10. Circulation of Blood Flow Flashcards
Functions of the Cardiovascular System
- maintain an adaptable supply of blood to tissues
- establishment of pressure differentials across tissues for the purposes of capillary exchange
Vascular Resistance is determined by what?
- Length of vessel
- Radius of vessel
- Fluid viscosity ( hight protein content = higher viscosity)
What is the difference between cardiac systole in the right and lift ventricle?
Cardiac systole in the left ventricle is of a higher pressure than the systole in the right ventricle, because LV has to pump blood to the body not just to the pulmonary system.
What is the difference in pressure between the right and left atria?
Left atria under more pressure than the right atria.
What maintains blood flow throughout the cardiac cycle?
During the relaxation phase of the cardiac cycle (diastole) large and medium elastic arteries act as a “Pressure Reservoirs” and maintain the blood of flow throughout cardiac cycle
Blood then enters elastic vessels. Pressure wave is continued by the elastic vessels as blood travels through the peripheral system. Elastic vessels bulge under pressure and then recoil
What does Dicrotic Notch on a blood pressure graph show?
small dip - where the valves open and close
What does Pulse pressure on a blood pressure graph show?
difference in values between the systolic pressure and the diastolic pressure. Allows us to determine the mean arterial pressure.
What does Pulse pressure on a blood pressure graph show?
the averagearterial pressure throughout one cardiac cycle.
more accurate reflection of tissue perfusion than systole alone.
Describe the electrical events in the cardiac cycle.
- Sinoartial Node generate electrical current
- Signal goes to the atria and is received by the atrioventricular node
- AV node delays the cycle to allow atrial contraction
- Impulse goes down bundle of His
- Rapid signal is sent to enable the ventricular cells to contract.
- Ventricular myocardium
Name the mechanical events of the cardiac cycle in order.
- Atrial systole
- Atrial diastole
- Ventricular systole
- Ventricular diastole
What happens in Atrial systole?
Atrial contraction forces a small amount of additional blood into relaxed ventricles.
What happens in Ventricular systole?
Ventricular contraction pushes AV valves closed, but doesn’t create enough pressure to open semi lunar valves.
As ventricular pressure rises and exceeds pressure in the arteries in the arteries, the semilunar valves open and blood is ejected.
Isometric ventricular contraction there is a significant increase in pressure in the chambers without a change in the volume associated with those chambers.
What happens in ventricular diastole?
As ventricles relax, pressure in the ventricles drops; blood flows back against cusps of semilunar valves and forces the closed. Blood flows into relaxed atria.
All chambers are relaxed. Ventricles fill passively.
What does an ECG detect?
ECG detects electrical responses across the heart.
The profile is an amalgamation of many action potentials across the heart.
