Chapter 16: Lymphatic System Flashcards
lymph nodes
found in groups or chains along the paths of larger lymphatic vessels through the body; contain lymphocytes and macrophages
what do lymphocytes do?
attack viruses, bacteria, & parasitic cells
what do macrophages do?
engulf & destroy foreign substances, damaged cells, & cellular debris
major lymph node locations (7)
- cervical
- axillary
- inguinal
- supratrochlear
- pelvic
- abdominal
- thoracic
where are lymph nodes NOT located?
CNS
lymph node function
- filter harmful particles from lymph
- immune surveillance; monitor body fluids
- center for lymphocyte production
thymus
- soft, bilobed
- in mediastinum
- divided into lobules
- T cells
- thymosin
t cells
mature in thymus; leave thymus and provide immunity
thymosin
hormone produced by thymus; stimulate t cells
lobules (thymus)
contain lymphocytes derived from progenitor cells in red bone marrow
spleen
largest lymphatic organ, contains venous sinuses filled with blood, filters blood
2 tissue types (spleen)
- white pulp
- red pulp
white pulp
lymphocytes
red pulp
rbc’s, lymphocytes, macrophages
pathogens
- disease causing
- bacteria, viruses, complex microorganisms
innate defense
- general defense
- protect against many types of pathogens
adaptive defense
- known as immunity
- more specific & precise, targeting specific antigens
- carried out by lymphocytes that recognize certain foreign molecules
types of innate defense (6)
- mechanical barriers
- chemical barriers
- inflammation
- fever
- natural killer cells
- phagocytosis
species resistance
refers to the fact that certain species are resistant to diseases that affect other species
mechanical barriers
skin & mucous membranes; prevent pathogen entrance, considered first line of defense
ex. saliva & tears
chemical barriers include:
- enzymes
- interferons
- defensins
- collectins
- complement
enzymes
chemical barrier to pathogens
ex. gastric juices & lysozyme in tears
interferons
block viral replication, act against growth of tumors, stimulate phagocytosis
defensins
peptides produced by neutrophils; cripple microbes, by making openings in cell membranes/walls
collectins
proteins that protect against many bacteria, yeast, & some viruses
complement
group of proteins in plasma & other body fluid that stimulate inflammation, attracts phagocytes & enhances phagocytosis
natural killer (NK) cells
- small population of lymphocytes
- very different from T & B cells that provide adaptive defenses
- defend against viruses & cancer cells by secreting cytolytic substances
perforins
secreted by natural killer cells, lyse cell membrane and defend against cancer cells & viruses
inflammation
- redness, swelling, heat, & pain
- process that walls off infection site & inhibits spread of infection
heparin & histamine
increases capillary permeability
phagocytosis
- removes foreign particles from lymph
- in blood vessels & tissues of spleen, liver, or bone marrow remove particles from blood
- most active are neutrophils & monocytes
- chemotaxis
- mononuclear phagocytic system
chemotaxis
chemicals from damaged tissue attract the phagocytic cells to the injury
mononuclear phagocytic system
reticuloendothelium; consists of monocytes & macrophages of the body
fever
begins when viral or bacterial infection stimulates lymphocytes to proliferate, procduing cells that secrete IL-1 which raises thermoregulatory set point
IL-1
endogenous pyrogen; fire maker from within
what does high body temp do?
increases phagocytic activity
dangerous temp
adult = 103
child = 105
macrophages
tissue
monocyte
blood
