Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
50 Cards in this Set
- Front
- Back
|
Structure of arteries
|
-Narrow lumen
-Thick muscular wall - withstands high blood pressure -Smooth muscle - alters diameter of lumen to suit blood flow -Elastic fibres - allows walls to stretch and recoil -Lined with smooth layer of endothelial cells - less friction to ease blood flow |
|
|
Structure of veins
|
-Thin wall - blood is constantly under low pressure
-Little smooth muscle and elastic fibres - no pulse of blood so no stretching or recoiling -Wide lumen - acts as blood reservoir -Valves - prevent backflow |
|
|
What happens in atrial systole?
|
-Atria fill from blood from the vena cava (right side) and pulmonary vein (left side)
-Pressure on atrioventricular valves forces them open and blood pours into ventricles |
|
|
What happens in ventricular systole?
|
-Ventricles contract increasing pressure in the chambers
-This pushes blood up and out through arteries -Pressure causes atrioventricular valves to close and prevents back flow into atria |
|
|
What happens in diastole?
|
-Elastic recoil of the heart walls relaxing lowers pressure in atria and ventricles
-Blood under high pressure in arteries is drawn back towards ventricles causing semilunar valves to close -Low pressure in atria during diastole allows them to draw blood into the heart from the veins |
|
|
How does atherosclerosis occur?
|
1. The endothelial lining in the artery becomes damaged by smoking or high blood pressure for example
2. Causes an inflammatory response causing white blood cells to move into artery wall - cholesterol builds up forming atheroma 3. There is a build up of calcium salts and fibres at site which form a plaque 4. Plaques narrow the lumen of the artery leading to a higher blood pressure meaning more damage will occur |
|
|
How does blood clot in arteries?
|
1. Stimulated when there is damage to a blood vessel exposing collagen fibres to which platelets attach to
2. Platelets release clotting factor thromboplastin 3. Plasma called prothrombin is converted into thrombin by thromboplastin 4. Thrombin causes soluble fibrinogen to be converted into insoluble fibrin which traps blood cells to form a clot |
|
|
What is coronary heart disease?
|
-The narrowing of the coronary arteries which supply the heart with oxygen - this may result in angina (heart pain) as the heart is forced to respire anaerobically
|
|
|
What is a stroke?
|
-When blood supply is cut off to a part of the brain
|
|
|
What is the definition of risk?
|
-The probability of an occurrence of some unwanted event or outcome
|
|
|
How can the risk of CVD be reduced?
|
-Stop smoking
-Moderate exercise regularly -Stop over consumption of alcohol -Dietary changed - lower cholesterol and saturated fat intake |
|
|
What are the medical treatments which can help lower the risk of CVD?
|
-Diuretics (antihypertensive)
-Beta blockers (antihypertensive) -ACE inhibitors (antihypertensive) -Statins -Anticoagulants -Platelet inhibitory drugs (e.g.aspirin) |
|
|
What do diuretics do to reduce the risk of CVD?
|
-Increase the volume of urine therefore lowers blood pressure
-Risks: Occasional dizziness, nausea and muscular cramps |
|
|
What do beta blockers do to reduce the risk of CVD?
|
-Block response of heart to hormones such as adrenaline to make heart contractions less frequent and less powerful
-Risks: Possible link with diabetes |
|
|
What do ACE inhibitors do to reduce the risk of CVD?
|
-Block the production of angiotensin which normally causes atrial constriction and a rise in blood pressure
-Risks: Dizziness, cough, impaired kidney function |
|
|
What do statins do to reduce the risk of CVD?
|
-Lower cholesterol in blood by blocking the liver enzyme which makes LDLs
-Risks: Muscle aches, nausea, rarely inflammation reactions could occur which could be fatal, rarely liver failure which could cause death, people will rely on satins and not have a healthy diet |
|
|
What do anticoagulants do to reduce the risk of CVD?
|
-Reduce the risk of clot formation
-Risk: Uncontrolled bleeding could occur, dosage control is essential |
|
|
What are the three monosaccharides?
|
-Glucose: Used for respiration, soluble so has osmotic effect
-Galactose: Soluble so has osmotic effect -Fructose: 'Fruit sugar', soluble so has osmotic effect |
|
|
What are the three disaccharides?
|
-Sucrose: Glucose+Fructose, main transport of sugar in plants, soluble
-Lactose: Galactose+Glucose, soluble -Maltose: Glucose+Glucose, soluble |
|
|
What are the three polysaccharides?
|
-Amylose: Unbranched, found in starch - energy storage molecule in plants, a-glucose molecules in tight spirals, insoluble so no osmotic effect
-Amylopectin: Branched, found in starch - energy storage molecule in plants, branched a-glucose molecules-terminal ends so digested more rapidly, insoluble so no osmotic effect -Glycogen: Energy storage in animals and bacteria, branched chains of glucose molecules, compact and insoluble |
|
|
What are the bonds that form between monosaccharides and how are they formed?
|
-Glycosidic bonds: Formed by a condensation reaction where one water molecule is lost
|
|
|
What is hydrolysis?
|
-The breaking of the glycosidic bond by adding a water molecule
-Reverse of an condensation reaction |
|
|
Which two molecules is starch made up from and what is the difference?
