Lab 2 - Glucose Transport Flashcards
What are the three regions of the small intestine?
Duodenum
Jejunum
Ileum
What facilities glucose transport across membrane?
SGLT - sodium glucose co-transporter
(Glucose coupled to sodium)
What is the Na+ gradient maintained by?
Na+ K+ ATPase
What sort of transporter is the Na+K+ATPase?
Primary active transporter (meaning it directly uses ATP to actively transport Na+ and K+)
Is K+ high intracellular or extracellular?
Intracellular (cells are like potatoes - high in K+ inside and you put salt/NaCl on the outside)
The mucosal side of the cell is also referred to as the..
Apical / luminal side (outer)
The serosal side of the cell can also be referred to as the…
Basolateral / interstitial fluid / inner
What does glucose move in response to?
A sodium gradient
The Na+ K+ ATPase moves how many K+ and Na+?
For every 2 K+ moved into the cell, 3 Na+ moved out of the cell.
Does the Na+ K+ ATPase move ions with or against their gradient?
Against
What direction does K+ move through leaky channels?
out of the cell
What is the glucose transporter called?
GLUT
What type of transporter is SGLT?
Secondary Active Co-Transporter (uses gradient to couple ions but does not directly use ATP)
What type of diffusion does GLUT facilitate?
Glucose transported by facilitated diffusion
What direction does Cl- move through the paracellular pathway during glucose transport?
Serosal / interstitutional fluid - it follows the positive charge
Why is Na+ the most desirable ion to couple with?
Because it has a chemical and electrical gradient
In addition to the intestine what other epithelial tissue utilises Na+ coupled glucose transport?
The Kidney
What SGLT is used in glucose transport in intestines?
SGLT 1
What GLUT is associated with glucose transport across epithelial tissues in the intestine?
GLUT2
What causes water to move through paracellular and trans cellular pathways?
It follows due to osmotic gradient
What does hypernatremic mean?
High blood sodium levels
How does glucose transport differ between the kidney and intestine?
In the intestine SGLT1 and GLUT2 are used. Whereas, in the Kidney SGLT2/GLUT2 (for proximal convoluted tubule/PCT) and SGLT1/GLUT1 (for the DCT) are used.
What does glucosuria mean?
Glucose in the urine (meaning that there is some failure in glucose absorption in the kidney - therefore something wrong with GLUT1 or GLUT2)
What carbohydrate is present in breast milk?
Lactose
What causes diarrhoea?
To much water
When you have too much water in the body, the kidneys can’t remove the excess liquid. It starts collecting in the body, leading to nausea, vomiting, and diarrhea
Which two sugars result from the breakdown of lactose during digestion?
Glucose and Galactose
If someone has diarrhea what does it imply about the normal function of small intestine in relation to water absorption?
Disfunction fo SGLT 1
What is meant by affinity?
ability to bind to something
What effects the affinity of something?
Concentrations
What is meant by capacity?
Ability to do something (movement)
Does SGLT1 or SGLT2 have higher capacity?
SGLT2
Does SGLT1 or SGLT2 have higher affinity?
SGLT1
What percentage of glucose reabsorption is done by SGLT2?
90%
How does Phlorisizin effect glucose transport?
It inhibits the SGLT1 - but it is reversible therefore not all transporters along the intestine are blocked at the same time so there is still some transport.
How does Ouabain effect glucose transport?
It irreversibly blocks the Na+K+ATPase. Therefore once the existing Na+ gradient is depleted there is no movement of glucose.
