chapter 1 : transport
DESCRIPTION
CHAPTER 1 : TRANSPORT. 1.5 - The Role of the Circulatory System in the Body's Defence Mechanism. LEARNING OUTCOMES. To state another function of the circulatory system To identify the three lines of defence mechanism To describe phagocytosis To state the meaning of antigen & antibody. - PowerPoint PPT PresentationTRANSCRIPT
To state another function of the circulatory system
To identify the three lines of defence mechanism
To describe phagocytosisTo state the meaning of antigen & antibody
WHY DO WE NEED THE BODY’S DEFENCE MECHANISM?
To defend the body against disease-causing microorganism (pathogens)
Pathogens are bacteria, viruses & parasites
Transmitted by air, contaminated food & water, animal (vector) & contaminated needles. Also by contact.
Non-Specific Defence : First line defence & Second line defence
Specific Defence : Third line defence
BODY’S DEFENCE MECHANISM
NON-SPECIFIC SPECIFIC
1ST LINE 2ND LINE 3RD LINE
SKIN : sweat, sebum
MUCOUS MEMBRANES : secretion of mucus
Phagocytosis by phagocytes
Antibodies produced by lymphocytes
Skin – physical barrier (dead keratinised layer difficult to penetrate
If there is a cut, the blood clots quickly to prevent blood loss & entry of m/organisms
Tears secreted by tear gland & acidic sebum (sebaceous gland) – contain lysozymes which destroy some bacteria
Mucus (mucous membrane) in nasal cavity & trachea traps dust particles & microbial spores
The cilia (respiratory tract) sweep the trapped particles to the pharynx swallow into stomach (secretes HCl)
The phagocytic white blood cell are attracted by chemicals produced at the sites of infection and move to these sites.
Engulf & digest the pathogensThe soluble products are absorbed &
assimilated by the phagocytesMay also be destroyed by toxins produced
by the pathogensNumber of leucocytes increases to try to
destroy the pathogen & neutralise the toxin
In higher group of animals have a more specific immune defence mechanism against pathogen IMMUNE SYSTEM
Two main types of lymphocytes :B-lymphocytes produce antibodiesT-lymphocytes attack cells infected by
pathogen or which produce certain chemicals to coordinate the immunes response.
ANTIGENS – large complex molecules (proteins/polysaccharides) that the immune system recognises as foreign found on the cell membrane of m/organisms/dissolved in the blood plasma/interstitial fluid.
ANTIBODIES – A protein produced by lymphocytes in response to the entry of an antigen into the body.
IMMUNE RESPONSE – interaction between antibody & antigen which result in the antigen being eliminated from the body
AGGLUTINATION : the clumping of antigens easy targets for phagocytes to destroy
NEUTRALISATION : toxin are made non-toxic by reaction with the antibodies
LYSIS : lysin (antibodies) bind to antigens cause antigens/pathogens to rupture
OPSONISATION : The binding of antibodies to antigens stimulate phagocytes (macrophage) to destroy the antigens.
IMMUNITY : The state in which the body is resistant to infection by a disease-causing pathogens @ the ability of an animal or plant to resist infection by pathogens
IMMUNISATION : The process of inducing immunity by administering a vaccine
VACCINE : A preparation of weakened, dead or non-virulent forms of a pathogen
Defence system
specificNon specific
1st line 2nd line3rd line
•Skin
•mucous membrane
Phagocyte
Phagocytosis
lymphocyte antibody
passive active
naturalartificial natural artificial
immunisation
immunity
Divided into
Divided into is
throughproduce
gives
Divided into
Divided into Divided into
are
Carry out
eg
ACTIVE IMMUNITY : when an individual’s own immune system produces its own antibodies to defend against specific antigens
Natural Active Immunity : after recovered from certain disease (examples : mumps, measles & chicken pox)
Artificial Active Immunity : can be established upon immunisation or vaccination. (mumps, rubella, measles & poliomyelitis)
PASSIVE IMMUNITY : when an individual is given the antibodies required to defend against the pathogen
Natural Passive Immunity : when antibodies produced by the mother are passed across the placenta to the foetus during development or in early infancy through breast milk (breast feeding). Colostrum (1st formed milk) – rich in antibodies
Artificial Passive Immunity : ready-made antibody or serum is injected into the individual. Prepared from cows or horses. (rabies, hepatitis, tetanus & snakebites)
Ooo…sleeping in Biology class ek?
So stubborn la.Let me ‘teach’ U first before Mr. FAZLI become angry!!!
Waa….mama! Help me…. I don’t want to fall asleep
in the class anymore!!!I SWEAR!!!