Module 2 Flashcards
What is an electrolyte?
A salt substance thats molecules’ dissociate into charged compounds when in water. They stabilise the membranes around the cell. Positive = Cation / Negative = anion.
Name 4 essential electrolytes?
- Sodium
- Potassium
- Magnesium
- Calcium
Name 4 essential electrolytes?
- Sodium
- Potassium
- Magnesium
- Calcium
Approximately how much of your body is made up of water?
50-60%
Describe the process of dissociation.
Molecules separate into other things such as atoms and ions and its typically reversable.
What is homeostasis?
The maintenance of a relatively constant internal environment.
What is blood composed of?
- Formed elements (approx. 45%): Platelets, white blood cells & red blood cells
- Plasma (approx. 55%): Water electrolytes, solutes, plasma proteins.
How is fluid loss directly impacted by a fever?
For every degree increased in fever an additional 200mls of fluid is lost per day.
What are the bodies main compartments of fluid?
Intracellular fluid (ICF): Found within the cells & accounts for 40% of total body weight. Extracellular fluid (ECF): Found outside the cells & accounts for 20% of total body weight. This includes intravascular (fluid inside the blood vessels) and interstitial (fluid the cells are bathing in). Blood plasma makes up 1/3 of ECF.
How do you calculate daily fluid requirements?
40mls/kg
What are the methods of fluid shifts?
- Diffusion (simple): solutes moving from an area of high concentration to an area of low concentration.
- Osmosis: Water moving to higher solute concentration to dilute the concentration.
- Active transport: Moving substances against the concentration gradient using ATP to move form low to high concentration (e.g. sodium potassium pump).
- Diffusion (facilitated): mediated transport mechanisms move large, water-soluble molecules (glucose) across the cell membrane through carrier molecules which are proteins that change shape to pass through the membrane and deliver the solute to the other side (e.g. insulin)
What is a concentration gradient?
The difference between the solute concentration inside and outside the cell.
What is an isotonic solution?
A solution in which there is no net movement of water molecules. Equal amount of solute and water as the patient (e.g. saline) will move where needed.
What is a hypotonic solution?
A solution which has a lower solute concentration than normal cells – very diluted, more water and not a lot of solutes. Useful for heatstroke or severe dehydration.
What is a hypertonic solution?
A solution which has a higher solute concentration than normal cells. Draws water out of cells – useful for oedema and brain trauma. E.g. 10% dextrose, 2-3% saline. Can be extremely irritating to veins, needs to piggyback on saline.
What is aldosterone?
A hormone secreted by the adrenal gland and stimulated the distal tubules to reabsorb sodium and water + secrete potassium. Triggered by a decrease in sodium levels or increase in potassium. Where sodium goes, water follows and increase blood pressure back up – negative feedback loop.
Where is Antidiuretic hormone (ADH) produced and what is it’s purpose? Additionally what conditions can trigger its secretion? **
Produced in the hypothalamus and secreted in the posterior pituitary to reduce the amount of urine production by making distal and collecting tubules more permeable to water.
Conditions that cause the secretion of ADH include Fever, dehydration, hypotension, renal failure.
Alcohol blocks the effectiveness of ADH
What is Atrial Natriuretic Factor (ANF)?
Secreted by the cells of the right atrium in response to increase pressure. ANF inhibits ADH secretion. Blood empties from vena cava into right atrium, once the blood volume returns to normal, stretch receptors of the myocardium secret ANF to tell the brain to stop aldosterone and ADH. Excretes water to lower the blood pressure.
What is Renin?
The glomerulus host juxtaglomerular cells (JG cells) that recognise low volumes into kidney and secret renin into the blood stream.
The secretion is then detected by the liver and the liver secretes angiotensinogen enzyme into the blood stream detected by the lungs which produces angiotensin 1 within the lungs converted to angiotensin 2 by ACE (angiotensin converting enzyme).
Angiotensin 2 (vasopressin) is the most powerful naturally occurring vasoconstrictor, resulting in increased BP. Additionally tells the adrenal glands to secrete aldosterone resulting in sodium and water reabsorption to boost BP.
What patient would use an ACE inhibitor?
A patient with hypertension to prevent high BP and vasoconstriction.
What is the role of ADH?
To regulate BP and boost volume.
What causes the release of aldosterone?
Low sodium and blood volume.
What is the role of ANF?
Inhibit the ADH and aldosterone to decrease BP and volume.
What are the 8 main electrolytes and their chemical symbols?
- Sodium Na+
- Potassium K+
- Calcium Ca2+
- Phosphate PO43-
- Magnesium Mg2+
- Chloride Cl-
- Bicarbonate HCO3-
- Hydrogen H
What is the difference between hyponatremia and hypernatremia?
Hyponatremia = excessive loss of Na+
Hypernatremia = excessive gain of Na+
What are mixed imbalances within the extracellular fluid?
- Hypotonic imbalance = more Na+ loss than water loss leading to hyponatraemia
- Hypertonic imbalance = more water loss than Na+ loss leading to hypernatremia
Where are electrolyte imbalances measured?
In the extracellular fluid.
What conditions cause hyponatraemia and what are the signs?
Causes:
- Severe haemorrhage
- Renal disease
- Prolonged GI upsets
- Excessive use of diuretics
Signs and Symptoms:
- Muscle weakness, twitching and fatigue.
- Swelling and oedema
- Cerebral oedema
- Rapid, thready pulse
- Cyanosis
- Seizure, coma, death
What conditions causes hypernatremia (too much Na+ not enough water) and the signs and symptoms?
