Cardiovascular Physiology III Flashcards
What is the primary function of the cardiovascular system?
The primary function is to deliver materials throughout the body to maintain metabolic needs.
Why is it important for physical therapists to understand blood?
Understanding blood is crucial for assessing and managing conditions related to circulation, hemorrhage, and overall patient health.
What materials are exchanged between the vasculature and tissues?
Gases, solutes, and fluids.
How is total body water divided?
Into three compartments: intracellular fluid, interstitial fluid, and plasma.
What is the role of the cell membrane in fluid compartments?
It separates intracellular fluid from extracellular fluid.
What are the two compartments of extracellular fluid?
Interstitial fluid (in tissues) and plasma (in blood).
What is the typical percentage of total body weight that total body water represents?
About 50% to 70%.
How does the ion composition differ between intracellular and extracellular fluid?
Intracellular fluid has high potassium and low sodium; extracellular fluid has high sodium and low potassium.
What is the significance of ion composition in fluid compartments?
It is important for maintaining resting membrane potentials and action potentials in tissues.
What determines the rate of fluid exchange in the microcirculation?
The permeability of the capillary wall and the pressure gradient between the capillary and interstitium.
What are Starling forces?
Forces that describe the pressure gradients (hydrostatic and oncotic) affecting fluid movement across capillary walls.
What is hydrostatic pressure in the context of capillaries?
The mechanical pressure of fluid against the capillary wall, driving fluid out.
What is oncotic pressure?
The osmotic pressure generated by proteins in the plasma that tends to pull fluid into the capillary.
How does fluid movement occur at the arterial end of a capillary?
There is a net filtration of fluid out due to higher hydrostatic pressure compared to oncotic pressure.
What happens at the venous end of a capillary regarding fluid exchange?
There is a net absorption of fluid into the capillary due to higher oncotic pressure compared to hydrostatic pressure.
What happens to the fluid not reabsorbed at the venous end of the capillary?
It is picked up by the lymphatic system to prevent tissue swelling.
How much fluid is typically filtered out of a capillary at the arterial end, and how much is reabsorbed at the venous end?
About 3 milliliters filtered out and 2.7 milliliters reabsorbed.
What is the role of the lymphatic system in fluid exchange?
It collects excess fluid not reabsorbed and returns it to the vascular system.
What is edema?
Edema is the accumulation of fluid in the tissues due to an imbalance between the filtration of fluid out of the vasculature and the reabsorption of fluid back into it.
What are the main mechanisms that can lead to the formation of edema?
- Disruption of the lymphatic system
- Changes in Starling forces (increased hydrostatic pressure or decreased oncotic pressure)
- Acute changes in capillary permeability
What is lymphedema?
Lymphedema is edema resulting from the disruption of the lymphatic system, leading to fluid accumulation in tissues.
What is the difference between primary and secondary lymphedema?
Primary lymphedema is due to congenital abnormalities in the lymphatic system, while secondary lymphedema is more common and often occurs after surgeries, such as lymph node resection due to cancer.
How can increased hydrostatic pressure lead to edema?
Increased hydrostatic pressure in capillaries can occur due to venous blockages (like DVT), leading to more fluid being filtered out into the tissues.
What role does oncotic pressure play in fluid exchange?
Oncotic pressure, primarily due to plasma proteins like albumin, pulls fluid into the vasculature. A decrease in oncotic pressure (e.g., due to hypoalbuminemia) results in less fluid reabsorption and contributes to edema.
