The Circulatory System Flashcards
What is blood
Blood is a liquid composed of plasma, red blood cells, white blood cells and platelets
What is the function of blood
Blood transports oxygen, digested food, hormones and waste materials
Blood destroys harmful bacteria and viruses and it clogs when we get cut, which helps prevent loss of blood and keeps out harmful bacteria and viruses.
Blood keeps body temperature constant by transporting heat all around the body as a result of chemical reactions that produce heat energy
Red blood cells
Haemoglobin is the red pigment found in the cell that picks up oxygen and transports it around the body
White blood cells
Fights disease by producing antibodies to fight off harmful bacteria, and gobbling up harmful bacteria and viruses
Platelet
Tiny fragments of larger cells that helps to clot blood
Plasma
Made up of water and dissolved substances like digested foods, gases, wastes and hormones (glucose, carbon dioxide, urea and insulin) and transports heat around the body
Body temperature
Normal human body temperature is 37*C, a change in body temperature could mean there is an illness
Arteries
Thick wall, small lumen, blood carried under pressure, no valves, carries blood away from the heart, contains oxygenated blood
Veins
Thin wall, large lumen, not carried under pressure, valves to prevent backflow of blood, carries blood to the heart, has deoxygenated blood
Capillaries
Wall is only one cell thick, tiny lumen, carried under low pressure, no valves, connects the arteries to the veins
The heart
Pushes blood into the arteries, made of cardiac muscle which never tires, consists of the two atria and two ventricles.
The ventricles are bigger than the atria. The left ventricle wall is thicker than the right because the blood has to go all around the body.
The sides are separated by a muscular wall called the septum.
Valves prevent the back flow of blood.
The pulmonary artery on the right side carries blood to the lungs.
The aorta carries blood around the body.
The vena cava carries blood from around the body to the heart.
The pulmonary vein carries blood from the lungs to the heart
How the heart pumps blood
Blood flows into the atria from the veins at the same time. The walls of the right atrium contract, pushing blood into the right ventricle and the valve closes, to stop the blood from flowing into the atrium. The walls of the ventricle then contract and push blood into the pulmonary artery which goes to the lungs. Then the blood goes into the pulmonary vein and enters the left atrium. The walls contract and the blood enters the left ventricle. The valve shuts. The walls of the left ventricle push the blood out the aorta and takes the blood around the body.
Pulse
The average adult heart beats about 70 times per minute. Every time the heart beats it forced blood into the eh arteries which produces a throbbing sensation. When we exercise we need more
What is the circulatory system made of
The blood vessels, the blood and the heart
