chapter 12 lymphatic system Flashcards
what are the 2 defense mechanisms that make up the immune system?
1) innate defense system (non-specific)
2) adaptive defense system (specific)
what is an immunity?
specific resistance to a specific disease
is the immune system an organ system?
no, it is a functional system
what is the function of the immune system?
defend the body from foreign materials
how many lines of defense does the body have? which are innate and which are adaptive?
3 lines of defense.
1st and 2nd lines of defence are innate.
3rd line of defense is adaptive
whats included in the immune systems first line of defense?
1) skin
2) mucus membranes
3) secrections of the skin and mucus membranes
whats included in the immune systems second line of defense?
1) phagocytic cells
2) natural killer cells
3) antimicrobial proteins
4) inflammatory response
5) fever
whats included in the immune systems 3rd line of defense?
1) lymphocytes
2) antibodies
3) macrophages and other antigen-presenting cells
which immune defense mechanism responds immediately (is faster)?
innate defense mechanism
when does the adaptive defense mechanism function?
when invaders make it passed the innate defense mechanism
what is diapedesis?
the process of neutrophils moving through capillary walls toward an infection
what are the 5 steps of phagocytosis?
1) phagocyte adheres to pathogen
2) phagocyte engulfs the particles forming phagosome
3) lysosome fuses with vesicle forming a phagolysosome
4) lysosomal enzymes digest foreign material
5) exocytosis of vesicle removes indigestible material from cell
fever =
abnormally high body temp which is a systemic response to invasion of microorganisms
what regulates body temp and what is normal body temp?
the hypothalamus
normal body temp is 98.6F (37C)
what can the thermostat in the hypothalamus be reset by?
pyrogen secretions of leukocytes
what does high body temp inhibit?
the release of iron and zinc (elements bacteria needs to survive) from the liver and spleen
what does fever increase the speed of?
the speed of repair processes
what are the 3 aspects of the adaptive defense mechanism?
1) antigen specific
2) systemic
3) memory
antigen specific aspect of adaptive defense means:
the adaptive defense mechanism recognizes and acts against particular foreign substances
the systemic aspect of the adaptive defense mechanism means:
immunity is not restricted to the initial infection site
the memory aspect of the adaptive defense mechanism means:
the adaptive defense mechanism recognizes and mounts a stronger attack on previously encountered pathogens
what are the functions of the lymphatic system?
1) return fluids from tissues to veins
2) collects excess fluid
3) scans and filters antigens and pathogens
what would happen if excess fluid was not removed by the lymphatic system?
excess fluid would accumulate and cause edema
what are the different ways that lymphatic cells monitor and defend against foreign substances?
1) some cells produce antibody proteins that bind to and mark pathogens
2) some cells attach to antigens directly
3) some cells become memory cells to quickly attach to the antigen if it appears again
what is the function of the lymphatic vessel network?
transport excess fluid back to the blood
what are the lymphatic vessels from smallest to largest?
1) lymphatic capillaries
2) lymphatic vessels
3) lymphatic trunks
4) lymphatic ducts
where does lymphoma originate?
originates in lymphatic organs
where does leukemia originate?
originates in bone marrow and circulates
lymphatic capillaries =
closed ended tubes interspersed among most blood capillary beds
what do lymphatic capillaries resemble and what is the difference?
they resemble blood capillaries but have overlapping endothelial cells that act as one way entry flaps
lymphatic capillary flaps are attached to what?
theyre attached by anchoring filaments to nearby structures
what are lacteals?
specializedd lymphatic capillaries in the gastrointestinal tract
what do lacteals collect?
lacteals collect interstitial fluid as well as lipids and lipid-soluble vitamins
what is chyle?
lymph collected from the gastrointestinal system
lymphatic capillaries merge to form what?
lymphatic vessels
lymphatic vessels resemble what?
small veins. they have all 3 vascular tunics and possess valves
afferent lymphatic vessels carry lymph where?
they carry lymph to a lymph node
efferent lymphatic vessels carry lymph where?
they transport filtered lymph away from a node
lymphatic vessels merge to form what?
lymphatic trunks
each lymphatic trunk drains lymph from where?
a specific region of the body
what are the 5 pairs of lymphatic trunks?
1) jugular trunks
2) subclavian trunks
3) bronchiomediastinal trunks
4) intestinal trunks
5) lumbar trunks
jugular trunks drain lymph from where?
the head and neck
subclavian trunks drain lymph from where?
upper limbs, breasts, and superficial thoracic wall
bronchiomediastinal trunks drain lymph from where?
deep thoracic structures
intestinal trunks drain lymph from where?
most abdominal structures
lumbar trunks drain lymph from where?
lower limbs, abdominopelvic wall, and pelvic organs
fusion of lymphatic trunks form what?
lymphatic ducts
what are the 2 lymphatic ducts and what are their locations?
