Chapter 12: Lymphatic System and Immunity Flashcards
What are the FUNCTIONS (2) of the LYMPHATIC SYSTEM?
to transport fluids which escape from the cardiovascular system back to the blood; plays a role in body defense and resistance to disease
During CAPILLARY EXCHANGE, ____ fluid exits the blood than returns
More
Why must escaped fluids be returned to the body?
so fluid doesn’t accumulate in the tissues, causing edema
What is the function of LYMPHATIC VESSELS?
pick up excess fluid from the body’s tissues and return it to the blood by forming a one-way system
What are LYMPH CAPILLARIES?
the point of entry into lymphatic circulation
WHY do capillary walls overlap?
to form mini-valves in order to prevent backflow of lymph into the tissue space
What are the functions (2) of LYMPHATIC COLLECTING VESSELS?
collect lymph from lymph capillaries and carry them to and from lymph nodes; return fluid to circulatory veins near the heart
What does the RIGHT LYMPHATIC DUCT drain?
lymph from the right arm and right side of the head and thorax
What does the THORACIC DUCT drain?
lymph from the rest of the body
How are lymphatic vessels similar to VEINS of the cardiovascular system?
they both have thin walls, the larger vessels have valves, and they have low pressure without a pump
Lymph transport is AIDED by (3):
milking action of surrounding skeletal muscles, pressure changes in the thorax, and smooth muscle in walls of lymphatics
What is the function of LYMPH NODES?
to filter lymph before it is returned to the blood
What are some of the things LYMPH NODES filter out (4)?
cell debris, bacteria, viruses, and cancer cells
What are the two important IMMUNE CELLS that lymph nodes contain?
macrophages and lymphocytes
What is the function of MACROPHAGES?
to engulf and destroy cell debris, bacteria, viruses, and other foreign substances in lymph
What is the function of LYMPHOCYTES?
to respond to foreign substance in lymph
What other LYMPHOID ORGANS (7) contribute to lymphatic function?
tonsils, thymus, red bone marrow, spleen , mucosa-associated lymphoid tissue (MALT), peyer’s patches, and appendix
What is the function of TONSILS?
to trap and remove bacteria and other foreign substances
Where is the location of T-CELL DEVELOPMENT?
in the thymus
The THYMUS functions at peak level only during ______?
youth; degenerates in adulthood
Where is LEUKOCYTE PRODUCED?
Red bone marrow
What are the functions (4) of the SPLEEN?
to filter and clean blood of bacteria, viruses, and cellular debris; destroys worn-out red blood cells; forms blood cells in the fetus; and acts as a blood reservoir
What is MUCOSA-ASSOCIATED LYMPHOID TISSUES (MALT)?
concentration of macropahges and lymphocytes below the mucosal surfaces of the respiratory, digestive, urinary and reproductive tracts
What does MALT include (2)?
peyer’s patches in the small intestine and appendix
What is the function of MALT?
acts as a sentinel to protect the respiratory and digestive tracts when the surface is breeched
What is IMMUNITY?
the ability to recognize infectious agents and defend against them
What are the two MECHANISMS that make up the immune system’s defense against foreign agents?
innate (nonspecific) defenses and adaptive (specific) defense
Why are INNATE DEFENSES “non-specific”?
innate immunity includes mechanisms which protect against a variety of invaders
Which immune system defense mechanism is the first to respond?
the innate defense
What other mechanisms (2) does INNATE immunity include?
surface barriers and internal defense mechanisms
Why is ADAPTIVE IMMUNITY “specific”?
it has the ability to identify specific invaders (that get past the innate system)
How does ADAPTIVE immunity IMPROVE?
with exposure
What other mechanisms (3) does the ADAPTIVE immunity include?
lymphocytes, antibodies, antigen-presenting cells
What happens is the SURFACE BARRIER is BREECHED?
Internal defenses immediately respond