Essay About Growthdead Cells And Major Factors

Pharm2812 Exam
SECTION B: SHORT ANSWER QUESTIONS1. Give four non-specific host defence mechanisms. Explain how each acts to keep us healthy.  Mechanism and Explanation: Non- specific host defences protect us against any pathogen regardless of species. They can be physical, chemical or biological:Physical Barriers:Skin:Dry, acidic environment helps prevents growthDead cells (keratin cells)discourage colonisationNormal flora of the skin competes with bacteriaFlushing Mechanisms:Lacrimal apparatus: a group of structures that manufactures and drains away tears thus inhibiting colonisation of microbes on the eye.Saliva: helps dilute microorganisms in the mouth and wash them awayUrine: cleansing of the urethra by the flow of urine.Chemical Barriers:Proteins:Complement: group of proteins in plasma. Circulate body in inactive form until activated by foreign substances; promote inflammation and lysing of cells.Interferon: anti-viral proteins that protect neighbouring cells by binding to them and stimulating further production of anti-virals.Biological Barriers:Inflammation:Acute inflammation: response is intense for a short period of time. Usually a result of tissue injury and infection. Steps are:Increase blood flowRise in tempFibrin clots which isolates sitePhagocytic action continues until bacteria destroyedChronic inflammation: response less intense, long lasting and difficult or impossible to remove.2. Give two specific host defence mechanisms. Explain how each acts to keep us healthy.  Mechanism and Explanation: Specific host defences include production of proteins called antibodies and specialised lymphocytes:Humoral Immunity:Involves production of antibodies by B-cellsDefends primarily against bacteria, bacterial toxins and virusesStimulation of B-cells by an antigen results in product of long-term memory cell.Cell Mediated Immunity:Involves specialised lymphocytes called T-cellsT-cells regulate activation and proliferation of other immune cells such as macrophagesEffective against bacteria and virusesCytokines: chemical messengers in immune system.3. Give four major factors that contribute to the emergence of infectious diseases. Explain how each factor is involved. Factor and Explanation:Human demographics and behaviour e.g. age, hygiene, socio-economic statusInternational travel and commerce e.g. spread of disease Microbial adaption and change e.g. antibiotic resistanceBreakdown of public health measures e.g. tuberculosis4. Give four factors that have contributed to the rise of tuberculosis in recent years and explain how each has contributed to this rise. Factor and Explanation:HIV: unsafe sex, drug use, sharing of needlesMovement of peopleHigh risk populationsBreakdown of public health measure: Poorly managed programmes5. Cell morphology can be used to classify bacteria. Draw and name the FIVE most common morphologies of bacterial cells. Give an example of a bacterium with each morphology (state the genus and species name).