Protection against disease Flashcards
List non-specific defence mechanism?
Skin
Tears
Saliva
Mucus
Cilia
Phagocytosis
How does skin work against pathogens?
Made of indigestible keratin
Secretion of sebaceous glands at hair follice have antiseptic properties agains some bacteria
Commensal bacteria competes with pathogens for nutrients on skin reducing number of pathogens
How does tears and saliva work against pathogens?
Contain lysozyme breaking cell wall of bacteria
How does mucus work against pathogens?
Secreted by epithelial cells
Traps bacteria and dust entering air passages
It contains lysozyme and other antibacterial substances
How does cilia work against epithelial cells?
Hairs on epithelial cells on upper parts of respiratory teact
Create current moving mucus and traped matterial to pharynx
Swallowing carries them to stomach where it gets killed
Coughing and sneezing also removes them
How does cilia work against epithelial cells?
Hairs on epithelial cells on upper parts of respiratory teact
Create current moving mucus and traped matterial to pharynx
Swallowing carries them to stomach where it gets killed
Coughing and sneezing also removes them
Describe phagocytosis?
Phagocyte detects pathogens and extends pseudopodia
around it
Then engulfs it forming phagosome
Lysosome fuse with vacuole causing hydrolysis of pathogens
Insoluble parts gets exocytosis and soluble parts gets absorbed
What is 2 main specififc defence system?
Humoral response
Cellural response
What is immune system?
Defense mechanism activating lymphocytes against antigens
What is antigens?
Protein or glycoprotein that is (or seems) foreign to organism
Stimulates antibody production
Present on:
-surface of cell
-Free molecule such as toxin
What is structure of antibodies?
Globular protein
Has 4 polypeptide chains - 2 heavy and 2 light joined via disulfide bonds
Each chain consisit of constant region and variable region
Variable regions form 2 antigens binding site
This allows binding to 2 different antigens
Allows also formation of lattice like antibody-antigen complex
These have specific tertiary structure complementary to antigens
What is constant region in antibodies?
Has sequence of amino acids is same in all molecules of the same type of antibody
What is variable region in antibodies?
Has amino acid sequence different in different molecules of the same type of antibody
What is 5 types of antibodies?
IgG, IgM, IgA, IgD and IgE
What is agglutination and how it happens?
Clumping cells having antigen(agglutinogen) against with specific antibodies(agglutinins) react
Antibody can attach to same antigens of same cells
This joins cells together, linking more form an agglutinated mass that can be all destroyed