Biology

Plasmodium

Female Anopheles mosquito

• Red blood cells
• Liver

HIV

Mycobacterium tuberculosis

• Kills 3 million per year
• Affects 300 million
• In tropical regions

• Speading in pandemic proportions
• 45 million living with it

• 1.6 million killed
• 30% of worlds population

• Skin
• Mucus
• Tear fluid
• Ear wax
• Stomach acid

• Phagocytes:
• Neutrophils- manufactured in bone marrow, released in large numbers
• Macrophages- larger cells, initiate immune response
• engulf and destroy pathogens

• Pathogen attached to phagocyte by antibody and surface receptors
• Pathogen engulfed by infolding of phagocyte membrane
• Lysosomes release lysins into phagosome
• Harmless end products of digestion are absorbed

• Produced by lymphocytes
• protein molecules that can identify and neutralise antigens
• 

• a diet that contains all the nutrients required for health in appropriate proportions
• contains: carbohydrates, proteins, fats, vitamins, minerals, water, fibre

• malnutrition
• deficiency
• obesity: consuming too much energy, causes cancer, type 2 diabetes, cardiovascular disease, gallstones and osteoarthritis

• high-density lipoproteins (HDL): produced by unsaturated fats, cholesterol and protein, carry cholesterol from body tissues to liver, reducing blood cholesterol levels, reduce deposition in the arteries
• low-density lipoproteins (LDL): produced by saturated fats, carry from liver to tissues, causes depostion in arteries

• caused by the deposition of fatty substances in the walls of the coronary arteries (atherosclerosis)
• diet: salt (decrease water potential of blood), fats, cholesterol

• cooking: denatues enzymes
• salting: dehydrate microorganisms
• smoking: antibacterial chemicals
• pickling: acid pH denatures enzymes
• irradiation: disrupt DNA structure, kills
• freezing: retard enzyme activity

• e.g. Quorn
• Advantages: production faster,no animal welfare issues, good source of protein for vegetarians, no animal fat
• Disadvantages: isolation of protein, protein has to be purified, infection, palatability

a state of mental, physical and social wellbeing, not just the absence of disease

a departure from good health caused by a malfunction of the mind or body

an organism that lives in or on another living thing, causing harm to its host

an organism that causes disease

• the specific response to a pathogen, which involves the action of lymphocytes and the production of antibodies
• primary: combating first infection
• secondary: responding to a second infection quicker

• attaching to antigens
• neutralisation: antibodies covering the pathogen binding sites prevent the pathogen from binding to a host cell and entering the cell
• agglutination: binding many pathogens together, the group of pathogens is too large to enter a host cell

molecules that stimulate an immune response

• have different receptor molecules on their surface
• If an antigen is presented to a T cell with a complementary shaped receptor, the T cell is stimulated, increases in size and starts to divide.
• A clone of identical T cells is formed, all with the correct shaped receptor. These T cells then differentiate to form 4 groups of specialised T cells. These are:

• Killer T cells
• Helper T cells
• Suppressor T cells
• Memory cells

kill infected cells

form a clone if it comes into contact with a complementary shaped antigen. The clone contains mostly plasma cells for immediate use and some memory cells for use in the future

manufacture antibodies

deliberate exposure to antigenic material which activates the immune systemto make an immune response and provide immunity

• Active: immunity achieved by activation of the immune system, last for many years
• Passive: provided by antibodies that have not been manufactured by stimulating the recipient's immune system
• Natural: gained by living processes
• Artificial: gained by deliberate exposure to antibodies or antigens

• microorganisms
• plants

• inflammation of the lining of the airways
• damage to cilia
• overproduction of mucus
• symptoms: irritation in the lungs, coughing, coughing up mucus, lung infection

• loss of elasticity in the alveoli- alveoli bursts, harder to exhale
• symptoms: short of breath
• chronic obstructive pulmonary disease

symptoms: coughing, short of breath, pain in chest, blood coughed up

• lumen of airway gets smaller
• destroyed cilia
• mucus and bacteria block airway
• lungs more susceptible to infections- influenza or pneumonia

• airways and alveoli become damaged- replaced with scar tissue
• frequent infections

• causes addiction
• mimics the action of transmitter substances
• causes release of adrenaline
• causes constriction of the arterioles
• makes platelets sticky

• combines with haemoglobin
• damage lining of the arteries

• CO damages endothelium of the arteries
• damage repaired by white blood cells
• growth of smooth muscle and deposition of fatty substances
• deposition known as atherosclerosis- occurs under the endothelium

• narrowing of lumen by plaques
• angina: severe pain in chest
• heart attack: death of part of the heart muscle
• heart failure: heart cannot sustain its pumping action

• death of part of the brain tissue
• causes: blood clot and artery leading to the brain bursting (haemorrhage)

• age
• gender
• smoking
• obesity
• high blood pressure
• high blood cholesterol levels
• physical activity
• diet
• high salt intake
• genetic factors
• diabetes
• stress

the study of the distribution of a disease in populations and factors that influence its spread