Food and Health

Four polypeptide chains (light and heavy) held together by disulfide bridges.

Constant region, same in all antibodies. Enables antibody to attach to phagocytic cells and helps in process of phagocytosis.

Variable region, specific shape, differs for each antibody as a result of its amino acid sequence. Ensures that the antibody can only attach to the correct antigen. The shape of the variable region is complemetary to the shape of the antigen and can bind to that antigen.

Hinge region, allows a certain degree of flexibility. Allows branches of Y-shaped molecule to move further apart in order to allow attachment to more than one antigen.

Lines airways and alveoli, increases diffusion distance for gaseous exchange.

Presence of many chemicals lying on the surface of the airway could cause an allergic reaction. Smooth muscles in the walls of airways contract, lumen gets smaller, restricts flow of air to alveoli.

Tar paralyses/destroys cilia on surface of airway, unable to move mucus. Stimulates goblet cells to enlarge and release more mucus which collects in all the airways.

->Bacteria/viruses that become trapped in mucus are not removed. Can multiply in mucus, eventually both mucus and bacteria may block bronchioles

-->Presence of bacteris/viruses means that lungs are more susceptible to infection so smokers are more likely to catch diseases, e.g. pneumonia/influenza.

Smoker's cough-attempt to shift mucus full of bacteria that collects in the lungs. Result of irritation of airways by mucus and bacteria, and airways need to be clear so air can get down to the alveoli. -> This constant cough produces effects: Damage to delicate lining of airways and alveoli. The lining is eventually replaced by scar tissue which is thicker and less flexible. Also, the layer of smooth muscle in the walls of the bronchioles thickens which reduces the lumen of the airway and permanently restricts the flow of air.        

Frequent infections will inflame lining of airways, which damages it, particularly the epithelium. It also attracts white blood cells, to deal with pathogenic microorganisms. These then release enzymes so that they can make their way out of the blood and into the airways. These enzymes digest parts of the lining of the lungs in order to pass through into the air spaces.      

(e.g. Elastase) Damages elastic tissue in lining of the lungs. Especially the alveoli and small bronchioles. Loss of elastic tissue reduces elasticity of alveolus wall. As we exhale, alveolus walls do not recoil to push air out. Bronchioles collapse, trapping air in the alveoli. Can burst alveoli as pressure in lungs increases.

Lung cancer-Smoke contains lots of carcinogenic compunds (e.g. Benzopyrene). They are in the tar that lines the delicate surface of the lungs, They enter the nucleus of the cells of the lung tissue, and have a direct effect upon the genetic material. If a mutation affects the genes that control cell division, then uncontrolled cell division may take place. Symptoms: continual coughing, shortness of breath, pain in chest, blood coughed up in sputum.

Chronic bronchitis-Inflammation of lining of airways. Accompanied by damage to cilia and overproduction of mucus, so mucus collects in lungs. Leads to an increased risk of lung infection. Symptoms: irritation in the lungs, continual coughing, coughing up mucus often filled with bacteria and white blood cells.

Emphysema-Loss of elasticity in alveoli, which causes them to burst. Lungs have reduced surface area as larger air spaces are formed. Less surface area for gaseous exchange. An affected person is often short of breath (esp. when exerting themsleves), loss of elasticity makes it harder to exhale, breathing will become shallow and more rapid. Blood is not as well oxygenated and fatigue occurs.

Chronic Obstructive Pulmonary Disease-combination of diseases, including chronic bronchitis, emphysema and asthma.

Nicotine  

• Mimics the action of transmitter substances at the synapses between the nerves. Make nervous system more sensitive, feel more alert.
• Causes release of adrenaline hormone, which has effects that prepare the body for activity. Increases heart rate and breathing rate
• Causes constriction of arterioles, which raises blood pressure in the arterioles. Especially in those leading to extremities, blood flow and oxygen delivery is reduced.
• Makes platelets sticky. Increases the risk that a blood clot/thrombus might form

Carbon Monoxide

• Enters red blood cells, combines with haemoglobin (much more readily than oxygen) to form the stable compund carboxyhaemoglobin. Reduces oxygen-carrying capacity of blood. When smokers exercise, body detects lower level of oygen may cause heart rate to increase.
• Also may damage lining of arteries.

CHD is a disease of the heart caused by the malfunction of the coronary arteries.

Multifactorial disease-number of factors that increase risk of developing CHD:

• High salt intake-decreases water potential of blood, more water held in blood, blood pressure increases, hypertension
• Hypertension-can damage inner lining of arteries
• Atherosclerosis-deposition of fatty substances (including cholesterol) in the walls of the arteries, under the endothelium
• Obesity
• Sedentary lifestyle
• Smoking
• High blood cholesterol concentration
• Age (older), Sex (male), Stress
• Absence of healthy fats (polyunsaturated)/antioxidants (e.g. vitamin A/C/E)
• Genetic factors/family history of cardiovascular disease
• Diabetes

Selective breeding is where humans select the indivdual organisms that are allowed to breed according to chosen characteristics.

Fertilisers are minerals needed for plant growth, which are adde to soil to improve its fertility.

A pesticide/fungicide is a chemical that kills pests/fungi.

