Topic 6.3/11.1 Flashcards
Pathogen
Microbes that cause disease
List the primary defence of the body
Skin and mucous membranes
Outline how the skin acts as a barrier to infection
- Tough layer and provides a physical barrier against the entry of pathogens
- Protection against physical and chemical damage
- Sebaceous glands secrete sebum that maintains skin moisture and lowers skin pH (inhibits the growht of bacteria and fungi)
Outline how the mucous membranes act as a barrier to infection
- Secrete a sticky solution of glycoproteins
- Pathogens and harmful particles are trapped in it (swallowed or expelled)
- Antiseptive properties because of the anti-bacterial enzyme lysozyme
Outline the benefits of blood clots
- Seals up the wound and prevents further loss of blood and blood pressure
- Prevents entry of pathogens until new tissue has grown to heal the cut
Outline reasons for a reaction mechanism to regulate blood clotting
- Clots can cause blockages if they occur inside blood vessels
- Should only occur when the skin is cut and the blood vessel is severed
Platelets
- Cellular fragments that circulate in the blood
- Release clotting factors
Outline the process of blood clotting
- Platelets aggregate at the site of injury, forming a temporary plug
- Release clotting factors that trigger off the production of thrombin (enzyme) - Thrombin converts soluble protein fibrinogen into insoluble fibrin
- Fibrin forms a mesh in cuts that traps more platelets and blood cells
- The clot is initially a gel, but dries and forms a hard scab when exposed to air
Coronary thrombosis
- Formation of blood clots in the coronary arteries
- Block suupply of oxygen and nutrient
- Can be fatal unless resolves naturally or through medical intervention
Outline how atherosclerosis cause occlusion in the coronary arteries
- Atheroma develops
- The endothelium of the arteries tends to become damaged and roughened (especially by deposition of calcium salts)
- Atheroma sometimes rupture and cuase a lesion
- Increases the risk of coronary thrombosis
List the factors of increased risk of coronary thrombosis and heart attack
- Smoking
- High blood cholesterol concentration
- High blood pressure
- Diabetes
- Obesity
- Lack of exercise
Describe how phagocytes provide non-specific immunity to diseases
- Squeeze out through pores in the walls of capillaries and move to sites of infection
- Engulf pathogens by endocytosis
- Digest pathogens with enzymes from lysosomes
- Dead phagocytes form pus
Antigen
- Chemicals that induce an immune response inside the body
- Proteins (glycoproteins or other macromolecules) on the surface of the cell membrane of the pathogen that are recognized by a specific antibody
Antibodies
- Protein molecules produced by B-lymphocytes
- Recognize and bind to the antigens on the foreign pathogens
- Each antibody is specific to each type of antigen
State the substance that stimulate a specific immune response
Antigen
Why does it take time for the body to fight off a disease (specific immunity)
- Initially there are few lymphocytes that target the specific antigen
- They produce few antibodies and cannot control a pathogen
- Antigens on the pathogen sticulate cell division of the specific lymphocytes and produce enough antibodies to ctonrol th epathogen and clear the infection
Describe the structure of antibodies
- Two functional regions
- Hypervariable region that binds to a specific antigen
- Another region that helps the body to fight the pathogen in several ways
Memory cells
- Some lymphocytes produced during an infection are not active plasma cells
- Become dormant until the body encounters the same pathogen again
- Then they replicate rapidly
Descibe why the immune response is faster for a second response than first response
- Memory cells can quickly replicate and produce enough antibodies to target the pathogen
Antibiotic
- Chemical that inhibits that growth of microorganisms
- Most ar antibacterial
- Blockprocesses that occur in prokaryotes but not in eukaryotes
- Used to kill bacteria inside the body wihtout causing harm to human cells
What processes in bacteria are targeted by antibiotics
- Bacterial DNA replication
- Transcription
- Translation
- Ribosome function
- Cell wall formation
State the type of cells that human immunodeficiency virus target
Helper T-cell
Outline the consequence of human immunodeficiency virus
- Progressive loss of capacity to produce antibodies
HIV positive
- Early stage of infection
- Immune system makes antibodies against HIV and can be detected
Retrovirus
- Virus that has inheritary information stored in RNA
- Use reverse transcriptase to make DNA copies of its genes once it has entered a host cell