Renal

Question 1

What are 3 hormones produced by the kidneys?

Answer 1

Renin, EPO and calcitrol

Question 2

How many nephrons are found in the body in total?

Answer 2

around 2.5 million.

Question 3

How much blood is filtered out from the glomerular arterioles?

Answer 3

around 20%

Question 4

Which fibres alter the blood flow to the glomeruli?

Answer 4

Sympathetic fibres

Question 5

How many nephrons are juxtamedullary?

Answer 5

Between 15-25%

Question 6

What is the importance of juxtamedullary nephrons?

Answer 6

They have very long loops of henle and collecting ducts allowing them to concentrate urine more than other types of nephrons.

Question 7

What do efferent arterioles recombine into?

Answer 7

The peritubular capillaries.

Question 8

What do the peritubular capillaries become when they are closely linked to the collecting duct and loop of henle?

Answer 8

The vasa recta

Question 9

Where does the majority of reabsorption take place?

Answer 9

The PCT.

Question 10

What does the PCT reabsorb?

Answer 10

Ions, Water and organic nutrients

Question 11

What does the PCT secrete?

Answer 11

Metabolites and other drugs such as xenobiotics.

Question 12

Name a renal tracer and explain its importance.

Answer 12

Para-aminohippurate is a renal tracer. It cannot be reabsorped by the nephorn once filtered so its concentration in urine is a useful indicator of GFR

Question 13

How much plasma do the glomeruli filter per minute?

Answer 13

125ml/min which is around 180l/day

Question 14

Which forces help to push solute out of afferent capillaries and what is it greater than?

Answer 14

Hydrostatic forces is greater than oncotic pressure.

Question 15

What is the net filtration pressure across the glomeruli?

Answer 15

10mmHg

Question 16

What components form the GFR co-efficient?

Answer 16

The slit surface area and barrier permeability.

Question 17

Which hormones can influence afferent arteriole resistance and flow to glomeruli?

Answer 17

Catecholamines and angiotensin 2

Question 18

What is the range of kidney autoregulation of GFR?

Answer 18

130-60mmHg

Question 19

What happens to 50% of the urea which is filtered by glomeruli?

Answer 19

It is reabsorbed.

Question 20

What substances are reabsorped by channel or carrier proteins?

Answer 20

Glucose, amino acids, phosphates and organic ions.

Question 21

What is a normal value of ECF [Na+]?

Answer 21

142mmol

Question 22

How much sodium is reabsorbed in the PCT?

Answer 22

65-75%

Question 23

Is Na+/K+ transport affected by transport maximum?

Answer 23

No.

Question 24

WHere are the hydrogen ions that are excreted in urine formed?

Answer 24

They are formed in the tubular lumen epithelium

Question 25

What does the inability to reabsorb everything mean for urine concentration?

Answer 25

It means that there will be a minimum amount of effective osmoles still in the urine, which draws water into the urine. This means that there is a maximum attainable concentration for urine.

Question 26

What happens to metabolites which are too large or charged to pass the glomerular barrier?

Answer 26

They are secreted into the PCT by unspecific carriers.

Question 27

What is the primary intracellular cation?

Answer 27

K.

Question 28

What is a normal ECF [K+]?

Answer 28

4mmol

Question 29

What concentration might be classed as hyperkalaemia?

Answer 29

>5.5mol

Question 30

What concentration might be considered hypokalaemia?

Answer 30

<3mmol

Question 31

What does hypokalaemia mean for cells?

Answer 31

They are hyperpolarised so struggle to reach threshold for action potential propagation.

Question 32

Name another tracer molecule.

Answer 32

inulin.

Question 33

What is renal clearance?

Answer 33

A measure of how well the kidneys are excreting substances.

Question 34

What is average plasma mOsm/l?

Answer 34

~285mOsml/l

Question 35

What is reabsorbed in the descending loop of henle?

Answer 35

Water, no ions

Question 36

What is reabsorbed in the ascending loop?

