Lymphatic System Flashcards
Define immune system
Defends the body from agents of disease
Functions of lymphatic system
Network of organs and vein like vessels that recover fluid
Inspect it for disease agents
Activate immune response
PROTECT BODY FROM INFECTION AND DISEASE
Return fluid to the bloodstream (MAINTAINS FLUID BALANCE)
What is considered to be a pathogen
Microorganisms
Bacteria, virus, fungus, parasites
Lymph
Recovered colorless fluid
Clear
Similar to plasma but with less plasma
Originates as extra cellular fluid drawn into lymphatic capillaries
Lymphatic tissues
Composed of aggregates of lymphocytes and macrophages that populate many organs in the body
Lymphatic organs
Defense cells are especially concentrated in these organs
Separated from surrounding organs by connective tissue capsules
Lymphatic capillaries
(Terminal lymphatics)
Penetrate nearly every tissue of the body
Absent from central nervous system, cartilage, cornea, bone, and bone marrow
Endothelium creates valve-like flaps that open when interstitial fluid pressure is high and close and when it is low
Lymphatic vessels have a ______ appearance
Beaded
Fluid recovery
Fluid continually filters from the blood capillaries into the tissue spaces
Blood capillaries reabsorb 85%
15% enter the lymphatic system and then are returned to the blood
Immunity
Excess filtered fluid picks up foreign cells and chemicals from the tissues
Passes through lymph nodes where immune cells stand guard against foreign matter
Activates a protective immune response
Lipid absorption
Lacteals in small intestine absorb dietary lipids that are not absorbed by the blood capillaries
Flow of lymph
Lymph flows similar to venous return, except no pump (heart)
Lymph flows at low pressure and slower speed than venous blood
Moved along by rhythmic contractions of lymphatic vessel
Stretching of vessels stimulates contraction
Flow aided by skeletal muscle pump
Arterial pulsation rhythmically squeezes lymphatic vessels
Thoracic pump aids flow from abdominal to thoracic cavity
Valves prevent backward flow
What are the primary lymphatic organs
Red bone marrow and thymus
What is the site where T and B cells become immunocompetent
Primary lymphatic organs
Red bone marrow
Thymus
Red bone marrow produces
RBCs, WBCs, Plateletsd
Thymus produces
T cells
What are the types of white blood cells
Neutrophils, macrophage, eosinophils, basophils, lymphocyte
What are the types of lymphoctes
B lymphocyte T lymphocytes (MADE IN THE THYMUS)
What are the secondary lymphatic organs
Lymph nodes
Tonsils
Spleen
Parts of the appendix
What tissues do immunocompetent cells populate ?
Lymph nodes
Tonsils
Spleen
Red bone marrow is involved in ___ and ___
Hemopoiesis (blood formation)
And
Immunity
What are the functions of thymus
Houses developing T lymphocytes
Secretes hormones regulating their activity
Found in between sternum and aortic arch
Degeneration with age
Lobes have cortex and medulla populated by
T lymphocytes
Where are lymph nodes found
Cervical
Axiliary
Thoracic
Abdominal
Intestinal
Mesenteric
Inguinal
Popliteal lymph nodes