1) right lymphatic duct - deep to the clavicle
2) left lymphatic duct (AKA thoracic duct) - begins just inferior to diaphram as a rounded sac-like structure named cisterna chyli
what is the largest lymphatic duct?
thoracic duct(left lymphatic duct)
which duct collects lymph from most of the body?
left lymphatic duct (thoracic duct)
which duct collects lymph from only the upper right portion of the body?
the right lymphatic duct
what are macrophages?
monocytes that have left the blood. they engulf foreign substances
what is the most abundant lymphoid cells?
lymphocytes
what are T-lymphocytes (T-Cells) and what % of lymphocytes do they make up?
lymphocytes that leave red bone marrow while immature and travel to the thymus to learn the bodys pathogens. they make up 70-80% of lymphocytes
what are B-lymphocytes (B-Cells) and what % of lymphocytes do they make up?
antigen receptors to 1 specific antigen that make up 15-30% of lymphocytes
what are natural killer cells (NK Cells)?
a small percentage of lymphocytes that kill a wide variety of infected cells and some cancerous cells
which lymphocytes migrate through the lymphatic system in search of harmful antigens?
all 3 types
(T cells, B cells, and NK cells)
what are lymphatic nodules?
clusters of lymphatic cells with some extracellular matrix but without a connective tissue capsule
what is a germinal center?
the center of a lymphatic nodule with b-lymphocytes and macrophages
where are t cells located within a lymphatic nodule?
outside of the germinal center
what is the function of lymphatic nodules?
filter and attack antigens
what does MALT stand for?
mucosa associated lymphatic tissue
what is MALT?
lymphatic nodules within mucosa of gastrointestinal, respiratory, genital, and urinary tracts
what is the function of MALT?
monitor and respond to antigens that may enter those tracts
what are peyer patches?
small masses of lymphatic tissue found throughout the ilium region of the small intestine
what are tonsils?
large clusters of lymphatic cells and matrix in the pharynx
what are tonsil crypts?
tonsils form crypts for trapping antigens. they facilitate antigen identification by lymphocytes
what can cause dysfunction of the crypts in the tonsils?
bacteria, food particles, mucus, and debris can get trapped in the crypts and cause dysfunction
what are lymphatic organs consisted of?
lymphatic cells and extracellular matrix which are completely surrounded by a connective tissue capsule
what are the main lymphatic organs?
1) thymus
2) lymph nodes
3) spleen
what is the structure of the thymus?
2 fused thymic lobes divided into lobules connected with connective tissue called trabeculae
what is the structure of each lobule?
each lobule has an outter cortex and inner medulla
how long does the thymus continue to grow?
thymus continues to grow until puberty then begins to regress
what is the site of T- lymphocyte differentiation and maturation?
the thymus
what types of cells are located in the cortex of thymic lobules?
immature T cells, nurse cells, and macrophages
what type of cells are located in the medulla of thymic lobules?
mature T cells and epithelial cells
how are T lyphocytes produced in adulthood?
in adulthood they can only be produced by cell division and not by the maturation of new cells in the thymus
what is the shape and location of lymph nodes in the body?
they are small, oval structures located along the pathway of lymph vessels. usually found in clusters
what is the function of lymph nodes?
they filter antigens from lymph and initiate immune response
what are lymph nodes surrounded by?
tough connective tissue capules
what is the location of lymphatic cells in the nodes?
they surround trabeculae and lymphatic sinuses and provide a pathway for lymph to flow
lymph nodes are divided into what?
outter cortex and inner medulla
the cortex of a lymph node consists of what?
nodules and sinuses called cortical sinuses
the medulla of a lymph node contains what?
medullary cords and medullary sinuses
what is the capsule of the spleen made of?
dense irregular connective tissue
what are trabeculae?
connective tissue that extends into an organ
what are trabecular vessels in the spleen?
branches of splenic arteries and veins that extend within trabeculae
the cells around trabeculae in the spleen are subdivided into what?
white pulp and red pulp
what is the function of red pulp in the spleen?
erythrocyte recycling
what is the function of white pulp in the spleen?
scanns blood for pathogen
what is the largest lymphatic organ?
the spleen
what are the functions of the spleen?
1) initiates immune response
2) a reservoir for erythrocytes and platelets
3) phagocytizes old and defective erythrocytes and platelets
4) phagocytizes bacteria and other foreign substances
what is the hilum?
where arteries and veins enter organ
what is lymphatic filariasis?
a tropical parasitic disease that affects lymph nodes and lymph vessels
how is lymphatic filariasis spread?
by infected mosquitos. their bite deposits a parasite that travels to the lymphatic system
what are the symptoms of lymphatic filariasis?
most cases are asymptomatic but in rare cases long term damage to the lymphatic system causes swelling in the legs, arms, and genitalia which also increases the risk of frequent bacterial infections that harden and thicken skin (elephantiasis)
what can interfere with normal immune function?
1) stress
2) sleep
3) nutrition
4) physical activity
5) substance use
efficeincy of the immune system wanes in old age and…
infections, cancer, immunodeficiencies, and autoimmune diseases become more prevalent
the ability of immunocompetent cells to regognize foreign antigen is determined by what?
genetics
