Sodium and Water balance

Question 1

What is the main hormone involved in the control of the bodies water balance?

Answer 1

ADH

Anti-Diuretic Hormone

Question 2

Where is ADH released from?

Answer 2

The posterior pituitary

Question 3

What is another word for ADH?

Answer 3

AVP

Question 4

If there is a high concentration of ADH what happens to the urine?

Answer 4

Small amount of very concentrated urine

Question 5

If there is a low concentration of ADH what happens to the urine?

Answer 5

Large amount of very dilute urine

Question 6

How is the concentration of urine measured?

Answer 6

Urine osmolality the more concentrate the higher the osmolarity

Question 7

How is water reabsorbed?

Answer 7

Via a countercurrent between the vascularised medulla and the collecting duct.

Question 8

How is the medullas high osmolarity maintained?

Answer 8

Na+ and Cl- is actively transported out of the loop of henle producing a concentration gradient.

Question 9

What is the importance of this concentration gradient?

Answer 9

Water moves via osmosis from an area of low osmolarity to an area of high, this gradient creates the conditions needed for water to leave the collecting ducts.

Question 10

Are the walls of the collecting duct permeable?

Answer 10

No, water can only pass through with the aid of Aquaporins.

Question 11

What are aquaporins?

Answer 11

Specific ion channels which are inserted into the wall of the collecting duct and allow water to leave via osmosis.

Question 12

What is the function of ADH?

Answer 12

Triggers the insertion of aquaporins into the collecting duct allowing more water to leave the collecting duct and enter the blood via osmosis.

Question 13

Once inserted do the aquaporins stay in the wall of the collecting duct?

Answer 13

No they have a very short lifespan, must be a continuous stimuli resulting in addition of more aquaporins.

Question 14

How is the sodium balance controlled?

Answer 14

Steroids

Question 15

What is the main mineralocorticoid that controls Na+?

Answer 15

Aldosterone

Question 16

What do steroids do to the sodium balance?

Answer 16

They increase reabsorption of Na+ in exchange for K+

Question 17

Where about does the Na+ reabsorption take place?

Answer 17

Within the distal tubules

Question 18

As a result of increased Na+ reabsorption what else happens?

Answer 18

Water follows via osmosis

Question 19

What is hypernatraemia?

Answer 19

High Na+ concentration

Question 20

What is hyponatraemia?

Answer 20

Low Na+ concentration

Question 21

What are the two reasons for being hypernatraemic?

Answer 21

High Na+ levels

Low water volume

Question 22

What are the two reasons for being hyponaetremic?

Answer 22

Low Na+ levels

High water volume

Question 23

Where is sodium most concentrated within the bodies fluid?

Answer 23

Within the extracellular fluid

140mmol/L

Question 24

Where is sodium most diluted within the bodies fluid?

Answer 24

Within the intracellular fluid

4mmol/L

Question 25

What compartment makes up most of the bodies fluid?

Answer 25

Intracellular around 66%

Question 26

What does intracellular fluid comprise off?

Answer 26

Fluid contained within the bodies cells

Question 27

What makes up the extracellular fluid?

Answer 27

Plasma | Interstitial fluid

Question 28

What happens between the compartments if water is lost?

Answer 28

Water is free to move between all compartments, as a results water loss is shared equally between compartments.

Question 29

What happens between the compartments if Na+ is lost?

Answer 29

Na+ is only lost from the extracellular fluid

Question 30

Why is sodium only lost from the extracellular fluid?

Answer 30

As it is confined to the ECF by the Na+/K+ ATPase

Question 31

Why is fluid also lost from the ECF if Na+ is lost?

Answer 31

As water follows via osmosis

Question 32

Loss of Na+ is more impactful on the body that simply loss of water?

Answer 32

True, BEWARE can look the same on lab results

Question 33

List some clinical symptoms that manifest as a result of a high Na+ concentration

Answer 33

Hypertensive Raised JVP Oedema Coughing

Question 34

List some clinical symptoms that manifest as a result of a low Na+ concentration

Answer 34

Hypotensive Dry mucous membranes Decreased skin turgor Concentrated urine

Question 35

What is the most common issue surrounding Sodium water balance?

Answer 35

A low Na+ concentration due to a high H2O volume

Question 36

What are some causes of a high H2O volume leading to low Na+ concentration?

Answer 36

Compulsive drinking | Reduced H2O excretion (SIADH)

Question 37

What is the treatment for Low Na+ due to high H2O volume?

Answer 37

Fluid restriction

Question 38

How likely is a low Na+ concentration due to increased Na+ excretion?

Answer 38

Very Rare

Question 39

What are some causes of a low Na+ concentration due to increased Na+ excretion?

Answer 39

D+V Excessive sweating Severe burns Low sodium intake - V.Rare

Question 40

What is the treatment for a low Na+ concentration due to increased Na+ excretion?

Answer 40

Give sodium

Question 41

List some causes of an increased Na+ level

Answer 41

Near drowning Some IV medication Increased Na+ intake Malicious - purposely giving to much

Question 42

What is the treatment for an increased Na+ concentration?

Answer 42

Remove Na+ | Loop diuretics

Question 43

List some causes of an increased Na+ concentration due low H2O volume

Answer 43

Increased water loss | Reduced rate intake

Question 44

Give a common cause of increased water loss?

Answer 44

Diabetes mellitus

Question 45

What is the treatment for too little water resulting in a high Na+ concentration?

Answer 45

IV dextrose 5%

Question 46

What are the types of IV fluid?

Answer 46

Blood and plasma 0.9% Saline 5% Dextrose

Question 47

What is blood and plasma used for?

Answer 47

Simple plasma volume replacement

Question 48

What is 0.9% saline used for?

Answer 48

Extracellular volume increased | Resuscitation fluid

Question 49

What is 5% dextrose used for?

Answer 49

'Too little water' | Increases all volumes within all body compartments

Question 50

What is SIADH

Answer 50

Syndrome of Inappropriate ADH

Question 51

What does SIADH mean?

Answer 51

ADH is inappropriately released for the bodies osmotic status

Question 52

What are the two stimuli for ADH release?

Answer 52

Osmotic (healthy) | Non-osmotic ( Disease)

Question 53

What are common non osmotic stimuli for ADH release?

Answer 53

Hypovalaemia Hypotension Pain Vomiting

Question 54

What is the pathology behind oedema

Answer 54

Blood volume loss leads to... Increased ADH and aldosterone release Increased water retention However most is retained as interstitial fluid

Question 55

What are some causes of oedema?

Answer 55

Heart failure | Hypoalbuminaemia

Question 56

Within the lab what causes Pseudohyponatraemia

Answer 56

An increased concentration of lipids and proteins causes machines to record Na+ Conc as low.