The Lymphatic System Flashcards
What does the lymphatic system consist of?
-Lymph
-Lymphatic vessels
-Lymphatic tissue
-Red bone marrow
What is lymph?
This is the fluid that flows through the system (vessels).
What are the three main functions of the lymphatic system?
-Drainage of interstitial fluid
-Transporting dietary lipids
-Facilitation of the immune response.
What is the structural relationship between blood vessels and lymphatic vessels?
It is an integrated network (all very close together to allow for return of fluid).
What colour are lymphatic vessels often shown as?
Green.
Where are lymphatic capillaries located?
Located in places where interstitial fluid is.
What happens to fluid when blood is under high pressure?
This can force fluid out of the vessels and it becomes interstitial fluid.
What is hydrostatic pressure?
This is the pushing force exerted by a fluid.
What is the interstitial fluid pressure?
Slightly more negative than pressure in vessels- contributes to outward pull of fluid from capillaries.
What is colloidal osmotic pressure?
This is pulling force created by blood proteins that are too large to pass through pores in membrane.
What is interstitial osmotic pressure?
This is pressure created by small number of plasma proteins that leaked into extracellular tissue space.
How does plasma become interstitial fluid (first step)?
Blood hydrostatic pressure pushes plasma out of capillaries- now known as interstitial fluid.
How is some fluid pulled back into vessel (second step)?
Protein albumin that is too large to leave creates osmotic pressure in capillary- pulls some interstitial fluid into capillary (move from low to high conc).
What happens if not all the fluid is drained?
Swelling will occur (oedema).
What are the features of the lymphatic capillaries?
-Internally, they have lower pressure than the interstitial fluid
-they have mini valves- once the fluid is inside, it can’t leave (one way system).
What do lymphatic capillaries join together to form?
Lymph vessels.
How do lymph vessels return lymph to blood?
Drains into one of two ducts.
Where does the right lymphatic duct drain to?
The upper right side of the body and right arm- right subclavian vein.
Where does the left thoracic duct drain to?
The rest of the body- begins with cisterna chyle and returns to left subclavian vein.
What are Lacteals?
These are lymph capillaries in the small intestine.
What do lacteals carry?
Carry fat laden lymph known as CHYLE.
Where do the vessels containing chyle drain into?
The cisterna chyle.
What is oedema?
This is palpable swelling produced by an increase in interstitial fluid volume.
What factors influence oedema?
-Increased capillary filtration pressure
-Decreased capillary colloidal osmotic pressure
-Increased capillary permeability
-Obstruction to lymph flow
What does a decrease of capillary colloidal osmotic pressure mean in regards to oedema?
This is when there are changes in the concentration gradient. There isn’t enough proteins to create a pull of fluid back into the vessels.
Where would you find increased capillary permeability?
In cases of inflammation or burn victims.
What are the lymph nodes in the body?
-tonsils
-thymus
-spleen
-peyer’s patches
-appendix
What are lymph nodes?
Bean shaped structures that receive the lymph from afferent vessels.
What are afferent vessels?
Vessels going towards.
Is lymph drained by afferent or efferent vessels?
Efferent (going away from) vessels.
What is the function of lymph nodes?
These filter lymph (get rid of any bacteria, pathogen in lymph).
What is held in the trabeculae of a lymph node?
Reticular (immune) cells sit and wait here until needed to create an immune response.
What are the 2 types of lymphocytes?
B and T lymphocytes.
What is between the reticular cells?
Lymphocytes.
What do lymphocytes produce?
Antibodies.
What happens when a lymph vessel becomes cancerous?
It is blocked with tissue so the fluid (lymph) can’t flow through it.
What are lymph nodules?
Compartments of a lymph node and are dense masses of lymphocytes and macrophages.
Where are lymph nodules found?
As well as being in this system (parts of lymph nodes), also found in mucosa of other tubular structures in respiratory, urinary and reproductive systems.
What are Lymph nodules- Peyer’s Patches?
Collectively known by MALT (Mucosa Associated Lymphoid Tissue).
Where are the tonsils located?
These surround the opening to the respiratory and digestive tracts.
What are the five tonsils?
2 Palatine
2 Lingual
1 Pharyngeal or adenoid
Where are Palatine tonsils?
Either side of oral cavity.
Where are Lingual tonsils?
At the base of the tongue.
Where is the Pharyngeal/ Adenoid tonsil?
On the posterior wall of nasopharynx.
Where is the thymus gland found?
The mediastinum.
What is the function of the thymus gland?
To produce thymic factor.
What is thymic factor?
This is important for setting up the immune system and the formation of T lymphocytes.
What happens to the size of the thymus as you age (age involution)?
In childhood, it is the biggest (fighting off lots of pathogens) but as you age, gets smaller and smaller.
Where is the spleen located?
At the left side of the abdominal cavity below diaphragm.
What is the spleen comprised of?
-Reticular cells
-Red pulp
-White pulp
What is red pulp?
This removes worn out platelets and RBC, stores platelets and prices RBC in foetus.
What is white pulp?
This carries out immune function and removes pathogens (filters blood).
