Lymphatic System Flashcards
Functions of the lymphatic system:
- Returns excess interstitial fluid to the blood to maintain homeostasis
- Fats and fat-soluble vitamins are absorbed from the intestinal tract into specialized lymph capillaries
- Defense against invading microorganisms and disease
Fluid in lymphatic vessels. Derived from blood plasma. Some plasma escapes at the arteriole end of a capillary. Most reenters the venule end of the capillary, but 10% remains in the tissue space as interstitial fluid. As fluid accumulates, tiny lymph vessels pick it up and it becomes this
Lymph
Carry fluid away from tissues and return it to the venous system.
Lymphatic Vessels
Lymph capillaries merge to form large and larger vessels until it reaches two lymphatic ducts. What are they? (2)
- Right lymphatic duct
- Thoracic duct
Receives lymph from the upper right quadrant of the body and empties into the left subclavian vein
Right lymphatic duct
Drains lymph from the remaining three quadrants of the body and empties into the left subclavian vein
Thoracic duct
Located along the various vessels of the lymphatic system. Job is to filter lymph. Walls are thin and have valves. No pressure, so flow is sporadic and sluggish. Obstructions may cause tissue fluid to accumulate, resulting in edema
Lymph nodes
Characterized by clusters of lymphocytes and other cells with a mesh-like framework of connective tissue fibers.
Lymphatic Organs
When the body is exposed to foreign substances, what proliferate then enter the blood and travel to the site of the foreign substance?
Lymphocytes
Small bean-shaped structures located along lymphatic vessels. Filter lymph as it flows through the vessels so it is cleansed by lymphocytes and macrophages.
Lymph nodes
Groin region
inguinal nodes
armpit
axillary nodes
neck
cervical nodes
Cluster of lymphatic tissue under mucous membrane of the nose, mouth, and throat.. Protect against pathogens that may enter the body through the nose and mouth
Tonsils
Near opening of nasal cavity in the pharynx, ADENOIDS
Pharyngeal tonsils
Near opening of oral cavity into the pharynx
Palatine tonsils
Near the base of the tongue
Lingual tonsils
Located in the upper left quadrant of abdominal cavity, under diaphragm and behind stomach. Largest lymphatic organ. Filters blood like lymph node filters lymph. Acts as a reservoir for blood and destroys old erythrocytes
Spleen
Soft, two-lobed organ located anterior to ascending aorta, posterior to the sternum.
Large in infants and children, decreases in size after puberty.
Primary function is the maturation of special lymphocytes called T lymphocytes.
Produces hormone thymosin, stimulates maturation of lymphocytes in other organs.
Thymus
First line of this:
Provide initial defense against invading agents.
First line of defense:
Intact of unbroken skin or mucous membranes.
Motion of fluids, such as tear, saliva, and urine.
Chemical protection against invaders.
Second line of defense:
Chemicals such as interferon and complement, phagocytosis, and inflammation
Nonspecific Defense Mechanism
Programmed to be selective and act against specific pathogens
Specificity
System remembers invading agents to launch quicker attack
memory
molecules that are called antigens
non-self
An immune response trigged against this can cause autoimmune disease.
self
