An Intro To Kidney And Body Fluids

Question 1

What do osmolarity and osmolality refer to?

Answer 1

The total concentration of osmotically active particles in solution

Question 2

What is the difference between osmolarity and osmolality?

Answer 2

Osmolarity is the measure of solute concentration per unit volume of solution and osmolality is per unit mass of the solvent

Question 3

What % of water are males?

Answer 3

60%

Question 4

What % of water are females?

Answer 4

50%

Question 5

What are the two main fluid compartments?

Answer 5

Intracellular and extracellular fluids

Question 6

What proportions are the body’s fluids stored in?

Answer 6

2/3 intracellular and 1/3 extracellular

Question 7

What must the Intracellular fluid and Extracellular fluid be in?

Answer 7

Osmotic equilibrium

Question 8

What happens if the solute concentration changes in either the intracellular or extracellular fluid compartments?

Answer 8

Generate an osmotic gradient, resulting in shifts of water between compartments

Question 9

What is regulated in the extracellular fluid compartment?

Answer 9

Osmolarity

Question 10

Why is osmolarity regulated in the ECF?

Answer 10

To avoid osmotic shifts of water between the ICF and ECF volumes

Question 11

What is the normal range of osmolarity?

Answer 11

280-300 mosm/L

Question 12

Why must large shifts in osmolarity be avoided?

Answer 12

Prevent changes in cell volume

Question 13

What are the main serious complications of a large shift in osmolarity?

Answer 13

Demyelination, decrease in cell volume -> blood vessels bursting

Question 14

What is osmoregulation?

Answer 14

Physiological process that maintains constant ECF osmolarity

Question 15

What is the ECF compartment subdivided into (and in what proportions)?

Answer 15

Interstitial (extravascular) compartment (75%)

Plasma (vascular) compartment (25%)

Question 16

What does maintaining salt and water balance require?

Answer 16

Integration of osmoregulation and volume regulation

Question 17

How does osmoregulation control salt concentration?

Answer 17

Adjusts the amount of pure water in the body

Question 18

What does volume regulation do?

Answer 18

Controls the amount of salt and water in the ECF and therefore ECF volume

Question 19

Which organ is central to both osmoregulation and volume regulation?

Answer 19

Kidney

Question 20

What is the function of the kidneys?

Answer 20

Homeostasis

Question 21

What are the other functions (not homeostasis) of the kidneys?

Answer 21

• osmoregulation
• volume regulation
• Acid-base balance
• regulation of electrolyte balance
• removal of metabolic waste products and foreign chemicals in the blood
• regulation of RBC production

Question 22

What are the four basic processes of renal function?

Answer 22

Glomerular filtration, tubular reabsorption, tubular secretion and excretion of water and solutes in the urine

Question 23

What drives water and solutes across the capillary membrane in glomerular filtration?

Answer 23

Balance of starling forces

Question 24

What causes plasma ultrafiltration in the bowmans capsule?

Answer 24

The inability of large proteins and cells to pass through the capillary membrane so creating an osmotic force

Question 25

What is the glomerular filtration rate?

Answer 25

The amount of filtrate produced by kidneys each minute

Question 26

What is the average glomerular function rate?

Answer 26

125mL/min

Question 27

What can glomerular filtration rate be used for?

Answer 27

As an indicator for renal function?

Question 28

How much of the salt and water is reabsorbed from the proximal tubule?

Answer 28

70%

Question 29

What is tubular secretion important in?

Answer 29

Eliminating toxins and metabolic byproducts and potassium and acid balance

Question 30

Where is excess potassium secreted?

Answer 30

Distal tubule and collecting duct

Question 31

What does the acid base balance rely on?

Answer 31

Hydrogen ion secretion in the distal tubule and collecting duct

Question 32

What is urine?

Answer 32

Tubular fluid that remains after reabsorption and secretion

Question 33

What is the amount of water and solutes equal to?

Answer 33

Amount filtered - amount reabsorbed + amount secreted

Question 34

What can be used to measure glomerular filtration rate?

Answer 34

Creatinine

Question 35

What happens if you add water to the ECF?

Answer 35

ECF diluted-> water moves down the osmotic gradient into ICF -> ECF and ICF both expand and there is increased renal water filtration

Question 36

What happens to the osmolarity if you loose water?

Answer 36

Increases

Question 37

What happens physiologically if your plasma osmolality rises?

Answer 37

Increased thirst and increased secretion of ADH

Question 38

What is a synonym for ADH?

Answer 38

Vasopressin

Question 39

What does ADH do?

Answer 39

Increase renal water reabsorption | So decreases urine volume and increases urine osmolality

Question 40

What happens to the plasma osmolality if there’s an increase in water intake?

Answer 40

Falls as there’s increased water absorption through the GIT

Question 41

What are the physiological responses to a decrease in plasma osmolality?

Answer 41

Decreased thirst and secretion of ADH

Question 42

What does decreased plasma osmolality result in for urine?

Answer 42

Increased volume and decreased osmolality

Question 43

How is ECF volume determined?

Answer 43

The amount of sodium in that compartment

Question 44

What must be balanced to maintain a constant ECF volume?

Answer 44

Sodium intake and excretion

Question 45

Where are the main volume sensors?

Answer 45

CV system

Question 46

What happens to the ECF and ICF volumes if you add an isotonic solution to the ECF?

Answer 46

Retained in the ECF as the overall salt concentration hasn’t changed, so no change in osmotic gradient

Question 47

What does the renin-angiotensin-aldosterone system do?

Answer 47

Increases renal sodium reabsorption and increases ECF volume

Question 48

What do cardiac natriuretic peptides do?

Answer 48

Decrease renal sodium reabsorption and decrease ECF volume