Ch8 - Transport In Animals

Question 1

Stage 1 in cardiac cycle - explain

Answer 1

Aortic systole
Contraction in the atria
Pressure increases
Semi lunar valves close
Pressure higher in atria than ventricles
Bicuspid and tricuspid (atrioventricular) valves open
Blood flows into ventricles
Pressure in atria decreases
Lasts about 0.1 seconds

Question 2

Stage 2 in cardiac cycle - explain

Answer 2

Ventricular systole
Ventricles contract
Pressure in ventricles increase
Bicuspid and tricuspid (atrioventricular) valves close
Semi lunar valves open
Pressure in ventricles decreases
Lasts about 0.3 seconds

Question 3

Stage 3 of cardiac cycle - explain

Answer 3

Diastole
Pressure in ventricles decrease
Semi-lunar valves close
All the heart muscles relax
Blood flows into atria from vena cava and pulmonary vein
BP remains low in atria and ventricles