Chapter 25 Flashcards
List the factors that influence the percentage of body fluid
Age of an individual and relative amounts of adipose connective tissue and skeletal muscle tissue
Explain the significance of percentage of body fluid relative to fluid balance
The lower percentage of body fluid, the more likely to experience a fluid imbalance
Fluid within our cells; composed of potassium, magnesium cations, phosphate anion, negatively charged proteins
ICF
Includes both intracellular fluid and blood plasma; contains sodium, calcium cations, chloride, bicarbonate anions; contains more proteins compared to ICF
ECF
Explain how fluid moves between the major body fluid compartments
Responds to osmolarity changes through osmosis. Water will move into a compartment to balance out the water concentration. Moves from hypotonic to hypertonic.
Fluid intake is equal to fluid output and a normal distribution of water and solutes is present in the ICF and ECF
Fluid Balance
Addition of water to the body, includes preformed water and metabolic water
Fluid intake
water absorbed from food and drink taken into the GI tract
Preformed water
Includes water produced daily from aerobic cellular respiration and dehydration synthesis
Metabolic water
loss of water from the body
Fluid output
How is fluid lost from the body?
Fluid is lost through breathing, sweating, cutaneous transpiration (evaporation of water directly through the skin), defecation, urination
fluid output does not equal fluid intake or when fluid is distributed unevenly
Fluid imbalance
Isotonic fluid loss is greater than isotonic fluid gain
Volume depletion
What are some examples of volume depletion?
hemorrhage, severe burns, diarrhea, chronic vomiting, hyposecretion of aldosterone
Isotonic fluid gain is greater than isotonic fluid loss; results when fluid intake is normal, but decreased fluid loss through the kidneys
Volume excess
What are some examples of volume excess?
renal failure, aldosterone hypersecretion
Water loss is greater than the loss of solutes and blood plasma becomes hypertonic
Dehydration
What are some examples of dehydration?
profuse sweating, diabetes mellitus, intake of alcohol, hypo secretion of ADH, insufficient water intake, over exposure to the cold
Caused by blood plasma becoming hypotonic and fluid moving from blood plasma to ICF and then into the cells; cells will swell with water
Hypotonic hydration
What are some examples of hypotonic hydration?
ADH hypersecretion, and not drinking electrolytes after excessive sweating
Total body fluid is normal but distributed unequally; fluid accumulates in a particular location but not available to use elsewhere
Fluid sequestration
What are some examples of fluid sequestration?
edema hemorrhage, pericardial effusion, pleural effusion, ascites
Describe the stimuli that increase fluid intake
Decreased salivary secretions, increased blood osmolarity, decreased blood pressure
Describe the stimuli that decrease fluid intake
Increased salivary secretions, distension of the stomach, decreased blood osmolarity, increase in blood pressure
Explain the stimulus for angiotensinogen II formation
Low blood pressure or stimulation by the sympathetic division
Explain the four primary effects of angiotensin II
Stimulates vasoconstriction of systemic blood vessels, decrease urine output, stimulates the thirst center in hypothalamus, stimulates hypothalamus and posterior pituitary to release ADH and aldosterone
Explain the stimulus for the release of ADH from the posterior pituitary
Released in response to nerve signals from the hypothalamus; low blood pressure, low blood volume, increase in blood osmolarity
What are the 3 actions of ADH?
Stimulates the thirst center, increases water absorption of the kidneys by increasing the number of aquaporins in the tubular membrane, vasoconstriction of systemic blood vessels that increase peripheral resistance
Explain the stimulus for the release of aldosterone
Response to angiotensin II, decreased blood plasma sodium levels, increased blood plasma potassium levels
Describe the changes that occur in response to the binding of aldosterone by the kidney cells
Bind to principle cells in the kidneys that cause an increased reabsorption and retention of sodium and water and increased secretion of potassium by increasing the number of sodium potassium channels
Describe the stimulus for the release of atrial natriuretic peptide
Increased stretch of hear chambers from an increased blood volume and blood pressure
Decreases blood volume and blood pressure by binding onto…
- Blood vessels: dilates systemic blood vessels, decreasing total peripheral resistance
- Kidneys: causes vasodilation of afferent arterioles in the kidneys and relaxation of mesangial cells; increase glomerular filtration rate
ANP
