Circulatory System and cardiovascular disease Flashcards
What word is used to describe the circulatory system and why?
Double
Two circuits joined together
What is the circulatory system composed of?
Heart
Blood vessels
Blood
Describe the two circuits that form the double circulatory system
Right ventricle pumps deoxygenated blood to the lungs to take in oxygen before returning to the heart
Left ventricle pumps oxygenated blood around all the other organs of the body
Describe the process by which the heart pumps blood (start with the atria)
Blood flows into the two atria from the vena cava and the pulmonary vein
The atria contract, pushing the blood into the ventricles
The ventricles contract, forcing the blood into the pulmonary artery and the aorta and out of the heart
The blood then flows to the organs through arteries and returns through veins
The atria fill again and the whole cycle starts again
What are the walls of the heart made of?
Muscle tissue
What is the purpose of the valves in the heart?
Prevent the blood from flowing backwards and maintain the direction of the flow of blood
How does the heart muscle gain its own oxygen?
Coronary arteries
What is the purpose of the coronary arteries?
Gives the heart muscle its own blood supply
Ensures oxygenated blood is delivered to the the heart muscle
Removal of waste products from the heart muscle
Where do the coronary arteries branch from?
Aorta
What is resting heart rate controlled by?
Group of cells located in the right atrium that act as a pacemaker
How do the pacemaker cells act to control the resting heart rate?
Produce small impulses which spreads to the surrounding muscle cells causing them to contract
Describe the use of an artificial pacemaker?
Used to control heartbeat if natural pacemaker cells do not work properly (irregular heartbeat)
Device is implanted under the skin and a wire goes into the heart
Produces electrical current causing the heart beat to become regular
List the 3 types of blood vessel
Artery
Capillary
Vein
What is the function or arteries?
Carry blood away from the heart
What is the function of veins?
Carry blood to the heart
What is the function of capillaries?
Involved in the exchange of materials at the tissues
Describe the structure of arteries
Thick walls
Strong walls
Elastic walls
Smaller lumen
What is the purpose of the structure of the artery
Carry blood under high pressure
Allow the artery to stretch and spring back
Strong
Describe the structure of capillaries
Small
Permeable walls
Thin walls - one cell thick
Where are capillaries found?
Between arteries and veins
Close to cells
Why are capillary walls permeable?
So diffusion can occur
Why are capillary walls one cell thick?
Reduce the diffusion distance
and increases the rate of diffusion