BIO 403L Autonomic Nervous System (ANS) Lab

What information does a Pincare HRV plot provide?

-HRV RR values - easy identification of any outliers - possible insights into short and long-term heart variability

Explain how sweat production caused by stimulation of the median nerve, was measured in the lab.

1. Measuring the sympathetic skin response (SSR): the change in the potential difference across a hand or foot following peripheral nerve stimulation 2. Measuring an increase in skin conductance: the electrical resistance between two electrodes when a very weak current passes between them

Explain what a Valsalva Maneuver is

A forcible expiration against a closed airway

In assessing autonomic nervous system function in healthy person, which of the following may the Valsalva maneuver result in?

An appreciable increase in heart rate.

Every organ or tissue that has a sympathetic innervation also has a parasympathetic innervation.

False

Explain why a difference is expected between the latencies observed in the hand and foot.

Nerve impulses travel a greater distance to the foot which would cause a greater latency is the foot than the hand

In measuring the autonomic nervous system skin potentials, which of the following is true for stimulation of the median nerve?

Stimulation can be on either side.

Describe what happens to the heart rate when the volunteer stands after lying down in a relaxed position?

The heart rate increases when the volunteer stands up.

Explain why stimulation of the median nerve results in change in potential across the hand and foot.

The sweat glands on the palm and sole are activated by sympathetic stimulation. However, sweat glands on the dorsal, hairy surfaces of the hand and foot are not activated by sympathetic stimulation. They are active instead by increased body temperature, so are inactive under these experimental conditions. Thus sympathetic nerve activation results in a brief potential difference across the hand and foot.

Explain the relationship between normal or deep breathing and heart rate variability

There is greater variation during deep breathing. The deeper the breathing, the greater variations in heart rate will be during a respiratory cycle

Describe what a Poincare HRV plot is

Used to assess the integrity of the autonomic nerves supplying the heart