Medical Surgical CNS vs PNS #3

Question

A person going through the sympathetic response will show which bodily action?

Answers

  1. Constriction of pupils
    • Rationale:

      This answer is not correct because constriction of pupils is part of the parasympathetic response, or the “rest and digest” response. This is activated when the body needs to restore energy and rest.

  2. Peripheral vasoconstriction
    • Rationale:

      This answer is correct since peripheral vasoconstriction is when blood flow is diverted to muscles needed during a fight or flight response. The overall effect of vasoconstriction is to increase cardiac output. Enhanced sympathetic activity such as vasoconstriction is particularly important during the fight or flight response.

  3. Contraction of bladder.
    • Rationale:

      This answer is not correct because contraction of the bladder happens during the parasympathetic “rest and digest” phase. The internal sphincter muscle relaxes and the bladder contracts.

  4. Stimulation of the digestive system.
    • Rationale:

      This answer is not correct since digestion plays a part in the need to restore energy. Chewing food triggers the parasympathetic nervous system to produce saliva, which increases digestion.

Overview

The sympathetic nervous system is known as the “fight or flight” response. It preps your body for the stressful or alarming situation you are facing so you can respond appropriately.

Explanation

Learning Outcomes

The sympathetic nervous system is known as the “fight or flight” response. It preps your body for the stressful or alarming situation you are facing so you can respond appropriately. The pupils will dilate so the eyes can allow more light so vision will be better. Vasoconstriction will occur to increase cardiac output. Epinephrine and norepinephrine will release causing constriction of the blood vessels. This leads to the kidneys inhibiting flow of urine, and the bladder will increase its capacity, but the internal sphincter will stay closed. The digestive systems will also slow down.

Test Taking Tip

Know the body functions that occur during sympathetic and parasympathetic responses. Remember “fight or flight” and “rest and digest”.

Video Rationale