Causes:
- Diabetes (not enough insulin to transport glucose into cells – the water then leaves the cells to dilute the glucose and gets excreted by the kidneys).
- GI upset or impaired thirst reflex/those who cant access water
- Sodium excess (rare) caused by hypertonic fluid administration or excessive aldosterone secretion.
Signs and Symptoms:
- Oliguria (reduced urine) or Anuria (no urine)
- Fever
- Neurological symptoms due to crenation of brain cells
- Dry, sticky mucous membranes
- Intense thirst
What is the importance of potassium (K+)?
- Positively charged ion in the intracellular fluid.
- Maintains normal functions of nerves, cardiac and skeletal muscles.
- Significant role in action potentials, enzyme action, glycogen storage and acid/base balance.
- Narrow homeostatic range of 3.5-5.5 mEq/L
- Can usually be altered through diet (bananas, beans, fish, potato) and kidneys
What is hypokalaemia and hyperkalaemia?
Hypo = excessive loss of K+ Hyper = Excessive gain of K+
What conditions causes hypokalaemia and the signs and symptoms?
Causes:
- Reduced dietary intake
- Poor potassium absorption
- Increased GI losses – vomiting and diahorrea
- Renal disease
Signs and Symptoms:
- Hypopolarized nerves requiring more stimulus and causes muscle weakness, craping, paralysis,
- shortness of breath.
- Flattened T wave, arrythmias and weak pulse
What is the most dangerous of all the electrolyte imbalances and why?
Hyperkalaemia: Abnormally high potassium in the blood. Hyperpolarised myocardial cells causing arrhythmia and cardiac arrest.
What are the causes of hyperkalaemia and signs and symptoms?
Causes: - Renal failure - Crush injuries resulting in cell death and therefore bursting cells and releasing the potassium within the cells. - Severe infections - Excessive use of potassium salts (used for high BP) Signs and Symptoms: - Peaked T wave on ECG - Respiratory distress - Irritability - Abdominal distension - Nausea and diarrhoea - Oliguria - Weakness and paralysis
What body functions is calcium essential for?
- Muscles contraction. Calcium triggers release of acetylcholine acetylcholine results in depolarisation and muscle contractions.
- Helps stabilise cell membrane permeability
- Hormone secretion: Parathyroid calcitonin
- Growth and ossification of bones
What are the causes of hypocalcaemia and signs and symptoms?
Causes: - Endocrine dysfunction – typically parathyroid gland. Thyroid secretes calcitonin to keep calcium in the bone, parathyroid pulls calcium from bones into the blood. - Renal insufficiency - Decreased Ca intake - Toxic shock syndrome Signs and Symptoms: - Hyperpolarised: paraesthesia, numbness & tingling - Tetany and muscle twitching - Cramps - Neural excitability - Heart failure - Convulsions
What causes hypercalcaemia and its signs and symptoms?
Causes: - Tumours/cancer: break down of bone realises calcium into blood stream - Overactive parathyroid - Thyroid dysfunction - Diuretic therapy - Excessive vitamin D Signs and Symptoms: - Stones: renal colic - Altered mental status (depression, hallucination, confusion) - Deep bone aches - Hypotonicity of muscles - Cardiac dysrhythmias - Coma, seizure, death
What happens when there is an excess of calcium in the body?
The body tries to buffer it by depositing it into various tissues causing the development of stones.
Impacts the: GI system, CNS, Renal System, Neuromuscular System and Cardiovascular System
What are the signs and symptoms of renal colic?
- Flank pain radiating down to bladder in waves
- Nausea & vomiting
- Blood in urine
What is the importance of phosphorous?
- P in ATP – main role in energy production, oxygen utilisation and acid/base balance.
- Phosphorus is proportional to calcium.
What are the causes of hypophosphatemia and what are the signs and symptoms?
Causes: - Increase renal excretion - Hyperparathyroidism - Respiratory alkalosis – movement of hydrogen ions - Hyperglycaemia - Alcohol abuse Signs and Symptoms: - Decreased levels of energy - Decreased levels of oxygen utilisation - Fatigue - Muscle weakness - Respiratory failure
What are the causes of hyperphosphatemia?
- Impaired renal excretion
- Phosphate intake (infants fed cows milk)
- Hypoparathyroidism
- Tissue destruction
A patient that is exhibiting anxiety, confusion, irritability, muscle cramps, seizures and tetany should be suspected of suffering from…
- Hypocalcaemia
Antidiuretic Hormone Acts on which of the following structures?
- Collecting ducts
- Descending loop of Henle
Vomiting, diarrhoea, diaphoresis, CCF and renal failure may lead to…
- Hyponatraemia
Which of the following conditions would not result in a metabolic acidosis?
- Chronic steroid use
During the decompensatory phase of shock a decrease in the amount of oxygen to the cells results in which acid base imbalance?
- Respiratory acidosis
Crystalloid solutions do not exert as much ___________________ pressure as colloid solutions resulting in faster equilibrium between the intravascular and extravascular spaces.
- Osmotic
During an airway obstruction and subsequent respiratory acidosis the body will attempt to compensate for the acid base imbalance by;
- Kidneys conserve bicarbonate and excrete hydrogen ions
The acid base imbalance respiratory _________________ is caused by an increased elimination of carbon dioxide through hyperventilation.
- Alkalosis
Which of the following electrolytes has a significant role in action potentials, glycogen storage and acid base balance?
- Potassium
