Signaling
Galpha-s, Galpha-i, Galpha-q
What produces bile?
The liver
Gallbladder stores it
What type of junction anchors a cell's intermediate filaments to the basement membrane?
Hemidesmosomes
(While desmosomes anchor intermediate filaments from cell-to-cell)
What disorder involves inability to relax the lower esophageal sphincter
Achlasia
(Probably loss of ganglion cells, imbalance of excitatory and inhibitory neurotransmitters)
What injection can be given to treat achalasia?
Botox (Botulinum toxin)
inhibits acetylcholine release, causes muscle relaxation
What ion is most important in stimulating exocytosis?
Ca++
- Internal stores (ex. sarcoplasmic reticulum)
- Also calcium from ECF through ion channels that open upon depolarization
What are bile acids conjugated with?
Taurine and glycine
(Increases water solubility)
What is more important? Tonicity or Osmolarity?
Tonicity
Tonicity takes a cell membrane into account (if something freely passes through a membrane, it doesn't exert tonicity (urea))
What population is likely to present with non-alcoholic fatty liver disease?
Metabolic Syndrome
Does atropine totally inhibit gastric acid secretion?
No. --> Inhibits direct acetylcholine effect on parietal cells
However, we still have GRP (vagal) and histamine mediated release of acid
This G-protein subunit has intrinsic GTPase activity
alpha subunit - Binds GTP in its active state and has intrinsic ability to deactivate GTP into GDP
What is the most significant molecule for gastric acid release from the parietal cells?
Histamine
Acts on H2 receptors to cause increased cAMP release
(released from enterochromaffin like cells)
As bile flows from hepatic ducts to the gallbladder, __________ increases in concentration?
Bicarbonate (HCO3-)
What disorder likely has disruption of tight junctions?
Celiac disease
(Hypersensitivty to gluten products like gliadin)
What is the antidote for acetaminophen posioning?
N-acetylcysteine
What is the major second messenger in Galpha-s cascade?
cAMP (generated via adenylate cyclase)
Where does bile acid reuptake occur?
Terminal ileum
Ileal enterocytes contain ASBT transporter - bile acids then return to the liver via NCTP transporter on hepatocytes
What transporter brings glucose from the intestinal cell into the interstitial space?
Glut-2
(also carries galactose and fructose)
What is the most sensitive antibody seen in ~90% of celiac's patients?
Anti endomysial antibodies
What is THE treatment for hemochromatosis
Phlebotomy (just keep bleeding em)
ANP signals through what receptor type?
Receptor guanylyl cyclase
Binding causes conversion of GTP --> cGMP which is best known for its effects on smooth muscle relaxation
What portion of the small intestine is the major site of iron absorption? What about folate (B9?)
Duodenum - iron
Jejunum - Folate
What ligand gated receptor is common among somatic, sympathetic, and parasympathetic nervous systems?
Nicotinic acetylcholine receptor
Hemochromatosis
What is the triple therapy for H.Pylori?
PPI, Amoxicillin(aminopenicillin), Clarithromycin(macrolide)