Chapter 23 - Lympatic System Flashcards
What are the functions of the lymphatic system?
Produce, maintain, and distribute lymphocytes.
Maintain normal blood and interstitial fluid volume.
Alternate route for the transport of materials.
What materials does the lymphatic system transport?
Nutrients, hormones, waste.
What do lymphatic vessels do?
Transport fluid called lymph from tissues to the venous system.
Do lymphatic vessels have varied size?
CLARO QUE SI
What are the different sizes of vessels?
Small lymphatic capillaries, medium lymphatic vessels, large lymphatic trunks, and lymphatic ducts.
What are lymphatic vessels usually found associated with?
Blood vessels.
Where are lymphatic vessels located?
Most tissues.
Where are lymphatic vessels absent?
Avascular tissue and CNS.
What is lymph?
A fluid CT.
Where does lymph occur?
ONLY in lymphatic vessels.
What is lymph derived from?
Interstitial fluid of the tissues, lymphocytes, and macrophages.
Where does lymph orginate?
From plasma.
How is interstitial fluid formed?
Water & dissolved materials leak out of capillaries due to diffusion & filtration.
How many L/day enter interstitial spaces?
27L/day.
Interstitial fluid characteristics?
Lacks proteins and lower O2.
What is interstitial fluid called when it enters the lymphatic capillaries?
Lymph.
What percent of interstitial fluid is absorbed?
90%.
Lymphatic capillaries characteristics?
- Closed ended tubes.
- In interstitial spaces.
- Form networks.
- Single layer of squamous cells with incomplete basal lamina. 5. Fenestrated
How do lymphatic capillaries differ from blood capillaries?
Larger diameter, thinner walls, flat & irregular, have anchoring filaments to keep the passage open, and overlapping endothelial cells.
How does interstitial fluid enter lymphatic capillaries?
Overlapping cells function as one way valves, moves through fenestrations, and large things such as viruses and debris follow.
How are medium lymphatic vessels formed?
Merging of lymph capillaries.
How are medium lymphatic vessels similar to veins?
Have interna, media, adventitia, and valves.
What do medium lymphatic vessels form?
Lymphatic trunks.
What do medium lymphatic vessels travel with?
Arteries of the same size.
How are lymphatic trunks named?
By the region they drain.
Examples of lymphatic trunks?
Lumbar, Intestinal (NOT interstitial), Broncomediastinal, subclavian, jugular.
Where do lymphatic trunks drain?
Into ducts.
What are the lymphatic ducts?
Thoracic, and right lymphatic.
Where do lymphatic ducts deliver lymph?
Venous circulation at subclavians.
What happens when lymph is delivered to venous circulation?
Reintroduced to bloodstream and becomes part of plasma and is circulated.
What does the thoracic duct drain?
Lower body, left arm, head, and neck.
What route does the thoracic duct take?
Arises from cisterna chyli, through diaphragm, ascends in front of vertebral column, and empties into left subclavian vein.
What does the lymphatic duct drain?
Right side of head, neck, and right arm.
What route does the right lymphatic duct take?
Starts in right thorax to right subclavian vein.
Do the ducts drain evenly?
NOT AT ALL BEBE.
Where are valves located in lymphatic vessels?
At bulges.
What do valves prevent?
Backflow.
Is pressure lower in lymphatics than in veins?
SI.
How is lymph moved?
Skeletal muscles and breathing.
If drainage does not occur what happens?
Lymphedema.
What are the primary cells of the lymphoid system.
Lymphocytes.
What do lymphocytes allow for?
Specific (or adaptive) immunity.
What are the types of lymphocytes?
NK, B, & T cells.
Where are NK cells derived from?
Directly from bone marrow.
Are NK cells specific or non specific immunity?
NON specific.
What do NK cells do?
Detect chemical signals other than specific antigens and induce apoptosis.
Where do B cells originate and develop?
In bone marrow.
B cells characteristics?
Stimulated by an antigen to produce antibodies, can survive for years as memory cells, and become active once exposed to a similar antigen.
Where do T cells originate and develop?
Originate in bone marrow and develop in thymus.
What do T cells attack?
Cells with antigens indicating viral infection or detrimental mutations (cancer)
Do T cells have memory cells?
Yes, they are similar to B cells.
What do T cells induce?
Apoptosis.
What are lymphoid nodules?
Reticular CT dominated by lymphocytes.
Are lymphoid nodules organs?
NOOOOOOOOOOOO!!
What does MALT stand for?
Mucosa associated lymphoid tissue.
What are MALTs?
Digestive lymph nodules.
What are the MALTs of the body?
Tonsils, aggregated lymphoid nodules, and appendix.
Where are tonsils positioned?
Around the pharanx.
What do tonsils do?
Remove pathogens that enter via air or food.
What are the 3 types of tonsils?
Pharyngeal, palatine, and lingual.
Pharyngeal tonsil location and number?
One nodule in nasopharynx.
What is another name for the pharyngeal tonsil?
Adenoids.
Palatine tonsils location and number?
On the soft palate and two nodules.
Lingual tonsils location and number?
At base of the tongue and two nodules.
aggregated lymphoid nodules location?
Line mucosa of the small intestine.
Appendix location?
Blind tube at beginning of large intestine.
What is infection of the appendix and its cause?
Appendicitis. Is caused by intestinal flora enter underlying tissues.
What are the lymphatic organs?
Lymph nodes, thymus, and spleen.
What are lymphatic organs surrounded by?
A fibrous CT capsule.
What is the shape of lymph nodes?
Bean.
What are lymph nodes between?
Severa afferent and one efferent vessel.
What is a hilus?
Indented region where BVs, nerves, and efferent lymph vessels connect.
Lymph node structures?
Cortex and medulla.
Cortex characteristics?
Capsule has trabeculae that subdivide it.
What are the 2 regions of the cortex?
Outer and inner cortex.
What does the outer cortex consist of?
Aggregated B celss.
What happens at the inner cortex?
T cells enter blood here.
What happens at the medulla?
B cells leave through the efferent vessel.
What are the locations of lymph nodes?
Cervical, axillary, inguinal, pelvic, abdominal, and thoracic.
Spleen location?
Found on the left side of stomach.
What is the largest lymphatic organ?
SPLEEN.
What are the 2 compponents of the spleen?
White pulp and red pulp.
White pulp characteristics?
Resembles lymph node.
Red pulp characteristics?
Large amounts of RBC.
What is in red pulp?
Sinuses, macrophages, T & B cells.
What are the functions of the spleen?
Remove old RBCs, store/ recycle iron, initiate immune response, blood reservoir, and RBC production in fetus.
Where is the thymus located?
In the mediastinum.
What is the first lymph organ to develop?
The thymus.
Thymus characteristics?
Grows until puberty, shrinks with age, and replaced by fibrous & adipose tissue.
How many lobes are in the thymus?
2.
What are the lobules of the thymus?
Cortex and medulla.
Cortex characteristics?
Mostly immature T cells.
Medulla characteristics?
Mostly reticular epithelial cells.
T cells in the thymus?
Cortex produces T cells, mature and migrate into medulla, and enter BVs & go into circulation.
What do reticular cells in the thymus do?
Produce thymosin and promote T cell differentiation.
