Flashcards in Physiology 2 Deck (108)
The GI Tract is all smooth muscle except?
upper 1/3 of esophagus and anal sphincter (striated)
Types of Smooth Muscle Contraction?
1. Phasic - parastalic
2. Tonic - can last hours
1. breaks down food particles
2. mixes food with saliva
3. increase surface are to digest better
Functions of stomach?
1. storage-most in orad area
2. break down food particles in small cubic sizes
3. gastric emptying
-hiatal hernia, pregnancy, failure of secondary peristalsis
Parietal Cells, in body of stomach, weak motility
antrum, very strong contractions, muscle is thicker in this area
Cells of Caja
-slow waves always present from these intestinal cells
Vagal Stimulation effect on slow waves
-increase height of waves (so increase frequency of contraction)
What empties fastest in the stomach?
-isotonic water (everything becomes isotonic when it goes in duodenum)
CCK effect on emptying?
Effect of acid on peristalsis?
decrease from neural reflex
Failure of Gastric Emptying
-fullness, loss of appetite, nausea
Increased Gastric Emptying
-diarrhea, duodenal ulcer
Reason for irregular contractions in small intestine?
propulsion, moves food only 4-5cm at a time, short
Migrating Motor Complex
-goes away when you start to eat
-# of contractions per minute except areas of extreme contractility (90min) b/c of motiline (creates wave beginning in stomach)
Small Intestine Motility
-must have spikes to have contraction
-segmentation in colon, can disappear and reappear in different areas
food stuck in esophagus
when rectum is distended, it will contract external sphincter
absent in paraphalgicts (rectal sphincter causes defication)
voluntary rexed for deification
Salivary Secretion Components
1. alpha amylase - pH 7, lingual lipase (acidic), solubilization (to taste food)
2. lubrication - needed for speech
3. protective function - allows drinking hot, dilute noxious substances, dec. cavities, sec. F, Ca, P, lysosomes to wash particles from teeth
1. Parotid - watery 25-40% of output
2. Submaxilary - watery and mucus
-recieve lots of blood flow, CN nerves VII & IX both sympathetic and parasympathetic
secretion goes unchanged in intercalated duct, then modified: abs NaCl, sec. K+ and bicarb in striated duct
-absence of saliva
Ion concentration with flow rate
-hypotonic at all rates
-high K+ concentration all the time
-Na+ concentration low at low rates
-bicarb high at high rates
Changes in concentration as saliva moves from acinus to duct opening?
-Na+ decreases, K+ increases (secreted into duct)
-more happens the longer it stays in the gland