An antibiotic is a chemical that kills or prevents reproduction of bacteria.

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

Disease is a departure from good health due to malfunction of the mind or body.

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

A pathogen is an organism that causes disease.

The primary defences are those that attempt to prevent pathogens from entering the body.

The immune response is the specific response to a pathogen, which involves the action of lymphocytes and the production of antibodies.

Antigens are molecules that stimulate an immune response.

Antibodies are protein molecules that can identify and neutralise antigens.

Cell signalling is the communication between cells that allows effective coordination of a response.

A vaccination is deliberate exposure to antigenic material, which activates the immune system to make an immune response and provide immunity.

The skin-the epidermis contains keratinocytes (cytoplasm replaced by protein keratin in process of keratinisation), layer of dead cells is an effective barrier to pathogens.

Mucous membranes-(airways, lungs and digestive system). Epithelium has ciliated and goblet cells, waft layer of mucus along.

Eyes are protected by antibodies in tear fluid.

Ear canal lined by wax, which traps pathogens.

Vagina protected by maintaining relatively acidic conditions.

Phagocytes engulf and destroy pathogenic cells.

Neutrophils-mulitlobed nucleus, maufactured in bone marrow, travel in blood/tissue fluid, found on epithelial surfaces, e.g. lungs. Short-lived, released in large numbers because of an infection. Die after ingesting a few pathogens.

Macrophages-larger cells maunfactured in bone marrow. Travel in blood as monocytes. Settle in body organs, such as lymph nodes where they develop into macrophages. Important role in specific responses to invading pathogens.

Phagocytes have membrane-bound proteins that acts as receptors, and bind to antibodies already attached to a pathogen. (May be assisted by opsonins, proteins)

Infected cells release chemicals, e.g. histamine, which attract neutrophils to the area. Also causes response of making capillaries more leaky so more fluid leaves capillaries in area of infection. Causes swelling and redness, also more fluid passes into lymphatic system so pathogens are led towards macrophages waiting in the lymph nodes.

Macrophages activate lymphocytes in the blood to help fight disease.

Phagocytosis-end products are harmless nutrients that can be absorbed into the cytoplasm.

Neutralisation-antibodies covering the pathogen binding sites prevent the pathogen from binding to a host cell and entering the cell.

Agglutination-a large antibody can bind many pathogens together. The group of pathogens is too large to enter a host cell.

Primary response-takes a few days before the number of antibodies in the blood rises to a level that can combat the infection. Antibodies do not stay in the blood.

Secondary immune response-Production of antibodies starts sooner and reaches a higher concentration.

Antibodies are large proteins produced by lymphocytes, also known as immunoglobulins. Specific complementary shape of a particular antigen. Antibodies attach to antigens and render them harmless.

Cytokines and cell surface molecules used for communication.

Antigen-presenting cells are macrophages that act like phagocytes to engulf and digest the pathogen but they do not fully digest it. They separate out the antigens and incorporate them into a cell surface molecule, which is exposed on the surface of the macrophage. Function-to find lymphocytes that can neutralise that particular antigen.

Natural immunity is gained in the normal course of living processes, e.g. as a result of an infection that stimulates an immune response.

Artificial immunity is gained by deliberate exposure to antibodies or antigens, e.g. vaccine, tetanus injection.

Passive immunity is provided by antibodies that have not been manufactured by stimulating the recipient's immune system, e.g. via mother across placenta, breast milk or tetanus injections.(Short-lived form of immunity)

Active immunity is acheived by activation of the immune system. (Can last for many years or a lifetime)

Deliberate exposure to antigenic material that has been rendered harmless, immune system treats it as a real disease so the immune system manufactures antibodies and memory cells-these provide long-term immunity.

Vaccines can be a harmless/attenuated version, a dead pathogen, a preparation of antigens from a pathogen or a harmless toxin.

Herd vaccination-80-85% of population, enough people are immune that disease no longer spreads.

Ring vaccination-all people in the immediate vicinity of the new case.

Control livestock disease.

Many pathogenic organisms can form a new strain by mutation. Existing vaccines will have little/no effect on new strain. (Influenza virus)

Need for new drugs-antibiotic resistance(selection pressure->evolution), new disease emerging, still no effective treatments for many diseases.

Nutrition is nourishment-the nutrients and energy needed for health and growth.

Carbohydrates-energy source.

Proteins-growth and repair of muscle and other body tissues

Fats-energy source, cell membranes, waterproofing, absorption of fat-soluble vitamins

Vitamins-important roles in chemical processes taking place inside cells.

Minerals-inorganic elements essential to normal functions.

Fibre-indigestible, for healthy functioning of digestive system.

Malnutrition-obesity (adipose tissues)

• Factor in: cancer/cardiovascular disease/type 2 diabetes
• Linked to: gallstones/osteoarthritis/hypertension

Monounsaturated fats are beneficial for health

Cholesterol is found in many foods and is made in the liver from saturated fats. Too much in the blood is harmful. Essential to normal functioning of the body, found in cell membranes and the skin, used to make steroid sex hormones and bile.

Insoluble, needs to be transported around the body so converted to lipoproteins which are transported in the blood.