A&P CHAPTER 20 PT.1

wow freestyle-jay rock & kendrick (20.1 & 20.2)

reticular tissue

contains specialized cells and thin reticular fibers; interweave to form nets that trap disease causing pathogens. predominant tissue type of lymphatic system. found in lymphoid organs and also as independent clusters.

macrophages

mature monocytes that are very active phagocytes

reticular cells

particularly abundant in organs such as spleen and lymph nodes; produce reticular fibers composed of a specialized, thin type of collagen protein.

mucuosa-associated lymphatic tissue (MALT)

loosely organized clusters of lymphoid tissue that protects mucous membranes, which are exposed to a large number of pathogens, protect oral and nasal cavities; found scattered throughout GI tract, respiratory passages, and, to a limited extent, the genitourinary tract. consists of loosely organized clusters of B and T cells that lack a connective tissue

tonsils

specialized malt located around oral and nasal cavities. consists of pharyngeal (posterior nasal cavity), palatine (posterolateral oral cavity), and lingual (base of tongue). has crypts that trap bacteria and debris. can become inflamed.

peyer’s patches

specialized malt located in last portion of small intestine (ileum). defend against any bacteria that have escaped from the large intestine.

appendix

specialized malt that protrudes from large intestine. a blind ended, worm shaped tube that defends the body from bacteria in the large intestine, specifically those that could be pathogenic.

lymph nodes

clusters of lymphatic tissue located along lymphatic vessels throughout the body. have an external connective tissue capsule that surrounds a network of reticular fibers filled with macrophages, lymphocytes, and dendritic cells.  trap approx. 90% of pathogens in lymph, preventing them from being delivered to blood.

spleen

largest lymphoid organ in LUQ. filters blood and processes old RBCs. consists of a network of reticular fibers.

red pulp

component of the spleen that destroys RBCs

white pulp

component of the spleen that has WBCs and dendritic cells, filters pathogens from the blood

thymus

small, encapsulated organ in superior mediastinum; doesn’t trap pathogens. secretes hormones that enable it to generate a population of functional T cells, which is its primary function.

1st line of defense

cutaneous (skin) and mucos membranes (surface barriers) that act as physical and chemical surface barriers that block pathogen entry

2nd line of defense

consists of the responses of the cells and proteins that make up our innate immunity

3rd line of defense

consists of the responses of the cells and proteins that make up our adaptive immunity

innate/nonspecific immunity

responds to all pathogens or classes of pathogens in the same way. consists of antimicrobial proteins and certain cells that respond quickly; dominant response to pathogens for the first 12 hours after exposure. cells and proteins exist in bloodstream, even in absence of a stimulus

adaptive/specific immunity

consists of cells and proteins that must bind to specific antigens to become activated. takes 3-5 days to activate, after that it becomes the dominant response. 

antigens

present on all cells and most biological molecules. identify a cell or molecule as belonging to a specific group.

cell mediated immunity

carried out by T lymphocytes

antibody mediated immunity

carried out by B cells and proteins produced by plasma cells (antibodies)

immunological memory

characteristic of the adaptive immunity in which exposure to an antigen is remembered. allows for a more rapid and efficient response on subsequent exposures to pathogens. 

sebum

gland secretion that has slightly acidic pH that deters growth of most pathogenic organisms

mucous membranes

line all passageways in the body that open to outside, including respiratory, GI, and genitourinary tracts. epithelia lack keratin and are less resistant to mechanical abrasion. 

mucus

secreted by mucus membranes, traps pathogens and other debris and protects underlying cells from chemical and mechanical trauma. 

stomach acid

secreted through mucus membranes in stomach. kills ingested pathogens. 

phagocytes

eat foreign or damaged cells

natural killer cells

located in blood and spleen, function primarily in innate immunity. formed in the bone marrow

dendritic cells

located in many lymphoid organs; part of innate immune response, but main role is to activate T cells of adaptive immunity.

cytokines

diverse group of proteins secreted by cells of both innate and adaptive immunity; have a variety of effects, including regulating development and activity of immune cells.