Lymphatic system Flashcards
The rate of flow of fluid is dependant on what
blood pressure within the capillaries
The higher the flow of fluid the greater or smaller the leakage
greater
Swollen limbs and extremities are caused by what
result of high blood pressures
A signficant portion of fluid that has not been reabsorbed by capillaries remains where and as what
within the tissues as interstitial fluid
A large accumulation of interstitial fluid is called what
oedema
What are lymphatic vessels
drainage system of special blind-ended capillary structures
what is the function of lymphatic system via the vessels
return the extracellular fluid to the blood stream
What is the fluid within the lymphatic vessels called
Lymph
Are the lymphatic vessels or blood capillaries more permeable
Lymphatic vessels
How are lymphatic capillaries similar to blood capillaries
one layer of endothelium
How do the endothelial cells in the lymphatic capillaries combine
overlap to forms flap like mini valves
What is the need for cellular overlapping in the lymphatic capillaries
To maintain the amount of fluid inside the capillary. So when the volume of lymph increases, the internal pressure forces the flaps to close
Where are the highly specialised lymphatic capillaries called lacteals located
small intestine
Why is the lymph from lacteals milky as opposed to clear?
Fat is present as the lacteals absorb fats from the diet
what is fat filled lymph from lacteals called
chyle
Lymphatic vessels converge into larger vessels called what
Lymphatic ducts
Name the 2 major lymphatic ducts
Right and thoracic
The right lymphatic duct does what
collects lymph from the right arm and the right side of the head and chest
The thoracic duct does what
collects lymph from the rest of the body
The 2 major lymphatic ducts drain lymph directly back into what
major veins located above the heart
What 4 things are required to move lymph through the vessels (similar to blood transportation) to propel lymph towards the bloodstream for recycling
1) contraction of skeletal muscles 2) breathing 3) small valves to prevent backflow 4) smooth muscle cells located in walls of ducts which contract in rhythmic manner
Swelling of lymphoid tissues is caused by what
increase in permeability of blood vessels at sites of inflammation
Cancerous cells that have broken free of solid tumors can end up in lymphatic vessels and be transported to other parts of the body, this is called what
metastasis which can give rise to secondary tumors
What are lymph nodes
small filter units through which lymph travels before returning to blood stream
Lymph nodes contain what type of defence cells known as what
phagocytic known as macrophages
Macrophages are derived from what
Phagocytes
How are macrophages and lymph correlated
macrophages engulf and digest forein materials as the lymph fluid passes through the node
Lymph nodes contain an abundance of what arganular leukocyte
Lymphocytes
what do lymphocytes do
produce appropriate antigens to the foreign material encountered in the lymph fluid
Each lymph node is surrounded by what
dense fibrous capsule
what are lymphoid organs
where permanent lymphoid tissues reside
Name 8 examples of lymphoid organs
spleen, thymus, tonsils, lymph nodes, peyers patches (found in small intestine), liver, appendix, bone marrow
Most lympoid organs are encapsulated with what
outer layer of CT
What are lymph nodules
non encapsulated lymphoid tissue
Tissues next to epithelial lining of the digestive tract and respiratory system become filled with what
islands of lymph nodules
The appendix has an abundance of what
lymph nodules in its wall
Appendictis and tonsillitis result when what happens
when appendix and tonsils become inflammed in response to infection with bacteria
Name the 4 sets of tonsils
palatine, lingual, pharyngeal and tubal
where is the palatine tonsil located
back of the throat
where is the pharyngeal tonsil located
back of the nose
where is the tubal tonsil located
around openings of the auditory tubes into the back of the throat
Where does the spleen sit
under left side of the stomach
What 4 things is the spleen the site for
1) storage of breakdown products of RBCs 2) storage of blood platelets (for clotting) 3)Lymphocyte proliferation/immune surveillance 4) Reservoir for blood
Where is the thymus located
above the heart
The thymus is the site for what
t lymphocyte maturation
Describe what happens in t lymphocyte maturation
thymus secretes hormones (thymopoietin and thymosin) to activate T-lymphocytes in an immune response
Describe how the thymus is in infants and then in adults
large in infants but then the thymic tissue is replaced with connective fat tissue as adult gets older
How does the action of breathing help the movement of lymph
creates a pressure gradient in the chest cavity
Within the lymph node, follicles in the cortex are the site of what
B Lymphocytes
Within the lymph node, deeper cortex is the site of what
T lymphocytes in transit
Within the lymph node, the medulla is the site of what
macrophages
Name the 5 steps of phagocytosis by a macrophage
chemotaxis > adherence > ingestion > digestion > killing
What virus causes cold sores and genital herpes
HSV Herpes simplex virus
What virus causes chicken pox and shingles
VZV Varicella zoster
What virus causes glandular fever
EBV Epstein Barr
Herpesviruses have what in terms of structure
envelope and contain a double stranded DNA genome
