Question

The Autonomic Nervous System can be challenging to understand because it is connected to virtually every body function in opposite ways. We are going to explore the physiology of the ANS in this discussion by looking at specific examples of how it works.

For your first discussion post, describe how the parasympathetic nervous system influences one function in your body. For example, the parasympathetic nervous system causes decreased blood pressure. If you chose this body function, you would describe the physiology behind the decreased blood pressure. How does it happen? What occurs in the heart/blood vessels? Which scenarios or external factors would cause the parasympathetic nervous system to activate this response?

Answer 1

Autonomic nervous system consists of both sympathetic and para-sympathetic system

Sympathetic system - stimulates heart rate , causes broncho dilation , constipation , decrease urine outflow , decreases all watery secretions and dilation of pupil

Parasympathetic system - retards heart rate , causes broncho constriction , diarrhea , increase urine outflow , increase all watery secretions and constriction of pupil

-------> para sympathetic causes decreased blood pressure:

Para sympathetic mainly releases acetylcholine

It activates vagal postganglionic nerves and releases acetylcholine , which activates muscarinic receptors . It activates NO synthase through guanylate cyclase , this causes inhibition of calcium channels . It causes decreased blood pressure