Renal

Question 1

Does filtration occur in the renal cortex or medulla?

Answer 1

Cortex

Question 2

Which part/s of the nephron dip down into the medulla?

Answer 2

The loop of henle, the collecting ducts

Question 3

Do the peritubular capillaries connect to the afferent or efferent arterioles?

Answer 3

Efferent.

Question 4

Describe the vascular structure of the nephron. Include: afferent arterioles, efferent arterioles, peritubular capillaries and renal vein and artery

Answer 4

Renal artery supplies the afferent arterioles, which supplies blood to the glomerulus. The glomerulus contains many capillaries where filtration occurs, then the efferent arterioles take blood away from the glomerus to the PT capillaries then to the renal vein

Question 5

Location of PCT vs DVT?

Answer 5

Proximal tubule is after the bowmans capsule, DCT is after the loop of henle.

Question 6

Excretion = _____ - reabsorption + ____?

Answer 6

Filtration - reabsorption + secretion

Question 7

Describe the movement of substances that occurs during glomerular filtration

Answer 7

Movement of fluid + solutes from the glomerular capillaries into the bowmans space

Question 8

Describe the movement of fluid and solutes that occurs during tubular reabsorption

Answer 8

Moves from the tubules into the peritubular capillaries (back into the body / won’t be excreted)

Question 9

Describe the movement of fluid and solutes that occurs during tubular secretion

Answer 9

Moves from peritubular capillaries into the tubule to be excreted

Question 10

What is the main site of sodium reabsorption?

Answer 10

Proximal tubule

Question 11

Does sodium reabsorption happen in the descending or ascending loop of henle?

Answer 11

Ascending

Question 12

Does water reabsorption happen in the ascending or descending loop of henle?

Answer 12

Descending

Question 13

ADH / vasopressin increases permeability at which part of the nephron?

Answer 13

Collecting duct and distal tubule

Question 14

Explain how ADH works in dehydration.

Answer 14

Dehydration causes an increase in ECF osmolarity. This is detected by osmoreceptors, which signals to the posterior pituitary to release ADH as well as increasing thirst. ADH acts on the nephron to increase water reabsorption and reducing its excretion

Question 15

Where is aldosterone released from

Answer 15

The adrenal gland

Question 16

What stimulates the release of aldosterone

Answer 16

Angiotensin 2 and increased concentration of potassium

Question 17

Action of aldosterone?

Answer 17

Acts on the distal tubule and collecting duct to increase sodium reabsorption (promotes the secretion and excretion of K and reabsorption of water)

Question 18

Which substances are commonly secreted back into the tubule for excretion?

Answer 18

Uric acid, urea, drugs, H+ and HCO3-

Question 19

What % of the CO do the kidneys receive?

Answer 19

20-25%

Question 20

Why do kidneys need so much blood?

Answer 20

To ensure a high enough hydrostatic pressure to drive fluids and solutes across the filtration barriers

Question 21

Name 2 barriers to filtration

Answer 21

• negatively charged basement membrane
• endothelial fenestrations
• podocytes and slit diaphragm

Question 22

Name 2 factors that oppose filtration

Answer 22

• pressure in the filtrate / bowmans capsule

- osmotic pressure of plasma (due to proteins)

Question 23

Factor that favours filtration?

Answer 23

Glomerular capillary pressure

Question 24

What effect does an increase in GFR have on tubular flow rate?

Answer 24

Increases it. Causes a reduction in reabsorption, leading to the loss of important solutes

Question 25

Consequence of a slow GFR?

Answer 25

Increases reabsorption since the tubular flow rate is so slow. Leads to waste not being excreted

Question 26

Name an example of something that would increase plasma osmotic pressure

Answer 26

Water loss - dehydration or diarrhoea

Question 27

If the clearance of a drug is less than the clearance of creatinine (125), what does this indicate?

Answer 27

It is being reabsorbed

Question 28

If the clearance of a substance = 125, what does this indicate?

Answer 28

Not being reabsorbed or secreted. If more than 125, it is being secreted

Question 29

Where are macula densa cells found?

Answer 29

In the distal tubule

Question 30

Explain what juxtaglomerular cells are

Answer 30

Smooth muscle cells in the afferent arterioles that secrete renin

Question 31

Which cells detect NACL Levels in the distal tubule and respond by changing release of renin?

Answer 31

Macular densa cells

Question 32

Name 2 Intrinsic factors for bp regulation

Answer 32

Myogenic mechanism and tubuloglomerular mechanism

Question 33

Name 2 extrinsic factors for BP regulation

Answer 33

Hormonal and neural (SNS activity)

Question 34

Which cells are responsible for the secretion of renin? And where are these cells located?

Answer 34

The juxtaglomerular cells in the afferent arterioles

Question 35

Other than low blood pressure, what else can stimulate the release of renin? (3 answers)

Answer 35

Low sodium concentration detected by macular densa cells in the distal tubule, decreased blood volume and increased beta sympathetic activity

Question 36

Force that favours filtration?

Answer 36

Glomerular capillary pressure

Question 37

2 forces that oppose filtration

Answer 37

Plasma-colloid osmotic pressure (oncotic)

Bowmans capsule hydrostatic pressure