T1 - Lifestyle, health, and risk Flashcards
Open circulatory system
A simple heart pumps blood between cavities. Blood circulates in open areas. Substances diffuse between blood and cells.
Closed circulatory system
Blood is enclosed within vessels, generating higher pressure. Blood travels from arteries to arterioles to capillaries and returns by venules to veins.
Single circulatory system
Carbon dioxide diffuses from blood out, oxygen diffuses into the blood.
Double circulatory system
The right ventricle pumps deoxygenated blood to the lungs, left ventricle pumps oxygenated blood round the body. Leads to a high metabolic rate.
What are the properties of water that make it a good transport medium?
- Water is polar as hydrogen is slightly positive and oxygen is slightly negative, forming a dipole. Other polar substances can easily dissolve in water.
- The specific heat capacity of water is very high to maintain homeostasis. Meaning that a lot of energy is required to change the temperature of the water, therefore minimising temperature fluctuations in living things.
- Water has a high boiling point due to the hydrogen bonds.
- Hydrogen bonding between water molecules creates cohesion and adhesion, which enables effective transport of water and dissolved substances through xylem vessels.
Atrial systole
- Atria fill with blood from the Vena Cava/Pulmonary Vein.
- Atrioventricular valves open because pressure in the atrias are higher than in the ventricles.
- Blood flows into the ventricles. Atria contract.
Ventricular systole
- Ventricles fill with blood.
- Semi-lunar valves open due to higher pressure in ventricles than in arteries, and atrioventricular valves close
- Ventricles contract.
Cardiac diastole
- Low pressure.
- Atria and ventricles relax.
- Semi-lunar valves close.
- Coronary arteries fill.
What is atherosclerosis
- The endothelium becomes damaged.
- There is an inflammatory response causing white blood cells to move into the artery wall.
- A fatty deposit (atheroma) builds up.
- Calcium salts and fibrous tissues build up, causing a plaque.
- The artery loses elasticity, narrows and hardens.
- Causes a rise in blood pressure and damaging endothelium more - positive feedback.
Consequences of atherosclerosis
- Increases chance of blood clots blocking the artery.
- Cells are permanently damaged.
- May result in heart attack, stroke, tissue death
- An artery may burst due to build up of blood.
What is the process of blood clotting
- A series of cascading reactions
- When a blood vessel is damaged, sticky platelets attach to exposed collagen fibres
- Platelets release the protein thromboplastin.
- This activates an enzyme which catalyses inactive prothrombin into active enzyme thrombin in the presence of vitamin K and Ca2+ ions.
- Thrombin then catalyses soluble fibrinogen into insoluble fibrin.
- Fibrin network traps platelets and red blood cells to form a clot.
Risk factors of CVD
- Age
- Heredity
- Physical environment
- Social environment
- Lifestyle
- Behavioural choices
What must a study have?
- A clear aim
- A representative, large sample
- Controlled variables
- Valid and reliable results
How are disaccharides formed?
- Monosaccharides are joined together in a condensation reaction, producing water.
- They are joined by a glycosidic bond.
- They can be split by hydrolysis.
Formation of starch
- Found in plants.
- Starch is made up of amylose, which is an unbranched chain
- has 1,4 glycosidic bonds and is coiled thus compact - storing lots of energy.
- Amylopectin, branched and 1,6 and 1,4 glycosidic bonds.
- branches allows for rapid hydrolysis quickly releasing energy
- Starch is low solubility in water and is compact.
- Can store lots of glucose because it is compact
Formation of glycogen
- Made up of alpha glucose.
- Has numerous side branches allowing rapid hydrolysis.
- 1,4 and 1,6 glycosidic bonds.
- large and compact meaning it can store lots of energy
- Stored in the liver and muscles.
- Used by bacteria, fungi and animals as an energy store.
Triglycerides
- Insoluble in water but soluble in organic solvents.
- Made up of a glycerol backbone and three fatty acid tails, linked by ester bonds in a condensation reaction producing three molecules of water.
Difference between saturated and unsaturated lipids
- Saturated lipids are found in animal fats. They are straight, long chains with no double bonds. Solid at room temperature.
- Unsaturated lipids are found in plants and have double bonds, causing links in the chain, preventing it from packing closely together.
Low-density lipoproteins LDL
- Triglycerides, proteins and cholesterol combine.
