Name the protective reflex that serves to rid the stomach and intestine of toxic substances and prevent their further ingestion.
What are the three phases of Vomiting?
Pre-ejection phase (gastric relaxation & retroperistalsis), Retching (rhythmic action of respiratory muscles preceding vomiting and consisting of contraction of abdominal and intercostal muscles and diaphragm against a closed glottis), Ejection (intense contraction of the abdominal muscles and relaxation of the upper esophageal sphincter
The process of Emesis appears to be coordinated by what two areas of the Brain?
Vomiting center (VC), Solitary tract nucleus (STN) of the vagus nerve
Where does the VC receive signals from what (5) things?
Chemoreceptor trigger zone (CTZ) in the area postrema (AP) at the bottom of the fourth ventricle., Gastric irritation, Solitary Tract Nucleus (STN), Higher Centers (pain, sight, other sensory inputs), Inner Ear Vestibular Apparatus
The chemoreceptor trigger zone has high concentration of which (4) receptors in regards to emesis?
5-HT3, D2, M1, and NK1
Toxic substances, Ketoacidosis, and Uremia send signals to which Emetic Center?
Gastric irritation stimulate_________ and _________afferents.
vagal and sympathetic
Which receptor predominates in gastric irritation?
The Solitary tract nucleus (STN) is rich with which (5) different receptors?
enkephalin, histamine (H1), Ach (M1), 5-HT3 and D2
STN can receive signals from which (5) different means?
confined largely to the upper digestive tract, Increases lower esophageal sphincter tone, Stimulates antral and small intestinal contractions, No effect on large-bowel motility
Pharmacokinetics of Metoclopramide, T1/2, Onset, duration, metabolized, excreted.
4-6 hours, 30 to 60 min, 1-2 hours, sufation and glucuroide conjugation, in the urine
Therapeutic Uses of Metoclopramide (Reglan)
Prevention of chemotherapy-induced emesis, Relief symptom associated with GERD, Treatment of gastroparesis (delayed gastric emptying), Adjunctive measure in medical or diagnostic procedures such as intestinal intubation or contrast radiography of the GI tract (as injection).
Adverse effects & Interactions of Metoclopramide (Reglan)