Lymphatics of the Head and Neck Flashcards
What is the lymphatic system?
A network of drainage vessels
What does the lymphatic system consist of?
- Fluid - lymph
- Drainage vessels
- Lymphatic tissues
What are the lymphatic tissues?
Lymph nodes, a type of lymphoid organ
How many lymph nodes are there in the body?
800
How many lymph nodes are there in the neck?
300
Describe the structure of lymph nodes
Connective tissue structures, with a tough, fibrous outer capsule, and reticular connective tissue inside
What do lymph nodes contain?
Large collections of lymphocytes and macrophages
Where do lymph nodes play a key role?
In immune defence
What do all substances transported in lymph pass through?
1 or more lymph nodes
What immune defences do lymph nodes have?
- Physical filter
- Phagocytic filter
- Full of lymphocytes
What happens to the lymphocytes in lymph nodes?
They activate and proliferate in response to antigens
Where are the specific regions in the body where lymph nodes may be palpable?
- Neck (cervical)
- Armpit (axillary)
- Diaphragm
- Spleen
- Abdominal
- Pelvic
- Groin (femoral)
What may lymph draining into lymph nodes contain?
Pathogens
What are the lymphoid organs?
- Spleen
- Thymus
- Tonsils
What happens to the lymph fluid?
It returns to the blood circulation
Where are lymph vessels found?
Throughout the body, with a few exceptions
What parts of the body do not have a lymphatic circulation?
- Eyeball
- Cornea
- Lens
- Inner ear
- Cartilage
- CNS
Why is there debate regarding the lymphatic circulation of the CNS?
Recent research has identified small lymphatic vessels lining the dura
How can lymph nodes be organised?
Into regional (or superficial) and terminal (or deep) groups
How are regional and terminal lymph nodes seperated?
By investing layer of deep cervical fascia in the neck
What are the regional groups of lymph nodes found in the area of the head and neck?
- Occipital
- Pre- and post- auricular
- Submandibular
- Sternocleidomastoid
- Submental
What do regional lymph nodes do?
Drain specific areas
Where do regional lymph nodes in the neck lie?
Superficially within superficial cervical fascia
What is the result of regional lymph nodes lying superficially within superficial cervical fascia?
They can be readily palpated, especially when enlarged
Where does lymph from superficial lymph nodes drain?
Into the deep lymph nodes