Lecture 2 - Lymphatics Flashcards
What are the 4 parts of the lymphatic system?
- Fluid (lymph)
- Vessels (lymphatics)
- Structures and organs that contain lymphatic tissue (nodes)
- Red bone marrow (site of lymphocyte production)
Where is lymph fluid found?
Almost every tissue in the body
Describe the lymphatic system.
Immune system combined with cardiovascular system
What are the 3 main functions of lymphatic tissue?
- Drain interstitial fluid
- Transport dietary lipids (triglycerides)
- Protect against invasion
Which lymphatic tissue function does gross anatomy focus on? What is the purpose of this function?
- Drain interstitial fluid
Because 10% of plasma fluid does not return into circulation via normal venous return after being distributed to the tissues
Describe a lymphatic capillary. How does it work?
Blind-ended capillaries wrapped around cardiovascular capillaries with openings/flaps open in one direction (so fluid cannot flow back) when the interstitial fluid pressure on the outside is larger than it is on the inside of the capillary
What lymph capillary structure allows it to embed itself in most tissues?
Anchoring filaments
What are the specialized lymph capillaries of the gut called? Where are they found?
Lacteals
Mostly in microvilli of small intestine and a little in large intestine
What does each intestinal microvilli contain?
A vascular capillary and a lacteal
What do the GI lymphatics bypass in the first go around of fat absorption? Where do they bring the lipids instead?
Liver is bypassed and fats are brought directly to the heart
What does the vascular capillaries of the GIT absorb? Where do they bring these first? How?
Water soluble nutrients
Liver via portal circulation and the hepatic portal vein connecting the 2 capillary beds
What are the 2 circuits of the heart? What does each end with?
- Systemic
- Pulmonary
Each ends with capillaries
What is the pathway of interstitial fluid through the lymphatic system?
Fluid stuck in tissues => blind end of lymphatic capillaries => lymph nodes => lymphatic vessels with valves => cardiovascular venous circulation => heart right atrium
What is the function of the lymphatic vessel valves?
They can only move the lymph in one direction
What are lymph nodes?
Dilated portions along lymphatic vessels where the immune system interacts with the lymph
Are lymph nodes evenly distributed throughout the body?
NOPE
What are the 4 body parts where lymph is not found?
- Avascular tissues
- CNS
- Portion of spleen
- Red bone marrow
What are 3 examples of avascular tissues?
- Cartilage
- Epidermis
- Cornea of eye
How many lymph nodes in our body?
~500
In what color is lymph depicted in in graphics?
Green
Where are lymph nodes usually not found?
Legs, forearms to hands
Are lymph nodes symmetrically distributed throughout the body?
NOPE
What plays the role of the lymphatics in the CNS?
Cerebrospinal fluid
Why are lymphatics hard to find in a body?
Because they are very small and look just like connective tissue and are within it
Where are most lymph nodes found?
The trunk
How do we categorize lymph nodes? Describe the first kind.
- Superficial: can be palpated
2. Deep
What are the 3 superficial lymph nodes?
- Cervical nodes
- Axillary nodes
- Inguinal nodes
When do axillary nodes become enlarged?
- Pulmonary infection
2. Breast cancer
What is the major site of breast cancer metastasis?
Axillary lymph nodes
When do inguinal nodes become enlarged?
Superficial infection below the belly button
When do cervical nodes become enlarged?
Throat infection
What nodes are enlarged in the bubonic plague?
Inguinal nodes
What are the 3 major deep lymph nodes?
- Tracheo-bronchial nodes
- Aortic nodes
- Iliac nodes
Where are the tracheo-bronchial nodes found?
Trachea and bronchioles
Where are the aortic nodes found?
Abdominal aorta
Where are the iliac nodes found?
Iliac vessels
When do tracheo-bronchial nodes become enlarged?
Lung cancer