Chapter 20: Lymphatic System Flashcards
Lymphatic System
returns fluiids leaked from vascular sys back to blood; consists of lymphatic vessels, lymph, and lymph nodes
Lymphatic Vessels
aka lymphatics; one way sys of drainage vessels; transport lymph
Order of Lymph Transportation
lymphatic capullaies to collecting lymphatic vessels to lymphatic trunks to lymphatic ducts
Lymphatic Capillaries
blind ended tubes; endothelial cells overlap to form flaplike mini valves (open in response to increased interstitail volume) ; more permeable than blood capillaries (proteins easily enter as well as cell debris, pathogens and cancer); absent from bones and teeth;
Lacteals
specialized lymph capillaries in intestinal vili; transport fatty lymph called chyle
Collecting Lymphatic Vessels
have same 3 tunics as veins but thinner walls; more valves than veins; low pressure conduits sprinkled with lymph nodes; largest lympahtic vessles nourished via vasa vasorum; empty into lymphatic trunk
Lymphatic Trunks
drain large areas; named for regions drained; empty in lymphatic ducts
Right Lymphatic Duct
drains lymph from righ upper limb, right side of head and thorax
Thoracic Duct
begins at cisterna chyli nd drains lymph from rest of body
Both right lymphatic and thoracic duct…
empty into venous circulation at junction of internal jugular vein and subclavian vein
What is lymphangitis?
inflammation of lympahtic vessels; those near surface become visible as red streaks tender to the touch
Lymph Transport
slow and sporadic; depends on same mechanisms as being to enhance flow
Lympederma
anything that hinder flow; certain parasites invade lymphati vesesls and blood flow of lymph (such as filanal worms which if untreated leads to elephantiasis)
What are the lymphoid cells?
lymphocytes, macrophages, dendritic cells, reticular cells
Lymphocyes
protect against antigens that provoke an immune response; T Cells and B cells
T Cells
when activated, mediate cellular immunity; some directly attack and destroy infected cells
B Cells
when activated, mediate humoral immunity; descendants produce antibodies which mark foreign antigens for destruction
Macrophages
phagocytize foreign microbes; help activate T Cells
Dendritic CElls
engulf antigens and migrate to lymph nodes; present antigens to T cells initiating their activation
Reticular Cells
cells that produce reticular fibers
Lymphoid Tissue
made up of reticular CT; contains macrophages and lymphocytes
Diffuse Lymphoid
loose arangement of cells and fibers; found everywhere
Follicular Lymphoid TIssue
solid, spherical structures containing tightly packed cells and fibers; often have light staining germinal centers where B cells proliferate
Primary Lymphoid Organs
where B and T cells mature (become immunocompetent); B cells mature in RBM; T cells mature in thymus
Secondary Lymphoid Organs
where mature B and T cells first encounter antigens and are activated (lymph nodes, spleem, MALT)
Lymph Nodes
large clusters in cervical axillary and inguinal artery; cleanse lymph; site for B and T cell activation and proliferation; lymph enters via many afferent lymphatic vessels and exists via fewer effeerent lymphatic vessels
What is a bubo?
swollen lymph node
FLow of Lymph thru Node
afferent vessels to subscapular sinus to medullary sinus to efferent vessels
Sinuses
large lymphatic (sinooidal) capillaires; contain lg population of macrophages
Sentinel Lymph Nodes
receive lymph from a body area suspected of cancer
Spleen
largest lymphnoid organ; cleanses blood and removes aged or defective RBCs; store platelets, monocutes and iron; site of RBC production in infants; site for B and T cells activation and proliferation
White Pulp
where immune functions take plave (primarily lymphocytes)
Red Pulp
where old RBCs broken down and blood borne pathogens destroyed (primarily erythrocytes and macrophages)
MALT
mucosa assiciated lymphoid tissues; lymphoid tusses found in mucous membrane of digestive and respiratory tract; includes tonsils, peyers pathces and appendix
Tonsils
form a ring around entrance to pharynx; bacteria trapped i tonsilar crypts and destroyted by resident macrophages and lymphocytes; invite infection and promote immunity
Peyers Patches
clusters of lymphoid folliccles in wall of ileum; ontain macrophages, B cells, T cells and dendritic cells; prevents bacteria from reaching intestinal wall; generate memory lymphocytes
Appendix
blind sac extending from cecum (1st portion of large intestine); contains numerois lymphoid folicles
Tonsilites
inflammation of the tonsils
Splenomegaly
enlarged spleen due to septicemia, leukemia, mononucleosis or malaria
Lymphadenopathy
any disease of lymph nodes
Lymphoma
tumor of lymphoid tissue (benign or malignant)
Non-Hodgkins Lymphoma
all cancers of lymphoid tissues except Hodgkin’s; uncontrolled multiplication & metastasis of undifferentiated lymphocytes
Hodgkins Lymphoma
malignancy of lymphoid tissue; observe swollen, nonpainful nodes & giant malignant B cells
