Lymphatic System Flashcards
Functions of the Lymphatic System
- fluid recovery (2-4 L/day, prevents edema)
- immunity (lymph and blood monitored for pathogens and cancer cells)
- lipid absorption (via lacteals in small intestine)
6 Types of Lymphatic Cells
T Lymphocytes - develop in thymus
B Lymphocytes - develop in red bone marrow, produce antibodies
Macrophages - develop from monocytes, phagocytotic
Natural Killer Cells (NK cells) - large lymphocytes that attack and lyse bacteria, foreign tissue, infected host cells
Dendritic Cells - branched cells in skin, antigen presenters
Reticular Cells - branched cells in stroma of lymphatic organs
Lymphatic Fluid
- what is it?
- how is it produced?
AKA Lymph
- produced by filtration of plasma through capillaries
Pathway of Lymph Flow
- towards the heart
- begins in dead-ended lymphatic capillaries where blood capillaries are (except: brain, teeth, bones, marrow)
What is this structure?
Where is it found and where does it lead?
lymphatic capillaries
- smallest lymph vessel (larger than blood capillaries)
- permeable to lymph fluid and proteins via its valve-like overlapping endothelial cells
- dead-end at blood capillary beds and drain into lymph collecting vessels
- absent in cornea, bone marrow, CNS
What lymphatic structures do lymphatic capillaries drain into?
What is their structure like?
lymphatic collecting vessels
- contain valves to molve lymph towards heart
- have the same three tunics as blood vessels, but thinner walls and lower pressure
- have lymph nodes along length to filer lymph
- lie along with veins in superficial tissues and arteries in deeper tissues
The convergence of several lymphatic collecting vessels
lymphatic trunk
the five major lymphatic trunks
- Lumbar Trunk
- Intestinal Trunk
- Bronchomediastinal Trunk
- Subclavian Trunk
- Jugular Trunk
Paired lymphatic trunks branching off of the inferior end of the thoracic duct
Lumbar Trunks (left and right)
- carry lymph from lower limb, pelvic region and anterior abdominal wall
Single lymphatic trunk branching off of inferior thoracic duct
Intestinal Trunk
- drains lymph from stomach, intestines and other digestive organs
part C
bronchomediastinal trunks (left and right)
- carries lymph from thoracic viscera
- usually open into junction of internal jugular and subclavian veins
- sometimes join right lymphatic duct and thoracic duct
part B
subclavian trunks (left and right)
- lymph from upper limbs, inferior neck and superior thoracic wall
- open either into junction of internal jugular and subclavian veins or into jugular trunk and thoracic duct
part A
Jugular Trunks
- drains lymph from head and neck
- right side joins the venous angle (right internal jugular and subclavian veins)
- left side joins thoracic duct
Where do the lymphatic trunks drain?
- into the lymphatic ducts
- two major ducts: thoracic duct and right lymphatic duct
cisterna chyli
- dilated sac at inferior end of thoracic duct
- receives lymph from intestinal and lumbar trunks
- contains lots of chyle, fat-rich intestinal lacteal lymph
Thoracic Duct
- joins junction of left subclavian and internal jugular veins (the venous angle)
- drains left side of face, most of left thorax and lower body
top left question-marked structure:
right lymphatic duct
- joins right venous angle
- drains right side of head and upper body
- only present in 20% of people