Lymphatic System Flashcards
Lymphatic system returns fluid to
The vascular system
Lymphatic system consists of
lymphatic vessels, lymph, & lymph nodes
Lymphoid organs & tissues are
The structural basis of the immune system
Lymphatic organs are
Spleen, thymus, tonsils, other lymphoid tissues, lymph nodes
Lymph nodes
Filter lymph
Lymph is
The fluid of the lymphatic system
Capillary fluid exchange is
The return of fluid back to the blood
In filtration, fluid is forced out by
hydrostatic pressure at arterial end from blood pushing on the walls of the vessel
In absorption fluid is returned
By colloid osmotic pressure at the venous end from pressure within the blood
Fluid returned to the blood is
Interstitial fluid
Lymphatic vessels collect interstitial fluid that
Does not circulate back into blood (one-way system towards heart)
Lymphatic capillaries are
The start of the lymphatic transport system
Lymphatic capillaries are found
Between tissue cells and blood capillaries in loose connective tissue
Highly permeable/large molecules easily pass through describes the
Lymphatic capillaries
Similar to veins but thinner with more valves
Lymphatic collecting vessels
Lymphatic trunks
Drain large areas of the body
Lymph from right arm and right side of head and thorax delivered back to circulatory system via
Right lymphatic duct
Lymph from rest of body (left side and portion of right) delivered back to circulatory system via
Thoracic duct
Lymphatic vessels are low or high pressure
Low pressure
Prevent backflow of lymph
Valves
Induces pressure changes when breathing
Respiratory pump
Responsible for skeletal muscle compression
Skeletal muscle pumps
Immunity present from birth; relies on common characteristics of many pathogens; first line of defence
Innate immunity
Immunity involving T and B lymphocytes; helps the immune system learn, adapt, and remember pathogens
Adaptive immunity
Lymphocytes arise in
The red bone marrow
Mature in the thymus; manage immune response and attack and destroy infected cells
T cells
Mature in the bone marrow; activate into antibody-secreting plasma cells
B cells
innate cytotoxic immune cells
Natural Killer cells
Phagocytes, help activate T cells
Macrophages
Play role in T cell activation
Dendritic cells
Make up stroma that supports other cell types
Reticular cells
Key functions of the lymphoid tissue are:
Site for housing, activation and proliferation of lymphocytes; ideal location for macrophages and lymphocytes to survey for infection/disease
Lymphocytes enter and exit back into blood via
Reticular connective tissue
Types of lymphoid tissues
Diffuse, follicle/nodules, organs
Has a loose arrangement of lymphoid cells with reticular fibres; located in most body tissues
Diffuse lymphoid tissues
Are solid, tightly packed spherical bodies packed with lymphoid cells and reticular fibres
Lymphoid follicles
Primary lymphoid organs are
Where T and B cells mature (red bone marrow, and thymus)
Secondary lymphoid organs are
Where most immune responses occur (lymph nodes, spleen, MALT, tonsils, appendix, etc…)
Maturation is
Lymphocytes developing immunocompetence and self-tolerance
2 main functions of lymph nodes
Cleansing/filtering lymph (via macrophages) and activating the immune system (houses lymphocytes)
Contains densely packed follicles with germinal centers for B cell proliferation
Lymph node cortex
Contains medullary cords containing B and T cells
Lymph node medulla
What lymph flow through: large lymphatic capillaries spanned by crisscrossing reticular fibres with macrophages
Lymph sinuses
Lymph enter through
afferent lymphatic vessels
Lymph exits via
Fewer efferent lymphatic vessels (slows down flow to give lymphocytes and macrophages time to do their jobs)
Vaccine antigens travel through
Lymphoid follicles (contain antibody producing B cells)
Buboes are
Inflamed, swollen lymph nodes
Largest lymphoid organ; removes old/defective RBCs and platelets
Spleen
Where old RBCs are destroyed
Red pulp of spleen
Where immune function occurs
White pulp of spleen
MALT
Prevent pathogens from penetrating mucous membranes
Tonsils
Ring of lymphoid tissue around pharynx opening
Tonsillar crypts
Catch bacteria and food particles to train immune cells
Peyer’s patches are found
In the small intestine (ileum)
Appendix is found
Near the large intestine
Purpose of the thymus
Maturation site for T lymphocytes (contains no B cells or reticular fibres); most active in childhood
Cortex of thymic lobules contain
Rapidly dividing T cells (maturing/proliferating)
Medulla of thymic lobules contain
Mature T cells
