Biology - Year 9 - Non-Communicable Diseases

Homeostatsis is the bodys ability to maintain a state or internal environment.

Negative feed back happens if a condition changes and the body works to correct it eg. temperature increase and decrease, sugar levels fall or rise and water levels.

An example of the sugar level negative feedback:

Type 1:

• The body is unable to create insulin
• They must control their diet and inject themselves with insulin
• Type 1 diabetes is more serious thn Type 2

Type 2:

• "Late onset diabetes"
• More common than Type 1
• Usually found in people over the age of 40
• Linked to obesity
• The pancreas has a decreased ability to create insulin
• It can be controlled by physical exercise and a low-glucose diet

BMI is used to qualify the amount of tissue mass in someone and tehn put them in the category of underweight, normal, overweight or obese.

      BMI =     Mass (kg)                                           Under = < 18.5

                    Height (m²)                                         Normal = 18.5 - 24.9

                                                                               Over = 25 - 29.9

                                                                               Obese = > 30.0

      Waist : hip ratio =    waist cirumference

                                       hip circumference

People become obese when there is an imbalance between energy intake (food) and enery experditure (physical activity).

The excess energy becomes fat.

intake = output    ->    Balance

intake > output    ->    Positive energy balance : gaining weight

intake < output    ->   Negative energy balance : Losing weight

• Cancer in the breast, bowels and womb
• Heart disease: this can increase the risk of having a heart attack 
• High blood pressure: the high blood pressure in the arteries in the brain can burst (stroke) and cause brain damage 
• Diabetes: the liver cannot control the blood glucose level
• Arthritis: the excess of weight on the joints can increase the risk of them getting worn or inflamed

Obesity can be linked to many non-communicable diseases and is a lifestyle factor that people are told to change if they have one of those diseases. They will be asked to improve their diet or exercise more.

• Nicotine increases heart rate which increases blood pressure. It causes a build up of mucus in organs which can effect the way they function. Nicotine is the thing that makes smokers addicted
• Smoking can lead to lung cancer, trouble breathing, strokes, heart attacks and emphysema which is damage to the lungs and alveoli. 
• Carbon monoxide combines with haemoglobin in red blood cells and it decreases the amount of oxygen the cells can carry
• Alcohol can lead cirrhosis of the liver which can then lead to liver cancer, it slows down the brains reaction times as it gets to the nervous system and brain

Malnutrition:

• Having too much or too little of a nutrients can lead to malnutrition
• Scurvy (Vitamin C deficiency), stroke (excess sodium), liver disease (excess Iron)

The coronary vein supplies the heart with blood, oxygen and glucose fro respiration. Cholesterol is a fatty substance that is used to create cell membranes. Cholesterol is a fatty substance that is used to create cell membranes, it can build up in the arteries and restricts the blood flow. The deposits build up where the artery wall has been damaged.

Lifestyle changes can treat CVD for example:

• Eat a healthy diet that is low in saturated fat 
• Regular Exercise
• Weight Loss
• Stop Smoking 

All these factors can reduce the risk of developing and repeats of stokes or heart attacks. 

These drugs are generally used when lifestyle changes alone aren't enough. They are taken by many people but they must take them for the rest of their lives after a stroke or heart attack.

• Statins reduce the amount of cholesterol in the bloodstream. It slows the development of fatty deposits but they can cause aching muscles and liver damage.
• Anticoagulants make blood clots less likely to form but these can cause excessive bleeding after an accident.
• Antihypertensives reduce blood pressure therefore preventing damage to blood vessels but they can cause headaches and fainting.

• Blocked Arteries = Stents are tubes put inside the arteries that have become too narrow, to make sure blood can pass through to the heart muscles. They lower the risks of heart attacks. However over time the arteries will narrow and the stents will irritate the arteries and make scar tissue grow. Patients have to tae drugs to stop blood clotting on the stent. 
• Donor Hearts = Are usually used when there is nothing to help the patients current heart . The new heart may not be accepted or pump correctly so patients must take drugs to stop the body rejecting the new heart but these drugs can make you ore vunerable to infections and diseases.

Other surgeries related to the heart are coronary bypass surgeries, replacement valves and artifical blood products.

• Using computer models they look at molecules and screen 100,000's of chemicals and a possible drug is synthesized in the lab
• They are tested on grown cells and tissue cultures, many drugs fail as they damage cells or they don't seem to work
• If the drug seems to work they it passes on the stage where animal testing happens, this helps us understand the side effects and the dosage to give 
• The animal tests continue or they go on to test it on humans (clinical trials) the recipient is healthy so that they can check that the drug is safe before testing on humans with the illness to make sure that they work
• The drug is then tested on a large amount of people to make sure it works on different types of people 
• Once the drug has passed all the tests and the laws set in place it will be licensed and doctors can use the drug on patients
• The drug will be monitored while in use to make sure it is okay and safe