lymphatic system Flashcards
lymphatic system
- acts as a secondary circulatory system by transporting and filtering interstitial fluid (lymph)
- responsible for returning tissue fluid to the blood
- also monitors the body for pathogens (critical role in immunity)
central lymphoid system
‘central’ because these tissues can replenish lymphocytes
thymus- site of T c ell maturation
bone marrow- produces lymphocytes
peripheral lymphoid tissues
CANNOT replenish lymphocytes
lymph nodes
peripheral
contain leukocytes that filter lymph and can initiate an immune response
spleen
peripheral
filters blood as it passes through
adenoids
peripheral
mass of lymphatic tissue that inspects incoming food and air for pathogens
located in face
appendix
contains lymphoid tissue that helps destroy bacteria before they breach the intestinal wall during absorption
Peyer’s patches
large aggregates of lymphoid tissue in the small intestine
lymph
fluid that starts as blood plasma forced out of capillaries (known as interstitial fluid before it is absorbed into the lymphatic system)
lymphatic capillaries
thin-walled vessels that collect excess interstitial fluid and other substances from the tissues and transport them to the lymphatic vessels
movement of lymph fluid
- interstitial fluid floating between cells is absorbed by lymphatic capillaries at the ends of lymphatic vessels and is then referred to as lymph
- movement of lymph is assisted by one-way valves, skeletal muscle contraction, and smooth muscle lining
- lymphatic capillaries drain lymph all over the body
- lymph is ultimately returned to the blood
lymph system blockage
an obstruction (ex: tumor pressing against a lymph vessel) can lead to swelling and edema
edema
swelling that can further constrain blood flow
swelling occurs because
fluid pools in the tissue instead of being brought back to circulation
lymph node biopsy
use to detect cancer and determine where the cancer cells have traveled
