Week 2 - Lesson 2 (Part 1) Flashcards
What are the different types of pumps involved in the arterial system that has to do with circulation? (5)
- The heart
- The aortic pump
- The muscular venous pump
- The respiratory pump
- Gravity
What is the principle force behind blood flow?
The pumping of the heart
What is the primary pump in circulation?
The heart
What system is the heart mostly apart of?
The arterial system
- but does play a role in the venous system too
What does the secondary residual force in cardiac contraction help with?
It helps with forcing venous blood flow back towards the heart
What exists in the right atrium during the right ventricular filling phase?
A partial vacuum
What does the partial vacuum do?
It serves to “suck” venous blood flow from the IVC into the right atrium
What kind of pump does the aortic pump act as?
A subsidiary pump
Subsidiary
Less important
What must happen to the energy resulting from the cardiac contraction?
It must be stored
Why must cardiac contraction energy be stored?
Because of the holdup of blood flow that occurs in the capillary bed
What serves to store the cardiac contraction energy? (2)
- The aorta
2. Other elastic arteries near the heart
How does the aorta and other elastic arteries store the cardiac contraction energy?
By “stretching” with each systole
What does stretching of the aorta during systole allow?
It allows the aorta to act as a “reservoir”
- storing much of the blood expelled by the heart
What happens to the cardiac contraction energy that is stored during diastole?
It dissipates the large volume of blood stored in the aorta by forcing blood forward in the arteries
What does dissipating the large volume of blood stored in the aorta cause?
The aorta to return to normal caliber
- allows a contraction to occur
What can cause a great increase in blood pressure?
Arterial walls not being able to stretch
Why may cause the arterial walls not to stretch? (4)
- Atherosclerosis
- Age
- Diabetes
- Smoking
- chemicals
What is the approximate pressure in venules?
16mmHh
What is the approximate pressure of great veins near the heart?
4mmHg
What does there need to be in the venous system in order to help move the blood back to the heart? (2)
- Valves
2. Pressure gradient
What is the pressure gradient a measure of?
The force of blood as it moves blood through the vessels
What does the muscular pump do?
Squeezes the veins and propels the blood forward
Where is the muscular pump more effective?
In the lower legs where powerful calf and thigh muscles can compress the soleus and gastrocnemius sinusoids
How does blood like to flow?
From an area of high pressure to an area of low pressure
What kind of path does blood like to follow?
The path of least resistance
What specific type of blood vessels store blood in the lower legs? (2)
- Soleus sinusoids
2. Gastrocnemius sinusoids
What is the action of the muscle pump?
Is to assist the one way valves
Where are valves more plentiful?
In the lower extremities
What is flow initiated by?
By cardiac contraction
What is cardiac contraction further assisted by? (2)
- Muscular contraction
2. Venous valve action
