SFBH S4 Flashcards
Identify the first line of defence non specific barriers
skin. mucous membranes. cilia. chemical barriers, Body secretions.
Give a description of the defence barrier ‘skin’
- Skin continually grows through new cells developing beneath
- Cells fit tightly together to form protective layer
- Outer layer contain keratin microorganisms cannot penetrate unless broken
What does the defence barrier of skin do?
- Mechanical barrier
- Protects other tissues
- Collects and holds pathogens
- Secretes sebum produce acids that inhibit growth of bacteria and fungi
- If skin broken? blood-clotting mechanism rapidly seals wound to prevent entry of pathogens
Give a description of the defence barrier ‘Mucous Membranes’
• Line digestive, respiratory, reproductive and urinary tracts with mucus
Give a description of the defence barrier ‘Cilia
• Tiny hairs projected from cells lining nose, trachea and bronchial tubes
Give a description of the defence barrier ‘Chemical Barriers’
- Acid in stomach
- Alkali in small intestine
- Enzyme lysozyme in tears
Give a description of the defence barrier ‘Other Body Secretions’
- Secretions from sweat glands
* Oily secretion from hair
What does the defence barrier of mucous membranes do? do?
• IgA antibody Protects against invasion of pathogens
What does the defence barrier of Cillia do?
• Movement of mucous any particles trapped in mucous move to nose opening or pharynx coughed out or swallowed
What does the defence barrier of Chemical Barriers do?
- Stomach acid destroys pathogens, Inc. those carried to throat by cilia and swallowed
- Alkali destroys acid resistant pathogens
- Lysozyme destroys cell membranes of bacteria
What does the defence barrier of other body secretions do?
- Protect body from invasion
* Contains chemicals that destroy bacteria and fungi
What do antigens do?
they trigger an immune response
What is an Antigen?
• Antigen: any foreign substance e.g. virus
o Protein molecules that trigger immune response because of production of specific antibodies
o Each pathogen has its own antigen
Why do organ transplants trigger an immune response?
- Antigen-antibody response result from rejection of transplanted tissue
- Transplanted tissue fails to live and become part of organism
- Transplanted tissue contains antigens identified by body as containing foreign antigen triggers immune response
The second line of defence - non specific responses- name the defence adaptions there are.
inflammation response, phagocytosis, lymph system, cell death to seal off pathogen
Give a description of the second line of defence adaption ‘inflamation response’
• Designed to isolate and destroy foreign particles
• Prepare tissues for healing
• Dilation of blood vessels increasing blood flow and raising temperature of tissue
Helps confine pathogen for WBC to destroy it
• Mediated by chemicals such as histamine and prostaglandins released by damaged tissues
Give a description of the second line of defence adaption ‘Phagocytsis’
- Phagocytes WBCells that engulf and destroy micro-organisms
- Important body’s immediate defence against infection
- Acute inflammation (lasting hours or days) neutrophils
- Chronic inflammation (weeks or months) macrophages
Give a description of the second line of defence adaption ‘Lymph System’
• Fight disease at second and third line of defence
• System of vessels
• Drains intercellular fluid back to blood
• Contain spleen, bone marrow and thymus
• Lymph nodes filter out foreign bodies e.g. harmful bacteria and cell debris
contain lymphocyte and macrophages
found in armpits, neck and groin
enlargement sign of infection
Give a description of the second line of defence adaption ‘Cell death to seal off pathogen’
• After phagocytes destroy antigen die
• Phagocytes – Macrophages and Lymphocytes Form region that contains dead cells and phagocytes
Thick layer of dead cells off pathogen in structure like cyst
Prevents entry of nutrients to pathogen killing it
Name a disease that results from an imbalance of microflora in humans
Candidiasis
Candidiasis is caused by…
• Caused by fungus Candida albicans
o Natural micro-organism
o Occurs in mouth, respiratory tract, female genital tract and gastrointestinal tract
Candidasis occurs when…
there is an when imbalance of Candida albicans cells
o Usually kept in balance by competition from other micro-organisms, such as lactobacilli (bacteria found in gastrointestinal tract)
The increase of Candida can be caused by?
o Taking antibiotics or steroids o Use of oral contraception o Pregnancy o Malnutrition o Diabetes mellitus
