Lymphatic System Flashcards
What is lymphatic vessels
Network of vessels and capillaries
What are the three parts of the lymphatic system
Lymphatic vessels, lymph fluid and lymph tissues
What is lymph fluid
Fluid in vessels (+ lymphocytes, proteins)
What is lymph tissue
Nodes, spleen, thymus, tonsils and malt
What are the functions of the lymphatic system
Returns leaked fluid to blood vessels, defence of bodies
Describe the lymphatic vessels
One way flow of fluid, vessels have valves. Lymph flows toward heart. Vessels merge to form thoracic duct which empties into vena cava
Describe lymph formation
Plasma, interstital fluid, lymph
Describe the lymphatic capillaries
Microscopic blind ended, highly permeable: picks up pathogens and cancerous cells as well as plasma proteins: role of lymph nodes. Mini valves which open when interstitial osmotic pressure is greater than lymphatic. Blind ended tubes in which adjacent endothelial cells overlap each other forming flap like minivalves.
What are lacteals
SpecialiZed lymph capillaries present in intestinal mucosa - absorb digested fat and deliver fatty lymph (chyle) to the blood
What are lymphoid tissues
Place for lymphocytes (B+T cells) to live and patrol for pathogen. Composed mainly of loosely connective tissues ( reticular connective tissues ).
How is lymphoid tissue dispersed
In organs. Diffused or found in clusters (nodules). Peyers patches in wall of ileum.
What are large nodules
Lymph nodes
What are lymph nodes
Principal lymphoid organs of body, in clusters along the lymphatic vessels.
What are the defence functions of lymph nodes
Filter lymph - macrophages destroy pathogens and prevent them from entering blood.
Activate immune system: B cells and T cells lymphocytes attack pathogens or infected cells
Describe the spleen
Largest lymphoid organ, also has a hematologic function
What is the function of the spleen
Site of some clonal selection + antibody production in immune response. Rbc graveyard - destroys old red blood cells and platelets, macrophages remove debris.
Stores blood
Is the spleen essential for life
Nope, other organs can take over function in event of splenectomy
What is the thymus
Found in cervical region. Partially overlies heart and trachea. Important functions early in life (neonate). Gradually atrophies and replaced by fatty fibrous tissues
What is the thymus the site of
Site of T-Cell maturation
Contains no B cells
What are tonsils
Differ from lymph nodes: no fibrous capsule surrounding them. Found in moist epithelial mucosal surfaces not a long lymph vessels in middle of body.
Gather and remove pathogens in food (digestive tract) or air (respiratory tracts). Mainly found in pharynx
What is malt
Lymphoid tissue in mucous membranes throughout body. Protects from pathogens trying to enter body. Large collections of malt in tonsils, peyers patches. Also in mucosa of respiratory and genitourinary organs: rest of digestive tract - galt
What is neoplasia
Abnormal growth of tissue
What is lymphoma
Cancer of lymphatic tissue types: B cell/T cell proliferation: multicentric: lymph nodes, spleen, liver, bone marrow
Mediastinal: thoracic structures
Extranodal: skin, eyes
What are the symptoms of lymphoma
Enlarged lymph nodes, lethargy, depression, and weight loss, fever, vomiting, diarrhea
What is cbc abnormal symptoms:
Anemia, lymphocytosis
What are abnormal fna symptoms:
biopsy: lymphocytosis
What is fiv: feline immunodeficiency virus
Virus that targets lymphocytes and macrophages causing lymphopenia: progressive. Most often transmitted through bites: vertical transmitted is less common.
How do you test for fiv and how do you treat it
Test for antibodies: vaccinated cats may test positive. Negative cats may have not yet produced antibodies. No cure : time of death: 5 yrs after infection
What is felv:
Also caused by retrovirus. More easily transmitted than FIV: mainly through saliva and nasal secretions, urine feces and milk. Progressive disease. Causes leukaemia, lymphomas, and suppression of immune systems
Is there a vaccination for felv
Vaccine available but not beneficial if infected. Test for antigens
