The immune system Flashcards
Immune cells originate in the ______
Bone marrow
What is the difference between the innate and adaptive immune system?
The innate immune system is always active, but does not respond to specific threats. For this reason, it’s also called non-specific immunity
The adaptive immune system is active only when there is a threat, so it’s slower to act but develops ways to fight against specific pathogens and maintains memory of them in the case of reinfection. Called specific immunity
This type of immunity occurs when antibodies act in the blood instead of within the cell
Humoral immunity
In the adaptive immune system, humoral immunity is driven by _____ while cell-mediated immunity is driven by ____
B cells (humoral immunity is done via antibodies)
T cells (cell-mediated immunity involves attacking the cell directly)
This non-cellular defense is a bacterial enzyme found in saliva and tears
Lysozymes
This non-cellular defense is made up of blood proteins that destroy bacteria by punching holes in their cell wall and disrupting their osmotic regulation. The proteins do this by either the classical (requiring antibodies) or alternative (not requiring antibodies) pathway
The compliment system
These proteins are released by a virus-infected cell. They prevent viral replication, alert nearby cells to decrease their protein production and be on alert, and upregulate MHC I and II to tell the immune system about the infection
Interferons
(Interfering with the viruses ability to transmit)
These cells are part of the innate immune system, originate as monocytes and take up permanent residence in tissues (meaning they don’t migrate around). They perform three duties: Phagocytize invader –> digest invader and break into smaller parts –> bring to the invader to other cells using MHC so that it may be recognized by other immune cells. They also create an inflammatory response
Macrophages
What is the difference between MHC I and MHC II?
MHC I is produced by all nucleated cells. It’s referred to as the endogenous pathway because it deals with proteins already in the cell, and alerts the T-cells to kill the infected cell
MHC II is only produced by professional anti-gun producing cells (like macrophages). It’s referred to as the exogenous pathway because it deals with proteins that have come from outside the cell
How are macrophages and dendritic cells, among others, able to identify the invader and create the appropriate response?
They have pattern recognition receptors which determine what class the pathogen falls into and what is the best defense against it
These cells are non-specific lymphocytes that detect low levels of MHC on cells and induce apoptosis
Natural killer cells
These granulocytes are the most populous granulocyte in the blood but only live for about 5 days. They are phagocytic and target bacteria through chemotaxis, meaning they’re able to follow the chemicals released by bacterial movement and find the source
Neutrophils
These granulocytes release histamines in response to allergens or parasites
Eosinophils
These granulocytes are the least populous granulocyte in the blood. They react like mast cells to allergens, releasing histamines
Basophils
These cells of the adaptive immune system mature in the spleen and bone marrow and produce one type of antibody each.
B-cells
What are the two classes of agranulocytes?
Lymphocytes (B and T cells) and monocytes (macrophages)
What are the three granulocytes?
Eosinophils, neutrophils and basophils
This cell class contain granulocytes and agranulocytes
Leukocytes
How do the granules on granulocytes attack invaders?
They work through exocytosis in the cytoplasm. Toxic chemicals/enzymes attack bacteria, fungi and parasites
These cells of the adaptive immune system mature in the thymus and are responsible for cell-mediated response
T-cells
What is the difference between passive and active immunity?
Passive immunity is acquired when antibodies are injected into the patient, so the immunity doesn’t require any effort from the patient
Active immunity occurs when the pathogen is introduced and the body makes its own antibodies in response
Antibodies are Y shaped and have __ heavy chains and __ light chains
2 and 2
These cells capture, process and present antigens to lymphocytes in order to activate the adaptive immune system
Dendritic cells
How do B-cells attack pathogens? (including where they stay, what kind of cells they create, and the two kinds of response)
B-cells wait in the lymph nodes until they’re exposed to the correct antigen. Then they create two daughter cells: a plasma cell that increases the amount of antibodies produced, and a memory cell that stays in the lymph node for future infection.
B-cells also have primary and secondary responses. The primary response is the initial division occurring during the first infection, and the secondary response is the subsequent attack when the left over memory cell divides into a plasma and memory cell to combat infection
What are the three methods by which antibodies attack antigens?
-Can bind to the antigen and attract leukocytes to phagocytize (called opsonization)
-Can clump antigens together (auggluntinization)
-Can block pathogen invasion by activating B-cells or causing structural changes on the cell surface
T cells undergo two types of selection: positive for _____ and negative for ____
Positive for mature cells that can recognize MHC
Negative for mature cells that cannot recognize MHC and undergo apoptosis
In this type of selection, only the cells that are the best at their job survive. Ex: B-cells with the best match to their antigen survive because they’re able to react the fastest
Clonal selection
(only the best at their job survive in order to make sure the pathogen can be fought off as efficiently as possible)
These T cells recognize MHC II, so they are most effective against bacteria. They secrete lymphokines that recruit other immune cells
Helper T-cells (CD4+ T)
(Help the body mount a better response against the invader)
These T cells recognize MHC I, so they are most effective against viruses. They kill cells by injecting them with toxins that induce apoptosis
Killer (cytotoxic) T-cells (CTL, CD8+)
These T-cells tone down the immune response once infections have been contained
Suppressor T-cells
These T-cells wait for the next exposure
Memory T-cells
These antigens are present on the surface of every native cell in order to let the immune system know the cell isn’t foreign. Autoimmunity occurs when the immune system is not able to recognize these antigens
Self-antigens
B-cells proliferate and develop in this system. It’s made of one-way vessels that increase in size the closer they get to the center of the body and drain into the subclavian vein
Lymphatic system
These nodes provide space for immune cells to be exposed to pathogens, return excess fluid from tissues to veins, and transport biomolecules (like fats) out of the digestive system and into the blood
Lymph nodes
