What is the function of the lymphatic system?
cleans lymph from blood with pathogens and return it to the venous system
What are the 3 parts of the lymphatic system? What are they/what are their functions?
- lymphatic vessels (return IF & plasma proteins back to blood; carry pathogens from tissue bed to lymph nodes)
- lymph (fluid in the vessels)
- lymph node (cleanses lymph, has T/B cells, macrophages)
What do Lymphoid Organs and Tissues do? (2)
provide structural basis of immune system
House phagocytic cells and lymphocytes
What are the lymphoid structures? (5)
tonsils, thymus, spleen, peyer’s patches, appendix
What is a whole blood, plasma, interstitial fluid, and lymph?
- whole blood = plasma + WBC + RBC
- plasma = water + protein
- once interstitial fluid (liquid/water not in cell/organ) from the blood enters the lymphatics, called lymph (lymph = water + WBC)
What is the flow of lymph through the lymphatic system? What is its direction?
- impurities taken out from lacteals in the intestine > capillaries > vessels > node > trunks > ducts > vena cava > arterial system > intestine
- unidirectional
What 3 things does the lymphatic vessels include, from smallest to largest? Where do they collect fluid/lymph from?
lymphatic capillaries (collect fluid from tissue bed) > collecting lymphatic vessels (collect lymph from capillaries) > lymphatic trunks/ducts
What are the differences between lymphatic and blood capillaries? (6)
- highly permeable (to even cancer cells)
- due to one way mini valves
- due to anchored by collagen filaments to prevent collapse of capillaries
- more anatosomes
- thinner walls
- deliver chyle (fatty lymph) to the blood
What are the similarities between lymphatic vessels and blood vessels? (3)
- both have 3 tunic layers
- both have valves
- anatomical distribution varies between individuals
What is the lymphatic system’s role in relation to the cardiovascular system?
maintains blood volume & pressure
Lymphatic capillaries are absent in which parts of the body?
teeth, bone, CNS, bone marrow
Describe the formation of lymph
IF collected through lymph capillaries, which mixes with WBC
Describe the path of lymph circulation.
lymphatic capillaries > lymphatic vessels (deep vessels travel with arteries, skin with superficial veins) > trunks > duct > venous circulation
Describe the lymph circulation of the right lymphatic and thoracic ducts
- right lymphatic duct drains upper arm & right side of head & thorax
- thoracic duct drains rest of body (left side body & right abdomen & leg)
What are the largest vessels that empties lymph into venous circulation? What do they join with?
- thoracic & right lymphatic duct
- junction of internal jugular & subclavian veins
The union of which ducts forms the trunks? (5)
lumbar, bronchomediastinal, subclavian, jugular trunks, intestincal trunks
How is the lymph propelled? (6)
- Milking action of skeletal muscle
- Pressure changes in thorax during breathing
- Valves to prevent backflow
- Pulsations of nearby arteries
- Contractions of smooth muscle in walls of lymphatics
- movment of body
What are the 2 types of lymphoid cells/lymphocytes? What do they protect agains (broad vs specific). What is the mechanism of invasion?
- T & B lymphocytes
- protect against antigens (virus, bacteria, mismatched RBC, cancer)
- antigens mimic shape to match target cell receptor and gain access to what is inside the cell
What do T and B cells do?
- T cells destroy infected cells
- B cells produce plasma cells that produce antibodies
What do antibodies do?
mark antigens for destruction by phagocytosis or other means
What do macrophages do? (2)
phagocytize foreign substances; help activate T cells
What do dendritic cells do (2) ?
-capture antigens and deliver them to lymph nodes; activate T cells
What do reticular cells produce and do?
produce reticular fiber stroma that supports other cells in lymphoid organs
What do lymphoid tissues do? (3)
- Houses, and provides proliferation site for, lymphocytes
- Surveillance point for lymphocytes and macrophages
- where dendritic cells try to find uneducated T/B cell
