lecture 31 - renal / urinary physiology

Question 1

what do kidneys balance in our body

Answer 1

• water
• ions (sodium)
• pH

Question 2

what are things that we consume that kidneys remove from our blood

Answer 2

drugs / medicines and toxins

Question 3

what are things our cells produce that the kidneys remove from the blood

Answer 3

• from metabolism
• from breaking down old cells

Question 4

what are the endocrine functions of the kidney

Answer 4

• kidney detects low EPO, which stimulates the release of EPO
• bone marrow then produces more red blood cells and therefore more oxygen can be carried

Question 5

what is gluconeogenesis

Answer 5

during fasting or when the body is under stress : the kidneys make glucose from lactate

Question 6

what are the two main sources of acid in the body

Answer 6

• acids coming from food + drink and metabolism
• acids coming from CO2 = more CO2 leads to more H+ production because of equilibrium equation

Question 7

how is the pH of the blood controlled

Answer 7

• lungs = exhalation of carbon dioxide
• kidneys = by reabsorption and secretion of bicarbonate and hydrogen ions

Question 8

how are hydrophilic drugs and toxins excreted from the body

Answer 8

excreted directly by the kidneys

Question 9

how are lipophilic drugs and toxins excreted from the body

Answer 9

excreted by the kidneys after they have been metabolised ( as they are fat soluble )

Question 10

what percentage of our total body water is extracellular fluid

Answer 10

1/3 (33%)

Question 11

what percentage of our total body water is intracellular fluid

Answer 11

2/3 (67%)

Question 12

what percentage of our ECF is plasma

Answer 12

1/5 (20%)

Question 13

what percentage of our ECF is interstitial fluid

Answer 13

4/5 (80%)

Question 14

what does an increase in the ICF fluid do in terms of cell size

Answer 14

swelling of cells

Question 15

what does an decrease in the ICF fluid do in terms of cell size

Answer 15

shrinking of cells

Question 16

what is osmolarity

Answer 16

the total number of solute molecules in a solution

Question 17

what is the normal osmolarity of both the ECF and ICF

Answer 17

275-300 mosmol/L

Question 18

what is a isosmotic solution

Answer 18

same amount of solute molecules per litre
- some osmolarity

Question 19

what is a hyposmotic solution

Answer 19

increase in water
- less solute molecules per litre
- decrease in ECF/ plasma osmolarity

Question 20

what is a hyperosmotic solution

Answer 20

decrease in water
- more solute molecules per litre
- increase in ECF/ plasma osmolarity

Question 21

where will water initially enter when you drink water

Answer 21

the ECF

Question 22

what occurs if there is a loss of WATER ONLY

Answer 22

• water will be lost from the ECF
• ECF osmolarity increases = so water moves from the ICF to the ECF until balanced
• loss of water from both ICF and ECF = cells shrink

Question 23

what occurs if there is a gain of WATER ONLY

Answer 23

• water gain to the ECF
• ECF osmolarity decreases = so water moves from the ECF to the ICF until balanced
• gain of water to both ICF and ECF = cells swell

Question 24

what occurs if there is a loss of isosmotic fluid

Answer 24

• loss of isosmotic fluid in the ECF
• osmolarity in ICF and ECF still the same
• no water movement = decrease in ECF volume only

Question 25

what occurs if there is a gain of isosmotic fluid

Answer 25

- gain of isosmotic fluid in ECF - osmolarity in the ICF and ECF still the same - no water movement = increase in the ECF volume only

Question 26

where does filtration occur

Answer 26

- occurs in the renal corpuscle / glomerulus

Question 27

what is filtration

Answer 27

movement of plasma from the glomerulus capillaries into the glomerular capsule

Question 28

what substances are not filtered

Answer 28

large proteins e.g albumin and substances bound to proteins

Question 29

what is secretion (nephron)

Answer 29

movement of solutes from peritubular capillaries into the tubular fluid

Question 30

where does secretion occur

Answer 30

proximal tubule

Question 31

where does reabsorption occur

Answer 31

proximal tububle, nephron loop and distal tubule and collecting duct

Question 32

what is reabsorption

Answer 32

movement os solutes from the tubular fluid into the peritubular capillaries

Question 33

what occurs in the proximal tubule

Answer 33

bulk reabsorption and secretion

Question 34

what happens in the distal tubule and collecting duct and what is it regulated by

Answer 34

fine tuning / regulated by hormones reabsorption of ions (sodium) and water