Lecture 10

Question 1

Role of Na K ATPase

Answer 1

Creates sodium and potassium gradients.

Secondary transport for movement of calcium and hydrogen out of cell in anti port. Glucose symport

Question 2

How is cellular calcium levels controlled?

Answer 2

Primary active-
PMCA high affinity low capacity

SERCA high affinity low capacity into sarcoplasmic or endoplasmic reticulum

Secondary active transport

Sodium calcium exchanger

Facilitated transport
Mitochondrial calcium uniport which acts as a buffer when calcium concentration dangerously high

Question 3

What’s interesting about the sodium calcium exchanger?

Answer 3

It’s flow of movement depends on the membrane potential.

Sodium will flow in direction of negativity. Reversed during depolarisation which helps with calcium influx and contraction in cardiac action potential

Question 4

What happens to the sodium potassium ATPase during ischemia and how does this affect intracellular calcium levels?

Answer 4

Ischemia no oxygen so no oxidative phosphorylation so no ATP. No ATP means sodium potassium ATPase doesn’t work and sodium accumulates in cell. Membrane potential becomes positive and so sodium calcium exchanger switches and calcium flows into cell and leads to calcium toxicity

Question 5

Ion transporters in pH regulation

Answer 5

Na K ATPase creates sodium gradient.

Sodium hydrogen antiport

Sodium bicarbonate co-transport (NBC)

Anion exchange of bicarbonate and chloride (acidifies cell)

Question 6

What is the pH set point?

Answer 6

PH maintained in cell by actions of transporters. Any deviance from set point should be corrected by various transporter activation.

Question 7

How to regulate cell volume?

Answer 7

Move osmotically active ions like sodium, potassium and chloride in or out of the cell

Question 8

Where does sodium reuptake occur in the kidney?

Answer 8

Thick ascending limb of

Question 9

How can loop diuretics or water tablets be used to treat hypertension?

Answer 9

Prevent sodium uptake in ascending limb which means water is not retained and is removed from body

Question 10

What does ADH work on?

Answer 10

Aquaporins and encourages water retention

Question 11

How does sodium get reabsorbed in kidney?

Answer 11

Diffusion- lower concentration in cell

Question 12

Give an example of a drug that prevents sodium being reabsorbed in the kidney?

Answer 12

Amiloride

Question 13

How to raise intracellular calcium?

Answer 13

Receptor calcium channels

Voltage calcium channels

IP3 gates channels in sarcoplasmic endoplasmic reticulum

Ryanodine receptor

Mitochondrial uniports

Sodium potassium exchanger