The Lymphoid and Immune Systems Flashcards
Microbiome
microorganisms that reside on and in the human body
immune system
not an organ system, but a cell population that inhabits all organs and defends the body from agents of disease
Lymphoid (lymphatic) system
lymphatic vessels that penetrate nearly every tissue, and a collection of lymphoid tissues and organs that produce immune cells(sewer system)
Thoracic duct
cisterna chyli
; empties into left subclavian vein
Right lymphatic duct:
receives lymph from right arm, right side of head and thorax; empties into right subclavian vein
Lymph flows at
low pressure and slower speed
Lymph flows under
forces similar to those that govern venous return,
Lymphoid nodules (follicles)
lymphocytes and macrophages gather in dense masses
Primary lymphoid organs
red bone marrow and thymus
Thymus
-in endocrine, lymphoid, and immune systems
-Houses developing T cells and secretes hormones regulating their activity
-involution—degeneration, shrinkage
-By age 65, unable to make new T cells
Secondary lymphoid organs
lymph nodes, tonsils, and spleen
Metastasis
Metastasizing cells easily enter lymphatic vessels
Cancerous nodes are usually
swollen, firm, painless
Tonsils
Guard against ingested or inhaled pathogens
Single pharyngeal tonsil (adenoids)
on wall of pharynx
Pair of palatine tonsils
at posterior margin of oral cavity
Numerous lingual tonsils
concentrated on each side of base of tongue
the body’s largest lymphoid organ
spleen
Spleen is highly…
vascular and vulnerable to trauma and infection
spleen produces
red pul[ and white pulp
Adaptive immunity
developed only upon exposure (adaptive), and maintains immune memory
Innate immunity
defenses we are born with (innate)
Complement system
Synthesized mainly by liver
Interferons
serves as an “alarm” to nearby cells
