Immunity Pt 2 Flashcards
Define pathogen and what is meant by communicable, contagious, and vector
Disease causing micro-ogranism
-communicable/infectious/ and transmissible
Communicable disease-disease passed from one person to another by infection with micro-organisms (also called infectious/transmissible)
Contagious- disease passed on by direct human contact
Vector-agent such as insect capable of transferring a disease-causing organisms from one person to another
Define bacteria. How to reproduce? Pathogenic or not?
Examples
prokaryote, cell wall, lack organelles and nucleus
-binary fission reproduction
-non-pathogenic
-Cholera, Chlamydia, Whooping cough, meningitis
Define virus and it’s structural characteristics. How to reproduce? Pathogenic or not?
Examples
Small, infectious agentl protein sheath surrounding core of nucleic acid;
-depend on living cells to reproduce
-pathogenic
-HIV, AIDS, bird flu, chicken pox
How do pathogens transmit x6 and quick explanation
(direct or indirect for each)
-By contact: direct or indirect physical
-Ingestion: contaminated food/drink
-Transfer of body fluids: blood to mucous membrane contact
-Infection by droplets: breathing, talking, coughing, etc
-Airborne transmission: dehydrated particles
-Transmission by vectors: by animals, insects, ticks, or mites
Difference between specific vs non-specific defences
Specific: defence of the body directed against a specific pathogen e.g. B and T cells
Non-specific: defence of the body that acts against all pathogens e.g. external and internal defences
What are the external non-specific defences x4
-skin: physical barrier
Sebum: oily secretion that kills some pathogenic bacteria
Sweat: salts + fatty acids that prevent bacteria growth
-mucous membranes : Line body cavities that open to exterior. Goblet cells produce the mucus which traps particles
e.g., digestive, urinary, reproductive tracts protected by mucus in nose, lungs, etc
-cilia: tiny beating hair like projections, found in nasal cavity+trachea, move trapped particles in mucus to throat to cough
-hairs: found in nasal cavity to trap particles
Bottom three aid respiratory protection
What are chemical external non-specific defences x3
Acids: Stomach: gastric acids that kill bacteria in food
Vagina: secrete lactic acid reduce growth of micro-organisms
Sweat glands: slightly
Urine: slightly
Lysozyme: Enzyme that kills bacteria. Found in most body fluids and cerumen (protects outer ear against infection by some bacteria, it is slightly acidic earwax)
Fluid movement: flushing action urine and tears
What are the internal defences x4
phagocytosis, fever, inflammatory response, lymphatic system
What are three main types of phagocytes/APC’s (add explanation)
Describe phagocytosis and add diagram
Cellular process for ingesting and eliminating particles
-neutrophils: lifespan few days, make up pus that forms after infection, destroy via phagocytosis
-dendritic cells: use info about ingested particles to assist with specific immunity
-macrophages: mono differentiate into macro once entering tissues
Meaning of itis. Define purpose of inflammation and it’s signs
(it’s non-specific)
itis=inflammation of specific organs/tissues
purpose: reduce spread of pathogens, remove damaged tissue and cell debris, begin repair of damaged tissues
signs: redness, swelling, pain, heat
Define whole process of inflammatory response
(7 steps)
- damage or chemical change will cause mast cells or WBC’s to activate and release histamine and heparin
- Histamine ^blood flow via vasodilation=excess heat loss via radiation/redness due to blood pigment. Also ^permeability of capillaries=more fluid to site of infection=swelling
- Other chemicals released by mast cells attract phagocytes and stimulate pain receptors
- Phagocytes begin to die=pus
- New cells produced via mitosis to repair tissue
reduce spread of pathogens, remove damaged tissue and cell debris, begin repair of damaged tissues
Define fever, e.g.
how it occurs
role of pyrogens
benefits
Elevated body temperature. Body’s thermostat is set at higher temperature (39)
1.macrophage is activated and releases pyrogens (e.g. interleukin-1)
2.pyrogens act on the hypothalamus to increase the set point
3.causes body to produce heat (e.g. shivering, vasocon.)
4.when fever breaks, normal set point re-established
benefits:
-inhibits some microbe growth
-inhibits virus replication through release of interferon
-speed up chem. reactions in body
What does lymphatic system; function and how it differs to circulatory system
-function:macrophagespick up bacteria from tissue, bacteria in lymph, forced to percolate through lymph nodes. There, white blood cells (lymphocytes) attack and kill bacteria.
-differ: lymph vessels are blind ended, unidirectional and absorbent circulatory are none.
What is the immune system composed of
Different types of cells that occur in most organs of the body and that protect against foreign organisms, alien chemicals and abnormal cells.
Define immune response. Function? What are the two part of response?
Homeostatic mechanism triggered by entrance of foreign substances or microorganisms into body (body doesn’t recognise protein)
Helps deal with invasion and restore internal environments to normal condition.
-humoral response/antibody-mediated immunity (B cells)
-cell-mediated response (T cells)
Explain how B-cells and T-cells get their names
Both are produced in the bone marrow and end up in lymphoid tissue. Half the cells go to thymus to mature into T cells before being incorporated into lymphoid tissue. Other half mature in bone marrow to become B cells then become part of lymphoid tissue.
