EP 2 Flashcards
What are the three blood vessels and what are their adaptations
Arteries- thick muscular walls, small lumen
Veins- larger lumen and pocket valves
Capillaries- one cell thick
What are the two circuit of blood
Systemic and pulmonary
How does vasodilation and vasoconstriction work
Blood vessels going to active muscles are widened to increase blood flow
Blood flow to lower priority areas in the body is limited by narrowing blood vessels
What do pre capillary sphincters do
Open and close to control blood flow to specific areas
Explain the pathway of blood
Superior and inferior vena cava to right atrium to tricuspid valve to right ventricle to pulmonary valve to pulmonary artery to lungs
Lungs to pulmonary vein to left atrium to bicuspid valve to left ventricle to aortic valve to aorta to body
What does myogenic mean
The heart can generate its own electrical impulses and doesn’t require brain stimulation
What is the cardiac cycle and what are the stages
Atrial diastole, ventricular diastole, atrial systole, ventricular systole
Describe the cardiac conduction system
-cardiac diastole
-SA node fired
-impulse causes atrial systole
-impulses delayed at AV node fired
-impulse passes Bundle of His
-impulse passes along the purkinje fibres causing ventricular systole
What are the three functions of the blood
-transport of gases and nutrients
-thermoregualtion
-protection and healing
What is venous return
The flow of blood that returns to the heart via the venules and veins
How many mechanisms of venous return are there
4
What is the skeletal muscle pump
When skeletal muscles compress the veins during movement, they force blood back towards the heart via
How do pocket valves assist venous return
They stop backflow in veins and venules
What is the respiratory pump
When a person inhales the pressure inside the thoracic cavity decreases compared to the rest of the body. This causes a small flow of blood towards the heart as blood moves down a pressure gradient
What is cardiac suction
As the ventricles contract, the atrioventricular valves are pulled down increasing the size of the atria. This causes a pressure difference between the atria and the veins sucking blood towards the heart
What is the equation for cardiac output
Stroke volume multiplied by heart rate
What is stroke volume
The volume of blood ejected from the left ventricle per beat
What does starlings law state
Cardiac output is dependant on the extensibility of cardiac muscle fibres
What are the two reasons that cardiac output increases as we exercise
Increased hear rate and venous return increases
How does an increase in venous return increase cardiac output
Venous return increases which stretches the cardiac tissue even more. This causes a more powerful contraction of the heart forcing out more blood each beat
What is ejection fraction
The percentage of blood pumped out of the left ventricle each beat. At rest it is approx 55%
How does exercise increase ejection fraction
The elastic fibres are stretched out due to venous return increasing and forcefully contract back, pushing out more blood from the heart
What is ejection fraction approximately during exercise
70%
What is cardiovascular drift
A drifting upwards of heart rate when exercising at a constant work rate over a prolonged period or in a hot environment
How does sweating impair energy production
Sweating causes a decrease in blood volume and venous return, as plasma contains a lot of water. So stroke volume and cardiac output decrease.
Hear rate increases to compensate for the lower SV and maintain a constant cardiac output
What is blood pressure
The force exerted by the blood on the inside walls of the blood vessels
How and where is blood pressure measured
In the left brachial artery using a sphygmomanometer
What are the average blood pressure numbers
Systole=120
Diastole=80
How does aerobic exercise effect blood pressure
Systolic pressure increases but diastolic pressure does not
How does anaerobic exercise effect blood pressure
Systolic and diastolic pressure increases dramatically mainly due to athlete holding their breath
