11. Lymphatic system Flashcards
compare antibody vs antigen
- Antigen
- surface market that body can notice as foreign
- bacteria & toxins, virues, mismatched RBCs, cancer cells
- surface market that body can notice as foreign
- Antibody
- protein released by a plsma cell that binds to antigen
- immunoglobulins are type of antibodies
- protein released by a plsma cell that binds to antigen
what makes up the circulatory system
- cardiovascular and lymphatic systems
what are the parts of the lymphatic system
- Vessels (lymphatics)
- starts @ peripheral tissues
- End @ venous system
- Fluid (lymph)
- flows thru lymphatics
- resembels plasma with less proteins
- Organs
- connected to lymphatics
- contain many lymphocytes
what is the function of your lymphatic system
- produce, maintain and dsitribute lymphocyes and fluids
- return fluid & solutes from interstitial fluid to blood to maintain net filrations pressure
- distribute hormones, nutrients and waste products
- filters fluid to remove foreign substances and aged infected and cancerous cells
- provides structural basis of immune system
what is the pathway of lymph
Bloodstream Capillaries -> Interstitual space -> lymphatic capillaries -> lymphatic vessels -> lymphatic trunks -> lymphatic ducs -> venus blood
how are lymphatic capillaries different then blood capillaries
they are similar but differences are:
- > blind ended (not a loop)
- > very permeable
- > endothelial cells (simple squamous epithelium) overlap to crease one way minivalves
- anchored by collagen filaments (prevents capillary colapse)
*fluid pressure is what pushes the cels
Where are lymphatic capillaries absent
bones, bone marrow, teeth and CNS
what are lacteals
specialized lymph capillaries in small intestinal mucosa (lining layer in GI tract)
*Absorb digested fat & deliver chyle to bloodstream (goes into lymphatic system not venous sytstem
desccribe lymphatic collecting vessels
- lined by simple squamous epithelium (endothelium)
- surrounded by thing layer of connective tissue + small amounts of smooth muscle
- contains internal valves (low pressure system fluids, prevent backflow)
- anastomose frequently (forms mesh, vessels come together)
- travels with blood vessels
describe lymphatic trunks
- brains out body of lymph from different regions
- jugular trunk (right and left): drains head
- subclavian
- bronchomediastinal: drains thorax
- lumbar trunk: drains lower limbs
drainage of right lymphatic duct vs thoracic duct
- right lymphatic: drians right body superior to diaphragm
- Thoracic duct: drains everything inferior to diaphragm and left body superior to diaphragm
how is lymph transported
- lacks pumping organ
- vessels are low pressure conduits so moves very slow
- lymph is propelled by same mechanisms that promtoe venous return:
- > respiratory pump (breathing pressure moved blood and lymph)
- > values (unidirectional flow)
- > skeletal milking (muscle contracts, squeezes lymph)
*if blocked lymph would get accumulation of fluid
what are the classes of lymphocytes
t cells: cytotocic, helper and suppressor
B cells: plasma cells
NK cells
describe the types of T cells
- Cytotoxic T cells
- attack foreign cells or body cells infected by the virus
- primary cells involved in cell mediated immunity
- Helper T cells
- stimulate activation and function of both T and B cells
- Supporessor T cells
- inhibit activation and function of T and B cells
- establish contron and sensitivity of immune response
describe B cells
- become plasma cells -> make antibodies
- responsible for antibodiy mediated immunity
stops of action of NK cells
- if cell has an unusual Ag in plasma membrane the NK will regognize
- NK cell activated and adheres to target cell
- NK golgi apparatus moves to points to abnormal cell
- produces secretory vesicles containsing perforins which travel thru cytoplasm towards NK cell surface
-
Perforins released at NK cell surface ia exocytosis
- diffuse and pynch holes in membrane of cells so cant maintain and external and internal env
- Pores cause cell to quickly disintegrate
what are other types of lymphoid cells (not T, B or NK)
- mecrophages
- phagocytize foreign substances and help activate T cells
- Dendritic cells
- capture antigens and deliver to lymph nodes
- Reticular cells
- produce stroma that supports other cells in lymphoid organs
primary lymphoid organs vs seconary
Primary: where B and T cells mature
Secondary: where B & T cells encounter Ag
how do lymphocytes develop, mature and activate
-
Origin
- B&T lymphocyte precursors originate in red bone marrow
-
Maturation
- precursors destined to beocme T cells -> thymus to mature
- precurors destined to become B cells -> bone marrow
-
Seeding secondary lymphoid organs & circulation
- immunocompetent but naive lymphocytes leave thymus & bone marrow
- “seed” secondary lymphoid orangs and cirulte thru blood and lymph until can recognize antigen
-
Antigen encounter and activation
- lymphocytes are activated when Ag receptor binds to its specific Ag
-
Proliferation & differentiation
- immune response
- activated lymphocytes proliferate (multiply) and differentiate into effector cells & memory cells
- memory cells & efector T cells circulate continuously in blood & lymph & thoughout secondary lymphoid organs
Describe lymphoid tissue
- houses and provides a site for proliferation of lymphocytes
- furnishes a surveillance vantage point (check pt that everything moving throuhg belongs to self)
Types:
-
diffuse lymphatic tissue:
- lymphoid calls & reticular fibers found in almost every body organ
-
Lymphoid folicles (lymphoid nodules)
- solid spherical bodies of tightly packed lymphoid cells & reticular elements
- germinal center of proliferating B cells
- may be isolated aggregation or form part of larger lymphoid organs
- *found in palces w/ lots of potential foregn invaders
- solid spherical bodies of tightly packed lymphoid cells & reticular elements
describe the structure of a lymph node
- Cortex
- surrounded by capsule with inward extensions (trabeculae)
- contains follicles with germinal centers (dendritic cells nearly encapsulate follicles)
- medulla
- medullary chords; inward extenstions from cortex (containing B and T cells)
- Medullary sinuses: large lymph capillaries containing marcophages
describe circulation in lymph nodes
- lymph (with T cells) enter via afferent lymphatic vessels
- travel through cortex, large subcapsular & medullary sinuses
- exist node at hilum vai efferet vessels
*have more afferent to slow movemnt so you encounter more foreign things
describe the spleen
- largest lymphoid organ
- on left side of body between stomach, kidney and diaphragm
- has a fibrous capsule and trabeculae
- contains lymphocytes, macrophages and lots of RBC
two pats of the spleen
- White pulp
- mostly lymphocytes and reticular fibers
- allows B and T cells to interact with substances in blood and mount an immune response
- Red pulp
- rich in macrophages
- disposal of worn out RBCs and bloodborne pathogens
