defense against disease! immunity. diseases can be caused by a variety of organisms. bacteria or...
TRANSCRIPT
Defense against disease!Immunity
Diseases can be caused by a variety of organisms. • Bacteria or single cell organisms invade cells or tissues. Some
produce a toxin. This post is probably full of bacteria!
• This may cause a staph infection – caused by the bacteria staphylococcus aureus which invades cuts and breaks in the skin
Viruses! use a host cell to duplicate (this is the lytic cycle)
Ebola, AIDS and the Bird Flu are all examples of viruses.
Worms and Parasites!
Worms and parasites invade the body and take away tissue or other nutrients
• Note that many very gory pictures were omitted… most of them involved an anus and roundworms
Heart worms in a dog can grow 14” long.
• Roundworms can cause Trichinosis – a food borne illness that involves eating undercooked pork infested with the worm.
• Flatworms – most common to you is the tapeworm – YUCK!
Fungi!• Causes Ringworm….• Ringworm is caused by several
different fungus organisms that all belong to a group called "Dermatophytes”
• Can be transferred through direct or indirect contact.
Protozoa-Amoebic dysentery
1st line of defense: Barriers against microbes
Skin is slightly acidic- pH of 3-5, and relatively dry
• Skin covers the body
Mucous membranes trap foreign material –wet and sticky!
Cilia of the trachea will beat the ‘crap’ back up to the oral cavity where the trapped material meets its doom in the digestive system.
Don’t Eat your boogers! Flick them!
How do pathogens get in?
• Inhaled – respiratory tract
• Food, water and other things – digestive tract.
• External invasion route – cuts and abrasions in skin.
• Point of entry may determine disease.
What happens when something gets inside the body?
Trypanosomes – African Sleeping Sickness – Transmitted by the Tsetse Fly
2nd line of defense is usually Phagocytosis – eating by the cell
‘phago’ = eat.
‘cyto’ = of the cell.
‘leuco’ = ‘white’
‘phagocytosis is the process where a leucocyte recognizes a foreign body and engulfs it.
ANTIGEN?
• Antigen is a bad or foreign thing in the body
3rd line of defense: ANTIBODIES!
Antibodies are globular ‘Y’ shaped proteins. – 1. The body makes
antibodies to fight antigens.
– 2. Specific antibodies bond to specific antigens.
The ‘Y’ Shaped antibodies attach to an antigen and make a clump. The clump gets filtered out at the lymph nodes.
B-cells vs. T-cells
• Find a partner to work with.• Determine the difference between B-cells and T-
cells.• Know the difference between them for tomorrow.
We will collaborate our findings. – Where do they come from?– What do they do?– Interesting info
(write, define, draw pictures, etc)
Tuesday, March 20th, 2007.• Syllabus Notes or presentations 1st ?
• Protein synthesis presentations due by Wed.
• Transcription/Translation/Mutation worksheets also due on Wed.
• Mid-term questions on Immune, Circulatory, and Respiratory systems for you on Thursday or Friday.
Syllabus Notes:
• 5.4.1. Explain how skin and mucous membranes act as barriers against pathogens.– Skin almost impossible for
microorganisms to penetrate
– Mucus : traps and prevents organisms from entering
– Eyes: tears contain lysozymes which destroy bacterial walls
– Stomach: very acidic; difficult for survival
What your stomach would do to most bacteria!
Syllabus Notes:
• 5.4.2. Outline how phagocytic leucocytes ingest pathogens in the blood and in body tissue.
Leucocytes or white blood cells are our body’s defense against pathogens!
They are found in the blood and in tissue.
Phagocytic Leucocytes recognize foreign “codes”
on the outside of cell membranes!
Syllabus Notes:
5.4.3. State the difference between antigens and antibodies
ANTIGENMolecule recognized as
foreign by the immune system.
ANTIBODY:
Globular protein that recognizes an antigen.
Phagocytes stimulate
B Cells T CellsB cells mature in the bone marrow T cells mature in the thymusB cell make antibodies to get T cells work on cells that antigens which are ‘loose in the body’ have been invaded by antigen
How do phagocytes and antibodies work together?
B and T cell review:
• Antigen is loose in the body? What is going to kill it?
• B Cells!
•Antibodies are needed? Where do they come from?
•What patrols the body and looks for body cells that have been invaded by a foreign body?
•B Cell!
•T Cells!
Illustration, Robin Hotchkiss
Leucocytes ingest the antigen
Travel to B-cell in lymph nodes. Phago. Leuco.
Will present antigen to B-cell
Helper T-cell will then cause B-cell
to clone its self
Few cloned cells remain as memory
cells.
Majority are plasma cells; secrete large amounts of
specific antibodies.
Drain into blood stream.
5.4.4. Explain antibody production.
How does bonding to an antibody get rid of the antigen?
1. Phagocytes to come and eat the antibody-bonded-to-the-antigen usually in the lymph
OR, if the antigen is a cell, the antibody can make it lyse
How else does an antibody stop an antigen?
• A big clog or glob of antigen-antibodies drop out or precipitate of the area and get trapped in the lymph nodes
• Bonding to the antigen neutralizes it.
Matching Review:
1. Make antibodies
2. Residence in Thymus
3. Disease causing agent
4. Mature in bone marrow
5. Elicits an immune response
a. B cell
b. Pathogen
c. Antigen
d. T cell
e. Plasma cell
Today and Tomorrow’s Relaxing yet Educating Experience
• Draw a diagram of the heart showing all 4 chambers, associated blood vessels and valves. – Include the direction of blood flow!– Include arteries vs. veins, structure and function.
• Tell me about blood, what is it composed of, what does it transport – through pictures or words.
• Draw a diagram of the ventilation system – trachea, bronchi, bronchioles, and lungs.– Use this diagram to explain the mechanism of ventilation…
how does it work? THIS IS AN ASSIGNMENT TO BE TURNED IN! (2-3 pages)
- more notes to come on heart and lungs
