The Lymphatic System Flashcards
What are lacteals?
The lymphatic vessels of the small intestine which absorb digested fats
What is chyle?
A milky fluid containing fat droplets which drains from the lacteals of the small intestine into the lymphatic system during digestion
Name four lymphatic ducts in the body
Right lymphatic duct, thoracic duct, right subclavian duct and lumbar trunks
Describe the right lymphatic duct?
This drains the right upper quadrant of the body including the right side of the head, neck, thorax and right arm. This duct drains into the right subclavian vein at the junction with the internal jugular vein (the right venous angle)
Describe the thoracic duct?
This duct drains the rest of the body apart from the right upper quadrant and it begins in the abdomen as the cisterna chyle and drains at the left venous angle (Virschow’s node)
What structures drain their fluid into the cervical lymph nodes?
Fluid from the skin above the clavicle
What structures drain their fluid into the axillary lymph nodes?
Fluid from the skin between the clavicle and umbilicus
What structures drain their fluid into the inguinal lymph nodes
Fluid from the skin below the umbilicus
What is the role of superficial lymph nodes? Name three.
To drain the fluid from the skin. Examples are cervical, axillary and inguinal lymph nodes.
Describe the lymphatic drainage of the head and neck
Some fluid enters the superior cervical lymph nodes, others drain into the deep cervical lymph nodes
Describe the horizontal inguinal lymph nodes
These are superficial and run on top of the inguinal ligament; they drain fluid from the anterior abdominal wall, perineum and external genitalia apart from the testes
Describe the vertical inguinal lymph nodes
These lie at the termination of the greater saphenous vein in the leg, and provides most of the superficial lymphatics of the leg
What is the lymphatic drainage of the abdomen and the lower limb
To the horizontal and vertical inguinal lymph nodes
Describe the lymphatic drainage of the posterior abdominal wall
To the lumbar lymph nodes, pre-aortic lymph nodes and the intestinal lymphatic trunk
Where are the lumbar lymph nodes located?
On the external and internal iliac arteries
Where are the pre-aortic lymph nodes and intestinal lymphatic trunk located?
On the abdominal blood vessels
Where is the cisterna chyle found?
This is the beginning of the thoracic duct and it is found anterior to L1/L2 vertebra
What structures drain into the cisterna chyle?
Intestinal, right and left lumbar trunks
What is the function of the lymphatic system?
It drains excess fluid and leaked plasma proteins and provides defence against pathogens (antibodies and phagocytosis)
How does fluid drain into the lymphatic vessels?
When the pressure in the tissue fluid is high, this causes the endothelial cells of the lymphatic vessels to be opened, allowing entry of the excess fluid (and proteins – large gaps, highly permeable). The collagen fibres allow the valves to open without collapse, but the valves (endothelial cells) close when the pressure within the lymphatic vessel itself is high.
How is lymph transported around the body?
Travel in low-pressure conduits, so active skeletal muscle is required for movement in addition to valves and pressure changes int he thorax.
Name the lymph nodes of the head and neck that are palpable
- Preauricular
- Postauricular
- Occipital
- Submandibular
- Submental
- Superficial anterior cervical
- Deep cervical
- Posterior cervical
- Supraclavicular
Name four palpable lymph nodes of the axilla
o Anterior axillary (pectoral)
o Lateral (brachial)
o Mid axillary (central)
o Posterior (subscapular)
Name the palpable lymph nodes of the legs
- Superficial superior inguinal
- Superficial inferior inguinal
- Popliteal (occasionally)
Outline the role of the spleen as a lymphoid organ
Provides site for the proliferation of lymphocytes, extracts aged blood cells, stores and secretes bilirubin
Outline the role of the thymus as a lymphoid organ
Secretes thymopoietin and thymosins which cause T lymphocytes to mature (become immunocompetent)
Outline the role of the tonsils as a lymphoid tissue
Gather and remove some pathogens which enter the pharynx in food or inhaled air.
Outline the role of Peyer’s patches as lymphoid tissue
These are isolated clusters of lymphoid tissue located in the ileum (also concentrated lymphoid follicles in the appendix. These patches work to destroy bacteria so that they do not breach the intestinal wall as well as to develop memory/adaptive immunity.
What is Virchow’s node and what is it’s clinical significance?
This is the left venous angle and palpable nodes here may be indicative of metastatic cancer in the liver and/or lungs
Describe the course of the superficial cervical lymph nodes.
They run alongside the external jugular vein over the SCM muscle
Describe the course of the deep cervical lymph nodes.
These travel in the vertical chain along the internal jugular vein
Where are Peyer’s patches found?
In the ileum
