Water balance

Question 1

What determines the plasma volume that perfuse organs?

Answer 1

Amount of water in the blood

Question 2

What is hyperosmolality?

Answer 2

Too little water

Question 3

What are the symptoms of hyperosmolarity?

Answer 3

Diarrhea

Vomiting

Negative water balance

Reduced water volume

Increased blood viscosity

Headache

Cramps

Question 4

What are the symtoms of hyposmolality?

Answer 4

Low serum sodium levels

Headache

Vomiting

Confusion

Seizures

Coma

Muscle weakness

Question 5

How much water is lost by insensible losses?

Answer 5

0.5 - 1L

Question 6

What are insensible losses?

Answer 6

Non-urine losses

Sweating, breathing, faeces

Question 7

How much water is lost in the urine a day?

Answer 7

1.5 L

Question 8

What is the recommended volume of water that should be taken in during a day?

Answer 8

2 - 2.5 L

Through consumption of food and drink

Question 9

What is the percentage of water in the body?

Answer 9

60%

Question 10

What percentage of body water is found in the cells?

Answer 10

40% inside the cells - intracellular fluid

Question 11

What percentage of body water is found between cells?

Answer 11

15% in between cells - interstitial fluid

Question 12

What percentage of body water is found in blood plasma and lymph?

Answer 12

5%

Question 13

Is water distribution between intracellular and extracellular compartments interchangeable?

Answer 13

Yes

Question 14

What regulates the movement of water to and from the intracellular compartment?

Answer 14

Osmotic pressure

Question 15

What is the major solute determining osmotic pressure in the intracellular compartment?

Answer 15

Potassium

Question 16

What is the major solute determining osmotic pressure in the extracellular compartment?

Answer 16

Sodium

Question 17

What is the plasma oncotic pressure?

Answer 17

Pressure exerted by plasma proteins that cannot move across capillary walls

Question 18

What are the forces that determine the water distribution in the vascular compartment?

Answer 18

Oncotic pressure

Hydrostatic pressure

Question 19

What does the hydrostatic pressure do to water distribution?

Answer 19

Pushes water out of the vascular space

Question 20

What does the oncotic pressure do to water distribuyion?

Answer 20

Draws water into the vascular space

Question 21

What happens to the blood pressure in high plasma protein levels?

Answer 21

High blood pressure

Question 22

What is plasma oncotic pressure?

Answer 22

Pressure exerted by plasma proteins that cannot move across capillary walls

Question 23

What are examples of specialised structures maintains perfusion of vital organs?

Answer 23

Baroreceptors in the aortic arch and carotid sinus

Osmoreceptors in the hypothalamus

JG cells in the kidney

Question 24

Where are baroreceptors found?

Answer 24

In the aortic arch and carotid sinus

Question 25

Where are the osmoreceptors found?

Answer 25

In the hypothalamus

Question 26

Where are the JG cells found?

Answer 26

In the kidney

Question 27

What do baroreceptors react to?

Answer 27

Changes in vascular tone and cardiac output

Question 28

What do baroreceptors do to maintain homeostasis?

Answer 28

Cause volume changes

Question 29

What do osmoreceptors in the hypothalamus react to?

Answer 29

Thirst Vasopressin release

Question 30

What do osmoreceptors do to maintain homeostasis?

Answer 30

Causes osmolality changes

Question 31

What do JG cells in the kidney react to?

Answer 31

Salt and water reabsorption Renin-angiotensin system

Question 32

What do JG cells in the kidney do to maintain homeostasis?

Answer 32

Cause pressure changes

Question 33

What is the effective circulating volume?

Answer 33

Part of the extracellular volume in the arterial system perfusion the organs

Question 34

What is the average effective circulating volume of a 70 kg person?

Answer 34

700 ml

Question 35

What maintains the effective circulating volume?

Answer 35

Total body sodium Main extracellular solute holding water

Question 36

Control of sodium balance through renal excretion is key to control circulating volume TRUE or FALSE

Answer 36

TRUE

Question 37

Pathogenesis of heart failure

Answer 37

Reduced blood pressure induces fluid retention by the kidneys and expansion of the extracellular compartment Effective circulating volume is low Water is in the same volume but in the wrong place - should be in the vascular space, not extracellular compartment

Question 38

During heart failure, the decreased volume of water in the vascular space arises since the total body water is decreased TRUE or FALSE

Answer 38

FALSE The volume of water in the body is normal, just in the wrong compartment

Question 39

What is water immersion?

Answer 39

Bathing in cold water after exercise

Question 40

Why is water immersion beneficial?

Answer 40

Increases the pressure of the body and causes blood to go from the legs to the heart

Question 41

What does water volume do to circulating volume and urine output?

Answer 41

Increases them

Question 42

What are the benefits of water immersion?

Answer 42

Induces natriuresis by inducing vasopressin release Induces diuresis

Question 43

What is natriuresis?

Answer 43

Decrease in sodium concentration in the extracellular space More sodium lost in the urine

Question 44

Why is the induction of diuresis helpful?

Answer 44

Increases volume of water lost in conditions of water and salt retention

Question 45

What is diuresis?

Answer 45

Increased urine output