Lymphatic System and Lymphoid Organs Flashcards
What is the role of the lymphatic system
return leaking fluids from the blood vessels back into the bloodstream.
What are the 3 components of the lymphatic system
lymphatic vessels
lymph
lymph nodes
What problem does the lymphatic vessels remedy?
lymphatic vessels collect the extra fluid ( becomes lymph) bc blood capillaries leak fluid into extracellular tissue sites and that fluid has to be returned.
What is the flow of the lymph
lymph only flows in the direction of toward the heart
Define lacteals
transport fat from small intestines to bloodstream. Contains milky white lymph called chyle that flow into cisterna chyli
What are the 5 major lymphatic trucks
lymbar bronchomediastinal subclavian jugular trunks intestinal trunk
What are the 2 lymphatic ducts
right lymphatic duct
thoracic duct
Where does the right lymphatic duct drain to
drains lymph from the right upper limb and right side of head and the thorax
Where does the thoracic duct drain into
receives lymph from rest of body. starts at the cisterna chyli
What are the 2 supporting lymphoid cells
dendritic cells
reticular cells
What is the job of the dendritic cells
process ( engulf) antigen and give them to the T cells
What is the job of the reticular cells?
produce reticular collagen fibers which support lymphoid organs and tissues
What organs are part of the primary lymphoid organs and what are there jobs
Red bone marrow: origin and where B cells mature
thymus: where T cells mature
What 5 organs are part of the secondary lymphoid organs?
lymph nodes spleen tonsils peyer's patches in small intestines appendix
What is the job of the secondary lymphoid organs
where mature lymphocytes are activated.1st encounter of antigens
What is the function of the primary lymphoid organs
places where B cells and T cells develop
What are 3 characteristics of secondary lymphoid organs
1) reticular fiber network
2) presence of lymphoid follicles
3) germinal centers: where B lymphocytes multiply
What is the difference between primary and seconday lymphoid follicles(2)
primary: “resting” follicles
secondary: “ active “ follicles. develops an immune response and develops germical centers
What is a germinal center
where b lymphocytes multiply
Where are lymph nodes located?
located along routes where lymphatic vessels to truck
i.e inguinal
axillary
cervical
What are the 2 major functions of lymph nodes
1) Cleansing the lymph ( contains many immune cells)
2) Immune system activation
Identify the structures of a lymph node and the order the lymph flows through?
Enters afferent vessels
then through subcapsular sinuses
into cortex then passes through lymphoid follicles
in follicles lymph passes through germinal centers…flowing into the medulla and through the medullary sinus
finally lymph exits through the efferent vessels at the hilum
What is located in the subcapsular sinuses
has dendritic cells, macrophages
is where reticular fibers are located
What is the medulla full of
B cells
What are the 3 main functions of the spleen
1) Recycle worn and broken red blood cells
2) stores blood platelets and monocytes
3) can also induce erythropoiesis when red bone marrow can’t keep pace
4) contains half of the body’s monocytes
Where is the spleen located?
left side beneath diaphragm
What are the 2 tissue types of the spleen
1) white pulp
2) red pulp
What is white pulp
lymphocytes tissue around the splenic artery
What is red pulp
place of destruction of RBCs and pathogens. Has many erythrocytes and macrophages. has only efferent lymphatic vessels
Define MALT
MUCOSA-ASSOCIATED LYMPHOID TISSUE
What is MALT
LYMPHOID TISSUE LOCATED WITHIN MUCUS MEMBRANES
Where are the tonsils located and what are there purpose
ring of lymphoid tissue around entrance to pharynx and job is to trap microorganisms within tonsillar crypts
What are the 4 main tonsils
1) paired palatine tonsils
2) lingual tonsil
3) pharyngeal tonsil
4) tubal tonsils
What are peyer’s patches
full of immune cells which destroy pathogens associated with gut (GALT)
Located in the lowest portion of the small intestines
high during the ages of 15-25
What is the function of the appendix
functions debatable but could store healthy microbiota for replacing colonies in the colon
Describe changes in T cell maturation in the thymus throughout an individuals’ lifespan
thymmus grows during embryogenesis and through 1st year
thymus starts to degrade slowly after puberty with decreasing maturation of T cells
biggest contributor is age related disease
What is Thymic involution
3% loss until 35-45 years, then 1% after that
sex hormones increase involution
Describe Hassall’s corpuscles
produces regulatory T cells
prevent autoimmune responses by hunting down faulty T cells
Define cisterna chyli
a dilated sac at the lower end of the thoracic duct in most mammals into which lymph frpm the intestinal truck and two lumbar lymphatic trucks flow
What are shared characteristics of secondary lymphoid organs
reticular fiber network
presence of lymphoid follicles
mostly b cells and t cells
What is the difference between primary and secondary lymphoid follicles
primary: resting follicles
secondary: active follicles ( immune response) and develops germinal centers
Define germinal centers
where B lymphocytes multiply
Which direction does lymph flows
flows in the direction toward the heart
How is lymph pushed back to the heart
skeletal muscles and breathing
Where is lymph collected
lymphatic capillaries that are weaved around the blood capillaries and tissue cells
Do lymphatic capillaries exist in bone and teeth
no
How does the minivalve open
With increase interstitial fluid
When does the minivalve close
pressure inside lymphatic vessels is greater then outside then it causes them to close
Do lymphatic vessels contain more proteins or capillaries
contain more plasma proteins than capillaries
