Lymphatics Flashcards
How do Lymphatic vessels differ from blood vessels?
- Completely different vascular network- Collects extravasated fluid from tissues (whereas blood vessels deliver fluid)- Filter lymph- Return lymph to circulation
How are lymphatic vessels similar to blood vessels?
Both blood vessels and lymphatic vessels come from a COMMON embryiologic origin that separates during development, which allows for common, yet distinct pathways.
What are the two main functions of the lymphatic system? What are two specifics for each function?
- Maintain homeostasis - Cardiovascular assistance with fluid management - Transportation of fats from small intestine to veins- Immunologic role - Filter particulate matter - Develop and deliver antibodies
How does homeostasis impact fluid management?
It is the pathway for fluid return from the interstital tissues back to the vascular system
How much fluid per day is returned back to the vascular system via the lymphatic system?
2 liters/day
What are lacteals?
Lymphatic vessels found in the intestines that are responsible for the transport of lipids into lymph fluid (aka. chyle)
Where do the lymphatic vessels transport fat to?
To the blood via the thoracic duct and sent to the liver for processing
What are primary lymph organs?
Red bone marrow Thymus
What are secondary lymph organs?
- Lymph nodes- Spleen- Lymphatic Nodules (Pharygeal Tonsils)
How are primary valves different than secondary valves?
Primary valves are :- Are on smaller vessels- Have only ONE valve (secondary have two to prevent retrograde)- Have only endothelial cells (secondary have smooth muscle and endothelial cells)
Describe the basic outline of the Lymph System
- Thin walled channels of endothelial cells- Join together to form larger vessels- Primary lymph valves have ONE-WAY microvalves- Large vessels collect lymphatics (have endothelium and smooth muscles w/ secondary valves that restrict retrograde)- Nodes - located along the path of the collecting lymphatics- Large lymphatic vessels ultimately drain into left and right subclavian veins
What is a lymphagion?
Pre-nodal or “afferent” collecting vessels
Where do trunks return the lymph to? via?
Venous system via lymphatic ducts.
Describe the superficial Lymph System
Drains the skin (not epidermis), musculoskeletal structures, located in groups near veins and travel through the fascia to the deep system
Describe the movement of the lymph flow.
Movement goes from peripheral tissues toward the midline of the body then toward cervicothoracic junction.
Describe the Deep Lymph System
Drains the thorax, abdomen, pelvis and perinerium
How does interstitial fluid get into the lymph capillary?
Hydrostatic GradientsOncotic gradients (dependent on proteins inside and outside the vessels)Mechanical forces (local arterial pulsations and vasomotion, local alveolar expansions, local musculoskeletal compressions upon lymph vessels, passive motion of extremities)
Describe the piston activity of the respiratory diaphragm
Inhalation = Diaphragm descends –> increases pressure in intra-abdominal space causing fluid to flow into the terminal vesselBecause aveolar sacs are expanded, there is external mechanical pressure on surrounding pleural lymph nodes.
How much of lymph fluid is derived from abdominopelvic fluids?
50%
True or False: Respiratory function holds little or no effect on the efficiency of the lymphatic system
False. Proper respiratory function improves the efficiency of the lymphatic system.
What is in Lymph Fluid?
Fatty AcidsFatChyleImmune Cells (WBC, lymphocytes in post-nodal duct, antigen-presenting cells, dendtric cells)
What are key properties of Lymph capillaries (terminal lymphatics)?
- Larger than blood capillary- One way permeability (fluid only goes in)- Single layer of non-fenestrated endothelial cells that overlap- Incomplete Basement Membrane- No tight junctions : therefore permeable to large particles and proteins- Lack smooth muscle
Describe a Lymphangion.
- Begins at the first bicuspid valve, which marks the beginning of the lymphangion or pre-nodal collecting vessel- Drain superficial capillary network- Transport lymph to regional nodes (via affarent vessels)- Possess smooth muscle layer for intrinsic contractile properties and coordinated flow- Pump like arteries: has a filling phase (7 seconds); contraction phase (1 second) and refractory period (1 second). - 130-150 microns in diameter
Does lymphatic fluid enter or exit the lymph capillaries during the expansion phase of the capillaries?
Enter! (Influx)
What occurs during the compression phase?
The hydrostatic pressure inside the initial lymph increases, causing microvalves to shut and bicuspid valves to open (flowing lymph fluid into the lymphagion
Describe lymph nodes shape, contents, and function.
-Kidney bean shaped- Contents: - B Cells - T cells - other immune cellsDistributed widely in the bodyActs as filters or traps for foreign particles (bacteria, viruses, cancer cells etc)
Describe the structure of a lymph node
- Afferent lymph vessels enter through the capsule- The Cortex is a fibrous capsule separated into internal segments with geminal centers and an inner medulla- Efferent lymph vessels exit at the Hilum with the artery and veins.
Describe the Cysterna Chyli
It’s a VERY IMPORTANT collecting reservoir located at L2 vertebrae that drains into the thoracic duct. All fluids distal (inferior) to the Cysterna Chyli drain into it
True or False: Lymph through the cervical lymph nodes will travel through the Cysterna Chyli to the Thoracic Duct
False; Cervical lymph nodes are superior to the cysterna Chyli, therefore do not pass through the CC to the Thoracic Duct
What are the two major Lymphatic ducts? What are general properties of both?
1) Thoracic Duct2) Right Lymphatic DuctProperties include:- thin walled- have smooth muscle- secondary vessels- have organized lymphangions- under sympathetic nervous system control
Where is the Thoracic Duct? What does it drain lymph from? Where does empty into?
The Thoracic Duct is located at the level of thoracic vertebra.Drains lymph from: left head, neck arm, arm left thorax (partial left lung) cysterna Chyli (hence also, abdominal, pelvic and LEX)Empties into the LEFT internal jugular and subclavian veins
Where does the Lymphatic Duct drain lymph from? Where does it return lymph to?
Drains from: Right upper extremity right side of head, neck and chest right lungDrains to: veins at right subclavian veins
What is the rate for the movement of lymph? What does it depend on?
10 mm/secDependent on: - Hydrostatic pressure - interstitial oncotic pressures - Intrinsic contraction of lymphangion smooth muscle - External compressive forces.
What is the definition of lymphangion?
The space between bivalve to bivalve.
What is edema? What is the cause of Edema?
Edema is the flow of lymph back into the interstitum.This is caused by obstruction that cause swelling of vessels that disrupt cause back flow and the anchoring filaments.
What are causes of Flow Disturbance?
Local: Interstitial fluid pressures and ECM strainSystemic: Contraction of lymphangion smooth muscles (intrinsic) and external forces acting on lymph vessels (extrinsic; ex. venous stasis and local cardio pulmonary pressure)
What is an intrinisic systemic problem that can cause flow disturbance?
contraction of lymphangion smooth muscles
What is an extrinsic systemic problem that can cause flow disturbance?
External forces acting on lymph vessels. local cardiopulmonary pressures and venous stasis
What is lymphanopathy and what type of screening is required to see it?
Lymphanopathy are enlarged lymph nodes.Require X-rays to visualize
