B5 - The cardiac cycle Flashcards
Why does amoeba not need a circulatory system?
Because they are so small that all parts of their body can get oxygen directly from the water they live in.
What is a closed circulatory system?
A closed circulatory system is when the blood is closed at all times within vessels of different size and wall thickness.
What is an open circulatory system?
Blood flows freely through the body cavity, carrying nutrients to the cells. Oxygen is delivered directly to the tissues through tiny tubes that open to the outside.
What does blood carry?
Blood carries oxygen and nutrients all around the body.
What is a single circulatory system?
Blood system with only one circuit.
What is a double circulatory system?
Blood system with two circuits.
What are the two circuits in a double circulatory system?
- from the heart to the lungs
- from the heart to the rest of the body
Why does blood pressure decrease from arteries to veins?
Blood pressure decreases the further away from the heart the blood vessels are.
What is the high blood pressure in arteries caused by?
The high blood pressure is caused by the heart muscles contracting to force the blood around the body.
What are the two chambers in the heart used for in a SCS?
One is used for pumping blood out and the other is used for receiving blood.
How many chambers does the heart have in a double circulatory system?
The heart has four chambers.
What do valves do?
Valves prevent the back flow of blood.
What do ventricles do?
Ventricles contract from the bottom upwards which forces blood into the pulmonary artery or aorta.
Why is blood pressure low in a single circulatory system?
Blood pressure is low because it has to go through capillaries before it reaches the muscles.
Why is blood pressure high in a double circulatory system?
Blood pressure is high in order to quickly transport material around the body.
