6 renal and endocrine systems

Question 1

Describe some functions of the kidney

Answer 1

Removal of waste products

Question 2

What is normal blood pH?

Answer 2

7.4

Question 3

What is the equation for pH?

Answer 3

-log[H+]

Question 4

What is a buffer?

Answer 4

Any substance that can reversibly bind to H+

Question 5

What is the equation for a weak acid?

Answer 5

H+ + buffer- <-> Hbuffer (weak acid)

Question 6

What is the major extracellular buffer?

Answer 6

The CO2/ HCO2 system

Question 7

What are the major intracellular buffers?

Answer 7

Phosphates and proteins

Question 8

What is the reaction of carbon dioxide and water?

Answer 8

CO2 + H2O <—> H2CO3 <—> H+ +HCO3-

Question 9

What does bicarbonate loss also mean?

Answer 9

Hydrogen ion gain

Question 10

How is hydrogen ion gained?

Answer 10

From CO2

Question 11

How is hydrogen ion lost?

Answer 11

Use of ion in metabolism

Question 12

What is respiratory acidosis caused by?

Answer 12

Retention of CO2

Question 13

What is respiratory alkalosis caused by?

Answer 13

Excessive elimination of CO2

Question 14

What is metabolic acidosis caused by?

Answer 14

Gain of H+

Question 15

What is metabolic alkalosis caused by?

Answer 15

Loss of H+

Question 16

Describe the respiratory system response to H+ concentration balance

Answer 16

Very rapid (minutes)

Question 17

Describe the renal system response to H+ concentration balance

Answer 17

Slow responding (hours to days) and can eliminate imbalance

Question 18

How do kidneys eliminate or replenish H+?

Answer 18

By altering bicarbonate concentration

Question 19

Describe what occurs within the kidneys during acidosis

Answer 19

Plasma H+ concentration increases and kidneys do not excrete bicarbonate in urine and kidney tubular cells produce new bicarbonate and add it to plasma. All filtered carbonate is reabsorbed and their is a net gain of bicarbonate as H+ is secreted and combines with non bicarbonate buffers

Question 20

Describe what occurs within the kidneys during alkalosis

Answer 20

Kidneys response is to excrete large quantities of bicarbonate

Question 21

What does carbonic anhydrase do?

Answer 21

Break down carbonic acid to water and CO2 which can enter the cell while another form allows CO2 to bind to water to form bicarbonate and be absorbed through the base membrane to the bloodstream

Question 22

Describe renal metabolism of glutamine and new bicarbonate in acidosis?

Answer 22

All filtered HCO3- is reabsorbed

Question 23

What are juxtaglomerular cells?

Answer 23

Intrarenal baroreceptors

Question 24

Describe the action of JG cells when BP is low

Answer 24

They are stretched less and secrete more renin

Question 25

What are JG cells innervated by?

Answer 25

Sympathetic renal nerve

Question 26

Where is the macula dense?

Answer 26

At the end of the ascending limb of loop of Henle

Question 27

What does the macula densa do?

Answer 27

Sense sodium in tubular fluid

Question 28

What is aldosterone?

Answer 28

A steroid hormone secreted by the adrenal cortex that stimulates sodium reabsorption at the DCT and CD

Question 29

Describe sodium reabsorption when plasma aldosterone is high

Answer 29

All the sodium is reabsorbed

Question 30

What does aldosterone do?

Answer 30

Stimulate sodium reabsorption and potassium excretion

Question 31

What secretes ADH?

Answer 31

Posterior pituitary gland in response to severe physiological stimuli

Question 32

What stimulates ADH release?

Answer 32

Angiotensin II - when the body is dehydrated

Question 33

When is ADH secreted?

Answer 33

When blood osmolality increases and BV or BP is low

Question 34

What is water permeability dependent on?

Answer 34

The permeability of the membrane

Question 35

Where is water permeability under physiological control?

Answer 35

The cortical and medullary collecting ducts

Question 36

What is water permeability controlled by?

Answer 36

ADH

Question 37

How does ADH control water permeability?

Answer 37

Stimulates insertion of aquaporin channels in apical membrane of CDs

Question 38

What is ANP?

Answer 38

A 28 amino acid peptide that is synthesised

Question 39

What is ANP secretion increased by?

Answer 39

An increase in BV and BP

Question 40

How does ANP affect GFR?

Answer 40

Acts on renal blood vessels to increase GFR

Question 41

How does ANP affect sodium absorption/ excretion?

Answer 41

Acts on tubules to inhibit sodium reabsorption and promote natriuresis

Question 42

What does ANP do to BV and BP?

Answer 42

Decreases them