- Transports cholesterol to body cells. May be deposited in artery walls causing atheromas.
- LDL receptors in liver determine if excess LDLs need to be broken down
High-density lipoproteins
- Triglycerides with a higher percentage of protein and a lower percentage of cholesterol.
- Transports cholesterol from body tissue to the liver, where it can be broken down.
- Lowers blood cholesterol levels and reduces plaques formed from atherosclerosis.
Describe smoking as a risk factor
- Carbon monoxide binds to haemoglobin instead of oxygen, reducing the supply to cells, increasing heart rate.
- Nicotine produces adrenaline, increases heart rate, causes arteries and arterioles to constrict, raises blood pressure.
- Chemicals in smoke damage the endothelium of arteries.
- Linked with reduced HDL
The benefits of exercise
- Halves the risk of CHD.
- Raises HDL cholesterol.
- Reduces the development chance of Type 2 diabetes.
Describe stress as a risk factor
Releases adrenaline, arteries and arterioles constrict, raises blood pressure.
Describe salt as a risk factor
Kidneys retain water, higher fluid levels leads to higher blood pressure.
Describe alcohol as a risk factor
- Leads to an irregular heartbeat, direct tissue damage, and increases risk of CVD.
- Moderate consumption linked with raised HDL levels.
Describe ACE inhibitors
- Antihypertensives.
- Reduces synthesis of protein (angiotensin II) which causes vasoconstriction.
- Reduces vasoconstriction which lowers blood pressure.
- side effects: dizziness, cough, heart arrhythmia
Describe diuretics
- Increases the volume of urine.
- Decreases blood plasma volume and cardiac output and lowers blood pressure.
Describe statins
- Inhibits an enzyme producing LDLs/cholesterol in liver
- reducing likelihood of plaque building up - lowering risk of CVD
- side effects: nausea, diarrhoea and constipation
Describe the use of aspirin as an anticoagulant
- Reduces the stickiness of platelets and the likelihood of clot formation.
- inhibits clotting factors like vitamin K and calcium ions
- side effects: uncontrolled bleeding
Define basal metabolic rate
The amount of energy used, per day, whilst at rest.
Which two monosaccharides make sucrose?
Glucose and fructose.
Which two monosaccharides make maltose?
Glucose and glucose.
Which two monosaccharides make lactose?
Glucose and galactose.
What is the calculation for the waist-to-hip ratio?
Waist circumference divided by hip circumference.
Properties of phospholipids
- one of the fatty acids of a triglyceride is substituted by a phosphate-containing group.
- Phosphate heads are hydrophilic and the tails are hydrophobic
- phospholipids form a bilayer in the cell membrane as heads face watery environments whereas the tails move away from them.
Definition of correlation
A measure of the extent to which two variables are related.
Definition of a causal relationship
When a factor directly causes a specific effect/outcome.
Why do large animals have a mass transport system?
- Diffusion alone is insufficient
- Because they have small surface area : volume ratio
- Diffusion distances increase
- Metabolic rate increase
- Require network of blood vessels to carry oxygen and glucose around body
- Require high blood pressure from heart and elastic blood vessels
Characteristics of arteries
- Carry oxygenated blood to the body tissues (other than the pulmonary artery)
- Have a small lumen to maintain high blood pressure
- Smooth inner endothelial lining (less resistance to blood flow)
- Thick layer of smooth muscle (contract and relax to dilate and constrict blood vessels - controlling their diameter) and elastic fibres (stretch and recoil)
- Lots of collagen fibres (for strength and support)
Characteristics of veins
- Carry deoxygenated blood to the lungs (except the pulmonary vein)
- Large lumen and smooth endothelium (minimises resistance to flow)
- Thinner layer of muscle and elastic fibres
- Reduced collagen fibres
- Valves (to prevent backflow)
Characteristics of capillaries
- Very small (to fit between cells)
- Narrow Lumen
- Thin endothelium - one cell thick (to maintain short diffusion distance and fit between cells)
- Poreus to allow red blood cells to slightly enter to exchange materials
What are the four main blood vessels in the heart?
- Pulmonary vein - carrying oxy-blood to left atrium
- Aorta - carrying oxy-blood from left ventricle to body
- Vena cava - carrying deoxy-blood to right atrium
- Pulmonary artery - carrying deoxy-blood from right ventricle to lungs
