Physiological effects of the Parasympathetic Nervous System

Question 1

what are the parasympathetic effects on the heart?

Answer 1

• sends AP to vagus nerve
• decrease force of contraction, reduce HR
• RP is more -ve and height of depolarisation is lower so the fq of contraction decreases

Question 2

what are the parasympathetic effects on the blood vessels?

Answer 2

• there is not a strong PS innervation to the arteries

- Ach produces considerable vasodilation if it can reach the artery

Question 3

what are the parasympathetic effects on the male genitalia?

Answer 3

-one arterial bed is rich w PS innervations
-dilation of penile artery, engorgement of the corpus and cavernosum
-increases blood in penis
=erection

Question 4

what are the parasympathetic effects on non-vascular SM?

Answer 4

causes contraction: bladder detrusor, airways, GI tracts

Question 5

what are the parasympathetic effects on the eyes?

Answer 5

• contracts circular muscle so narrows pupil

- contraction of ciliary muscle relaxes suspensory ligaments so tense bulge in order to focus on near objects

Question 6

what are the parasympathetic effects on various secretion?

Answer 6

-increases saliva production, tears, gut acid, sweat