Respiratory and Circulatory System

Alveoli have:

• a huge surface area
• moist walls to maximise diffusion
• milions of tiny blood capillaries

Exercise strengthens the intercostal muscles and diaphragm making breathing more efficient.

Asthma causes the linings of the airways to swell up and become irritated.

Smoking damaged the ciliated cells that line the gas exchange system. These ciliated cells move mucus and pathogens out of the airways. Since the cells are now damaged, smokers develop a cough to try to remove the mucus.

Smoking also irritates the bronchi (causing bronchitis), and can break down the lining of the alveoli leading to COPD.

Cigarette smoke contains carcinogens such as tar, which can cause lung, heart and throat cancer.

The purposeof the circulatory system is to transport oxygen, carbon dioxide, glucose, water, amino acids, fatty acids, glycerol, hormones and urea.

• The pacemakers are located in the right atrium - they generate the heartbeat.
• Valves prevent the back flow of blood.
• The left side receives oxygenated blood and the right side receives deoxygenated blood.
• The cardiac muscles receive their own blood supply via the coronary artery.

Treating coronary heart disease, artherosclerosis, build up of cholesterol:

• Stents - they open up the arteries. Possible damage to artery walls when putting stent in

Treating leaky valves:

• Animal heart valves - lasts 12-15 years, no medication required
• Mechanical heart valves - lasts indefinitely, medication required to prevent clots

Mechanical heart:

• Keeps patient alive until a heart transplant is available
• Risk of clots or mechanical heart failing

Blood is a tissue consisting of plasma.

Plasma is a yellow liquid. It transports: red blood cells, white blood cells, platelets and other substances.

Red blood cells pick up oxygen from your lungs and supply oxygen where needed. They have biconcave discs to allow more diffusion because of an increased surface area. They are packed with haemoglobin to pick up oxygen. And they have no nucleus to make more space for haemoglobin.

White blood cells have a nucleus. Lymphocytes create antibodies and phagocytes engulf invading pathogens.

Platelets are small groups of cells with no nucleus. They convert fibrinogens to fibrin, creating a network of protein fibres that capture red blood cells.