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monosaccharide transporters) Glucose/Galactose active transport and passive-This mechanism involved 2 transporters, which are they?
-sodium/potassium ATPase pump on basolateral membrane
-sodium/glucose facilitated diffusion symport
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monosaccharide transporters) glucose/galactose active transport- what does the sodium/potassium ATPase pump on basolateral membrane do?
creates a sodium gradient in enterocyte by removing sodium from cell
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monosaccharide transporters) glucose/galactose active transport- what does the sodium/glucose facilitated diffusion symport create?
sodium gradient pulls sodium through SGLT1 but only if glucose or galactose monosaccharide comes too.
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monosaccharide transporters) Passive- what are 3 steps glucose/galactose have to take when they go through passive?
-glucose/galactose enter apical surface through GLUT2
-exit basolateral membrane through GLUT2
-migrates to cell surface in response to insulin
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monosaccharide transporters) what route does fructose take?
apical surface GLUT5 (facilitative) and exits GLUT2
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Is fructose abosrobed slower or faster than glucose and galactose?
slower
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how can one increase their absoprtion rate of fructose?
by adding the presence of glucose or galactose
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why is fructose absorption increased in the presence of glucose/galactose?
- -an increase of GLUT2 receptors which are produced due to glucose presence
- *these are capable of taking glucose into the cell
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after the monosaccharides exit the enterocyte through GLUT2 transporters in basolateral membrane, where do they enter?
portal vein
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After entering the portal vein, where do the monosaccharides travel to?
- the liver
- *most of metabolism occurs here
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At the liver) fructose and galactose gets converted to...
glucose
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At the liver) monosaccharides enter...
hepatocytes through facilitated diffusion
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Why is it good that very little fructose or galactose are found in the blood stream?
fructose and galactose do not respond to hormonal regulation.
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what 3 things may happen to glucose once its in the liver?
-stored as glycogen in the liver
-return to blood stream to maintain blood glucose levels
-catabolized for energy according to livers needs
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Does the liver remove all the glucose from the bloodstream? (2)
no some passes through bloodstream and some get distributed to muscle,kidney,brain,and fat tissues
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How does glucose enter muscle,kidney,brain,and fat tissues?
facilitated diffusion
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when cell receptor senses insulin, in what 4 ways does the cell respond?
-more GLUT4 is translated/transcribed and sent to golgi
-golgi releases the stored GLUT4, these migrate to cells plasma membrane membrane
-GLUT4 fuses with membrane and glucose is removed from the blood
-glucose is taken into the cell for storage or use
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How is diabetes described?
condition which impairs the body's ability to clear glucose from the blood stream
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description of type 1 diabetes
the pancreas has trouble secreting insulin
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what are 2 causes for type 1 diabetes?
-no glut 4 migration
-autoimmune attack on pancreas
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description of type 2 diabetes
pancreas secretes insulin but the cells signaling is unresponsive (insulin resistant)
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3 causes for type 2 diabetes
-no glut4 migration
-obesity/sedentary lifestyle
-abdominal adiposity
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type 1 diabetes treatment
-exogenous insulin injections
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type 2 diabetes treatment (3)
-insulin sensitizing drugs
-lifestyle changes
-exogenous insulin in advanced stages
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what 3 effects can tight blood glucose control prevent?
-kidney disease
- -glycosylation of nerves
- *neuropathy,retinopathy
-infections
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What can foods with high GI cause? and what do they lead to?
an over response of insulin which may make the blood sugar swing down below baseline which leads to carb chasing (craving for more carbs)
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which 5 factors make GI fluctuate?
-temperature of food
-growing conditions
-how the food was processed
-patients insulin sensitivity
-patients activity levels
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Where are most of monosaccharides absorbed?
by the end of jejunum
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Once the saccharide is broken down by di-trisaccharides, where is glucose absorbed and by which 2 methods?
-glucose is absorbed into enterocyte through active transport and facilitated transport
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What is active transport used for?
move items against their concentration gradient
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What does active transport create?
concentration gradients
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description of facilitated diffusion
-special protein transporters transport large substances to cross membrane
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Is facilitated diffusion passive or active?
passive
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Facilitated diffusion- Cotransport:
a way to move an item against its concentration gradient without energy expenditure
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how does Cotransport work?
attach the item to another item that is already moving down to a concentration gradient
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