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
What are the three INTERNAL DEFENSES?
Inflammation, Phagocytes, and Fever
What are the FUNCTIONS (4) of the INFLAMMATORY RESPONSE?
prevents the spread of damaging agents; dispose of cell debris and pathogens through phagocytosis; increases metabolic rate to help fight infections; sets the stage for tissue repair
What are the four common INDICATORS of acute INFLAMMATION?
redness, heat, pain, and swelling (edema)
What is the PROCESS of the INFLAMMATORY RESPONSE? (3)
- Neutrophils migrate to the area of inflammation by rolling along the vessel wall; 2. Neutrophils squeeze through the capillary walls by diapedesis to sites of inflammation; 3. Neutrophils gather in the precise site of tissue injury and consume any foreign material present
The HYPOTHALAMUS regulates body temperature at ______
37C (98.6F)
High temperatures INHIBIT the release of _____ and _____
iron and zinc (from the liver and spleen)
The hypothalamus thermostat can be reset higher by ______
pyrogens
Fever increases the speed of _____ and ______
immune response and repair processes
What are ADAPTIVE BODY DEFENSES?
the body’s specific defense system or third line of defense
What are the three aspects of ADAPTIVE DEFENSE
?
Antigen-specific; systemic; and memory
What is the ANTIGEN-SPECIFIC aspect of Adaptive Defense?
the adaptive defense recognize and act against particular foreign substances
What is the SYSTEMIC aspect of Adaptive Defense?
immunity is not restricted to the initial infection site
What is the MEMORY aspect of Adaptive Defense?
the adaptive defenses recognize and mount a stronger attack on previously encountered pathogens
What is ANTIBODY-MEDIATED immunity?
immunity provided by antibodies present in body fluids
What is CELL-MEDIATED immunity?
immunity by T cells targeting virus-infected cells, cancer cells, and cells of foreign grafts
What are ANTIGENS?
any substances capable of exciting the immune system and provoking an immune response
What are six examples of NON-SELF ANTIGENS?
foreign proteins (provoke the strongest response), nucleic acids, large carbohydrates, some lipids, pollen grains, and microorganisms
What do LYMPHOCYTES do in the Adaptive Defense System?
respond to specific antigens
What do B-CELLS do in the Adaptive Defense System?
produce antibodies and are responsible for antibody-mediated immunity
What do T-CELLS do in the Adaptive Defense System
constitute the cell-mediated arm of the adaptive defenses
What do ANTIGEN-PRESENTING CELLS (APCs) do in the Adaptive Defense System?
help the lymphocytes, but do not respond to specific antigens
What is IMMUNOCOMPETENCE?
the capability to respond to a specific antigen by binding to it with antigen-specific receptors that appear on the lymphocyte’s surface
Where are LYMPHOCYTES produced?
in red bone marrow
Where are B-CELLS produced?
in bone marrow
Where are T-CELLS produced?
in the thymus
What two major types of cells behave as APCs?
Dendritic cells and macrophages
What is the function of APCs?
engulfing antigens, then present fragments of them on their own surfaces
What CHEMICAL is released when APCs activate T-CELLS?
cytokines
What is the function of CYTOKINES?
to coordinate immune activity
The antibody response is ____ and ____ for the first response?
slow and weak
What are the two major PATHWAYS that adaptive immunity can be acquired through?
active immunity and passive immunity
When does ACTIVE immunity occur?
when B cells encounter antigens and produce antibodies
How is ACTIVE immunity NATURALLY acquired?
during bacterial and viral infections
How is ACTIVE immunity ARTIFICIALLY acquired?
from vaccines
When does PASSIVE immunity occur?
when antibodies are obtained from someone else
How is PASSIVE immunity NATURALLY acquired?
from mother by the fetus during gestation or in breast milk
How is PASSIVE immunity ARTIFICIALLY acquired?
from immune serum or gamma globulin
What is the STRUCTURE of ANTIBODIES?
four polypeptide chains form a Y-shaped molecule
What do the ARMS of the antibody contain?
specific antigen-binding sites
What does the BASE of the antibody do?
bind macrophages (only when antigen is bound to ABS
What are the five CLASSES of antibodies?
IgM, IgD, IgG, IgA, and IgE
What two ANTIBODY CLASSES are BOUND TO B CELL MEMBRANES
IgM and IgD
Which antibody class is the PRIMARY SERUM ANTIBODY?
IgG
Which antibody class is found mainly is SECRETIONS?
IgA
Which antibody class is involved in ALLERGIES?
IgE
What do T LYMPHOCYTES do for the immune system?
directly engage infected, cancerous, or abnormal host cells
What are the two major classes of EFFECTOR T CELLS?
Helper T-Cells and Cytotoxic T-Cells
What is the function of HELPER T-CELLS?
recruit other cells to fight invaders
What is the function of CYTOTOXIC T-CELLS?
killing infected or abnormal cells
How does cytotoxic t-cells kill infected/abnormal cells?
by secreting perforin and granzyme molecule on to thre affected cell
What is the function of PERFORIN?
to form pores on the cell’s cell membrane
What is the function for GRANZYME?
to enter the abnormal cell and trigger its death
