The Heart Flashcards
what are 2 properties of atria and why are these properties useful?
thin and elastic walls so they can stretch easily when filled with blood
what are 2 properties of ventricles and why are these properties useful?
thick and muscular walls to pump blood under high pressures
which ventricle is thicker and why?
the left ventricle is thicker so it can pump blood around the whole body
describe the function of the Vena Cava
brings deoxygenated blood into the heart from the body
describe the function of the Pulmonary vein
brings oxygenated blood into the heart from the lungs
describe the function of the Pulmonary artery
takes deoxygenated blood from the heart to the lungs
describe the function of the Aorta
takes oxygenated blood away the heart to the body
what are 3 structural features of an artery and how are they useful?
- narrow lumen to maintain BP
- thick, muscular walls to withstand high pressures
- elastic tissue to allow recoil
what are 2 structural features of a vein and why do they have them?
- thin walls as they don’t need to withstand high pressures
- valves to prevent backflow
what are 2 structural features of a capillary and how are they useful?
- walls one cell thick = short diffusion pathway
- very narrow lumen = to control blood flow
what does a capillary bed provide?
a large surface area for gas exchange
describe what happens during cardiac diastole [6]
- heart is relaxed
- blood flows into atria
- increased pressure in atria
- AV valves open
- blood can now flow into ventricles
- reduced pressure in atria
describe what happens during atrial systole [2]
atria contract pushing any remaining blood into ventricles
describe what happens during ventricular systole [6]
- ventricles contract
- pressure increased in ventricles
- AV valves close to prevent backflow
- semilunar valves open
- blood flows into arteries
- reduced pressure in ventricles
