L4 - Lymphatic System Flashcards
give three functions of the lymphatics and immune system?
- draining excess interstitial fluid
- transporting dietary lipids
- immune responses
how does interstitial fluid re-enter circulation?
- capillaries at venous ends
- lymphatic capillaries
what are lymph capillaries?
smallest lymph vessels, high permeability allows entrance of tissue fluid and bacteria, viruses and cancer cells
what is the function of lymphatics?
collect lymph from lymph capillaries, accompany blood vessels
give three features of lymphatics
- walls similar to blood vessels
- contain more valves than veins to ensure one way flow
- lymph nodes scattered along lymphatics
which tissues do NOT have lymph capillaries?
CNS, bone marrow and avascular tissues e.g. cartridges, nails, cornea and hair
what are lacteals?
- specialized lymphatic capillaries
- located in villi of small intestine
- receive digested fats
- fatty lymph (chyle)
what surrounds lymph nodes?
fibrous capsule
what type of lymph vessel enters the lymphnode?
afferent
what type of lymph vessel leaves the lymphnode?
efferent
give two functions of lymph nodes
- lymph percolates through
- antigens destroyed and activate B & T lymphocytes
name the two lymph ducts
- right lymphatic duct
- thoracic duct
where does the right lymphatic duct drain and where does it empty into?
drains the right side of the head, right upper limb and right thorax
empties into the right internal jugular vein and subclavian veins
where does the thoracic duct drain and where does it empty into?
drains remainder of body
empties into venous circulation - left internal jugular vein and left subclavian veins
begins as cisterna chyli
give three functions of the immune system
- recognize foreign molecules
- destroys pathogens
- main cells - lymphocytes - attack infectious organisms
what are the primary lymphoid tissues?
immature lymphocytes acquire receptors to recognize antigens
- thymus - maturation of T lymphocytes
- bone marrow - maturation of B lymphocytes
what are the secondary lymphoid tissues?
lymphocytes are activated in response to antigen
- lymph nodes
- spleen
- mucosal associated lymphoid tissue (tonsils, Peyer’s patches, mucosae of GIT, resp tracts)
give 4 characteristics of the thymus
- immature lymphocyte develop into T lymphocytes
- functions strictly in lymphocyte maturation
- most active in childhood
- atrophies with age
give 3 characteristics of the spleen
- largest lymphoid organ
- 2 blood-cleansing functions (removal of blood-borne antigens & removal and destruction of old blood cells)
- site of haematopoiesis in foetus
describe the pulp in the spleen
white pulp: thick sleeves of lymphoid tissue
red pulp: surrounds white pulp, composed of venous sinuses and splenic cords
give 3 facts about tonsils and name the three types
- simplest lymphoid tissue
- form a ring around border between oral cavity + pharynx
- gather & remove pathogens
palatine, pharyngeal, lingual
where are Peyer’s Patches located?
in distal part of small intestine
where is the appendix located?
tubular offshoot of caecum
