Immune System Flashcards
What is the immune system
Refers to the collection of cells, tissues and molecules that mediate reactions to pathogens and some non infectious substances (e.g. harmless environmental molecules, tumours and self molecules)
What is the immune response
The coordinated, tightly controlled response of these cells and molecules in the immune system
What is immunity
Often described ass resistance to infectious diseases
E.g. resistance to bacterial, viral, fungal, parasitic infections. However non infectious subatces, damaged and tumour cells can also elicit some immune responses
What are the functions of the immune system
Prevent infection
Eradicate established infections
Control tissue regeneration (wound healing)
Detect and eliminate tumours
Tolerate self (i.e. coexist with our own cells without causing damage)
What are congenital (primary) immune deficiencies
Patients who completely lack key cells and molecules of the immune system. This has severe outcomes
What are acquired (secondary) immune deficiencies
secondary immunodeficiencies (SIDs) are acquired declines of immune cell counts and or/function.
What happens when the immune system overreacts
Asthma
Atopic or allergic reactions
Autoimmune diseases such as sclerosis, SLE, type 1 diabetes
Where is the immune system
It is integrated with other systems such as GI, cardiovascular, respiratory, nervous, endorcine, skin etc
Immune cells are scatterd throughout the body, many of which actively travel (migrate) around it. Whereas others must sit in one place for a long period of time (tissue ‘resident” immune cells)
What is an autocrine function
Autocrine signaling is a form of signaling in which a cell secretes a hormone or a chemical substance that binds to the receptors on the same cell, leading to functional changes in the cell,
What is a paracrine function
paracrine signaling is a form of cell signaling in which the target cell is near the signal-releasing cell
What is an endocrine function
Signalling throughout the whole body
What is the anatomy of the immune system
Physical and chemical barriers
Cells and molecules of the immune system which access most organ systems in the blood: i.e. blood and lymphatic vessels
What are the physical and chemical barriers of the immune system
Epithelial cells of skin, gut, respiratory tract
Secretions including sweat, wax and tears
Mucus in the nose, trachea, gut
Urine
Proteolytic enzymes
Low stomach pH
Normal gut flora
Central and peripheral immune system/tolerance
What are hallmarks of the innate immune system
1) Speed - it is early and rapid - fast acting
2) Short lived duration
3) Repetitive - responds the same way each time a microbe is encountered
4) Interactive - with other cells of the innate and adaptive immune system
5) Non reactive to the host
What are the components of innate immunity
1) Epithelial barriers
2) Cells in circulation and tissues; phagocytes, exocytes
3) Molecules such as cytokines and blood proteins
What do phagocytes do
Their main role is to circulate and migrate through tissues to ingest and destroy both microbes and cellular debris.
What do exocytes do
Contains granules which has toxic enzymes to kill pathogens
What do cytokines do
These are small proteins produced and secreted by many different cell types
They modulate inflammatory and immune reaction
Key mediators of communication between cells
Can target cells in an autocrine/paracrine/endocrine manner
What do chemokines do
These are chemo-tactic cytokines
Different cells express different chemokine receptors allowing them to respond to different chemokines
It helps move cells from a low chemokine concentration to a chemokine concentration
What do blood proteins do
Plasma proteins, sometimes referred to as blood proteins, are proteins present in blood plasma. They serve many different functions, including transport of lipids, hormones, vitamins and minerals in activity and functioning of the immune system.
What is the function of the epithelial barrier
Form of physical protection