Electrolyte Disorders

Question 1

Function of water

Answer 1

• Solvent for all body processes
• Transport nutrients to cells
• Regulates cell volume
• Removes waste products -> urine
• Body coolant -> sweating

Question 2

Water balance in healthy individuals

Answer 2

Water intake from things such as fluid intake,moist food and metabolic processes=2500ml

Water loss in things such as urine,faeces,insensible loss(breath,perspiration)=2500ml

Question 3

Functions of electrolytes

Answer 3

Maintenance of body pH

Cofactors in enzyme reactions

Oxidation-reduction reactions

Correct functioning of muscles and nerves

Water balance by maintaining osmotic pressure

Question 4

Osmolality

Answer 4

-measure of solute in a solution
-indicator of fluid balance
-285 – 295 mOsm/kg in both ECF and ICF
-Water moves from a region of low osmolality to a region of high osmolality

Question 5

Ecf

Answer 5

-Extra cellular fluid divided into 2 sub categories:intertidal fluid,blood plasma
-na2+ most important ion

Question 6

Icf

Answer 6

-intracellualr fluid
-k+ Most important ion

Question 7

How is fluid distribution regulated

Answer 7

-through osmosis and maintaining electrolyte balance preventing cells from bursting
-maintenance of electrical neutrality due to the ionic gradient (sodium potassium pump)

Question 8

Distribution of water in the body compartmented

Answer 8

1)1/3 in extra cellular fluid
-within that there is water movement through glomerular filtration,trans cellular fluid and secretions
2) 2/3 in the intracellualr fluid

Question 9

Loss of water from ecf

Answer 9

-during dehydration water is lost from ecf increasing ecf osmolality
-ions can’t be exchanged to maintain the balance so water moved from the icf
-normal osmolality is 290

Question 10

What will be the immediate effect when there is a rise in plasma osmolality due to a rise in blood glucose as in diabetes mellitus?

Answer 10

Cells dehydrate

Question 11

Regulation of blood volume

Answer 11

Water deprivation results in rising plasma osmolality causing osmoreceptors in the brain to detect Low water volume and either to :
A)increase thirst which will increase liquid consumption and therefore increase total body volume resulting in correct osmolality
B)release adh which will cause water retention and reduced urinalysis output and result in correct osmolality

Question 12

Adh

Answer 12

Vasopressin that helps blood vessels construct and helps the kidneys to control the amount of water and salt in the body causing eater retention

Question 13

Macula dense cells

Answer 13

Salt sensors that generate signals that control vital kidney functions including renal blood floe,glomerular filtration and renin release

Question 14

Role of the affront arteriole in the juxtaglomerular apparatus

Answer 14

Detect low blood pressure which will results in release of renin

Question 15

Granular cells

Answer 15

Control blood volume
Synthesise store and secrete the enzyme renin

Question 16

Reninangiotensin aldosterone system

Answer 16

-low blood pressure sensed by afferent arteriole
-granular cells in the jga complex secrete renin which then joins with a protein called angiotensionogen produced in the liver
-Angiotensin 1 (10aa) is then converted using ace(angiotensin converting enzyme) to angiotensin 2 (8aa)
-angiotensin 2 then either a)causes increased blood vessel tone which increases blood pressure inhibiting jga cells from secreting further renin
B)causes the release of adh from posterior pituitary gland increasing blood volume and blood pressure therefore inhibiting jga cells from secreting further renin or c)binds to the adrenal cortex and leads to the production of aldosterone ,this results in incartesed na+ reabsorption

Question 17

Clinical features of dehydration

Answer 17

-increased pulse
-decreased blood pressure
-decreased skin turgor
-soft/sunken eyeballs
-dry mucous membranes
-decreased ursine output
-creased consciousness

Question 18

Clinical features of over hydration

Answer 18

-normal pulse
-Normal or increased blood pressure
-increased skin turgor
-Normal eyeballs
-Normal mucous membranes
-Normal or decreased urine output
-decreased consciousness

Question 19

Conns syndrome

Answer 19

-Also primary hyperaldosteronism
-Adrenal adenoma Adrenal hyperplasia
-Aldosterone ↑
-Renin ↓
-Hypokalaemia

Question 20

Addison’s disease

Answer 20

-Also primary hyperaldosteronism
-Adrenal adenoma Adrenal hyperplasia
-Aldosterone ↑
-Renin ↓
-Hypokalaemia
-hyponatreamia

Question 21

Cushing disease

Answer 21

-Pituitary tumour ACTH ↑
-Cortisol ↑
-Hypernatraemia
-hypokalemia

Question 22

Clinical symptoms of hyponatreamia

Answer 22

• Mild confusion
• Fatigue
• Muscle cramps
• Brain oedema, seizures • Respiratory arrest
• Death

Question 23

Sodium levels in plasma

Answer 23

Average adult man: 3700mmol Sodium
Normal plasma sodium concentration (135 –145 mmol/L)
• Renal regulation to maintain sodium balance
Below reference range: hyponatraemia Above reference range: hypernatraemia
Hypo-and hypernatraemia are primarily problems of water, rather than Na+ balance
Parameter for hydration status:
• Concentration of urea in plasma
• Changes in body weight

Question 24

Clinical symptoms of hypernatremia

Answer 24

• Thirst
• Drymucousmembranes • Decreasedtissueturgor • Disorientation,confusion • Muscleweakness
• Convulsions
• Coma
• Severbrainshrinkage

Question 25

Types of hyponatreamia

Answer 25

Hypolovemic
Euvolemic
Hypervolemic

Question 26

Hypovolemic hyponatreamia

Answer 26

-Na2+ and water deficit
-Caused by gastrointestinal loss,diuretics,burns
-Treatment:isotonic saline

Question 27

Euvolemin hyponatreamia

Answer 27

-Water excess,normal body na2+
-caused by siadh,water overload,post surgery,hypothyroidism
-treatment:water restriction

Question 28

Hypervolemic hyponatreamia

Answer 28

-na 2+and water excess
-caused by:congestive heart failure,liver ,renal failure
-na and water restriction

Question 29

Hypernatreamia

Answer 29

Predominantly Deficit of water relative to sodium rather than excess of sodium
• Diabetes Insipidus
• Gastrointestinal loss
• Accidental or deliberate salt ingestion
• Inadequate water intake