Circulatory System & the Cardiac System Flashcards
Why do single celled organisms not need a circulatory system?
They are in contact with the environment directly and they can rely on diffusion to supply oxygen and nutrients.
What is meant by an open circulatory system?
A body with no blood vessels, the blood fills up the body system. Special tubes deliver air directly to the respiring cells.
What is meant by a closed circulatory system?
A body with blood vessels and a heart to pump blood around these blood vessels
Name the blood vessels which deliver oxygen and glucose to the heart muscles
Coronary arteries
Describe the heart structure of an animal with a single circulatory system?
The heart has just two chambers: one atrium and one ventricle.
What is the advantage of a double circulatory system?
Blood is under high pressure which moves materials around the body quickly.
Harvey was a British doctor who investigated the circulatory system, what did he discover about arteries and veins?
He discovered that arteries carry blood under high pressure away from the heart and that veins have valves to prevent back flow
Name the blood vessel which delivers deoxygenated blood from the body
Vena Cava
Which heart chamber accepts blood from the pulmonary vein?
Right Atrium
Which side of the heart has a thicker muscle wall?
The left side
Where are the semi-lunar valves found?
They separate the ventricles from the blood vessels which carry blood away from the heart (the pulmonary artery and the aorta)
Summarise the cardiac cycle
The heart relaxes and blood fills the atria. Both atria contract and blood enters the ventricles. Ventricles contact from the bottom up, pushing blood upwards towards the arteries
Which method is used by doctors to investigate the electrical impulses in the cardiac cycle?
An ECG
Which method is used by doctors to investigate the structure of the heart?
An echocardiogram
Which hormone increases heart rate?
Adrenaline
