Cardiovascular system Flashcards
Explain the role of the cardiovascular system in maintaining perfusion.
The heart pumps blood around the body via blood vessels, transporting materials + delivering sufficient blood to maintain the health of all body cells.
Identify the key requirements for effective perfusion.
- contraction of the left ventricle
- peripheral vascular resistance
- elasticity of the arterial walls
- viscosity + volume of blood
Identify the common signs and symptoms of altered perfusion and discuss the physiological basis of why these may occur.
peripheral perfusion
- decreased hair distribution
- coolness + cyanosis if the extremities
central perfusion
- painful / difficulty breathing + shortness of breath (dyspnea)
- dizziness or fainting (syncope)
- chest pain
Discuss the homeostatic processes that can alter perfusion.
- baroreceptors detect changes in blood pressure
- chemoreceptors detect changes in pH
- The precapillary sphincter mechanism regulates blood flow to capillaries
- ADH secreted when blood volume is high enough to cause extreme stretching of cardiac cells
- EPO is released when blood flow +/or oxygen levels decrease
Identify physiological changes in the blood, blood vessels and heart that result in altered perfusion.
- cardiac output (HR X SV)
- blood volume - blood pressure
- system vascular/peripheral resistance
- blood viscosity
What is perfusion?
Perfusion is the process of oxygenated blood being delivered to the body’s tissues.
Describe the passage of blood through the right side of the heart. (De-oxygenated blood).
(superior and inferior) Vena Cava
Right atrium
Right AV valve
Right ventricle
Semi lunar valve
Pulmonary Artery
Describe the passage of blood through the left side of the heart (oxygenated blood).
Pulmonary vein
Left atrium
Left AV valve
Left ventricle
Semi lunar valve
Aorta
Relate the structure of the heart’s chambers to their functions:
- Artia (atrium)
- Ventricles
- Artia = Thin-walled and elastic, so they can stretch when filled with blood.
- Ventricles = Thick muscular walls pump blood under high pressure. The left ventricle is thicker than the right because it has to pump blood all the way around the body.
Describe the function of the heart’s major blood vessels.
Vena cava = brings deoxygenated blood from the body to the heart.
Pulmonary artery = takes blood from the heart to the lungs.
Pulmonary vein = Brings oxygenated blood from the lungs to the heart.
Aorta = takes blood from the heart around the body.
Relate the structure of the arteries to their function
Thick, muscular walls to handle high pressure. Elastic tissues that recoil. Narrow lumen to maintain pressure.
Relate the structure of the veins to their function
Thin walls due to lower pressure. Requires valves to prevent backflow.
Describe what happens during cardiac diastole.
The heart is relaxed. Blood enters the atria, increasing the pressure and pushing open the atrioventricular valves. Allowing blood to flow into the ventricles. Pressure in the heart is lower than in the arteries, semilunar valves remain closed.
Describe what happens during atrial systole.
The atria contract, pushing any remaining blood into the ventricles.
Describe what happens during ventricular systole.
The ventricles contract. The pressure increases, closing the atrioventricular valves to prevent backflow. Blood flows into the arteries.
