Circulatory System Flashcards
What is the function of circulatory system?
Carries food and oxygen to every cell in body & carries waste products
What does the right side do?
- Right ventricle pumps deoxygenated blood to lungs to take in oxygen
- Blood returns to heart
What does the left side do?
- Left ventricle pumps oxygenated blood around other
organs of body - Blood gives up its oxygen at body cells and deoxygenated blood returns to heart to be pumped out to lungs again
What is your resting heart rate controlled by?
Pacemaker cells
Where are pacemaker cells found?
Right atrium wall
What do pacemaker cells do?
Produce a small electric impulse → spread to surrounding muscle cells = causing them to contract
If you pacemakers cells stop working, what can you do?
Can use an artificial pacemaker to control heartbeat
What is an artificial pacemaker?
Little device implanted under skin and has wire going to heart
How does an artificial pacemaker work?
Produces electrical current to keep heart beating regularly
What is a heart and what does it do?
Pumping organ that keeps blood flowing around body & exchange substances
What are walls of heart mainly made out of?
Muscle tissue
Why does the heart have valves?
Prevent blood flowing backwards (in wrong direction)
How heart uses its four chambers to pump blood around? (5 steps, name arteries, ventricles, etc.)
- Blood flows into two atria from vena cava and pulmonary vein
- Atria contract pushing blood into ventricles
- Ventricles contract forming blood into pulmonary artery and aorta → out of heart
- Blood then flows to organs through arteries and returns through veins
- Atria fill again and whole cycle starts over
How does the heart gets its own supply of oxygenated blood?
Via coronary arteries (branch off aorta and surround heart)
What do arteries do?
Carry blood AWAY from heat
What do veins do?
Carry blood TO the heart
What do capillaries do?
Carry blood really close to every cell in body to exchange substances with them
Why are artery walls strong and elastic?
Heart pumps blood out at high pressure
What are walls of artery like?
Thick compared to size of hole down middle (lumen)
What do arteries contain that makes them strong?
Thick layers of muscle
What do elastic fibres in arteries allow them to do?
Allow them to stretch and spring back
e.g. Less blood pressure = recoils
What allows arteries to stretch/recoil?
Its folded endothelium
What kind of walls do capillaries have?
Permeable walls that are usually one cell thick
Why do capillaries have permeable walls?
So substances can diffuse in and out
Why do capillaries have one cell thick walls?
Increases rate of diffusion by decreasing distance over which it occurs
Why are vein’s walls not as thick as arteries’?
Blood is at lower pressure in veins
Why do veins have a bigger lumen than arteries?
To help blood flow (lower pressure)
Why do veins have valves?
To prevent back flow of blood
What is blood?
A tissue → huge part of transport system