B2 - blood, heart, coronary arteries, CHD Flashcards
what kind of circulatory system do humans have?
double circulatory system
what kind of circulatory system do fish have?
single circulatory system
Describe the process of the double circulatory system (4)
- deoxygenated blood pumped from heart –> lungs where it collects oxygen
- this oxygenated blood then returns to the heart
- the heart pumps the oxygenated blood to the organs where the blood transfers oxygen to the body cells
- the blood now returns to the heart
what is an advantage of a double circulatory system?
The blood passes through the heart twice, so it can travel rapidly to the body cells, delivering the oxygen that the cells need
Blood flow around body/ heart/ lungs (6)
- oxygenated blood return to the heart via the pulmonary artery
- it then enters the heart at the left atrium and is pumped into the left ventricle
- the blood is pumped to the body via the aorta
- deoxygenated blood returns to the heart via the vena cava
- it enters the heart at the right atrium and is pumped into the right ventricle
- The blood travels back to the lungs via the pulmonary artery
what does the right ventricle do?
pumps deoxygenated blood to the lungs to take in oxygen. then the blood returns to the heart.
what does the left ventricle do?
pumps oxygenated blood around all other organs of the body.
what is the role of the vena cava
brings in deoxygenated blood from the body
what do the valves do ?
- stop the blood from flowing backwards into the atria when the ventricles contract
- separate the atria and ventricles
does the right or left side of the heart have a thicker muscular wall? why?
the left because the left ventricle pumps blood around the entire body so needs to provide a greater force
where does the right ventricle pump blood to?
only the lungs
how heart uses its 4 chambers to pump blood around (4)
- blood enters the left atrium and right atrium
- the atria contracts and the blood is forced into the ventricles
- the ventricles now contract and force blood out of the heart
- valves stop the blood from flowing backwards into the atria when the ventricles contract
what is your resting heart rate controlled by?
a group of cells in the right atrium wall that act as a pacemaker.
- these cells have a small electric impulse which spreads to the surrounding muscle cells, causing them to contract
what are the 3 types of blood vessels and their functions
- arteries - carry the blood away from the heart
- capillaries - involved in the exchange of material at the tissues
- veins - carry blood to the heart
Arteries features (4)
- walls are strong and elastic because the heart pumps blood at high pressures
- thick walls
- contain thick layers of muscle to make them strong
- have elastic fibres to allow them to stretch and spring back
Capillaries features (4)
- are really tiny to see
- have permeable walls –> so substances can diffuse in and out
- they supply flood and oxygen and take away waste like CO2
- walls are usually one cell thick –> increase the rate of diffusion by decreasing the distance
what do capillaries join up to form?
veins
why do the walls in veins not need to be as thick as the artery walls?
the blood is at a lower pressure in the veins
Veins features
- have a bigger lumen than the arteries —> to help the blood flow despite the lower pressure
- have valves –> to help keep the blood flowing in the right direction
what is the role of conorary arteries?
provide oxygen to the muscle cells of the heart.
- the oxygen is then used in respiration to provide energy for contraction
INFO: platelets have NO nucleus
which blood vessels carry blood away from the heart?
arteries
which chamber in the heart contracts to force blood to the lungs
right ventricle
Describe how CHD can cause a heart attack
- fatty deposits build up on the wall of the coronary artery
- blood flow is restricted
- less oxygen reaches the heart muscle so heart muscle cannot respire
- this results in a heart attack
where is cholesterol made and transported?
made in the liver and transported in the blood
what cause a buildup of fatty deposits in the artery?
high levels of cholesterol
what are statins? what do they do?
drugs that are used to reduce the levels of fatty deposits in the blood
- they block an enzyme in the liver which is needed to make cholesterol
what are 3 advantages of statins
what is cholesterol?
an essential lipid that the body produces and needs to function properly.
- too much of (LDL) cholesterol = fatty deposits
advantage of beneficial heart?
less likely to be rejected by body’s immune system
how can the valves in the heart be damaged or weakened? what can it cause?
by heart attacks, infection or old age.
- it can cause the valve tissue to stiffen ir not open properly or become leaky, allowing blood to flow in both directions –> means that the blood doesn’t circulate as effectively as normal
what can faulty valves be replaced with?
biological or mechanical valves (2)
what are cardiovascular diseases?
diseases of the heart and blood vessels
are cardiovascular dieseases communicalble or non- communicable?
non- communicable
