15964751 Body Defence Mechanism
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Transcript of 15964751 Body Defence Mechanism
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TRANSPORT
CIRCULATORY SYSTEM IN
BODY DEFENCE MECHANISM
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BODY DEFENCE MECHANISM
To protect body against pathogens (disease-causing MO) that may enter.
Transmission of pathogens:
Air Contaminated food
Animal vectors
Contact
patho: disease
gens: agents
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LINES OF NATURAL DEFENCE
First Line
Second Line
Third Line
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BODYS DEFENCE MECHANISM
NON-SPECIFIC SPECIFIC
1ST LINE 2ND LINE 3RD LINE
SKIN : sweat, sebum
MUCOUSMEMBRANES :
secretion of mucus
Phagocytosis by
phagocytes
Antibodies produced by
lymphocytes
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FIRST LINE OF DEFENCE
Prevention of pathogens entering the body by
mean of physical and chemical barriers.
Skin
Sweat
Sebum
Tears and saliva
Mucous membranes
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Skin A physical barrier
It has dead keratinisedlayer that is hard to
penetrate
Continual shedding of
dead skin cells prohibit
growth of pathogens
If there is a cut, the
blood clots quickly toseal the wound
To prevent blood loss
and entry of pathogens
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Sweat and Sebum
Produced by skin as
chemical barrier
Protective film over skin
Acidic sebum secretedby sebaceous glands
contain lysozymes,
which destroy cell walls
of certain bacteria
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Tears and Saliva
Tears and saliva
contain lysozymes,
which destroy bacteria
(protect eyes andmouth)
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Mucous Membranes
Lines trachea, respiratory passageways, digestiveand urogenital tracts.
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Mucous Membranes:Methods of Defense
Mucussecreted in the nasal cavity and
trachea
traps dust particles and microbial spores
contains lysozyme to destroy bacteria
The ciliain the respiratory tract sweep the
trapped particles to the pharynx.
The hydrochloric acidin gastric juice can killmany microorganisms
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SECOND LINE OF DEFENCE
The non-specific killing action by
phagocytic WBC (e.g. neutrophil-blood, macrophages-IF;some dissolved e.g. venom and toxin).
They are attracted by chemicals produced at
the sites of infection, engulf and ingest MO or
other particles (like debris) by phagocytosis. Some phagocytes may also be destroyed by
toxins of pathogens.
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THIRD LINE OF DEFENCE
Immune System
System triggered in response to the presence
of foreign substance (antigen= proteins /
polysaccharides usually found on cell membrane
of MO or foreign tissues) in our body.
Specific / targeted response
Immunity The state which the body is resistant to
infections by pathogens
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Lymphocyte
Lymphocytes
B Lymphocytes
produce antibody
T Lymphocytes
attack infected cells
or secrete certain
chemicals to
coordinate immune
response
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Antibody
Protein produced by lymphocytes in response
to the entry of an antigen into the body.
Each type of antibody is specific to a
particular antigen.
They help to destroy pathogens in different
ways.
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Types of Antibody
Action
Neutralisation neutralizes toxins
Agglutination binds to surface of antigens and
cause clumping of bacteria cells Precipitation precipitates soluble antigens to
form immobile precipitates
Opsonisation binds to surface of antigens tostimulate phagocytosis by macrophages
Lysis binds to surface of antigens to form poreson cell membrane, which leads to cell rupture
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OPSONIZATION
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AGGLUTINATION
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Memory Lymphocyte
After recovery, some lymphocytes remain fora period of time. Memory lymphocytes
Defend against future infection.
Infection by the same type of antigen
Therefore, we are immune against particular
diseases. Immunity ability of organism to resist infection
by pathogens or their toxin effects.
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Types of Immunity
Naturally Acquired
Active
Passive
Artificially acquired
Active
Passive
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Homework
Find the graphical representation of each
type of immunity.
Draw the line graph(s) in a piece of A4 paper
Make sure there are: Title
Axis labels and units
Graph labels
1
3
2
4Your A4 paper must be divided into 4
equal parts for this assignment
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HIV and AIDS
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HIV Replication
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Effects
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Symptoms
Some people get fever, headache, sore muscles and joints,stomach ache, swollen lymph glands, or a skin rash for one or twoweeks. Most people think it's the flu. Some people have nosymptoms (AIDS.ORG 2003). In the later stages of HIV symptomsmay include:
Persistent, unexplained fatigueSoaking night sweats
Shaking chills or fever higher than 100 F for several weeks
Swelling of lymph nodes for more than three months
Chronic diarrhoea
Persistent headaches
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Transmission
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How can you avoid infection?
The only 100% safe way to avoid HIV
infection are through abstinence and never
sharing needles.
If you decide to be sexually active, youshould use a condom.
For medical procedures, you can donate your
own blood in advanced.
http://www.learnitliveit.org/english/definitions.asphttp://www.learnitliveit.org/english/definitions.asp -
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World AIDS Day 1st Dec
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CV disorders (eg.)
Anemia (ah-NEE-me-yah): Diseased condition in which there is adeficiency of red blood cells or hemoglobin.
Arteriosclerosis (ar-tir-ee-o-skle-ROW-sis): Diseased condition inwhich the walls of arteries become thickened and hard, interfering withthe circulation of blood.
Atherosclerosis (ath-a-row-skle-ROW-sis): Diseased condition in
which fatty material accumulates on the interior walls of arteries,making them narrower.
Hemophilia (hee-muh-FILL-ee-ah): Inherited blood disease in whichthe blood lacks one or more of the clotting factors, making it difficult tostop bleeding.
Hypertension (hi-per-TEN-shun): High blood pressure.
Leukemia (loo-KEE-mee-ah): Type of cancer that affects the blood-forming tissues and organs, causing them to flood the bloodstream andlymphatic system with immature and abnormal white blood cells.
Sickle cell anemia (SICK-el cell ah-NEE-me-yah): Inherited blooddisorder in which red blood cells are sickle-shaped instead of roundbecause of defective hemoglobin molecules.
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Appreciating a healthy CV system
Stick to a nutritious, well-balanced diet.
Control your blood pressure.
Control blood cholesterol.
Prevent and manage diabetes.
Quit smoking.
Minimize stress.
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An electron micrograph scan of a human aortic valve. The aorta is the main artery of the systemic circulation. (Photograph
by P. Motta. Reproduced by permission of Photo Researchers, Inc.)