Week 3 topic 2 Flashcards
(32 cards)
Define edema?
Edema is the presence of excess fluid in the body tissues.
Where does edema mainly occur?
Edema mainly occurs in the extracellular fluid component.
What is intracellular edema?
Intracellular edema is the accumulation of excess fluid within the cells.
What are 3 causes of intracellular edema?
-hyponatremia
-depression of metabolic systems of tissues
-lack of adequate nutrition to the cells from reduced blood flow
What is the role of Na+/K+ ATPase in intracellular edema?
When blood flow is low, Na+/K+ ATPase is depressed, leading to excess intracellular Na+ resulting in osmosis of water into the cells too
What are 2 causes of extracellular edema?
- Abnormal leakage of fluid from the plasma to the interstitial spaces across the capillaries
- Failure of the lymphatics to return fluid from the interstitial back into the blood
Mostly caused by excess capillary filtration
What are the factors that increase capillary filtration?
- ↑ Pc (capillary hydrostatic pressure)
- ↓ πc (plasma colloid osmotic pressure)
What is lymphedema?
Lymphedema is the failure of lymph vessels to return fluid and protein back to the blood.
What can cause lymphedema?
Causes include block or loss of lymph vessels and infections of lymph nodes.
What are common causes of extracellular edema?
- ↑ Capillary hydrostatic pressure (Pc)
- Decreased plasma proteins πc
- Increased capillary permeability Ki
How does heart failure lead to edema?
Heart failure occurs when the heart fails to pump blood normally from the veins into the arteries.
- Increased venous pressure - increase capillary filtration
- decreased CO
- Blood flow to the kidneys is reduced which activates RAAS leading to water and salt retention
What happens in advanced heart failure regarding edema?
Increased secretion of ADH stimulates water reabsorption, leading to hyponatremia and edema.
What is the effect of decreased kidney excretion on edema?
It leads to sodium and water retention, causing widespread increases in interstitial fluid volume.
How does decreased plasma proteins cause edema?
It decreases plasma colloid osmotic pressure, leading to increased capillary filtration.
What is the significance of interstitial fluid hydrostatic pressure?
It is slightly less than atmospheric pressure, which helps hold tissues together.
What is pitting edema?
Pitting edema is characterized by free fluid that leaves an indent when pressed.
What is non-pitting edema?
Non-pitting edema occurs when tissue cells swell instead of the interstitium.
What is the lymphatic system’s role in edema prevention?
It returns fluid and protein filtered from capillaries to circulation, preventing edema.
What are potential spaces in the body?
Potential spaces include pleural, pericardial, peritoneal, and synovial cavities.
What is effusion?
Effusion is the accumulation of fluid (edema) in the potential spaces.
What distinguishes inflammatory edema from non-inflammatory edema?
Inflammatory edema contains protein-rich exudate, while non-inflammatory edema contains protein-poor transudates.
What factors increase Pc?
- arteriolar dilation
- increased venous pressure or venoconstriction
- Renal retention of sodium and water (increased volume)
What factors decrease πc?
- Loss of plasma protein from denuded skin areas (burns) and kidneys (nephrotic syndrome)
- Reduced synthesis of plasma proteins (liver)
- protein malnutrtition
What factors increase capillary permeability?
- Burns
- inflammation
