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)