Chapter 16: Lymphatic System Flashcards
what type of system is the lymphatic system?
closed ended
3 functions of the lymphatic system
- defends body against diseases
- absorbs lipids from digestive system & transports them into bloodstream
- transports excess fluid away from interstitial spaces & returns it back to bloodstream
important cells to lymphatic system
T cells & B cells
lymphatic pathway
- lymphatic capillaries
- lymphatic vessels (afferent)
- lymph nodes
- larger lymphatic vessels (efferent)
- lymphatic trunks
- lymphatic collecting ducts
- subclavian veins in thorax
lacteals
found in small intestine; specialized lymph capillaries that absorb lipids/fats & transfer them back to bloodstream
capillaries
- microscopic, closed ended tubes
- thin walled
- networks parallel blood capillaries through body
- walls formed from simple squamous tissue
vessels
- similar to veins, but thinner
- contain semilunar valves
- 3 layers
3 layers of lymphatic vessels
- endothelial (inner)
- smooth muscle (middle)
- connective tissue (outer)
trunk
- drain lymph from lymphatic vessels
- named for region they serve
lymphatic trunks
- lumbar
- jugular
- subclavian
- bronchomediastinal
- intercostal
- interstitial
collecting ducts
- drain lymph from trunks
- thoracic duct (large) and right lymphatic duct (small)
the thoracic duct drains to
left subclavian vein near junction w/ left jugular vein
the small right lymphatic duct drains to
right subclavian vein
afferent vessel
leads to lymph node
efferent vessel
leads away from lymph node
lymph
interstitial fluid once its entered lymphatic vessels
what does capillary blood pressure do?
filers water & small molecules from the blood
resulting tissue fluid (after capillary bp filters)
- same composition as blood plasma
- contains water, nutrients, gases, & hormones
- exception: tissue fluid does not contain large plasma proteins
lymph formation
formation from the plasma normally exceeds reabsorption leading to the net formation of tissue fluid; increases the tissue fluid hydrostatic pressure within interstitial spaces, forcing fluid into lymphatic capillaries & forming lymph
edema
excess tissue fluid accumulation
when is lymph flow highest?
physical activity & exercise
lymph flow
muscle activity influences the movement of lymph through lymphatic vessels
what factors determine lymph flow?
- contraction of skeletal muscles compresses lymphatic vessels, moving the lymph
- respiratory process creates low pressure in thorax & high pressure in abdomen during inspiration; sends lymph from abdomen to thorax
- smooth muscle in larger lymphatic vessels contract to aid in flow of lymph
roles of lymphatic capillaries (6)
- absorption of dietary fat
- delivery of absorbed fats to bloodstream
- return of small proteins filtered by blood capillaries to bloodstream
- collection of excess interstitial fluid
- delivery of excess fluid to bloodstream
- delivery of foreign particles to the lymph nodes
what allows easy entry of tissue fluid?
flap like valves between cells of lymphatic capillaries
mucosa associated lymphoid tissue (malt)
unencapsulated lymphatic tissue of the digestive, urinary, respiratory, & reproductive tracts
tonsils & appendix
composed of lymphatic nodules (compact masses of lymphatic tissue)
peyers patches
aggregates of lymphatic nodules found in ileum (distal part of small intestine)
lymphatic organs
- consist of encapsulated lymphatic tissue
- lymph nodes, spleen, thymus
how do antibodies react to antigens?
in 3 different ways
3 ways antibodies react to antigens:
- direct attack on antigens
- activation of complement
- stimulation of local change, inflammation, to help prevent spread of infection
immune responses (2)
primary & secondary
primary immune response
produced by first encounter with antigen; 1st antibodies appear in 5-10 sys, and remain for several weeks; memory B cells also produced
secondary immune response
subsequent exposure to antigen produced high concentration of antibodies in 1-2 days; antibodies remain for months or years; memory B cells live for many years
colostrum
very first breast milk; antibody rich
autograft
transplant from self
isograft
transplant from identical twin
allograft
transplant from same species
xenograft
transplant from different species
which transplants tend to cause rejection?
allograft & xenograft
which transplants don’t usually cause rejection?
autograft & isograft
HIV
- virus that breaks down immune system
- caused by infected needles, sexual contact, birth/milk from infected mother
- attacks macrophages and helper T cells
- when helper T cells decrease, B cells can’t produce antibodies
- person dies from loss of immune response against pathogens
