BIOL 373 Final Exam Questions &
Answers For A+ Score!!
First Unit
Segmental Contraction CORRECT ANSWERS mixing/churning
maximizes exposure to digestive enzymes and epithelium
alternate segments contract
little or no net movement forward
Gut Motility CORRECT ANSWERS most gut muscle is a single unit of smooth muscle
connected by gap junctions
contract as a single unit
1) Tonic contraction
2) Phasic contraction
Between meals:
-migrating motor complexes
During/after meal:
-peristaltic contractions
-segmental contractions
Tonic Contraction CORRECT ANSWERS mins to hrs
anterior part of stomach is tonically contracted
- keeps food from moving backwards)
- smooth muscle sphincters
Phasic Contraction CORRECT ANSWERS secs
posterior stomach
small intestine
Slow Wave Potentials CORRECT ANSWERS
Regulation of GI Function (3) CORRECT ANSWERS 1) Long reflexes, integrated in
CNS
2) short reflexes, integrated within gut (enteric nervous system)
, 3) reflexes involving gut peptides (paracrine or travel via blood - endocrine)
Secretions in the Gut CORRECT ANSWERS 1) water and ions (into lumen, then
reabsorbed)
2) enzymes
3) mucus
4) saliva
5) bile (from liver)
Secretion of Water and Ions CORRECT ANSWERS (Na+, Cl-, K+, HCO3-, H+)
ions secreted via membrane transporters
water follows osmotic gradient
paracellular route
-water and ions in some regions can pass between cells
Ion Secretion Transporters (gut secretion) CORRECT ANSWERS Na+/K+ ATPase
NKCC cotransporter
Cl-/HCO3- exchanger
Na+/H+ exchanger (NHE)
H+/K+ ATPase
Ion Secretion Channels (gut secretion) CORRECT ANSWERS ENaC
K+ channels
Cl- channels (including CFTR)
Parietal Cells CORRECT ANSWERS epithelial cells that secrete H+ (and Cl=) acid from
apical side into LUMEN of stomach
makes lumen VERY acidic - pH of ~1
as H+ secreted, bicarb (HCO3-) is absorbed into the blood
Function of acid:
1) activates pepsin
2) denatures proteins (more accessible to pepsin)
3) anti-microbial
Long Reflexes CORRECT ANSWERS integrated in CNS
1) sensory info from GI tract to CNS
2) feedforward reflexes
-originate outside of GI tract
-includes cephalic reflexes
Answers For A+ Score!!
First Unit
Segmental Contraction CORRECT ANSWERS mixing/churning
maximizes exposure to digestive enzymes and epithelium
alternate segments contract
little or no net movement forward
Gut Motility CORRECT ANSWERS most gut muscle is a single unit of smooth muscle
connected by gap junctions
contract as a single unit
1) Tonic contraction
2) Phasic contraction
Between meals:
-migrating motor complexes
During/after meal:
-peristaltic contractions
-segmental contractions
Tonic Contraction CORRECT ANSWERS mins to hrs
anterior part of stomach is tonically contracted
- keeps food from moving backwards)
- smooth muscle sphincters
Phasic Contraction CORRECT ANSWERS secs
posterior stomach
small intestine
Slow Wave Potentials CORRECT ANSWERS
Regulation of GI Function (3) CORRECT ANSWERS 1) Long reflexes, integrated in
CNS
2) short reflexes, integrated within gut (enteric nervous system)
, 3) reflexes involving gut peptides (paracrine or travel via blood - endocrine)
Secretions in the Gut CORRECT ANSWERS 1) water and ions (into lumen, then
reabsorbed)
2) enzymes
3) mucus
4) saliva
5) bile (from liver)
Secretion of Water and Ions CORRECT ANSWERS (Na+, Cl-, K+, HCO3-, H+)
ions secreted via membrane transporters
water follows osmotic gradient
paracellular route
-water and ions in some regions can pass between cells
Ion Secretion Transporters (gut secretion) CORRECT ANSWERS Na+/K+ ATPase
NKCC cotransporter
Cl-/HCO3- exchanger
Na+/H+ exchanger (NHE)
H+/K+ ATPase
Ion Secretion Channels (gut secretion) CORRECT ANSWERS ENaC
K+ channels
Cl- channels (including CFTR)
Parietal Cells CORRECT ANSWERS epithelial cells that secrete H+ (and Cl=) acid from
apical side into LUMEN of stomach
makes lumen VERY acidic - pH of ~1
as H+ secreted, bicarb (HCO3-) is absorbed into the blood
Function of acid:
1) activates pepsin
2) denatures proteins (more accessible to pepsin)
3) anti-microbial
Long Reflexes CORRECT ANSWERS integrated in CNS
1) sensory info from GI tract to CNS
2) feedforward reflexes
-originate outside of GI tract
-includes cephalic reflexes
