epinephrine and norepinephrine. It is also known as Flight or Flight response.


Option 1)

Sympathetic nervous system is activated releasing epinephrin and norepinephrin from adrenal medulla.

This option is correct.

Option 2)

Neurotransmitters diffuse rapidly across the cleft and transmit a nerve impulse.

This option is incorrect.

Option 3)

Hypothalamus activates the parasympathetic division of brain.

This option is incorrect.

Option 4)

Sympathetic nervous system is activated releasing epinephrin and norepinephrin from adrenal cortex.

This option is incorrect.

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