Physiology of Emesis

Question 1

Neuro

Answer 1

Intestinal receptors
Visual/vestibular matching

Central - psychogenic, area postrema, pregnancy

Efferent - smooth muscle in sphincters relaxes and skeletal generates force

Loss of H and K so hypokalemic alkalotic

Question 2

Area postrema

Answer 2

Caudal end of fourth ventricle with poor BBB…nictoine and dopamine esp permeabile

Question 3

EMesis affarnets and efferents

Answer 3

Peripheral - duodenal irritation…syrup of ipecac stimulates duodenal receptors

Central - CTZ in area postrema

Vestibular/visual mismatch

Vomting center - NTS

Costal diaphragm contraction with sphincter relxaxtion

Question 4

Nausea
Retching
Vomitning
prjectile

Answer 4

Feeling of discomfort

LES relaxed and inc ab pressure leads to reflux but UES does not open…force duodenal contents into stomach where bile can damage

Vomiting - UES forced open

Projec - brainstem trauma, pyloric stenosis