Week 4 - Lecture 1a - Altered Electrolyte Balance

Question 1

cells function depends on what

Answer 1

continuous supply of nutrients
removal of waste products
physical and chemical homeostasis of surrounding fluids

Question 2

Water

Answer 2

universal solvent

Question 3

solutes

Answer 3

what is dissolved in water

- classified as non electrolytes and electrolytes

Question 4

non electrolytes

Answer 4

most organic

• do not dissolve in water: glucose, lipids, creatinine, and urea
• no charged particles created

Question 5

electrolytes

Answer 5

dissociate into ions in water
e.g. inorganic salts, all acids and bases, some proteins
ions conduct electrical current

electrolytes have a greater osmotic power than non-electrolytes
greatest ability to cause fluid shifts

Question 6

electrolyte concentration

Answer 6

expressed in miliequivalents per litre (mEq/L)

mEq/L = ion concentration *mg/L) / atomic weight of ion (mg/mmol) x

Question 7

extracellular and intracellular fluids

Answer 7

each fluid compartment has distinctive pattern of elctrolyte

Question 8

extracellular fluid

Answer 8

major cation : Na+

major anion : Cl-

Question 9

intracellular fluid

Answer 9

Low Na+ and Cl-
Major cation : K+
Major anion : HPO 4^2-

Question 10

electrolyte balance

Answer 10

electrolytes are salts, acids, bases, some proteins
electrolyte balance usually refers only to salt balance

1. salts control fluid movements
2. provide minerals for excitability
3. secretory activity
4. membrane permeability

salts enter body by ingestion and metabolism
lost via perspiration, feces, urine, vomiting

Question 11

altered sodium balance

Answer 11

most abundant cation in the extracellular fluid

only cation exerting significant osmotic pressure

• controls extracellular fluid volume and water distribution
• changes in Na+ levels
  • affects plasma volume
  • blood pressure
  • extracellular and intracellular fluid volumes

Question 12

Sodium balance altered

Answer 12

Na+ leaks into cells
- pumped out against electrochemical gradient
Na+ moves back and forth between the extracellular fluid and body secretions (eg. digestive secretions)

Concentration of Na+

• determines osmolality of extracellular fluid
  
  • influences excitability of neurons and muscles
• Remains stable due to water shifts out of or into intracellular fluid

Content of Na+
- total body content of Na+ determines extracellular fluid volume and therefore blood pressure

Question 13

Hyponatraemia (low sodium)

Answer 13

serum sodium <135mEq/L
cause 
- vomiting 
- diarrhoea 
-sweating 

manifestations are related to cellular swelling

• muscle twitching, weakness
• hypotension
• tachycardia
• oliguria
• anuria (no urine output)
• altered neuronal function (nausea, vomiting, lethargy)

Question 14

Hypernatraemia (high sodium)

Answer 14

serum sodium > 145mEq/L

cause

• related to sodium gain or water loss
• excessive dietary intake
• water movement from the intracellular to the extracellular compartment
• intracellular dehydration

Question 15

manifestations of hypernatraemia

Answer 15

intracellular dehydration 
agitation, restlessness, decreased level of consciousness 
hypertension 
tachycardia
edema
weight gain

Question 16

Importance of potassium

Answer 16

extracellular fluid has higher concentration of Na+ than intracellular fluid
- balanced chiefly by chloride ions (Cl-)

Intracellular fluid has higher concentrations of K+ than the extracellular
- balanced negatively charged proteins

K+ plays most important role in membrane potential

Question 17

What is hypokalaemia

Answer 17

low potassium(<3.5 mEq/L)

Question 18

Manifestations of hypokalaemia (low potassium)

Answer 18

dizziness, muscle weakness, and leg cramps

cardiac arrhythmia, hypotension, thirst, nausea, anorexia, poorly concentrated urine, polyuria

Question 19

What is hyperkalaemia

Answer 19

high potassium (>5mq/L)

Question 20

manifestations of hyperkalaemia

Answer 20

cardiac arrest

abdominal cramping, flaccid paralysis

Question 21

what is hypochloremia

Answer 21

low chlorine (<98mEq/L)

Question 22

manifestations of hypochloremia (low chlorine)

Answer 22

increased muscle tone, twitching, weakness, and tetany
shallow, depressed breathing
respiratory arrest
mental confusion

Question 23

what is hyperchloremia

Answer 23

high chlorine (>108mEq/L)

Question 24

manifestations of high chlorine (hyperchloremia

Answer 24

hyperchloremic metabolic acidosis rapid breathing
deep, rapid breathing
weakness, headache, and diminished cognitive activity
cardiac arrest

Question 25

What is hypocalcemia

Answer 25

low levels of calcium (<8.5mg/dL)

Question 26

manifestations of low calcium (hypocalcemia

Answer 26

enhanced neuromuscular irritability 
anxiety, irritability and seizure
muscle twitching, cramps, spasms, tetany and laryngospasm 
hypotension 
cardiac arrhythmia

Question 27

What is hypercalcemia )

Answer 27

elevated calcium levels (>10.5mg/dL)

Question 28

Manifestations of elevated calcium levels (hypercalcemia)

Answer 28

decreased neuromuscular irritability
confusion, fatigue, headache, and irritability
constipation, nausea and vomiting
cardiac arrhythmia

Question 29

What is hypomagnesemia

Answer 29

low magnesium levels (<1.5mEq/L)

Question 30

manifestations of low magnesium levels (hypomagnesemia)

Answer 30

tetany, muscle cramping, seizures, cardiac arrhythmia, hypotension

Question 31

What is hypermagnesemia

Answer 31

elevated levels of magnesium (>2.5mEe/L)

Question 32

Manifestations of elevated magnesium (hypermagnesemia

Answer 32

reduced neuromuscular transmission and excitability
flaccid paralysis, diminished reflexes, muscle weakness
hypotension, respiratory depression

Question 33

What is hypophosphatemia

Answer 33

low levels of phosphate (<2.5mg/dL)

Question 34

manifestations of low phosphate (hypophosphatemia

Answer 34

muscle weakness, tremor, and paresthesia
weight loss
bone deformity

Question 35

What is hyperphosphatemia

Answer 35

elevated levels of phosphate >4.5mg/dL

Question 36

manifestations of hyperphosphatemia

Answer 36

no associated manifestations