CB5 - Health, Disease and the Development of Medicines

• What is the definition of Health?

  A state of complete physical, mental and social well being and not merely the absence of disease or infirmity, by the WHO.
• What does WHO stand for?

  World Health Organization
• What are communicable diseases?

  Diseases that can be transmitted from one person to another.
• What are non-communicable diseases?

  Diseases that cannot be transmitted from person to person.
• What is the difference between communicable and non-communicable diseases?

  Communicable diseases are transmittable from one person to another whilst non-communicable diseases cannot be transmitted.
• What is a pathogen?

  A microorganism that causes diseases is called a pathogen.
• What are some examples of pathogens?

  Viruses, bacteria, fungi and protists.
• Why does the presence of one disease increases the susceptibility to other diseases?

  A diseases weakens the immune system and damages the body's natural barriers and defences, making it easier for other pathogens to cause disease.
• What are some of the common infections caused by pathogens?

  Cholera, tuberculosis, chalara ash dieback, malaria and HIV.
• What is cholera caused by, what is its main symptom and what is its scientific name?

  Cholera, Vibrio cholerae, is caused by a bacteria in contaminated water and causes severed diarrhoea. Cholera is transmitted through the water, so it can be prevented by having a good hygiene and treating water supply - this is way cholera is more common on developing countries.
• Who discovered tuberculosis, what is its main symptoms and who causes it?

  Tuberculosis is cause by a bacterium called Mycobacterium tuberculosis which infects and damages the lungs, resulting in blood-specked mucus after coughing, fever and weight loss. TB is transmitted through the air, as tiny droplets containing pathogens are released when an infected person coughs - this makes preventing further infection by using face masks near patients and having a good hygiene.
• Who causes Chalara ash dieback and what are its symptoms in plants?

  Chalara dieback is caused by fungi which infects plants and causes leaf loss and bark lesions. Chalara dieback is spread in the air - strong winds can carry the fungi through large distances, forcing scientists to monitor plants at the southern end of the UK.
• What causes malaria, and what are its main symptoms?

  Malaria is caused by a protist called Plasmodium, which multiplies inside red blood cells and liver cells, causing fever, weakness and sickness. Malaria is spread through animal vectors such as a mosquito, which injects the protist directly into the blood - controlling the spread of malaria involves controlling the spread of the vectors.
• What does HIV stand for?

  Human Immunodeficiency Virus
• What causes HIV and how does it affect the body?

  HVI, caused by a virus, attacks and destroys white blood cells in the immune system. It can be developed into AIDS because their immune system cannot protect them from secondary infections, leading to a high death rates.
• How are STIs such as HIV and Chlamydia are spread and how can this be prevented?

  Such STIs are spread through sexual fluids and can be prevented by using barriers which prevent the contact such as condoms.
• What are some physical barriers used by the human body against diseases?

  The skin, mucus and cilia are all forms of physical barriers that are used by the human body.
• How does the skin help to prevent infection from pathogens?

  The skin is thick throughout the body, preventing pathogens from passing through unless through a wound or animal vector
• How does mucus protect the body from infection by pathogens?

  Mucus is a sticky secretion which is produced in cells lining many opening throughout the body. It traps the pathogens and dust which enters, which later leaves the body with the help of ciliated cells.
• How does cilia help to prevent infection?

  Ciliated cells line the inside of the nose and tubes of the breathing system - ciliated cells move substances such as mucus across surfaces and helps to carry dust and pathogens away, either out of the body or to the digestive system where they are exterminated.
• What are some chemical barriers used by the body to prevent infection?

  Lysozymes and hydrochloric acid.
• How does lysozyme help to prevent infection from pathogens?

  Lysozyme is an enzyme that breaks down the cell walls of some types of bacteria, reacting with substances in the pathogen, killing them or making them inactive.
• How does hydrochloric acid help in prevention of diseases?

  Some cells within the digestive system secrete hydrochloric acid, reducing the pH of the stomach and killing the pathogens.
• What are antigens?

  Molecules on the outer surface of all cells and viruses.
• How does the immune system use antigens to tackle diseases?

  The immune system uses antigens to identify if something within the body is a cell which belongs in the body or something that has come from the outside such as a pathogen.
• What is the role of lymphocytes within the immune system?

  Lymphocytes have antibodies (molecules) in their surface which attach to the antigens in the pathogen. This perfect bonds triggers a response by the immune system in which lymphocytes multiply and release antibodies to kill the pathogen.
• Explain the process undertaken by the immune system when a pathogen enters the body?

  When the body is exposed to a pathogen, a lymphocytes within the blood attaches to the pathogen, linking their antibodies with the antigens on the pathogen's surface. This prevents the pathogen from working and triggers a response from the body, making clones of the particular lymphocyte and releasing large amounts of antibodies, destroying the pathogen. Some lymphocytes than stay as memory lymphocytes.
• What are memory lymphocytes and what are their role within secondary response?

  Memory lymphocytes are long-lasting cells that "remember" a pathogen - the antibodies (tiny connectors on their surface) match the antigens on the pathogen's surface. If the same pathogen tries to infect the body, the secondary response will be much faster and more effective, stopping any illness - this means you're immune to that pathogen for some time.
• How does vaccination make the body immune?

  A vaccine contains a weakened or inactive pathogen (that cannot cause such great or any illness). This injected pathogen provokes an immune response from our body, producing memory lymphocytes and immunity.
• Why can antibiotics be used to treat bacterial infections?

  Antibiotics are substances that either kill or inhibit cell processes in the bacterium, but have no effect in human cells.
• What are the processes of developing new medicines?

  Discovery, development, pre-clinical testing and clinical testing.
• Describe the process within developing new medicines?

  The pre-clinical testing stage shows if the medicine has the wanted effect and allow us to analyse any side effects. The clinical trial is done on a small amount of healthy people, to check its safety and guarantee no side effects. The large clinical trial involves testing on people who have the disease to work on a dosage.
• How are non-communicable diseases caused?

  There are many different factors that can cause non-communicable diseases - they can be genetic disorders caused by faulty alleles of genes or caused by lifestyle choices such as a poor diet or malnutrition which causes a deficiency disease.
• What are some examples of non-communicable diseases?

  Cardiovascular disease, cancer, cirrhosis.
• How is cardiovascular disease developed within the body?

  Malnutrition caused by a poor diet, can lead to obesity and cardiovascular disease - the large amount of fat surrounding the organs causes the circulatory system to malfunction, leading to cardiovascular disease.
• How does smoking have an effect on cardiovascular disease?

  Substances in tobacco, absorbed by the lungs and transported in the blood, can damage blood vessels and increase blood pressure. Such substances make the blood vessels wider and increase the risk of blood clots, leading to cardiovascular disease.
• How do you calculate body mass index?

  $BMI =$$\space mass/height²$
• How do you calculate waist to hip ratio?

  Divide waist measurement by hip measurement.
• What are the treatments of cardiovascular disease?

  A doctor may advise a patient to exercise more and give up smoking. Medicines may be given to reduce high blood pressure and narrowed blood vessels maybe widened by inserting a stent (a small mesh tube) to hold the vessel open. Blocked vessels can be bypassed by inserting other blood vessels.
• How does alcohol cause cirrhosis (liver disease)?

  Alcohol contains ethanol which is broken down by the liver - a large amount of ethanol taken over a long period of time can lead to cirrhosis.