Ch 21 Lymphatic System Part 2 Flashcards
T lymphocytes
Mature in thymus
B lymphocytes
Activation causes proliferation and differentiation into plasma cells that produce antibodies
Macrophages
- develop from monocytes
- phagocytize tissue debris, dead neutrophils, bacteria, and other foreign matter
- have antigen presenting cells
Dendritic cells
- branched, mobile APCs found in epidermis, mucous membranes, and lymphatic organs
- alert immune system to pathogens that have breached their surface
Natural killer cells
Large lymphocytes that attack and destroy bacteria, transplanted tissue, host cells infected with viruses or have turned cancerous
Metastasis
Phenomenon in which cancerous cells break free from the primary tumor, travel to other sites in the body and establish new tumors
Treatments of breast cancer
Lumpectomy, mastectomy, and removal of nearby axillary lymph nodes
Three lines of defense against pathogens
- External barriers
- Nonspecific defense mechanisms
- Immune system
External barriers
- skin: hard for microorganisms to enter body; includes keratin, peptides, and sweat that kill or prohibit growth of bacteria
- mucous membranes: protects organs, traps microbes, and has lysozymes that destroy bacterial cell walls
Fever
- abnormal elevation of body temp, an adaptive defense mechanism
- promotes interferon activity
- inhibits reproduction of bacteria and viruses
Exogenous pyrogens
- initiation of fever
- glycolipids on pathogen surfaces
- stimulate neurons in anterior hypothalamus to secrete Prostaglandin E2
PGE2
Raises hypothalamic set point for body temp
Antipyretics
Fever-reducing medications act by inhibiting the production/release of PGE2
Inflammation
Local defensive response to tissue injury
- limit spread of pathogens, then destroy them
- remove debris from damaged tissue
- initiate tissue repair
4 Cardinal signs of inflammation
Redness, swelling, pain, and heat
Cytokines
Class of chemicals that regulate inflammation and immunity
- secreted mainly by leukocytes
- alter physiology or behavior of receiving cell
- act at short range
Local hyperemia
Increasing blood flow beyond normal
- washed toxins and metabolic waste from the site more rapidly
Selectins
Cell-adhesion molecules that aid in the recruitment of leukocytes (make membranes sticky)
Diapedisis or emigration
Leukocytes crawl through gaps in the endothelial cells and enter tissue fluid
Basis of heat of inflammation
Results from hyperemia
Basis of redness of inflammation
Due to hyperemia, and RBCs in tissue
Basis of swelling of inflammation
Due to increased fluid filtration from capillaries
Basis of pain of inflammation
Nerve injury, pressure on nerves from edema, stimulation of pain receptors by prostaglandins, bacterial toxins, and a bradykinin
Fibrinogen
Filters into tissue fluid clots
- forms a sticky mesh that walls off microbes
Heparin
- prevents clotting at site of injury
- pathogens are in a fluid pocket surround by clot
- attacked by antibodies, phagocytes, and other defenses
Chemotaxis
Attraction to chemicals (bradykinin and leukotrienes) that guide them to the injury site
Monocytes
- primary agents of tissue cleanup/repair
- arrive in 8-12 hours, convert into macrophages which consume bacteria, damaged cells, and dead and dying neutrophils
Edema
- forces open valves of lymphatic capillaries promoting lymphatic drainage from swelling
- lymphatic vessels collect and remove bacteria, dead cells, proteins, and tissue debris better than blood capillaries
Pus
Accumulation of dead neutrophils, bacteria, other cellular debris, and tissue fluid form a pool of yellowish fluid
