Lymphatics Flashcards
What are 2 main functions of the lymphatic system?
- Maintaining fluid balance
- Immunity
What are 3 secondary functions of the lymphatic system?
- Distribution of fluids and nutrients
- Absorbing lipids from the small intestine
- Haematopoiesis
What is haematopoiesis?
Formation of new blood cells
Where does plasma filter into?
Interstitial spaces from capillaries
What happens when interstitial spaces receive plasma?
- Cells receive nourishment
- Cells discard waste material to tissue
What happens to waste material discarded by tissue?
Most of it is absorbed by tissue cells or re-enters the blood, a small percentage remains behind
What happens if too much fluid remains behind?
- Oedema
- Tissue destruction or death
What does the lymphatic system filter out?
- organisms
- toxic products
What are the two types of lymphatic filtration?
- mechanical: particles
- biological: phagocytosis
What happens if microorganisms infect the node?
lymphadenitis
What does the lymphatic system carry from the intestine?
- Absorbed fat
- Other nutrients
What is the final site for the maturation of some types of lymphocytes and monocytes?
- The lymphoid tissue of lymph nodes
What are the components of the lymphatic system?
- Lymph
- Lymphatic vessels (tubes)
- Lymph nodes
- Isolated nodules
- Lymphoid structures eg. tonsils, spleen
What are some functions of the spleen?
- Defence
- Haematopoiesis
- Phagocytosis of RBCs and platelets
- Blood reservoir
What is lymph?
a clear fluid containing tissue fluid, proteins, lymphocytes
What does lymph resemble?
- Interstitial fluid
- Blood plasma
What does lymph not do?
Clot- leakage can be fatal over time
What are lymphatic vessels?
Thin-walled vessels which transport lymph to the general circulation
What do lymphatic vessels do?
Transport lymph to the general circulation by a one-way valve system (lymph only flows towards the heart)
What are the two different types of lymphatic vessels?
- lymphatic capillaries in intracellular space and join to form…
- Large lymphatics (trunks, ducts)
What are the main lymphatic trunks?
- Right lymphatic duct
- Thoracic duct
How are lymphatic capillaries anchored to connective tissue?
tiny filaments
What do lymphatic capillaries have a high degree of?
Permeability
What is an important clinical feature of lymphatic capillaries?
Ability to pass very large molecules
What are some differences between veins and lymphatic vessels?
- Thinner walls
- More valves
- Lymph nodes along course
What type of lymphatic capillaries are present in the intestinal mucosa?
- Lacteals: highly specialised to absorb fats and other nutrients
- have milky lymph- chyle
Describe lymph flow
- no muscular pump
- flows slowly: approx 3l/day
- valves ensure one way flow
- skeletal muscle contraction and breathing movements assist this
What trunk drains lymph from the head and neck?
Jugular
What trunk drains lymph from the upper limbs?
Subclavian
What is the thoracic duct?
A major lymphatic channel that begins in the abdomen and terminates in the junction between the LIJ and the left subclavian veins
What do lymph nodes do?
Filter toxic products from the lymph to prevent their entry into the blood vascular system
- phagocytosis
- Haematopoiesis
How many lymph nodes are there?
More than 100 tiny oval or bean shaped nodes (vary in size and shape)
Where are lymph nodes located?
Clusters along the lymphatic vessels (sometimes grouped ie neck, groin, axilla
What do lymph nodes contain?
- Organised lymphoid tissue
- contain lymphocytes which are the white blood cells of the immune system and remove toxic products
- Afferent and efferent vessels
What are the classifications of lymph nodes?
- superficial or deep
- primary or secondary
What constitutes a normal lymph node?
- Small, soft
- Moveable
- Cannot visualise or palpate in EO
Where are tonsils located?
Near airway and food passages to protect against disease and toxic products- first line of defense
What is the pharyngeal lymphoid (Waldeyers) ring?
Masses of lymphoid tissue in a protective ring at the back of the throat under the mucosa
What constitutes the Waldeyers ring?
- pharyngeal tonsils (adenoid)
- tubal tonsils
- palatine tonsils
- lingual tonsils
Where does the Waldeyers ring drain to?
- Sup. deep cervical lymph nodes (specifically the jugulodigastric lymph node)
Why is lymphoid tissue examination important?
- Lymphoid tissue can be involved in spreading infections and cancers
What is meant by proper clinical examination?
- Patient consent
- Proper explanation
- Systematic approach
- Recording of findings
- Referrals as required
What does an infected lymph node feel like?
soft, tender, mobile
What does a cancerous lymph node feel like?
bony, hard, fixed?
- Cancer cells can travel in lymphatic vessels slowly to other nodes- spreads rapidly if reaches blood circulatory system
What does lymphoma feel like?
- firm
- large multinodular
- rubbery
