AS Level Biology Topic 1 - Lifestyle, Health and Risk

Cardio-vascular diseases (CDVs)

Diseases that affect the heart and circulatory systems. They are the main cause of death in the UK.

Arteries

The main

Hydrophilic

Polar molecules dissolve easily in water, because their polar groups become surrounded by water and go into solution. Such substances are said to be hydrophilic - "water loving".

Hydrophobic

Non-polar substances, like lipids, do not dissolve in water. They are hydrophobic - "water afraid". They have to bond to form lipoprotiens to be transported.

Collagen

A tough, fibrous protein found in arteries and veins, that makes them strong and durable.

Systole

The process by which blood is forced into the arteries, as the heart contracts it forces the artery walls to stretch to accommodate the blood.

Diastole

The process by which pushes the blood through the arteries, as the heart relaxes the artery walls recoil behind the blood and help to push it forward.

Cardiac cycle

One complete cycle of filling and pumping the blood. I.e. One contraction "systole" and one relaxation "diastole".

Coronary arteries

The two blood vessels which supply blood to the heart.

Atrial Systole

The atria fill and contract to fill the ventricles with blood

Ventricular Systole

Contraction of the ventricles forces blood up into the arteries.

Diastole

Elastic recoil as the heart relaxes, causing low pressure in the heart, which helps it to fill with blood.

Atheroscelorosis

The disease process that leads to coronary heart disease and strokes.

Thrombosis

A Blood Clot.

Myocardial infarction

A Heart Attack.

Atheroma

An atheroma is a fatty deposit in the intima (inner lining) of an artery.

Platelets

A type of blood cell without any nucleus.

Prombothin

Prombothin is a soluble plasma protien.

Thrombin

Thrombin is an enzyme that catalyses the conversion of the soluble plasma protien fibrinogen into long insoluble strands of fibrin.

Angina

A condition caused by the narrowing of coronary ateries, which means that teh heart does not recieve enough oxygen and so has to respire anaerobically. This is thought to trigger pain.

Coronary Heart Disease

CHD is the clogging of the vessels that nourish the heart muscle; the leading cause of death in many developed countries.

Coronary Heart Disease (Symptoms)

Intense pain, ache/discomfort/constriction of the chest and or/in the left arm and/or shoulder, heaviness/tightness/pain/burning behind th breastbone. Women may instead feel unusual fatigue and have shortness of breath.

Arrythmia

An irregular heart beat which can be cause by CHD and can lead to heart failure.

Stroke

A sudden loss of consciousness resulting when the rupture or occlusion of a blood vessel leads to oxygen lack in the brain.

Stroke (Symptoms)

Numbness, dizziness, confusion, slurred speech, blurred or lost vision, paralysis of one side of the body.

Aneurysm

A build up of blood behind the narrowing of an artery, which may have been cause by aetheroscelrosis.

Risk

Risk is defined as the probability of an occurence of some unwanted event or outcome.

Overestimated Risk

Involuntary (not under their control), not naturual, unfamiliar, dreaded, unfair, or if there is a very small risk.

Underestimated Risk

Long-term effects, false perceptions of safety, naturual, very large risk,

Correlations

Reliable associations between two or more events.

Causation

A cause and effect relationship in which one variable controls the changes in another variable.

Null Hypothesis

Assuming that there will be no differnce between an experimental group and a control group.

Cohort Studies

A group of people are followed over time to see who develops disease, comparing exposure to risk factors to draw conclusions, or following people exposed/not exposed to risk factors and comparing outcomes to draw conclusions.

Case Control Studies

Taking the histories of people with and without conditions to compare risk factors and draw conclusions.

Featuresof a Good Study

Clear aim, Representative sample, Valid and Reliable Results, Ethical,

Risk Factors of CVD

High Blood Pressue, Obesity, Blood Cholestrol (dietary factors), Smoking, Genetic inheritance,

Blood Pressure

The measure of the hydrostatic force of the blood against the walls of teh blood vessels. It is shown as systolic/diastolic pressure.

Systolic Pressure

The pressure in an artety at the point in the cardiac cycle when the ventricles have contracted and blood is being forced into the arteries.

Diastolic Pressure

The pressure in an artery when the ventricles are relaxed.

