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50 Cards in this Set
- Front
- Back
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What are the 3 major glands in the stomach?
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Cardiac
Pyloric Oxyntic |
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What do the cardiac glands do?
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Secrete mucus to protect stomach lining
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What do Pyloric glands do?
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Contain G-cell which secrete Gastrin --> gastric emptying --> HCL secretion
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What 2 cell types does the oxyntic glands have and what do they do?
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Parietal: HCL secretion
Chief: Pepsinogen secretion |
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What 3 mechanisms regulate HCl secretion?
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Gastrin --> CCK receptors on parietal cells --> increased Ca+
Ach --> muscarinic receptors --> increased Ca+ Histamine --> base level HCl secretion |
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What are the 2 major functions of the pancreas?
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Produce digestive enzymes and bicarb
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What 3 digestive enzymes are produced in the pancreas?
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Proteolytic- protein breakdown
P amylase- carb breakdown P lipase- fat breakdown |
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How is bicarb secreted and in what cells does this occur?
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Ductal cells
H2O + CO2 --> H2CO3--> H+ + CO3- CO3- moves into lumen in exchange for Cl- |
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What 3 mechanisms regulate pancreatic secretion?
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CCK- regulate secretion of digestive enzymes
Ach- regulate secretion of digestive enzymes Secretin- regulates release of bicarb |
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Follow the pathway of bile, including the enterohepatic circulation, starting with the hepatocytes
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Hepatocytes--> bile canaliculi--> bile ducts --> common bile duct --> gall bladder --> common bile duct--> Sphincter of Oddi --> duodenum --> reabsorbe in ileum --> portal blood system --> hepatocytes
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What are the 2 components of bile?
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Billirubin - broken down hemoglobin
Bile acids |
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What is digestion vs. absorption
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digestion- breakdown of complex molecules into simple ones
absorption- transfer of simple molecules from lumen through enterocytes and into blood or lymph |
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What are the primary functions of the duodenum, jejunum, and ilium respectively?
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Duodenum- absorption of nutrients
Jejunum- absorption of nutrients, water, and ions Ileum- absorbs water, ions, and bile |
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What are the crypts of lieberkuhn?
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Contain stem cell that can become absorptive epithelial cells or CCK secreters
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Where does the greatest absorption occur in the microvilli?
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apical tips
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How are carbs digested?
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Salivary amylase --> pancreatic amylase --> brush border enzymes --> monosaccharide
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How are carbs absorbed?
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Lumen --> SGLT1 (moves glucose and galactose w/ Na+) + Glut 5 (moves fructose) --> Epithelial cells --> Glut 2 (moves fructose, galactose, and glucose into blood)
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How are proteins digested?
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Pepsin in stomach --> Trypson, chymotrypsin, carboxy peptidase in duodenum and jejunum --> AA's
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How are proteins absorbed?
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Sodium co-transport (similar to carbs)
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How are lipids digested?
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Lingual lipase in mouth --> gastric lipase in stomach --> pancreatic lipase --> fat droplets + bile = micelles
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What are triglycerides broken down into?
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monoglycerides + 2 FFA
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What are cholesterol esters broken down into?
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choletseral + 1 FFA
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What are phospholipids broken down into?
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Lysolecithin + 1 FFA
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How are fat droplets absorbed?
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Micelles diffuse to enterocyte --> bile stays behind --> once in enterocytes, resynthesized and accumulated into vecicles --> Chylomicron --> exocytosis
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What does VLDL do?
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transport cholesterol to lymph then to blood
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How are fat soluble vitamins absorbed?
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In small intestine --> chylomicrons --> lymph --> blood
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What are some examples of fat soluble vitamins?
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A, D, E, K
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How are water soluble vitamins absorbed?
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Simple diffusion or specific transporters
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What are some examples of water soluble vitamins?
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C, B12
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Maldigestion vs. Malabsorption
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maldigestion- enzyme insufficiency
malabsorption- inability to absorb broken down products |
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What do goblet cells do?
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secrete mucus in intestine (primarily small intestine)
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How and where is Na+ absorbed?
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Primarily in jejunum
Monosaccharide and AA's bring Na+ into epithelial cells via cotransporters |
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How and where is Cl- absorbed?
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Passively.
In jejunum, Cl- follows Na+ to create charge balance In ileum and colon, bicarb exchanged for Cl- in epithelial cells |
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How is K+ absorbed?
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passively
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How is Ca+ and Mg+ absorbed?
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depends on Ca+ ATPase, occurs in proximal intestine
Mg+ competes with Ca+ for uptake |
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What does vitamin D3 do?
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Increases Ca+ transporters
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What is the major role of the kidney?
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maintain composition and volume of ECF
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How is the ECF fluid balance maintained?
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Input = output
Primary input (ingestion) Primary output (breathing and urine) |
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Trace the route for excretion starting in afferent capillaries
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afferent capillaries --> glomerulus --> bowman's capsule --> PCT --> loop of henley --> DCT --> collecting duct --> ureter
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Discuss the renin-angiotensin system
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Angiotensinogen in liver --> converted by renin into angiotensin I --> converted into angiotensin II in lungs --> vasoconstriction
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Where is renin produced?
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Juxtoglomerular cells
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Where does most glomerular filtration occur?
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Basal lamina
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Driving force for filtration (GFR) is calculated by?
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GFR = k (Pgc - Pt - TTgc)
or = k x net filtration pressure |
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How do the kidneys filter so much with such a small driving pressure?
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large surface area
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How is GFR regulated?
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Autoregulation
As MAP decreases afferent arterials dilate to keep Pgc constant Changes are made locally, not at baroreceptors |
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How is GFR maintained in hypovolemic shock?
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Barroreceptor mediated
Both afferent and efferent smooth muscle in arterials constric |
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What happens when you become hyponatremic?
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--> decrease ECF osmolarity --> decrease ECF volume --> decrease MAP --> increase renin --> increase Angiotensin II --> increase aldosterone --> Na+ reabsorption
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What happens to ECF in the case of severe sweating and what do the kidneys do?
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sweating --> ECF volume --> decrease MAP --> baroreceptor activation --> secretion of ADH by posterior pituitary
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Discuss diarrhea and recovery from diarrhea in terms of volume and osmolarity
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Diarrhea --> 3L ECF volume loss --> increase ADH
Recovery from diarrhea --> 2L of H20 ingested --> decrease in ECF osmolarity --> decreases ADH release --> secretion of H2O |
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How is K+ regulated?
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K+ filtered --> K+ reabsorbed --> K+ secreted
Elevated K+ in ECF --> increased aldosterone secretion --> increase Na+/K+ pump in DCT --> K+ secretion |
