Fluid Balance Flashcards
1 - Name the main hormones involved in water and electrolyte balance and describe their action to maintain homeostasis. 2 - Explain the causes and consequences of hypovolemia and hypervolemia. 3 - Describe how electrolyte concentrations are regulated. (29 cards)
How do ions form?
When electrolytes dissolve and dissociate
4 Functions of electrolytes
Control osmosis of water between body fluid
compartments
Help maintain the acid-base balance
Carry electrical current
Serve as cofactors
Name 6 electrolytes
Sodium
Potassium
Calcium
Magnesium
Chloride
Phosphate
Causes of fluid and electrolyte imbalances
Patients with illness
Directly cause by illness/disease - Burns, heart failure, renal disease, liver disease, diabetes insipidus
Laxative abuse
Marathon runners
IV fluid replacement
Diuretics
Hormones involved with fluid/electrolyte balance
Antidiuretic hormone (ADH)
Aldosterone
- Secreted by angiotensin II
Atrial natriuretic peptide (ANP)
What cells secrete renin?
Juxtaglomerular cells of the kidneys
What secreted angiotensinogen?
The liver
What secretes angiotensin-converting enzyme (ACE)?
The lungs
What secretes aldosterone?
Adrenal cortex
Steps of renin-angiotensin aldosterone system
A decrease in blood volume and pressure
Kidneys secrete renin, the liver secretes angiotensinogen
Renin converts angiotensinogen into angiotensin I
Angiotensin I converted to angiotensin II by an angiotensin-converting enzyme found on the surface of the lungs
Angiotensin II is a vasoconstrictor, causing blood vessels to narrow, and increasing blood pressure
Angiotensin II also stimulates aldosterone secretion from the adrenal cortex
Aldosterone causes renal tubules to increase the reabsorption of sodium and water into the blood and causing excretion of potassium, causing increased blood volume which increases blood pressure
How does NaCl increase blood volume/pressure?
Increased intake of NaCl increases plasma concentrations of Na+ & Cl-
Increases osmosis of water from ICF to interstitial fluid and plasma
Blood volume increased
Term for high and low sodium levels
Hypernatremia
Hyponatremia
Term for high and low potassium levels
Hyperkalemia
Hypokalemia
Term for high and low calcium levels
Hypercalcemia
Hypocalcemia
Term for high and low magnesium levels
Hypermagnesemia
Hypomagnesemia
Term for high and low phosphate levels
Hyperphosphatemia
Hypophosphatemia
Term for high and low chloride levels
Hyperchloremia
Hypochloremia
What is hypovolemia
Low extracellular fluid (ECF) volume
Causes of hypovolemia
GI sodium loss - vomiting, diarrohea
Skin sodium loss - sweating, burns
Renal sodium loss - diuretics, renal disease
Haemorrage
Definition of dehydration
Loss of total body water
What % of body weight reduction is mild-moderate dehydration? and symptoms
1-3% body weight reduction due to fluid loss
Thirst
Headache
Tirdness
Strong smelling urine
What % of body weight reduction is moderate dehydration? and symptoms
3-5% body weight reduction due to fluid loss
Loss of strength and stamina
What % of body weight reduction is severe dehydration? and symptoms
> 5% body weight reduction due to fluid loss
Severe thirst
Dry wrinkled skin
Inability to urinate
Low blood pressure
Weak pulse
Rapid heartbeat
What % of body weight reduction is complete dehydration?
> 10% body weight reduction due to fluid loss
Can lead to death if not treated immediateley