Answer 36

Ions, no water.

Question 37

What can alter ADH secretions?

Answer 37

Stress, pain and emotion

Question 38

What is neurogenic diabetes insipidus?

Answer 38

Deficiency of ADH production.

Question 39

What is nephrogenic diabetes insipidus?

Answer 39

Nephrogenic ADH insensitivity

Question 40

A moderate decrease in ECF is detected by which receptors?

Answer 40

Atrial receptors

Question 41

When do all baroreceptors detect a change in ECF volume?

Answer 41

When the change is very significant.

Question 42

Where is angiotensin secreted from?

Answer 42

The liver.

Question 43

Where is renin secreted from?

Answer 43

The kidneys.

Question 44

What does renin do?

Answer 44

Converts angiotensin to angiotensin 1

Question 45

Which enzyme converts angiotensin 1 to angiotensin 2?

Answer 45

Angiotensin converting enzyme (ACE)

Question 46

What is special about ACE?

Answer 46

It is an ectoenzyme meaning it is bound to a membrane

Question 47

What effect does ANG II have on the adrenal cortex?

Answer 47

Stimulates it to secrete aldosterone and initiate vasoconstriction.

Question 48

How does ANG II decrease heart rate?

Answer 48

By acting on the medullary cardiovascular centre

Question 49

What effect does aldosterone have on sodium and water reabsorption?

Answer 49

It stimulates the DCT to reabsorb more sodium and water to increase the blood pressure.

Question 50

Which cells in the DCT are directly stimulated by aldosterone?

Answer 50

P-cells

Question 51

When is atrial natiuretic peptide secreted?

Answer 51

When the atria are hyperdistended.

Question 52

What does 2 main roles does ANP have?

Answer 52

To inhibit aldosterone and increase GFR

Question 53

Why does ANP perform these roles?

Answer 53

To decrease the amount of sodium and therefore water that is being reabsorbed. This will result in reduced ECF volume and blood pressure.

Question 54

What is a normal pH range?

Answer 54

7.35-7.45

Question 55

What is a normal PCO2?

Answer 55

40mmHg or 5.33kPa

Question 56

What is a normal [HCO3-] concentration?

Answer 56

24mM

Question 57

What can cause metabolic acidosis?

Answer 57

Diabetic ketoacidosis.

Question 58

What can prolonged vomiting cause in terms of acid/base disorders?

Answer 58

metabolic alkalosis

Question 59

Acute respiratory acidosis may be cause by?

Answer 59

Breathing 7% CO2

Question 60

What acid/base disorder might emphysema cause?

Answer 60

Chronic respiratory acidosis.

Question 61

Prolonged time in high altitude might cause which acid/base disorder?

Answer 61

Chronic respiratory alkalosis.

Question 62

What might be a cause of acute respiratory alkalosis?

Answer 62

Hyperventilation.

Question 63

What is the first step in determing the acid/base disorder?

Answer 63

Is the pH high or low?

Question 64

What is the second step in determing the acid base disorder?

Answer 64

Whether it is metabolic or respiratory.

Question 65

How can you determine whether the acid/base disorder is metabolic or respiratory?

Answer 65

If it is respiratory then PCO2 is likely to be affected. | If it is metabolic then PCO2 is likely to be unaffected.

Question 66

What is the 3rd step in determining acid/base disorder?

Answer 66

Whether or not it is chronic or acute.

Question 67

How can you determine whether an acid/base disturbance is chronic or acute?

Answer 67

If the [HCO3-] has signficantly moved from a normal level then it is likely to be chronic, if not, then it is likely to be acute.

Question 68

If the acid/base disturbance is caused by a change in [HCO3-] is the cause likelt to be respiratory or metabolic?

Answer 68

Metabolic.

Question 69

When might renal compensation for an acid/base disorder occur?

Answer 69

When the cause if the disturbance is respiratory.

Question 70

What is respiratory compensation in response to?

Answer 70

A renal/metabolic issue causing an acid/base disturbance.