Transporting materials: heart Flashcards
What does the circulatory system do?
transports substances around the body
What is the heart? What is it made of?
- an organ which pumps blood around the body
- made of muscle tissue
what is double circulation?
- two separate circuits - one for lungs/ one for all the other organs of body
What are the four main chambers in heart?
- left/right atria
- left/right ventricle
Describe how the heart works
- atria contract and force blood down SEMI-LUNAR VALVE to ventricles
- ventricles also contract and force blood out of the heart through ATRIOVENTRICULAR VALVES
What do the valves do?
- prevent blood flowing backwards - ensue blood flows in one direction
What are coronary arteries?
- arteries which cover surface of heart providing oxygenated blood
What happens if coronary arteries are narrowed?
- lead to heart disease due to fatty deposits
- blood does not flow as efficiently so organs deprived of nutrients and oxygen
What are stents?
metal mesh inserted in blood vessels to keep them open - use balloon to open up vessel and mesh
What other method could be used if stents do not have an effect?
- bypass surgery by replacing coronary arteries with other veins from body
What are leaky valves?
- blood flowing in wrong direction due to pressure of blood weakening valves
What is the effect of leaky valves?
person becomes breathless - eventually die
Methods of fixing leaky valves
- biological: animal valves
- mechanical: artifical valves
Animal valves: advantages and disadvantages
e.g. pigs/cattle
+ patient doesnt need medication
- only last about 15 years
Artifical valves: advantages and disadvantages
made of titanium or polymer
+ lasts forever
- have to take medication for rest of life to prevent blood clotting
