Biology Unit 1

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  • Created by: Jen
  • Created on: 06-01-13 16:39
Name the 3 types of pathogen that there are
Bacteria, fungi, virus
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Name the 4 things that pathogens can do
Gain entry to the host; Colonize the tissues of the host; Resist the defences of the host; Cause damage to the host tissue
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What is an interface, and what is an example of an interface?
A surface/boundary linking two systems e.g. skin
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What must the linings of the body be, to allow exchange of material (including MOs) sufficiently?
moist, thin, large surface area, well supplied with blood vessels
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Common entry sites to the body?
Gas exchange system; Digestive system (food and water)
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What 3 defence mechanisms does the body have, to prevent the entry of pathogens?
Mucous layer; Stomach acid; Enzymes produced
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Once inside, what do the pathogens do?
Damage the host tissue; Produce toxins
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What is 'Epidemiology'?
Study of incidence and pattern of a disease; attempts to find prevention and control of disease
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Why can an evaluation NOT be based just on a correlation?
Correlation does not prove causation; It can be due to another factor
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What are the risk factors closely linked with cancer?
Smoking; Sunlight; Diet; Exercise; Obesity
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What are the risk factors closely linked with coronary heart disease?
Smoking; High blood pressure; Blood cholesterol levels; Obesity; Diet; Physical activity
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What is the difference between atmospheric pressure, and pulmonary pressure?
Atmospheric pressure is the air around us, whereas pulmonary pressure is the air within our lungs
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Explain the five steps of inspiration
External intercostals contract, internal interscostals relax; Ribs move up and out (incease volume of thorax); Diaphragm contracts (flattens); Increased volume, decreased pressure; Atmospheric pressure greater than pulmonary pressure, so air goes IN
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Explain the five steps of expiration
Internal intercostals contract, external intercostals relax; Ribs move down and in (decrease volume of thorax); Diaphragm relaxes (domes); Decreased volume, increases pressure; Pulmonary pressure greater than atmospheric pressure, so air goes OUT
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What is the pulmonary ventilation equation?
Pulmonary ventilation (dm3 min-1) = Tidal volume (dm3) x Ventilation rate (min-1)
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How do gases travel from an alveolus to the capillary?
Gases pass through thin walls of alveoli (through alveolar epithelium) & through capillary epithelium, and into blood stream
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What features are important for exchange on and exchange surface?
Large surface area to volume ratio; Very thin; Partially permeable; Movement of environmental medium; Movement of internal medium
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What is Fick's law?
Diffusion is proportional to: (surface area x difference in conc.) / length of diffusion path
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Why is there rapid diffusion?
RBCs slowed down; Distance between alveolar air & RBC very short; Thin walls between alveoli & capillaries; Large surface area; Diffusion gradient maintained
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What are the symptoms of the lung disease, fibrosis?
Shortness of breath; Chronic dry cough; Pain and discomfort in chest; Weakness and fatigue
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What is asthma?
Affects the lungs. Lining of airways become inflamed; cells of epithelial lining secrete more mucous; fluid leaves capillaries & enters airways; muscle around bronchioles contract so restrict airways
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What is emphysema?
Lung disease. Interferes with lung function of providing large surface area. Shortness of breath; Chronic cough; Bluish skin coloration
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What is tuberculosis (TB)?
Caused by rod shaped bacteria. Persistent cough; Tiredness; Loss of appetite; Fever; Coughing blood. Spread through air by droplets from infected people.
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Explain the "Double Circulatory" system
Deoxygenated blood pumper from heart to lungs; Blood receives oxygen & pumped back to heart; Oxygenated blood then pumped to rest of body; Oxygen leaves blood, used for respiration in body & blood goes back to heart
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What are the tendons that connect the valves to the muscles?
Chordae tendinae
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What is the only artery in the body that carries deoxygenated blood?
Pulmonary artery
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What is the cardiac output equation?
Cardiac output = Heart rate x Stroke volume
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What does 'myogenic' mean?
Generates its own contraction
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Explain what happens with atheroma
Fatty deposit forms on wall of artery; WBCs take up LDLs & white streaks occur; enlarge to become plaque; Plaque bulge into artery wall causing reduced blood flow
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Explain what happens with thrombosis
If atheroma breaks through endothelium of blood vessel, a blood clot results (Thrombosis); Blood flow reduced/stopped; Tissues die due to no oxygen
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Explain what happens with aneurysms
Weakened points swell & cause blood filled structure (Aneurysm); Frequently burst leading to haemorrhage;
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What is a myocardial infarction?
Often known as a heart attack. Reduced supply of oxygen to muscle of heart; Occurs close to coronary artery & aorta; Blockage further along artery, symptoms milder;
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Describe the process of phagocytosis
Phagocyte attracted to bacteria by chemicals; Engulf bacteria; Bacteria is contained within a phagosome; Lysosomes fuse with phagosomes & release enzymes; Bacteria is digested
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Where are T-cells and B-cells matured?
T-cells are matured in the thymus gland, N-cells are matured in bone marrow
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How do T-cells kill infected cells?
Produce a protein that makes holes in cell membrane; Cell becomes freely permeable so die as a result; Action of T-cells best with viruses as they live inside cells; This sacrifices body cell which hosts virus to stop virus multiplying
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What do B-cells do in humoral immunity?
Surface antigens on pathogen taken up by B-cells; B-cells present them on surface; T-helper cells attach to antigens, activate B-cells; B-cells divide by mitosis (clones); Some B-cells become plasma cells, antibodies produced (destroy pathogen)
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What are polypeptide chain held together by?
Peptide bonds
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What is passive immunity?
Introduction of antibodies from outside source. Not replaced when broken down in the body. Short lived
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What is active immunity?
Produced by stimulating the production of antibodies by the individuals own immune system. Generally long lasting
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Other cards in this set

Card 2

Front

Name the 4 things that pathogens can do

Back

Gain entry to the host; Colonize the tissues of the host; Resist the defences of the host; Cause damage to the host tissue

Card 3

Front

What is an interface, and what is an example of an interface?

Back

Preview of the front of card 3

Card 4

Front

What must the linings of the body be, to allow exchange of material (including MOs) sufficiently?

Back

Preview of the front of card 4

Card 5

Front

Common entry sites to the body?

Back

Preview of the front of card 5
View more cards

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