Circulatory System
- Created by: Abc312
- Created on: 12-05-18 20:04
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- Circulatory System
- The Heart
- Pumps blood around the body in a double circulatory system
- Flow of blood
- From the body (deoxygenated)
- Through the vena cava
- Into the right atrium
- The atria contract
- Pushing blood into the right ventricle
- The ventricles contract
- Forcing blood through the pulmonary artery
- The blood goes to the lungs
- Gas exchange happens
- Oxygenated blood flows into the heart
- Through the pulmonary vein
- Into the left atrium
- The atria contract
- Pushing blood into the left ventricle
- The ventricles contact
- The blood is pushed out of the aorta
- It flows around the body
- The blood is pushed out of the aorta
- The ventricles contact
- Pushing blood into the left ventricle
- The atria contract
- Into the left atrium
- Through the pulmonary vein
- Oxygenated blood flows into the heart
- Gas exchange happens
- The blood goes to the lungs
- Forcing blood through the pulmonary artery
- The ventricles contract
- Pushing blood into the right ventricle
- The atria contract
- Into the right atrium
- Through the vena cava
- Both sides happens the same time
- From the body (deoxygenated)
- The heart needs its own flow of oxygenated blood
- The coronary arteries branch off the aorta and surround the heart.
- The natural resting heart rate is controlled by cells in the right atrium
- They produce a small electrical impulse which causes them to contract
- If the natural pacemaker cells don't work then an artificial pacemaker is fitted
- It fits under the skin and has a wire going to the heart and produces an electric current
- Blood Vessels
- Arteries
- The heart pumps blood at high pressure.
- This means artery walls have to be strong and elastic
- Walls are thick compared to the lumen
- Thick layers of muscle to make them strong
- Have elastic fibres to allows them to stretch and spring back
- The heart pumps blood at high pressure.
- Veins
- Capillaries join up to form veins
- The blood is now at a lower pressure
- This means the walls are not as thick as in arteries
- Bigger lumen than arteries
- Help the blood flow better despite the lower pressure
- Have valves to help blood flow in the right direction
- Capillaries
- Arteries branch into capillaries
- They are tiny - too small to see
- They carry blood really close to every cell in the body to exchange substances
- They supply oxygen and food and take away waste like CO2
- Have permeable walls for easier diffusion
- Walls are only one cell thick
- Increases the rate of diffusion
- Because of a shorter distance to diffuse
- Increases the rate of diffusion
- Have a very small lumen
- Arteries
- Blood
- Plasma
- The liquid that carries everything.
- Red blood cells
- White blood cells
- And the antibodies and antitoxins that they make
- Platelets
- Nutrients
- Like glucose and amino acids that are soluble products of digestion and taken to body cells
- Carbon dioxide
- Urea
- Hormones
- Proteins
- The liquid that carries everything.
- Red blood cells
- Carry oxygen from the lungs to all body cells
- Shaped as a biconcave disc
- Gives a large surface area for absorbing oxygen
- Have no nucleus
- Gives more space to carry oxygen
- Contain a red pigment called haemoglobin
- When it binds to oxygen it becomes oxyhaemoglobin
- White blood cells
- Defend against infection
- Some change shape to swallow pathogens
- Phagocytocis
- Some produce antibodies and antitoxins
- They do have a nucleus
- Platelets
- Small fragments of cells
- Have no nucleus
- Help blood to clot at a wound
- If you don't have enough platelets you can bleed and bruise too much,
- Plasma
- Cardiovascular disease
- Coronary Heart Disease
- Layers of fatty material build up inside the coronary arteries
- This narrows them
- It causes reduced blood flow through the arteries
- Causing a lack of oxygen for the heart muscle
- Layers of fatty material build up inside the coronary arteries
- Stents
- Tubes that go inside arteries
- They keep them open
- Means blood can pass through
- They keep them open
- Positives
- Reduce the risk of a heart attack
- Effective for a long time
- Recovery time is relatively quick
- Negatives
- Could be complications during surgery
- Risk of infection from surgery
- Could develop a blood clot near the stent - called thrombosis
- Tubes that go inside arteries
- Statins
- Cholesterol is an essential lipid that you need to function
- Too much of certain bad cholesterol can cause problems
- It can lead to fatty deposits forming inside arteries
- Statins reduce cholesterol -slowing down the rate of fatty deposits developing
- Positives
- Reduce the risk of strokes, heart disease and heart attacks
- Can increase the amount of good cholesterol
- Negatives
- Long-term drug that you need to take regularly
- Could forget to take them
- Can cause negative side effects
- Headaches or more serious like kidney failure, liver damage and memory loss.
- Takes time for the effects to kick in.
- Long-term drug that you need to take regularly
- ArtificialHeart
- If a person has heart failure donor organs can be used
- However this can sometimes be hard to find or not suitable for the patient so an artificial heart can be used
- They are mechanical devices that pump blood.
- They are usually only used temporarily
- To allow someones heart to rest and heal or while waiting for a transplant
- Positives
- Less likely to be rejected than a donor heart
- Because they are made from metal or plastic so the body doesn't attack them like they would a donor heart.
- Less likely to be rejected than a donor heart
- Negatives
- Surgerycan lead to bleeding and infection
- They don't work as well as natural ones.
- Parts could fail or wear out.
- Blood doesn't flow through artificial hearts as smoothly
- This means the patient has to take drug thinners
- This can cause more problems
- This means the patient has to take drug thinners
- If a person has heart failure donor organs can be used
- Heart Valves
- Heart valves can be weakened by heart attacks, infection or old age
- It could become stiff not letting it open fully
- May become leaky allowing blood to flow in both directions
- Replacing a valve is a lot less drastic than a whole heart transplant
- Surgery is still risky though
- Valves can be:
- Mechanical- man made
- Biological- From another human or animal
- Heart valves can be weakened by heart attacks, infection or old age
- ArtificialBlood
- Even if a person loses a lot of blood the heart can still pump red blood cells with oxygen if the volume of blood can be topped up
- It is a blood substitute
- Used to replace the lost volume of blood
- It can keep people alive even if they lose two thirds of their blood.
- Coronary Heart Disease
- The Heart
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