411B Flashcards
Layers of the Jejunum from the lamina out.
Mucosa( epithelium, lamina propria, muscularis mucosa), sub mucosa, muscularis externa, adventitia serosa
Pathway for digestion of Vitamin B12
- Salivary R protien and HCL from parietal cells work to release food bound B12
- Trypsin from Pancreatic zymogen cells releases B12 from Salivary R protein.
- Intrinsic factor from Gastric parietal cell binds B12 and acts as a chaperon for transport into enterocytes in the ileum.
- From the ileum enterocyte B12 is associated with Transcobalamin II protien for transport to the portal venous system (into the liver).
Describe the Schilling test
Step 1 confirms malabsorption: radio labelled B12 (oral), large dose non-labeled IM, measure radio labeled B12 in urine. Malabsorption < 7-10% recovered in urine.
Step 2 confirm site: give oral intrinsic factor-> pernicious anemia, give pancreatic enzyme -> pancreatic insufficiency, give antibiotic -> SIBO (B12 is being consumed by bacterial overgrowth.
Site where pacreatic digestive products are secreted into the duodenum.
Major duodenal papilla
Enzymes produced by Acinar cells for digesting 1.Fats 2. Protein 3. Starch 4. DNA/RNA
- Lipases, Colipase, Cholesterol ester hyrolase, Phopholipase A2
- Trypsin, Chymotrypsin, Elastase, Carboxypeptidase A&B
- Amylase
- Deoxyribonuclease, Ribonuclease
The enzyme responsible for converting Trypsinogen to Trypsin, and the primary location that this occurs.
Enterokinase, Duodenum
What does CFTR stand for? what is it regulated by? and what is the downstream significance of its function?
Cystic Fibrosis Transmembrane Regulator, upregulated by upstream Secretin signaling. CFTR moves Cl- ions into the pancreatic ductal lumen setting up an electrochemical and osmotic gradient necessary for moving water and bicarbonate HCO3- into the lumen.
Differentiate Crohn’s and Colitis
Crohn’s: Any part of the GI, Patchy distribution, crosses the entire wall of the GI, may exhibit granulomas.
Colitis: Colon only starts in rectum, continuous involvement, inflammation limited to the mucosa, no granulomas.
Walk through the baroreceptor reflex
Baroreceptors on the aorta and internal carotid arteries inervate the medulla oblongata via sensory fibers. -> Parasympathetic fibres inervate the SA node, and Sympathetic fibers inervate the SA node and ventricles. –>Sympathetic nerve fibers inervate the adrenal gland
Describe the Renin-Angiotensin Aldosterone system
Liver produces Angiotensinogen.
In response to decreased renal perfusion the kidney releases Renin. Renin converts Angiotensinogen to Angiotensin I. Angiotenin I is converted to Angiotensin II in the lungs.
What are the downstream effects of Angiotensin II
a-Increased Sympathetic stimulation
b-Na, Cl and H2O are reabsorbed by the kidney while K is excreted.
c-adrenal cortex is stimulated to release aldosterone which increases b)
d- Arteriolar vasoconstriction
e-pituitary secretes ADH which increases water retention by the kidney.
Name 2 natriuretic peptides and their general function
ANP: Atrial natriuretic peptide
BNP: Brain natriuretic peptide
Both act to reduce blood pressure
Erythropoietin where is it made and what does it do?
Made in the kidneys it induces the bone marrow to produce more RBC’s
Define incidence and prevalence
Incidence: Number of new cases in a given time period
Prevalence: Total number of cases in a given population.
Define test sensitivity
The proportion of people with a disease who have a positive test.
