Lymphatic And Immune System 2 Flashcards
What is immunity?
Resistance to disease, specifically infectious disease
What is an immune response?
The coordinated reaction of the immune system and molecules to infectious microbes
What is the immune system?
The collection of cells, tissues and molecules that mediate resistance to infections
What is innate immunity?
Resistance that exists prior to exposure to the microbe(antigen)
Describe innate immunity
It is no specific and includes host defenses such as:
- Barriers to infectious agents (e.g. skin and mucous membranes)
- Certain cells (e.g. natural killer cells)
- Certain proteins (e.g. the complement cascade and interferons)
Involves processes such as phagocytosis and inflammation
Differentiate between innate immunity and acquired immunity
- innate immunity does not improve after exposure to the organism, acquired immunity
- innate immunity possess no memory but acquired immunity is characterized by long term memory
What are the first lines of defense in innate immunity?
- Skin
- Mucous membranes and secretions
- Normal flora
What is the second line of defense in innate immunity?
- Innate immune cells
- Inflammation
- Complement
- Antimicrobial substances
Describe skin
Many layers of closely packed, keratinized cells
How does the skin act as a first line of defense?
The outer epithelial layer of the skin- the epidermis- provides a formidable physical barrier to the entrance of microbes
How can pathogens penetrate the skin?
Pathogens can penetrate the epidermis and invade against tissues or circulate in the blood if there is a broken area in the skin (cuts, punctures, burns etc.)
Where are mucous membranes located ?
Line the body cavities like the GI, respiratory and reproductive tracts
How are mucous adapted to protect in innate immunity?
The epithelium of the mucus membrane secretes mucus which lubricate and trap many microbes and foreign substances
How are the mucous membranes for the upper respiratory tract better adapted for innate immunity?
Mucous membranes if upper respiratory tract contains cilia that propels inhaled dust and microbes that have become trapped in mucous toward the throat
How is gastric juice adapted for innate immunity?
It is a mixture of hydrochloride acid, enzymes and mucous that destroys many bacteria and most bacterial toxins
How does lacrimal apparatus respond to irritants?
Lacrimal apparatus of the eyes produce and drains away tears which contain lysosome , an enzyme capable of breaking down the cell walls of certain bacteria
In what substances in the body is lysozyme present?
Saliva, tears, perspiration, nasal secretions and tissue fluids
Describe the second line of defense
When pathogens penetrate the physical and chemical barriers of the skin and mucous membranes, this is what they encounter:
- Internal antimicrobial substances
- Phagocytes
- Natural Killer Cells
- Inflammation
- Fever
List the internal antimicrobial substances
(I cry in Amps)
- Interferons(IFNS)
- Complement system
- Iron-binding proteins
- Antimicrobial proteins (AMPs)
How do interferons assist in the second line of defense?
An important defense against viral infections by preventing their replication
How does the complement system aid the second line of defense in innate immunity?
Enhancing the immune reaction by causing bursting of microbes, promoting phagocytosis and contributing to inflammation
How does iron-binding protein aid in the secondary line of defense in innate immunity?
Inhibit growth of certain bacteria by reducing the the amount of available iron
How do antimicrobial proteins aid in the second line of defense in innate immunity?
Short peptides that have a broad spectrum of antimicrobial activity including killing a wide variety of microbes and attracting dendritic cells and mast cells, which participate in immune responses
Where are AMPs produced?
AMPs produced by sweat glands,neutrophils, macrophages, epithelial and platelets
How much of the lymphocytes in the blood are Natural Killer Cells ?
About 5-10%
Where are Natural Killer Cells present?
In blood, spleen, lymph nodes and red bone marrow
What type of cell do Natural Killer Cells attack?
Any body cell that display abnormal or unusual plasma membrane proteins
How Batural Killer Cells work?
Natural killer cells bind to target cells such as an infected human cell, Natural killer cells release granules containing toxic substances into the target cells