Circulatory System

• Carries oxygenated blood away from the heart
• Thick muscle allows stretching as blood is forced through at high pressure
• Small lumen

• Carries deoxygenated blood to the heart
• Thinner muscle as the blood is at a lower pressure
• Large lumen
• Has valves that prevent backflow

• Carries blood to the body cells in the tissue
• One cell thick walls so diffusion of oxygen and nutrients can happen
• Leaky walls allow diffusion

Cardiac output = heart rate x stroke volume

Heart rate - number of beats per minute

Stroke volume - volume of blood pumped from the left ventricle per beat

Cardiac output - volume of blood sent from heart to muscles each minute

• Heart needs glucose and oxygen for arteries and capillaries to work
• Coronary arteries supply heart with oxygen and glucose
• When CHD happens the fatty deposits block coronary artery
• When heart doesn't get oxygen and glucose cells die

• Carries oxygen from air to cells that need it
• Has haemoglobin which binds to oxygen
• No nucleus to make room for haemoglobin
• Biconcave shape to have more surface area for diffusion

• Protects body against infection
• Forms part of the body's defence system against harmful micro-organisms
• Some form antitoxins against poisons
• Others engulf and digest invading bacteria and viruses

• Small fragments of cells 
• No nucleus
• Helps blood clot at wound
• Protein fibres capture lots of RBC's and platelets to form blood clot
• Blood clot hardens to form a scab and stop bacteria entering wound

• Yellow liquid
• Transports blood cells and other substances around the body
• Waste carbon dioxide produced by cells is carried to lungs
• Urea carried to kidneys and removed from blood forming urine
• Small soluble products of digestion pass into plasma from small intestine and transported to individual cells

Health - the state of physical and mental wellbeing

CHD (card 5): treats with stent to widen the artery or replaces blocked part with a section of vein or statins are prescribed to reduce build of fatty material

Stents:

Advantages: can be used anywhere in body; no general anaesthetic; can release drugs to prevent blood clotting

Disadvantages: expensive because of drug release - worth it?

Bypass Surgery:

Advantages: works for badly blocked arteries that cant be helped by stents

Disadvantages: expensive; risks with general anaesthetic; faulty heart valves (card 11)

Heart valves prevent blood blackflow as it has to travel in one direction.

Over time the heart valves cant open and shut properly and they can leak and become less flexible → eventual death.

Treatment for heart valves:
1) Mechanical valves → made of titanium and polymers - long lasting + need to take medicine for life to prevent blood clotting

2) Biological valves → made from animals or human donors - doesn't cause clotting + less long lasting

Advantages:

- Gives your heart a rest - temporary heart

- Good for standing in when waiting for a heart trasplant

Disadvantages:

- Long waiting list - have to wait for a tissue match when waiting for transplant

- Expensive - only 1500 have had them

- Risk of blood clotting in artificial - can lead to death