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56 terms

A&P: Ch 21 Lymphatic System & Immunity Set 1

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Pathogens
disease-producing microbes (bacteria & viruses)
Immunity/Resistance
ability to ward off damage or disease through defenses
Susceptibility
Vulnerability or lack of resistance to damage or disease
Innate (nonspecific) immunity
defenses present at birth
Adaptive (specific) immunity
develops in response to contact w/ specific invader
Functions of Lymphatic System
1. drain excess interstitial fluid, 2. transport dietary lipids, 3. carry our immune responses
Lymphatic System consists of
lymph, lymphatic vessels, number of structures & organs, red bone marrow
Red bone marrow
stem cells develop into various types of blood cells, including lymphocytes
Lymph nodes
neck, armpits, groin
Lymphatic capillaries
begin as tiny vessels, located in spaces between cells
Capillaries unique because
vessel's unique one-way structure permitting interstitial fluid to flow into them
Lymph trunks & ducts
formed by lymphatic vessels
Skeletal muscle pump
"milking action" of skeletal muscle contractions
Respiratory pump
lymph flow is also maintained by pressure changes occurring during inhalation, trunks drain lymph
Primary lymphatic organs
red bone marrow and thymus
Secondary lymphatic organs
lymph nodes, spleen, lymphatic nodules
Thymus
T cells & scattered dendritic cells, epithelial cells, & macrophages
Lymph nodes
have capsule of dense c-tissue extending into node, functions as filter
Lymph nodes function as
a type of filter
Thymus
bilobed, in mediastium, functional until puberty
Thymus has what cells
T cells, dendritic cells, epithelial cells, & macrophages
Number of lymph nodes
600
Lymph nodes located along
lymphatic vessels
L nodes consist of
T cells, B cells, macrophages, dendritic cells, & plasma cells
Lymph's way of travel
lymph enters afferent lymphatic vessels & drains through efferent lymphatic vessels
Lymph nodes function as
a filter
Spleen
largest single mass of lymphatic tissue
Location of spleen
between stomach and diaphragm
2 types of spleen tissues
White pulp, red pulp
White pulp
lymphocytes & macrophages, location of immune response
Red pulp
RBC, macrophages, lymphocytes, plasma cells, & granulocytes
1 function related to blood cells
macrophages remove word out/defective blood cells & platelets
2nd function related to blood cells
storage of platelets, up to one-thir of body's supply
3rd function related to blood cells
production of blood cells (hemopoiesis) during fetal life
Lymphatic nodules
participate in immune response, small & solitary, some occur in large aggregates (tonsils)
Lymphatic nodules also called
Mucosa-Associated Lymphatic Tissue (MALT) because plentiful in mucus membranes
Innate immunity
acts against microbes in same way
First Line of Defense
skin & mucus membranes
First Line of Defense helps
physical & chemical barriers discouraging foreign substances from penetrating body
1st Line of Defense also helps
flow of urine & vaginal secretions; defecation & vomiting
Second Line of Defense
internal defenses antimicrobial proteins discourage microbial growth
Interferons (2nd defense)
proteins produced by cells infected w/ viruses
Complement System (2nd defense)
enhance certain immune, allergic, & inflammatory reactions
Make up of complement system
phagocytes & natural killer cells -> inflammation
Phagocytosis
Chemotaxis, adherence, ingestion, digestion, killing
Adherence
attachment of phagocyte to microbe/foreign material
Ingestion
plasma membrane of phagocyte extends projections (pseudopods) engulfing microbe, surrounding w/ phagosome
Phagocyte's projections called
Pseudopods
Digestion
phagosome fuses w/ lysosomes to form phagolysosome & lysosomal enzymes breakdown ingested cell
Killing
residual bodies kill materials that can't be digested further
Natural Killer Cells
inject cells with perforin
Perforin
causes perforations in plasma membrane & cytolysis movement of extracellular fluid to rush into cell
Perforations
penetrations, or holes
Perforin releases
granzymes = cell undergoes apoptosis
Apoptosis
programmed cell death
NK cells doesn't kill microbe but
releases it from cell so phagocytes destroy microbe