Ch. 16 - Immune System Flashcards
Neutrophils
Where is production/function
- Produced in bone marrow
- Functions: phagocytosis, release chemicals involved in inflammation (vasodiltors, chemotaxins, etc.)
Basophils
Where is production/function
- Produced in bone marrow
- Functions: carry out functions in blood similar to those of mast cells in tissues
Eosinophils
Where is production/function
- Produced in bone marrow
- Function: destroy mulitcellular parasites, participate in immediate hypersensitivity reactions
Lymphocytes
- Mature in bone marrow (B cells and NK cells) and thymus (T cells); activated in peripheral lymphoid organs
- Function: serve as recognition cells in scpeficic immune responses and are essential for all aspects of these responses
B cells
- Initiate anti-body mediated immune responses by binding specific antigens to the B cell’s plasma membrane receptors, which are immunoglobulins. - Upon activation, are transformed into plasma cells, which secrete antibodies.
- Present antigen to helper T cells
Cytotoxic T cells
Bind to antigenes on plasma membrane of target cells (virus-infected cells, cancer cells, and tissue transplants) and directly destroy the cells
Helper T cells
Secrete cytokines that help to activate B cells, cytotoxic T cells, NK cells, and macrophages
Regulatory T cells
Act as inhibitors on other immune cells
NK cells
- Bind directly and nonspecificially to virus-infected cells and cancer cells and kill them
- function as killer cells in antibody-dependent cellular cytotoxicity (ADCC)
Plasma Cells
- secrete peripheral lymphoid organs; differentiate from B cells during immune responses
- secrete antibodies
Macrophages
- produced in bone marrow; reside in almost all tissues and organs; differentiate from monocytes
- functions:
- phagocytosis,
- extracellular killing via secretion of toxic chemicals
- process and present antigens to helper T cells
- Secrete cytokines involved in inflammation, activation and differentiation of helper T cells, and systemic repsonses to infection or injury (acute phase response)
Dendritic Cells
Produced: almost all tissues and organs; microglia in the CNS
Function: phagocytosis, antigen presentation
Mast Cells
Produced: bone marrow; reside in almost all tissues and organs; differentiate from bone marrow cells
Function: release histamine and other chemicals involved in inflammation
Innate Immunity
Nonspecific in that the identity of the target is not recognized
Adaptive Immunity
specific in that the target’s identity is recognized
Lymphatic Vessels begin as:
Fenestrated capillaries composed of a single layer of endothelium attached to a basement membrane
What is transported through Lymphatic vessels?
Lymph (similar to plasma) is transported through progressively bigger vessels, through lymph nodes, until it reaches vena cava
Larger lymphatic vessels contain one-way valves and smooth muscle
Primary lymphoid organs
- bone marrow and thymus
- initial sites of lymphocyte development
- naive lymphocytes (have not been activated by a specific antigen)
Secondary lymphoid organs
- lymph nodes, spleen, tonsils, and lymphocyte accumulations in the linings of the intestinal, respiratory, genital, and urinary tracts.
- where the naive lymphocytes are activated to participate in adaptive immune responses
Thymus
- Flat, bi-lobed organ located in superior mediastinum above heart
- enlarges during childhood, then starts to atrophy as we enter our 20s
- each lobe is comprised of lobules held together by areolar connective tissue
- each lobe consists of a medullary region and cortical region
Bone marrow is the site of:
Leukopoiesis
Lymph nodes
follicles consisting of lymphatic and non-lymphatic cells surrounded by a network of lymphatic capillaries
- each is supplied by afferent lymphatic vessels and drained by efferent lymph. vessels
Outermost cortex of lymph nodes
B-lymphocytes, macrophages, dendritic cells
Paracortex of lymph nodes
T-lymphocytes, dendritic cells
Medulla of lymph nodes
B-lymphocytes, epithelial reticular cells
The spleen
- filters blood, stores erythrocytes, removes defective erythrocytes/platelets, recycles iron (important for fighting infection)
- lies between 9th and 11th rib on left side of body
- contains red pulp and white pulp
Red Pulp in spleen
contains macrophages, erythrocytes, platelets, granulocytes, reticular cells, fibers
Cluster of Differentiation (CD)
- numerical system for classifying proteins expressed on the surface of leukocytes
- CD antigen is protein expressed on the surface of some but not all lymphocytes
Common characteristics of Lymphocytes
contain a single, large nucleus, a small amount cytoplasm, and a wide range of proteins expressed on their surface