Anatomy of the lymphatic system Flashcards
What does the lymphatic system consist of?
- Lymph vessels (lymphatics), lymph nodes, and organs, such as tonsils, spleen, thymus, lymphatic mucus membrane tissue, and the tissue of the appendix.
What structures lack lymphatics?
- Epidermis, glandular epithelium, bone marrow, brain, cartilage, nails, lens and the vitreous body.
True or False? The lymph system does not have a major pump like the heart and it also has filtering stations or nodes along its path
True
What is the difference between lymph vessels and blood vessels?
- Lymph vessel system is an open system - draining in one direction
- Blood vessel system is a closed system-circulates blood
What are the 3 vascular compartments?
- Subcutaneous epifascial (skin, subcutis)
- Subfascial (muscles, joints, bones)
- Lymph vessel of organs
Which trunks do the vessels of the deep system empty into?
Large lymphatic trunks
What are the superficial and deep system linked by?
Perforating vessels
What does the deep system do?
Removes interstitial fluid from muscles, joints, organs and vessels
What does the superficial system do?
Removes interstitial fluid of the skin, subcutis
The lymphatic system can be divided into a _______ and a ________
Superficial (epifascial) & Deep system (subfascial)
The vessels of the deep system empty into the _______
Large lymph trunks
Describe the anatomy of the initial lymph vessels?
- Initial lymph vessels of the lymphatic vascular system
- They have a plexus like origin in the tissue, made of a single layer of endothelial cells which overlap each other and surrounded by a basement membrane
- Made of endothelial cells and are attached to the collagen fibres in the connective tissue by anchoring filaments
Describe the function of the initial lymph vessels?
- Absorption of the lymph obligatory load from the tissue due to the suction exerted by deeper situated collectors, pressure changes in the interstitium and osmotic processes
- Can also be an active process of the endothelial cell
- After entering the initial lymph vessels, the lymph obligatory load is called lymph
- Main task: lymph formation
Describe the anatomy of the precollectors?
- Made of endothelial cells which are surrounded by basement membrane
- In the pre collectors, there are only a few isolated mm cells and appear more toward the collector end of the vessel
- They only have a few isolated valves (rudimentary valves) - Fall more toward the collector end of the precollector
- They can absorb a small amount of Lymph obligatory load. They are called transport and collector vessel
What are the function of the pre collectors?
- Pre collectors connect the initial lymph vessels with the lymph collectors
- Function: transport lymph from initial lymph to collector and absorb some interstitial fluid
Describe the anatomy of the collectors (Lymphangions)?
- Made up of individual units called lymphangions
- Like small lymph hearts - help to pump lymph in one direction through vessels
- Innervated by sympathetic nerves which help to stimulate contraction of the lymph vessels
- There are receptors inside and outside of collectors that respond to stretch forces on the lymph vessels
- Made of 3 layers:
– Intima: inner - endothelial cells
– Media: middle - smooth mm cells
–Adventitia: outer - collagen + elastin fibres
What is the function of the lymph collectors?
- To maintain lymph flow, protein circulation, and recirculation of lymphocytes
- Function: transport lymph from pre collectors to lymph nodes
Describe the anatomy of the lymph node?
- Lymph nodes are lymphatic organs
- ~600 - 700 LNs in the human body, can vary to 1000. In the neck 1/3 ~ 160LNs
- size 2-30mm - bean shaped surrounded by connective tissue capsule that contains some smooth mm cells
- consists of an internal trabecular framework which surrounds the lymphatic tissue
- Each lymph node has several afferent vessels that enter through the convex side of the capsule and empty into the sinus (marginal, intermediary, and cortical sinus) of the node
- One of two lymph vessels exit the capsule at the hilum
What are the functions of the lymph node?
- Lymph filtration - filtering out everything harmful to the body and rendering it harmless - viruses, bacteria, fungi, and so
- Lymph concentration, if necessary also dilution
- Activation of the immune system (lymphocyte sensitization)
- Storage place for non degradable substances
- Fluid exchange
What does the term “lymph-obligatory load” signify?
Everything that cannot be absorbed by the venous system becomes lymph obligatory
What does the lymph obligatory node consist of?
Protein, water, cells (cell debris), fat (long-chain fatty acids), and foreign substances.
T/F: Every region of the body has its own group of regional lymph nodes
True.
- They consist of an internal trabecular framework, which surrounds lymphatic tissue. - - Each lymph node has several afferent vessels that enter through the convex side of the capsule and empty into the sinus of the node. — One or two lymph vessels exit at the capsule at the hilum
What are the functions of the lymphatic vascular system?
Absorption of lymph-obligatory load, maintenance of fluid balance, maintenance of protein circulation, recirculation of lymphocytes.
Where does the lymph from the entire body drain into?
The subclavian vein at the venous angle (terminus) and travels together with the venous blood into the right heart
The lymph flow is also maintained by so-called _____________
auxiliary pumps.
What factors exert external pressure on the vessels?
- MLD
- Contraction of skeletal muscles
- Pulsation of large arteries
- Increased intestinal peristalsis during MLD
- Pressure changes in the thorax during respiration that cause intensified contraction of the large lymph trunks and produce a suction effect in the venous angle
