Circulatory System—The Heart Flashcards
(15 cards)
What does the circulatory system do?
The circulatory system carries food and oxygen to every cell in the body. As well as being a delivery service, it’s also a waste collection service.
What is the circulatory system made up of?
The heart, blood vessels, and blood
What is a double circulatory system?
A circulation where the blood passes through the heart twice for each complete circuit of the body.
What happens in the first circuit of the double circulatory system?
The right ventricle pumps deoxygenated blood to the lungs to take in oxygen, and then the blood returns to the heart.
What happens in the second circuit of the double circulatory system?
The left ventricle pumps oxygenated blood around all the other organs in the body. They blood gives its oxygen at the body cells and all the deoxygenated blood returns to the heart to be pumped out to the lungs again.
What are the walls of the heart mostly made of?
Muscle tissue
Why does the heart have valves?
To make sure that blood flows in the right direction. They prevent the blood from flowing backwards.
What are the 4 chambers of the heart?
Right atrium, right ventricle, left atrium, left ventricle
How does the heart use the 4 chambers to pump blood around?
1) Blood flows into the 2 atria from the vena cava and the pulmonary vein.
2) The atria contract, pushing the blood into the ventricles
3) The ventricles contract, forcing the blood into the pulmonary artery and the aorta, and out of the heart.
4) The blood them flows to the organs through the arteries, and returns through veins
5) The atria fill again, and the cycle repeats.
What branch off the aorta?
Coronary arteries
What are the function of coronary arteries?
They surround the heart to supply the heart muscle with oxygen rich blood.
What is your resting heart rate controlled by?
Your resting heart rate is controlled by a group of cells in the right atrium wall that act as a pacemaker.
How do pacemakers work?
The body’s (natural) pacemaker is a group of cells in the right atrium wall. These cells produce a small electrical impulse which spreads to the surrounding muscle cells, causing them to contract.
What are artificial pacemakers used for?
An artificial pacemaker is often used to control the heartbeat if the natural pacemaker cells don’t work properly (e.g. if the patient has an irregular heartbeat).
What are artificial pacemakers?
A little device that’s implanted under the skin, and has a wire going to the heart. It produces an electrical current to keep the heart beating regularly.
