Lymphatic System Flashcards
What is the lymphatic system composed of?
- lymph
- lymphatic vessels
- lymphatic organs (red bone marrow, thymus, lymph nodes, tonsils, and spleen)
What is lymph?
transparent, colorless (or slightly yellow), watery fluid that closely resembles blood plasma, but more dilute
What do lymphatic capillaries collect? Why?
remnants of interstitial fluid along with cell debris and waste metabolic byproducts from different tissues (except nervous tissue) to form lymph
What do lymphatic capillaries receive?
- lipid droplets from gastrointestinal tract
- lymphocytes from blood
What are the 4 main functions of the lymphatic system?
- drain excess interstitial fluid
- lymphatic vessels pick up excess interstitial fluid from tissues and return it to the blood - transports dietary lipids
- lymphatic vessels transport lipids and lipid-soluble vitamins from gastrointestinal tract to blood - filters lymph and blood
- foreign substances carried by lymph are filtered by lymph nodes
- old or defective blood cells are filtered by spleen - carries out immunological responses
- some lymphatic organs (thymus) initiate responses against certain pathogens
What do lymphatic vessels carry? Where does it go?
carry lymph and pass it through lymph nodes to be filtered
Where are lymphatic vessels?
in all human organs, except CNS, eyeball, inner ear, and cartilages
What do lymphatic vessels join together to form?
lymphatic trunks (larger lymphatic channels) that form lymphatic ducts
What do lymphatic ducts drain into? Where?
venous system at junction of subclavian and internal jugular veins
What are lymph nodes?
bean-shaped structures usually found in groups, accompanying deep and superficial blood vessels
Where are lymph nodes particularly numerous?
axilla, neck, popliteal fossa, inguinal region, posterior abdominal wall, and mediastina
What are lymph nodes the site of?
- lymph filtration
- B lymphocytes proliferation
What is the thymus?
pinkish gland that weighs 10-15 g at birth, and reaches maximum of 30-40 g at puberty
What is the thymus replaced by after puberty?
connective tissue
What is the thymus gland formed by?
two lobes
Where is the thymus gland?
anterior and superior mediastina
What is the thymus the main site of?
T lymphocytes maturation
What is the spleen?
oval shaped, largest of lymphatic organs
Where is the spleen?
located in abdominal cavity in left hypochondriac region
How many surfaces, borders, and poles of the spleen are there? What are they?
- 2 surfaces (medial and lateral)
- 2 borders (superior and inferior)
- 2 poles (anterior and posterior)
What is the lateral or diaphragmatic surface of the spleen?
- smooth
- guarded by ribs IX-XI
What is the medial or visceral surface of the spleen?
mainly related to stomach and left kidney
What does the medial or visceral surface of the spleen carry?
What passes through this structure?
hilum
nerve fibers, splenic artery, splenic vein, and efferent lymphatic vessels pass through
What are the 2 main functions of the spleen?
- filter old and damaged red blood cells from blood
- store platelets
What are tonsils?
Where are they located?
aggregates of more or less encapsulated lymphoid tissue situated at entrances to pharynx
What is the function of the tonsils?
produce antibodies against antigens
What are the 5 tonsils?
- pharyngeal tonsil
- palatine tonsils (2)
- lingual tonsils (2)
Where is the pharyngeal tonsil?
roof of nasopharynx behind nasal cavity
When does the pharyngeal tonsil reach its maximum size?
What happens when it does?
before school age
replaced by connective tissue then
Where are the palatine tonsils?
lie at oropharynx (one on each side) between palatoglossal and palatopharyngeal arches
Where are the lingual tonsils?
located at posterior ⅓ of tongue
Describe the path of lymphatic drainage of the body.
lymph passes from lymphatic capillaries into lymphatic vessels, then through lymph nodes
What happens when lymphatic vessels exit the lymph nodes in certain regions of the body?
form lymph trunks
What are the main lymph trunks? (5)
lumbar intestinal bronchomediastinal subclavian jugular
What do lymphatic trunks join to form?
What do these structures do?
2 major channels: thoracic duct and right lymphatic duct
both ducts drain into blood circulation
Where does the thoracic duct start?
Where does it pass next?
Where does it drain into?
starts from cisterna chyli (lymphatic sac) located in front of vertebrae LI and LII
passes through diaphragm, ascends in posterior mediastinum
drains into junction of left internal jugular and left subclavian veins
What is the cisternal chyli?
lymphatic sac
What does the thoracic duct receive the lymph of?
- lower limbs
- pelvic cavity
- abdominal cavity
- left side of thoracic cavity
- left side of head and neck
- left upper limb
What is the right thoracic duct formed by?
union of right subclavian and right jugular trunks
What does the right lymphatic duct empty into?
junction of right subclavian and right internal jugular veins
What does the right lymphatic duct receive lymph of?
- right upper limb
- right half of thorax
- right side of head
Lower Limb and Pelvis Lymphatic Drainage
What is lymph of the lower limb collected by?
superficial and deep lymphatic vessels that accompany the corresponding veins
Lower Limb and Pelvis Lymphatic Drainage
What does the lymph of superficial and deep lymphatic vessels drain into?
inguinal lymph nodes, which in turn empty into pelvic lymph nodes
Lower Limb and Pelvis Lymphatic Drainage
What do pelvic lymph nodes also receive lymph of?
What are they drained by?
pelvic viscera
drained by lumbar trunks into cisterna chyli
Lower Limb and Pelvis Lymphatic Drainage
What do inguinal lymph nodes also receive lymph of?
- lower quadrant of anterior abdominal wall
- perineum
Abdomen Lymphatic Drainage
Where does the lymph of the alimentary canal, liver, pancreas, and spleen drain into?
pre-aortic lymph nodes, then into cisterna chyli via intestinal trunks
Abdomen Lymphatic Drainage
Where does the lymph of posterior abdominal wall, kidneys, glands, and adrenal glands drain into?
para-aortic lymph nodes, then into cisterna chyli through lumbar trunks
Thorax Lymphatic Drainage
Where does the lymph of thorax drain into?
parasternal, diaphragmatic, intercostal, and mediastinal lymph nodes
lymph of these nodes empties into thoracic duct on left side, and right lymphatic duct on right side via bronchomediastinal trunks
Head and Neck Lymphatic Drainage
Where does the lymph of the head and neck drain into?
superficial and deep lymph nodes (associated with superficial and deep veins, respectively)
these lymph nodes eventually drain into left thoracic duct on left side, and into right lymphatic duct on right side via jugular trunks
Upper Limb Lymphatic Drainage
Where does lymph of the upper limb drain into?
superficial and deep lymph nodes (associated with superficial and deep veins, respectively)
these lymph nodes eventually drain into axillary lymph nodes, that drain into subclavian trunk, that empties into right lymphatic duct on right side and thoracic duct on left side
Upper Limb Lymphatic Drainage
What do axillary lymph nodes also receive?
- superficial lymph nodes of anterior thoracic wall
- upper quadrant of anterior abdominal wall
