Lymphatics & Immunity Flashcards
functions of lymphatic system:
- fluid balance -between interstitial space & blood capillaries
- liquid absorption -absorbs lipids from digestive tract through Lacteals
- defense -against pathogens and foreign substances
tiny close-ended vessels consisting of simple squamous epithelium exchanging fluids with capillaries, very permeable,
endothelial cells overlap to form one-way flaplike minivalves
lymphatic capillaries
resemble small veins but with elastic membrane surrounding the epithelium , beaded appearance
collects lymph from lymph capillaries
carries lymph to & away from lymph nodes
returns fluid to circulatory veins near the heart
lymphatic vessels
movement of lymph fluid:
- contraction of lymphatic vessels -undirectional valves divide lymphatic vessels into a series of chambers & contract
- contraction of skeletal muscle -lymphatic vessels are compressed when surrounding muscles contract
- thoracic pressure changes -inspiration-pressure decreases in thoracic cavity, expiration-pressure increases in thoracic cavity
round oval bean-shaped bodies along the various lymphatic vessels connected in series & filters lymph before it is returned to the blood
lymph nodes
lymph node converge to form larger vessels called ____
lymphatic trunk
drain lymph from the head and neck
jugular trunks
drain lymph from the upper limbs, superficial thoracic wall & mammary glands
subclavian trunks
drain lymph from thoracic organs and the deep thoracic wall
bronchomediastinal trunks
drain lymph from abdominal organs
intestinal trunks
drain lymph from the lower limbs
lumbar trunks
largest lymphatic vessel
thoracic duct
lymphatic pathways:
lymphatic capillary–lymphatic vessel–lymph node–lymphatic vessel–lymphatic trunk–collecting duct–subclavian vein
lymph nodes cortex has _______
collections of lymphocytes
lymph nodes medulla has ______
phagocytic macrophages
dense connective tissue surrounding each lymph node
capsule
extension of the capsule and forms a delicate internal skeleton
trabeculae
subscapular sinus & cortical sinuses separated by diffuse lymphocytes
cortex
organized into branching, called the medullary cords separated by medullary sinuses
medulla
areas of rapid lymphocyte division
germinal centers
filters blood, destroy worn out blood cells, forms blood cells in the fetus & acts as blood reservoir
spleen
produces hormones (thymosin) to program lymphocytes, maturation of T-Cells
thymus
trap and remove bacteria and other foreign materials
tonsil
capture and destroy bacteria in the intestine
peyer’s patches
lymphatic tissue surrounding the arteries within the spleen
white pulp
associated with the veins within the spleen, fibrous network filled with macrophages & rbc
red pulp
trabeculae extend from the capsule into the substance of the glan division within the thymus
lobules
within the medulla of a thymus for development of regulatory T cells
thymic corpuscles
site for maturation of T cells
thymus
a hormone secreted by the thymus important for cell maturation process
thymosin
resistance to disease
immunity
2 intrinsic immune system:
- Innate (nonspecific) defense system
- adaptive(specific) defense system
ability of adaptive immunity to recognize a particular substance
specificity
ability of adaptive immunity to remember previous encounters with a particular substance
memory
lyse/kill infected & cancer cells
natural killer cells
free/fixed (microglial)
macrophages
phagocytic levels rise and fall
neutrophils
carry foreign bodies to lymph nodes
dendrite cells
move toward the source of chemotactic substances
chemotaxis
endocytosis & destruction of particles by cells called phagocytes
phagocytosis
most important phagocytotic cells
neutrophils & macrophages
proteins that are secreted by viral infected cells that bond to healthy cells and prevent virus from bonding
interferons
20 proteins when activated can punch holes in infected cells literally blowing them up
complement
proteins that recognize foreign structure arrangement and stick
collectins
substances that stimulates adaptive immunity
antigens
introduced from outside
foreign antigens
molecules the body produces
self-antigens
develop when self-antigens stimulate unwanted tissue destruction
autoimmune disease
involves the action of T cells
cell-mediated immunity
producing the effect of cell-mediated immunity
cytotoxic T cells
promote/inhibit the activities of both antibody mediated immunity and cell-mediated immunity
helper T cells and regulatory T cells
immune system does not distinguish between self and nonself
autoimmunity
