Circulatory System Flashcards
What organs are in the circulatory system and what is the purpose of the circulatory system?
Consists of your heart, blood vessels and blood. The heart is the engine room of the circulatory system. It pumps the blood around the body carrying the minerals it needs.
What are the arteries?
Arteries carry blood away from the heart. When the heart beats blood moves along the capillaries under pressure. The capillaries have very thick tough and elastic walls. If an arteries gets damaged or cut a lot of blood can be lost very quickly. So they are places deep in the body. Your arteries also carries the heartbeats.
What are the capillaries?
Arteries branch onto smaller and smaller blood vessels. Eventually they reach the very finest of the blood vessels called the capillaries. Capillaries walls are only one cell thick. This allows dissolved materials to pass through them. Materials needed by a cell pass out of the capillaries and into the cell, and waste products pass from the cell into the capillaries. At the end the capillaries join back together to form larger and larger blood vessels called veins.
What are veins?
Veins carry blood back to the heart. The veins don’t need thick walls like the arteries because the pressure is lost. Blood is pushed back up to your heart by the contraction of the muscles of your body pressing against the veins. To make sure blood flows the right direction, there are valves. Valves open if the blood is flowing towards the heart and closes if blood flows away from it. If you sit down for long periods of time. The flow of blood slows and can ‘pool’ in the veins. The blood may thicken and form a dangerous blood clot called a thrombosis.
What are bruises?
When you bump yourself hard the tiny capillaries near the skin burst leaving a bit of blood spilled on the tissue. This creates a red bump which changes to purple and yellow as it is broken down and cleared away by the body.
What is the heart?
The heart is the size of your fist and is in the middle of your chest. The heart is made of a special muscle called cardiac muscle, which means the muscle does not get tired how your legs and arms do. The circulatory system is referred to as a double system because there are two circuits in which the blood flows.
What is the first circuit of the heart?
Circuit 1 - The first circuit goes from the heart to the body and back to the heart. This circuit carries nutrients and oxygen to the cells.
What is the second circuit of the heart?
Circuit 2 – Blood goes from the heart to the lungs. In the lungs, carbon dioxide passes out of the blood and oxygen passes onto the blood. The blood rich oxygen then returns into the blood. The blood rich in oxygen then returns to the heart to get pumped through the body through circuit system 1.
What are the three main phases of a heart beat?
Three main phases of a heartbeat
1. The two atria (plural of atrium) contract, pushing blood down into ventricles.
2. The ventricles contract, forcing blood out of the heart to the body and lungs.
2. The heart muscle relaxes and the atria fill with blood.
What is heart disease?
Coronary muscles supply the muscles of the heart with blood. The inner walls of the healthy arteries are smooth and the blood flows easily. Plaque can build up in the arteries which narrows the arteries and reduces blood flow to the heart muscles, which also means oxygen supply is reduced to. A lack of oxygen to the heart causes a condition called angina. A person suffering angina has serious chest pains. If the arteries become completely blocked, then the part of the heart that the arteries normally supply with oxygen dies and the person has a heart attack. Plague is made up of various substances that occur naturally in the blood. These substances include calcium, cholesterol, and fibrin. Some scientists believe that damage to the artery walls lead to inflammation. Cholesterol along with other substances, moves to the inflamed area to protect it. Other scientists believe that to much animal fat will build up the plaque.
What is blood?
Blood is the only organ in the body that exists as a liquid. The average size adult contains about 5 Litres of blood. Blood carries oxygen, nutrients and water to the cells and carries carbon dioxide and other wastes away from the cells. It also helps maintain body temperature. In blood there are red blood cells, white blood cells, plasma and platelets.
What are the four things in the blood and what do they do?
Red blood cells – are made in the bone marrow of long bones such as the femur and ribs. The contain the chemical haemoglobin. Haemoglobin is a pigment that gives the cells their red colour, it also contains iron, and its job is to carry oxygen around the body. Oxygen is carried to cells as oxyhaemoglobin. There are about 300 million red blood cells in one drop of blood.
White blood cells – are bigger than red blood cells. White blood cells are a part of the immune system which helps fight diseases.
Platelets – are broken up bits of cells produced in the bone marrow. They help blood to clot. If you do not have enough platelets, then you could bleed excessively. But to many could cause blood clot in blood vessels. This can cause a heart attack and angina. A blood clot in the brain can cause a stroke, where part of the brain is starved by oxygen and dies.
Plasma – Clear yellowish liquid that is 90% water. The 10% is dissolved minerals such as nutrients and wastes. Red blood cells, white blood cells and platelets are suspended in plasma.
