Intro N/V Flashcards
2 Major physiologic function of the GI system
Digest food
Absorb nutrient into the bloodstream
describe the physiology of digesting food and absorbing nutrients?
- Food moves slowly along the digestive tract and are broken down into ions and molecules = absorbed into body through intestinal wall and into blood or lymph system
- un-absorbed nutrients and wastes are collected in the large intestine for elimination
6 functions of the GI system
- Ingestion - Occurs when solid food and liquid enter the oral cavity
- Mechanical digestion and propulsion - crushing/shredding of food in oral cavity and mixing and churning in the stomach
- Chemical digestion - Chemical and enzymatic breakdown of food into small organic molecules that can be absorbed by the digestive epithelium
- Secretion - release of water, acids, enzymes, buffers, and salts by the digestive tract epithelium and by accessory digestive organs
- Absorption - Movement of nutrients across the digestive epithelium and into the bloodstream
- Defecation - Indigestible food is compacted into material waste that is eliminated by defecation
3 parts of the GI system
- Upper - mouth, esophagus, stomach
- Where digestion starts - Middle - duodenum, jejunum, ileum
- Where most digestive & absorptive processes occur - Lower - cecum, colon, rectum
- Storage for elimination
why is the GI system lined with permanent ridges and temporary folds?
increases surface area for absorbing nutrients
what accessory organs produce secretions to aid in digestion?
salivary glands
liver
pancreas
what is nausea?
- Subjective feeling of a need to vomit
- Vague, intensely disagreeable sensation of sickness or “queasiness”
what spasmodic respiratory and abdominal movements usually follows nausea?
retching
Oral expulsion of gastrointestinal contents due to ?
- contractions of gut and thoracoabdominal wall musculature
Multiple afferent and efferent pathways exist which induce vomiting
The effortless reflux of liquid or food stomach contents
“Burping up” food contents
what is this term
regurgitation
The chewing and swallowing of food that is regurgitated after meals
what is this term
rumination
Normal function of the upper GI tract involves an interaction between what two things?
the gut and the CNS
The motor function of the gut is controlled at three main levels:
- parasympathetic and sympathetic NS
- enteric brain neurons
- smooth muscle cells
which is more bothersome and disabling, nausea or vomitting?
nausea
what causes nausea?
Gastric Rhythmic Disturbance
- Nausea correlates with a shift in normal 3-cycle-per min gastric myoelectrical activity (muscle contraction and relaxation)
- 3 cycles/min of smooth muscle contraction in stomach
- This activity increases with a food bolus
In disorders of stomach motility, the rhythm is (regular/irregular)?
irregular
2 disorders of stomach motility, describe each
- Tachygastria: increased rate of electrical activity in the stomach
- >4 cycles/min - Bradygastria: decreased rate of electrical activity in the stomach
- <2 cycles/min
Vomiting may be stimulated by 4 different sources:
- Afferent vagal fibers from GI viscera (serotonin 5-HT3)
- GI distention, mucosal or peritoneal irritation, infections - Fibers of vestibular system (histamine H1)
- sea-sick, dizziness - Higher CNS centers
- sights, smells, or emotional experiences - Chemoreceptor trigger zone
- stimulated by drugs, chemo agents, toxins, hypoxia, uremia, acidosis, radiation therapy
what type and where are the chemoreceptor trigger zones that cause vomiting?
- opioid, serotonin 5-HT3, neurokinin 1 (NK1), and dopamine D2 receptors
- located outside blood-brain barrier in the area postrema
what are the likely microbes that cause vomiting? include incubation period and likely food sources
- s. aures
- 1-6 h
- prepared foods, salads, dairy, meat - B. cereus
- 1-6 h
- rice, meat - norwalk-like viruses
- 24-48 h
- shellfish, prepared foods, salads, sandwiches, fruit
In both urgent care and routine outpatient settings, the following 3 steps should be generally undertaken in pts with N/v
- find etiology, see if acute or chronic sx
- Correct any consequences/complications of N/V
- fluid depletion, hypokalemia, and metabolic alkalosis - Targeted therapy when possible
- surgery for bowel obstruction or malignancy
- symptomatic tx
causes of acute sx w/o severe abdominal pain
- Inquiry should be made into recent changes in meds, diet, other GI symptoms, or similar illnesses in family members
- food poisoning
- infectious gastroenteritis
- drugs
- systemic illnesses
causes of Acute onset of severe pain and vomiting
- suggests peritoneal inflammation
- acute gastric/intestinal obstruction
- pancreatobiliary disease
causes of persistent vomiting?
suggests pregnancy
gastric outlet obstruction
gastroparesis
intestinal dysmotility
psychogenic disorders (think bulimia)
CNS/systemic disorders
recurrent episodes of N/V and abdominal discomfort in patients with prolonged marijuana use is called?
tx?
Cannabinoid Hyperemesis Syndrome
hot shower/bath
causes of morning vomiting?
pregnancy
uremia
alcohol intake
increased intracranial pressure
if a pt is Vomiting immediately after meals, what PE should you def do?
bulimia - TEETH EXAM
causes of Vomiting undigested food one to several hours after meals
- gastroparesis
- gastric outlet obstruction
- may hear a succussion splash
Acute or chronic sx you should ask about neurologic sx (CNS cause) with vomiting?
HA
stiff neck
vertigo
focal weakness/paresthesias
Feculent vomiting would indicate what?
Intestinal obstruction
what is Hematemesis?
Vomiting of blood or coffee-like material
labs for vomiting?
Screening tests can direct clinical care: severe or protracted vomiting
- CBC - Infection, anemia
- CMP - lyte disturbances, liver function, azotemia, met alkalosis from loss of gastric contents
- Amylase, Lipase - Pancreatic enzymes
- b-hCG
imaging for n/v?
Flat and Upright abdominal films: with severe or suspicion of mechanical obstruction