Chapter 6 Flashcards
What is hydrostatic pressure?
The pressure within the vascular system because of the weight of a column of blood.
What is transmural pressure?
The pressure exerted on the walls of a vessel
What is edema?
Excessive accumulation of fluid in cells, tissue or cavities of the body
What is venous valvular insufficiency?
Abnormal retrograde flow in veins.
Approximately how much blood does the venous portion of the vascular system hold?
66% to 67% of the total volume of blood.
A circular shape in the veins ____________ the resistance.
decrease
In a 6-foot-tall individual in a standing position, hydrostatic pressure will add approximately how much to the measured pressure at the ankle?
100 mm Hg
What is the minimum pressure inside a vein needed to prevent it from collapsing?
5 mm Hg
What is the pressure gradient across the capillary bed in an uplifted arm owing to the change in hydrostatic pressure?
40 mm Hg
Once a vein has acquired a circular shape, how can the volume of blood in the vessel only change with?
A large increase in pressure
When an individual moves from a supine to a standing position, which of the following pressures specific to the venous system increases?
transmural pressure
How does the action of the calf muscle pump, under normal circumstances, offset fluid loss in interstitial tissue?
It helps decrease the venous pressure
With total or partial thrombosis of proximal major veins of the lower extremities, what action is not unusual for the flow profile from distal nonoccluded veins to do?
To change from phasic to continous
Which of the following is essential to ensure the proper functioning of the calf muscle pump under normal conditions?
properly functioning valves
How much pressure can be generated by the contraction of an efficient calf muscle pump under normal conditions?
At least 200 mm Hg
How are primary varicose veins distinguished from secondary varicose veins?
Develop in the absence of deep venous thrombosis
What is a fibrin cuff?
Fibrin accumulation around the capillaries
What caused venous distension during pregnancy?
An increased compliance of the veins
What does a continuous venous flow profile from veins of the lower extremities mean?
The flow is no longer responsive to pressure changes from respiration
What are the major physiology components governing blood flow in the venous system?
Venous capacitance, transmural pressure and hydrostatic pressure
Veins are known as the capacitance vessels of the body because they act as a ________________.
Reservoir
The cross-sectional area of a distended vein could be ________________ larger than the area of the corresponding artery.
3 to 4 times
The fact that veins are usually paired in many area of the body increases the ________________ of the vascular system.
capacitance
A major force affecting the venous system is ________________.
hydrostatic pressure
