Immune System Flashcards
antigen
protein (or protein sequence) recognized by an antibody
antigen-presenting cell
large, typically dendritic cell that recognizes foreign cells/materials, internalizes and digests them, and presents the resulting antigens to effector immune cells (i.e. macrophages)
CD marker
cell surface protein that acts as a marker for a class of cells; CD stands for cluster of differentiation
B cells
- cells that will make antibodies
T cells
- cell-mediated immune responses
- differentiate in thymus
what is the function of the immune system?
to protect
what other systems does the immune system require?
- bone marrow and thymus
- spleen and lymph nodes
- skin, mucosa
what role does the bone marrow and thymus play in the immune system?
production & differentiation of immune cells
what role does the spleen/lymph nodes and skin/mucosa play in the immune system?
exposure to antigen and response
what is body’s first line of defense?
skin & mucosal layers
what is innate immunity?
- recognize non-self and attack it
- can kill bacteria directly without requiring any other immune system components
what is adaptive immunity?
- aka acquired immunity
- antibody or cell-mediated immunity
- T cells, B cells, antigen presenting cells
what cells are involved with innate immunity to fight off viruses?
- natural killer (NK) cells
- interferons
what is lamina propria?
- loose CT underneath mucosal epithelium
- typically very rich in immune cells b/c it is surveilling tissue & acts as a barrier
- tries to reduce any bacteria/viruses/etc going deeper into the body
name the resident immune cells in the lamina propria
- macrophages (has indented nucleus)
- mast cells (single central nucleus & contains granules containing histamine/heparin)
- plasma cells (mature B cells, clock face nucleus, comet-like shape)
what is a M cell?
- brings bacteria from lumen of gut to underlying CT
- specialized cell type found in epithelium whose job it is to actually bring bacteria thru epithelium
- occurs where there is a lymph nodule
what is GALT and where is it found?
- Gut-associated lymphatic tissue
- found in oral cavity, esophagus, stomach, intestines, rectum
what is BALT and where is it found?
- Bronchi-associated lymphatic tissue
- found in bronchial tree: bronchus, bronchioles, NOT in alveoli
what is MALT?
- mucosa-associated lymphatic tissue
what type of epithelium lines the respiratory tract?
ciliated pseudostratified columnar epithelium
describe the filtration pathway of the lymphatic system
lymph draining from tissue > lymphatic vessels > lymph node > filtered in node (anything infected should get stuck there) > lymph exits node > returns to blood
what is a high endothelial venule?
- blood vessel within lymph node
- used to regulate movement of immune cells into and out of cortex of lymph node
what can be found in a medullary sinus of a lymph node?
- lymph
- lymphocytes
- macrophages
- APCs
where do the precursors of mast cells mature?
spleen
where can you find a Hassal’s corpuscle?
medulla of the thymus
what does a Hassal’s corpuscle look like?
very eosinophilic cells wrapped in a concentric swirl
describe T cell maturation & quality control
- differentiation begins in CORTEX of thymus = T cell receptor and CD4 and CD8 expression must occur to get out of cortex, or else they will be killed by macrophages within the cortex
- specialize in medulla = express either CD4 OR CD8 and still express T cell receptor
- tested for function = eliminate those that cannot function because not properly expressing receptors (positive selection) AND eliminate those that recognize self (negative selection)
- managed by epithelioreticular cells that tag cells that fail selection process = macrophages digest failures
what are the majority of cells in the medulla of the thymus called?
thymocytes
how do T cells kill?
- cells that make protein that punches holes in target cell membrane; allows granzyme B to enter & start disintegrating the cell
- T cells can also induce apoptotic cell death by secreting Fas ligand that binds to a receptor on the target cell & induces apoptotic pathways
what is the PALS in the spleen?
- Periarterial lymphatic sheath = the lymphocytes immediately around an artery
describe red pulp of the spleen
- remove aging RBCs (destruction, iron recycling)
- blood storage
describe white pulp of the spleen
- in spleen
- T and B cell, and mast cell activation & proliferation
- monitor for blood-borne antigens
where are B cells produced?
bone marrow
where are mast cells produced?
their precursors mature in the spleen
what connects cords and sinuses?
reticular CT
how are antibodies produced?
- produced by mature B cells called plasma cells