Sphygmanometer

An instrument calibrated for measuring blood pressure in millimeters of mercury.

Oedema

A fluid build up in tissues causing swelling, which may be caused by high blood pressure.

Carbohydrates

A compound made up of carbon, hydrogen, and oxygen atoms; major source of energy for the human body.

Lipids

Fats & Oils

Calorie

A unit of heat defined as the quantity of heat required to raise the temperature of 1 gram of water by 1 degree centigrade at atmospheric pressure.

Joule

SI Unit of energy. 4.19J = 1 Calorie.

Monosaccharides

Monnosaccharides have the empirical formula CH2O and have between three and seven carbon atoms. They include glucose, galactose and fructose whiach are all hexose sugars.

Diassaccharides

Double sugars formed when two monosaccharides join in a reaction known as a condensation reaction - often forming water. Common diassaccharides include sucros, maltose and lactose.

Glycosidic link

Glycosidic links are the covalent bonds formed between monosaccharides

Sucrose

Formed from the combination of gluctose and fructose., the usual form in which sugar is transported around plants.

Maltose

Formed from the combination of two glucose molecules, it is teh diassaccharide formed when amylase breaks down starch.

Lactose

Formed by the combination of galactose and lactose. It is the sugar found in milk.

Hydrolysis

The reverse process of condensation - the process by which glycosidic links in diassacharrides are broken. Water is added to the link and the molecule splits in two. This process takes place in the gut.

Lipids

Lipids are fats and oils that are insoluble in water. They are composed of fatty acids and glycerol.

Triglyceride

A glyceride occurring naturally in animal and vegetable tissues. It is composed of three chains of fatty acids bound together with a glycerol molecule using ester bonds.

Starch

The storage carbohydrate found in plants - it is made up of two molecules, amylose and amylopectin.

Amylose

A molecule composed of a straight chain of between 200 and 500 glucose molecules with 1,4 glycosidic links between adjacent glucose molecules. This causes the chain to curl into a spiral shape.

Amylopectin

Amylopectin is a polymer if glucose (like Amylose), but it has side branches. Each branch is held onto the main chain with a 1,6 glycosidic link.

Glycogen

Glycogen is the storage carbohydrate found in plants, fungi and animals. It has numerous side branches which can be hydrolysed quickly to access stored energy. In humans this is stored in the liver and the muscles.

Cellulose

In the diet cellulose is known as a dietary fibre and it is referred to ass a non-starch polysaccharide. It is composed of up to 10,000 glucose molecules with no side branches (the glucose molecules have a different structure to those found in starch).

Saturated fat

If a fatty acid chain in a lipid contains the maximum number of hydrogen molecules it is said to be saturated. They form long straight chains, can be packed together closely, due to the strong intermolecular forces between triglyceride's made of saturated fats, are solid at room temperature.

Monosaturated fats

Monosaturated fats are fats that contain one double bond between two of the carbon atoms in each molecule.

Polysautrated fats

Polysautrated fats are fats that have more than one double.

Cholesterol

Cholesterol is a short lipid molecule. It is a vital component of cell membranes, many growth or sex hormone and bile salts are formed from cholesterol.

BMR

(Basic Metabolic Rate) - The amount of energy needed to maintain essential body processes, such as heart pumping, breathing and maintaining a constant temperature.

BMI

(Body Mass Index) = body mass (kg) / height^2 (m)

Obesity

Defined as a person with a BMI of 30-40, it increases the risk of CVD, Type II Diabetes, coronary heart disease, hypertension and strokes.

Type I Diabetes

The inability of the body to produce insulin, treated through insulin injection.

Type II Diabetes

The body does not produce sufficient insulin, or fails to respond to the insulin that is produced. It can be caused by continually high blood glucose levels, as this can reduced cells sensitivity to insulin.

Insulin

The hormone responsible for controlling blood glucose levels by forcing cells to absorb glucose. It is produced in the Pancreas.

LDL's (low-density liptoproteins)

The main cholesterol carrier in blood. The triglyceride from saturated fats combine with cholesterol and protein to form LDL's.

HDL's (high-density liptoproteins)

HDL's have a similar structure to LDL's but have a higher proportion of proteins and are formed when triglyceride's from unsaturated fats combine with cholesterol and protein.