|
-Amylose and Amylopectin
-Amylose has 1,4 glycosidic bonds -Amylopectin has 1,4 and 1,6 glycosidic bonds |
|
|
What is a triglyceride?
|
-Lipids made up of three fatty acids and a glycerol
-Three ester bonds form between the three fatty acid molecules, these bonds are formed by a condensation reaction |
|
|
What are the bonds formed between a triglyceride called and how are they formed?
|
-Ester bond and formed by a condensation reaction
|
|
|
What is made when starch and glycogen are digested?
|
-Glucose - Can be absorbed into the blood stream as they are smaller molecules
|
|
|
How do triglycerides vary?
|
-All glycerol molecules are the same
-Fatty acids vary in: length of hydrocarbon chain whether there is double bonds or not, and how many the mix of fatty acids |
|
|
Characteristics of saturated fats
|
-No double bonds
-When the fatty acid chains contain maximum number of hydrogen atoms, they are saturated -Straight chain molecule -Strong intermolecular bonds -Solid at room temperature |
|
|
Characteristics of monounsaturated fats
|
-One double bond
-Molecule with one kink in chain(one double bond) -Intermolecular bonds are weaker because of kink -Liquid at room temperature |
|
|
Characteristics of polyunsaturated fats
|
-Larger amounts of double bonds
-Intermolecular bonds are weaker due to kinks -Kinks prevent unsaturated fats from packing close together therefore is also liquid at room temperature |
|
|
What are HDL's?
|
-Made when triglycerides from unsaturated fats combine with proteins and cholesterol
-Transports cholesterol from body tissues to liver where it is broken down and removed |
|
|
What are LDL's?
|
-Made when triglycerides from saturated fats combine with protein and cholesterol
-Bind to cell surface receptors leaving LDL's in the blood -Too many in blood would overload membrane receptors and increase cholesterol levels resulting in atheroma |
|
|
What are the factors which increase the risk of CVD?
|
-Genetic
-Gender -Ageing -Diet -High blood pressure -Smoking -Inactivity -Obesity |
|
|
What are the features of cohort studies?
|
-Large number of people followed over a long space of time
-Monitored to see if they develop the condition under study -Two groups are made - one which developed disease, other that didnt -Various risk factors which patients have been exposed to are assessed |
|
|
What are the features of case-control studies?
|
-Group with condition is compared to control group
-Past history is looked at to identify factors to see why one group has condition and other one doesn't -Allows correlations to be found |
|
|
How do you work out the rate of diffusion?
|
Surface area x difference in concentration
_____________________________________________ thickness of the gaseous exchange surface |
|
|
What does an amino acid consist of?
|
-Central carbon atom attached to an amino group (NH2), A carboxylic group (COOH), A hydrogen atom and a R group (varies-can represent one of 20 different side chains)
|
|
|
What is the primary structure of a protein?
|
-Amino acids can join together to form dipeptide or polypeptide chains
-Will always have an amino group at one end and carboxylic group at the other so can join to other amino acids -Can form amino chains of infinite length |
|
|
What is the bond between two amino acids called and how is it formed?
|
Peptide bond which is formed by a condensation reaction
|
|
|
What is the secondary structure of a protein?
|
-Amino and carboxylic groups in chain carry small amounts of charge (negative on CO of carboxylic and positive on NH of amino group
-These charges result in hydrogen bonds being formed these can turn the amino acids into a helical structure |
|
|
What is the tertiary structure of a protein?
|
-Further folding forms a 3D shape held together by bonds between R side chains as well as hydrophobic interactions. These are:
Hydrogen bonds Ionic bonds between ionised R groups Covalent bonds (e.g. disulphide bridge) Polar interactions - hydrophilic and hydrophobic heads and tails arrange themselves |
|
|
What is the quaternary structure of a protein?
|
-Two or more polypeptide chains held together by hydrogen bonds, for example haemoglobin
|
|
|
What is a globular protein?
|
-Complex tertiary structure
-Soluble due to hydrophilic side chains -Enzymes are globular as the 3D shape allows them to form enzyme-substrate complexes and catalyse reactions |
|
|
What is a fibrous protein?
|
-Do not fold up, remain as long chains
-Can be cross-linked to add additional strength -Insoluble and are important for structural properties -Keratin for example in skin and hair |
|
|
What is an enzyme?
|
-A biological catalyst that speed up chemical reactions
|
|
|
What is the active site of an enzyme?
|
-The place where the substrate binds onto the enzyme, only certain shaped substrates can bind on different enzymes active sites
|
|
|
What is the lock and key hypothesis?
|
1. Enzyme and substrate with the same shape collide and substrate enters active site
2. Enzyme-substrate complex forms, the enzyme holds the substrate in a way it reacts quickly 3. Once reaction has taken place, the products are released and the enzyme is unchanged |
|
|
What is the induced fit theory?
|
- When substrate enters active site it changes it slightly, fitting more closely around the substrate
- The active site goes back to its normal shape once substrate is removed |
|
|
What is the activation energy?
|
-The energy needed to break the bonds and start the reaction
|
|
|
How do enzymes lower the activation energy?
|
-Creating a pH within the active site which makes the reaction more likely
-Assisting the breaking or making of bonds as charged groups in the active site interact and distort the shape of substrate |
