Kidney - Regualtion Of Fluid And Electrolyte Balace In Health And Disease

Question 1

Where is the bulk of sodium reabsorbed

Answer 1

The proximal consulates tubule

Question 2

What hormone is responsible for insertion of sodium channels

Answer 2

Aldosterone

Question 3

What is ANP

Answer 3

Inhibits the hormones ADH and aldosterone which leads to fluid excretion, large volume of dilute urine

Question 4

What does low blood pressure cause in the distal convulated tubule

Answer 4

A fall in blood pressure will signal for the release of ADH and aldosterone, they will increase fluid reabsorption and help to increase the blood pressure back to homeostatic levels

Question 5

What will a rise in blood pressure result in

Answer 5

A rise in blood pressure will lower the blood pressure, therefore ANP will be released and fluid excretion will increase from the distal convoluted tubule meaning the blood pressure will be restored to homeostatic conditions

Question 6

What factors influence the GFR

Answer 6

• glomerular hydrostatic pressure
• capsular hydrostatic pressure
• glomerular osmotic pressure
• systemic blood pressure
• renin-angiotensin-aldosterone system
• disease

Question 7

How much sodium is absorbed proximal convoluted tubule

Answer 7

65% of sodium is reabsorbed

Question 8

How much sodium is reabsorbed in the loop of henle

Answer 8

25%

Question 9

How much sodium is absorbed in the distal convulated tubule

Answer 9

8%

Question 10

What is the definition of the glomerular filtration rate

Answer 10

The rate at which blood is filtered through the glomerulus into the bowmans capsule

Question 11

The kidneys measure GFR as a…

Answer 11

Proxy for systemic blood pressure

Question 12

What is the juxta-glomerular apparatus

Answer 12

• connects the distal convoluted tubule with the glomerulus
• measures and responds to changes in Na+ conc of the filtrate

Question 13

What is the macula densa

Answer 13

They are a small group of specialised epithelial cells which measure and respond to changes in sodium concentration

Question 14

What are the juxta golomerular cells

Answer 14

Modified smooth muscle cells, they can adjust the diameter of the afferent arteriole by vasoconstriction and vasodilation the mascula densa cells tell the juxta to constrict or dilate

Question 15

What are mesangial cells

Answer 15

Supporting cells in the juxta glomerular apparatus

Question 16

How does blood pressure affect the sodium filtrate concentration

Answer 16

Blood pressure drives the glomerular hydrostatic pressure which in turn determines the sodium filtrate concentration

Question 17

What does a high blood pressure result in

Answer 17

A high blood pressure would result in a higher glomerular hydrostatic pressure hence a higher GFR and a higher Na+ filtrate concentration

Question 18

How does the body maintain a stable blood pressure

Answer 18

If blood pressure is within homeostatic conditions in the kidney the large diameter of the arteriole will be maintained

Question 19

What happens in the case of a high blood pressure(high na) in the kidneys

Answer 19

Because there is a high concentration of sodium, water will follow hence the mascula densa swell, this causes the relaase of adenosine which tells the juxta cells to vasoconstrict, this helps to protect the glomerular capillaries and glomerular hydrostatic pressure returns back to normal

Question 20

What happens when the blood pressure is low

Answer 20

The macula densa will release prostaglandins, these act on the juxtaglomerular cells and the cells secrete renin this activates the renin angiotensin system and returns the blood pressure to a normal level

Question 21

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