Topic 2a - Tissues, organs and organ systems ( 3. circulatory system - the heart) Flashcards
what is the function of the circulatory system
to get food and oxygen to every cell in the body. as well as being a delivery service, its also a waste collecting service. it carries waste products like co2 to he urea so they can be removed from the body. include the heart blood vessels and blood.
what is a double circulatory system
all humans have a double circulatory system, these are 2 circuits joined together
what happens in the first circuit of the circulatory system
right ventricle pumps deoxygenated blood to the lungs to take in oxygen. The blood then returns to the heart.
what happens in the second circuit
left ventricle pumps oxygenated blood all around the other organs of the body. the blood gives up its oxygen at the body cells and deoxygenated blood returns to the heart so it can be pumped out the lungs again
describe the structure of the heart
heart is a pumping organ that keeps blood flowing around the body. walls of the heart are mostly made of muscle tissue, the walls contract in order to pump blood. the heart also has 4 chambers right/left atrium, right/left ventricle, which the heart uses to pump blood around. the main blood vessels leading into and out of these chambers are the vena cava, pulmonary artery, aorta, pulmonary vein.
what are valves in the heart
to make sure blood goes in the right direction, prevent it flowing backwards.
why does the heart need coronary arteries
the heart needs its own supply of oxygenated blood. coronary arteries branch of the aorta and surround the heart making sure it goes all the blood it needs.
explain the process of blood flow through the heart
blood flows into the 2 atria through the vena cava and pulmonary vein.
the atria contracts pushing the blood into the ventricles
ventricles contract which force the blood into the pulmonary artery and the aorta and out of the heart
blood then flows through organs through arteries and returns through vein
whole cycle starts again
what is a pacemaker
you natural resting heart rate is controlled by a group of cells in the right atrium wall, this acts as a pace maker. the cells produce a small electric impulse which spreads to surrounding muscle cells, causing them to contract. However, artificial pacemakers are used when someones natural pacemaker cells do not work. It is a Device that is placed under the skin and has wires connected to the heart. it produces an electric current to keep the heart beating regularly.
