Lesson 2B Flashcards
What does the physiology of blood describe
The areas of vascular control regarding blood flow, the pumps that occur in circulation and how they affect venous dynamics and the types of energy that are present in the vascular system
What are the 5 pumps in the circulation
The heart The aortic pump The muscular venous pump The respiratory pump Gravity
WHAT IS THE PRINCIPAL FORCE BEHIND BLOOD FLOW
Pumping of the heart
WHAT IS THE PRIMARY PUMP
The heart
Does the venous system still get assistance from the pump of the heart?
Yes, there is a residual forse secondary to the cardiac contraction
a partial ______ exists in the right atrium during the right ventricular filling phase . This does what?
Vaccum
This serves to suck venous blood flow from the IVC into the right atrium
the aorta acts as a ________ pump
Subsidiary
Much of the energy resulting from the cardiac contraction must be _____. This is because
Stored
Because of the hold up of blood flow that occurs in the capillary bed
The aorta and other elastic arteries near the heart serve to store excess contraction energy by
Stretching with each systole
The stretching of the aorta during peak systole allows aorta to act as a
Reservoir, storing much of the blood expelled by the heart
What happens during systole to the energy stored in the arterial walls
It dissipates the large volume of blood stored in the aorta by forcing blood forward in the aorta
We see increase in blood pressure whe n
Arteries can no longer stretch due to atherosclerosis, age or diabetes
The pump of the venous system is
The muscular venous pump
What is the pressure in the venules
16mm/Hg
What is the pressure in the great veins near the heart
4mm/Hg
The pressure gradient in the venous system is enough to
Ensure the venous return at rest in a supine patient
What does the muscular pump do?
It squeezes the veins to propel blood
Needed in a erect position
Where is the muscular venous pump most effective
In the lower legs with the powerful thigh and calf muscles can compress the soleous and gastrocnemius sinusoids
Where are the one way venous valves most common
Lower extremities/ further away from the heart
Where is respiratory pump useful
Assisting venous return to the heart
Variation in thoracic and abdominal pressure occur with ____ motion
Diaphragm
Pressure in the thorax is always lower than
Atmospheric pressure
The suction action in the thorax tends to pull blood
Towards the chest
Inspiration causes an _____ in abdominal pressure and _______ thoracic pressure
Increase and decrease
Inspiration causes reduced flow in _____ and increase venouc flow in _______
The abdomen
The chest
Venous flow in the upper extremities is ______ to flow in the lower extremities during each phase of respiration
Opposite
In the upper extremities where does gravity aid in venous return
From the head and neck and any body part placed higher than the heart
