6- Lymphatics II Flashcards
What provides propulsion for capillaries?
Extrinsic forces b/c no smooth muscles in the capillaries
What are key points about lymph flow?
(hint: intra-capillary pressure, amount of leak per day, % reabsorbed? % drained from ISF, Rate of lymph through the TD per day)
- High intra-capillary pressure
- 20-30 liters of plasma leak per day
- become interstitial fluid (ISF)
- 90% is reabsorbed by veins
- 10% is drained form ISF by lymph capillaries
- 2-5L of lymph pass through the thoracic duct per day.
What part of the lymph flow system has smooth muscles?
The lymphangion (which are segments inbetween bicuspid valves)
What is the largest lymph vessel in the body?
Thoracic Duct
Where does the thoracic duct begin? Where does it travel? Where does it empty into?
- Begins at ~L2 (from the Cisterna Chyli)
- Travels through diaphragm within the aortic hiatus and arches 3-4 cm above the clavicle
- Empties into the venous system at the juncture of the left internal jugular vein and the left subclavian vein
Where does the Right lympahtic duct empty out into?
The juncture of the right internal jugular vein and the right subclavian vein
True or False: Only some organs contribute to the two main lymphatic functions of homeostasis and self defense.
False; ALL ORGANS contribute to the two main functions
Which tissues do not have lymphatics?
Vascularized Tissue: Central Nervous System (CNS)/Brain Bone Bone Marrow Maternal Placenta Endomyceum around muscle fibers
Nonvascularized Tissues: Cartilage Lens of the eye Cornea of the eye Epidermis Inner portion of the wall of blood vessels
Does the brain have a lymphatic system? How does it remove extra fluid?
No, it does not have a lymphatic system! It uses CAPILLARIES
What Non-Vascularized tissues lack lymphatics?
Cartilage Lens of the eye Corena of the eye Epidermis Inner portion of the wall of blood vessels
Describe the general gross anatomy of the diaphragm
- Parachute shaped
- a huge muscle with a central tendon
- Has left and right Crura that goes down to L2 (level of cysterna chylie)
What are functions of the Crura?
- Pump for cysterna chylie
- May obstruct flow when tense
How is the diaphragm like a sponge?
Has holes (called stomata) that absorbs fluid from the peritoneal/pelvic cavity, pleural cavity, pericardial cavity, lower body wall, and lower extremity
What does the Diaphgram absorb fluid from?
Peritoneal/Pelvic Cavity Pleural Cavity Pericardial Cavity Posterior body wall Lower extremity
What substance regulates stomata? What actions does it regulate?
Nitric Oxide (NO) regulates the opening and absorption of the stomata
Where does the Diaphragm drain into?
Cysterna Chylie and the Thoracic Duct
What technology do we use to study the lymphatic system?
Radiolabeled tracers
What percentage of peritoneal fluid is drained by the diaphragm?
42-55%
What happens to the diaphragm when you inhale? Exhale?
Inhale = Diaphragm contracts, descends, and flattens Exhale = diaphragm relaxes and domes back up
What are the two theories for where the lymphatics are located in the lungs?
1) Only in limited areas close to the bronchioles; no lymph vessels deep in the pulmonary lobule
2) In the deep tissues and around small blood vessels of the lungs
Where are the lymphatics in the GI Tract?
embedded in epithelial cells (in the lamina) along the GI tract
What are the two types of GI Tract tissues?
1) GALT - Gut Associated lymphoid tissue
2) MALT - mucosa associated lymphoid tissue
What three locations do lymphoid nodules generally organize and cluster up?
Tonsils
Appendix
Peyer’s Patches (in small intestine)
Describe the drainage of the GI Colon Lymph
Two parts:
1) Entire colon on the proximal 2/3 of the rectum drain into the para-aortic vessels (on either side of the aorta). These drain into cisterna chyle and then to the thoracic duct
2) Distal 1/3 of rectum drain into the internal iliac superficial inguinal area (pelvis region) that drains into the Cysterna Chyle, which drains into the thoracic duct.
