NSG 862: Antiemetics & Chemotherapeutic Agents
What is nausea? 1. Sensation of discomfort in the upper abdomen
2. Accompanied by the urge to vomit
How is nausea described in relation to the medulla and 1. Conscious recognition of the excitation of an area in the medulla
vomiting center?
2. This area is a/w the vomiting (emetic) center
Three phases of vomiting include: 1. Pre-ejection phase
2. Retching
3.Ejection
What happens in the pre-ejection phase of vomiting? Gastric relaxation and retroperistalsis
,What is retching? Abdominal, intercostal, and diaphragm muscles acting against a closed glottis
What happens during ejection in vomiting? 1. Intense contraction of abdominal muscles
2. Relaxation of the upper esophageal sphincter
What is another name for vomiting? Vomiting is AKA emesis
How is vomiting (emesis) defined? Forceful expulsion of stomach content through the mouth or nose
What can cause vomiting (emesis)? 1. Caused by many things
2. Certain smells
3.Irritation of the stomach
4. Infections
5.Stress or Pain
6.Motion sickness
7. Migraines
8. Certain medications
9. Diseases/conditions
10. Brain injury/concussion
Where is the medullaryvomiting center located? Located close to the fourth cerebral ventricle
What afferent inputs does the medullary vomiting center 1. Chemoreceptor trigger zone
receive?
2. Cerebral cortex
"Crazy Cats Love Naps"
3.Labyrinthovestibular center
4. Neurovegetative system
Impulses from these afferents lead to nausea and vomiting
, What receptors are found in the chemoreceptor trigger Receptors for:
zone? (4)
1. serotonin
2. dopamine
3.histamine
4. opioids
Where is the chemoreceptor trigger zone located, and 1. Located on the floor of the fourth cerebral ventricle
what happens when it is stimulated?
2. Stimulation of the chemoreceptor trigger zone initiates independently
of the vomiting center
Why can the chemoreceptor trigger zone be activated by 1. Not protected by the blood-brain barrier
circulating chemicals?
2. Can be activated by chemical stimuli received through the systemic
circulation
3.Can also be activated through the CSF
What is the role of the chemoreceptor trigger zone Serves as a link between the brain parenchyma and the cerebrospinal fluid
(CTZ)? (CSF), containing ventricles
What is another name for the CTZ? Area postrema (AP)
What is the CTZ made of and what structural features 1. Composition is glia and neurons
does it have?
2. Covered by a thin ependymal cover
3.Penetrated with convoluted capillaries lacking tight endothelial junctions
How does the CTZ structure affect what it can detect? 1. CTZ forms a permeable blood-brain barrier
2. Can detect emetic toxins in both the blood and the CSF
The chemo receptor Trigger Zone: - can see how and where specific triggers work
What is nausea? 1. Sensation of discomfort in the upper abdomen
2. Accompanied by the urge to vomit
How is nausea described in relation to the medulla and 1. Conscious recognition of the excitation of an area in the medulla
vomiting center?
2. This area is a/w the vomiting (emetic) center
Three phases of vomiting include: 1. Pre-ejection phase
2. Retching
3.Ejection
What happens in the pre-ejection phase of vomiting? Gastric relaxation and retroperistalsis
,What is retching? Abdominal, intercostal, and diaphragm muscles acting against a closed glottis
What happens during ejection in vomiting? 1. Intense contraction of abdominal muscles
2. Relaxation of the upper esophageal sphincter
What is another name for vomiting? Vomiting is AKA emesis
How is vomiting (emesis) defined? Forceful expulsion of stomach content through the mouth or nose
What can cause vomiting (emesis)? 1. Caused by many things
2. Certain smells
3.Irritation of the stomach
4. Infections
5.Stress or Pain
6.Motion sickness
7. Migraines
8. Certain medications
9. Diseases/conditions
10. Brain injury/concussion
Where is the medullaryvomiting center located? Located close to the fourth cerebral ventricle
What afferent inputs does the medullary vomiting center 1. Chemoreceptor trigger zone
receive?
2. Cerebral cortex
"Crazy Cats Love Naps"
3.Labyrinthovestibular center
4. Neurovegetative system
Impulses from these afferents lead to nausea and vomiting
, What receptors are found in the chemoreceptor trigger Receptors for:
zone? (4)
1. serotonin
2. dopamine
3.histamine
4. opioids
Where is the chemoreceptor trigger zone located, and 1. Located on the floor of the fourth cerebral ventricle
what happens when it is stimulated?
2. Stimulation of the chemoreceptor trigger zone initiates independently
of the vomiting center
Why can the chemoreceptor trigger zone be activated by 1. Not protected by the blood-brain barrier
circulating chemicals?
2. Can be activated by chemical stimuli received through the systemic
circulation
3.Can also be activated through the CSF
What is the role of the chemoreceptor trigger zone Serves as a link between the brain parenchyma and the cerebrospinal fluid
(CTZ)? (CSF), containing ventricles
What is another name for the CTZ? Area postrema (AP)
What is the CTZ made of and what structural features 1. Composition is glia and neurons
does it have?
2. Covered by a thin ependymal cover
3.Penetrated with convoluted capillaries lacking tight endothelial junctions
How does the CTZ structure affect what it can detect? 1. CTZ forms a permeable blood-brain barrier
2. Can detect emetic toxins in both the blood and the CSF
The chemo receptor Trigger Zone: - can see how and where specific triggers work
