Chapter 14 lymphatic system and immunity Flashcards
Lymph
the name for tissue fluid that enters lymphatic capillaries
lymph vessels
lymph vessels begin as dead end lymph capillaries found in most tissue spaces
Lacteals
Specialized lymph capillaries found in the vli of the small intestine that absorb fat-soluble end products of digestion
What do lymph capillaries form?
larger lymph vessels
What prevents backflow of lymph?
the one-way valves
Skeletal muscle pump
lymph vessels compressed by skeletal muscles that surround them
Respiratory pump
expand and compresses the lymph vessels in the chest cavity and keeps the lymph moving
cisterna chyli
lymph vessel formed by the lower body lymph vessels that is found in front of the lumbar vertebrae
thoracic duct
empties lymph from the lower body and upper left quadrant into the left subclavian veins
right lymphatic duct
empties lymph from the upper right quadrant into the right subclavian vein
What does lymph tissue produce?
lymphocytes and monocytes
Lymph nodes
masses of lymphatic tissue
larger than nodules
are found in groups along the pathway of the lymph vessels
what happens when lymph passes through a lymph node?
macrophages phagocytize bacteria and foreign material
Where are 3 most important lymph nodes located?
cervical, axillary and inguinal
Lymph nodules
masses of lymphatic tissue
found beneath the epithelium of all mucous membranes
placed near portals of entry for possible pathogen invasion
Where are lymph nodules located?
respiratory, digestive, urinary and reproductive tracts
Tonsils
are lymph nodules that form a ring of lymphatic tissue
Tonsils:
palatine- lateral walls of the pharynx
adenoid -posterior wall
lingual-base of the tongue
What are the lymph nodes of the small intestine called?
Peyer’s patches
Spleen location
located upper left quadrant just below the diaphragm and behind the stomach
In the fetus what does spleen produce?
red blood cells
After birth what does the spleen do?
produces lymphocytes and monocytes
Functions of the spleen after birth?
contains plasma cells that produce antibodies
contains fixed macrophages that phagocytize pathogens and other foreign material, including old RBCs
The spleen is not a vital organ because?
other organs compensate for its functions
a person without a spleen is more susceptible to pneumonia and meningitis
Thymus
inferior to the thyroid gland
larger in the fetus and infant
relatively little found in adults because it shrinks
What do the stem cells of the thymus produce?
T lymphocytes or T cells
What do the thymic hormones do?
allow the T cells to participate in recognizing foreign antigens and give immunity
At what age does our immune system become mature and fully functional?
Age 2
Immunity
Ability to destroy pathogens or other foreign material and to prevent further cases of certain infectious disease
Antigens
markers that identify cells as either self or non-self
Why are transplants a problem?
transplanted organs are foreign tissue and the immune system may reject a transplanted kidney or heart
What are the two main components of immunity?
Innate immunity and adaptive immunity
Innate immunity
non specific
does not create memory
responses are always the same regardless of the target
What are the innate immunity defensive cells?
Natural Killer Cells
Basophil/mast cells
Natural killer cells
rupture foreign cell membranes
found in blood, bone marrow, spleen and lymph nodes
Basophils/Mast cells
produce histamine and leukotrienes
What are the innate immunity chemical defenses?
Interferons
Complement
Inflammation
Interferons
produced by cells infected with viruses
prevent reproduction of viruses within cells
Complement
group of more than 20 proteins that circulate in the blood until activated
involved in the lysis of cellular antigens and the labeling of noncellular antigens
Inflammation
purpose is to try to contain the damage, keep it from spreading, eliminate the cause and permit repair of the tissue to begin
Adaptive immunity
Involves T and B lymphocytes
specific to its antigen- creates memory
may become more efficient with repeated exposure
can be either cell-mediated immunity or antibody-mediated immunity
T lymphocytes
produced in the bone marrow and thymus in the embryo, they pass through the thymus for maturation and then move into the spleen, nodes, and nodules
B cells
produced in the embryonic bone marrow, they move to the spleen, nodes, and nodules
Helper T cells (cell mediated immunity)
Compare the foreign antigen to the self antigens on the macrophage and become activated in antigen specific
Cytotoxic T cells (cell mediated immunity)
Chemically destroy foreign antigens by disrupting their cell membranes
Memory T cells (cell mediated immunity)
Initiate a rapid immune response if the antigen enters the body again
macrophages (cell-mediated immunity)
Phagocytize foreign antigens
Cytokines (cell mediated immunity)
Chemicals produced by cytotoxic T cells that attract macrophages
Helper T cells (Antibody mediated immunity)
Compare the foreign antigen with self antigen on the macrophages; are antigen specific and strongly activate
B cells
memory b cells (antibody mediated immunity)
Initiate rapid antibody production if the antigen enters the body again
Plasma cells (antibody mediated immunity)
Produce antibodies specific for one foreign antigen
Macrophages (Antibody mediated immunity)
Phagocytize antigen/antibody complexes
Antibodies (Antibody mediated immunity)
Proteins produced by plasma cells that bind to a specific foreign antigen
Complement (Antibody mediated immunity)
Plasma proteins that are activated by antigen/antibody complexes and lyse cellular antigens
Antibodies
(immune globulins)- proteins produced by plasma cells in response to foreign antigens
do not destroy cells, but merely attach themselves to the antigen in order to label it for destruction
are specific to one antigen
Mechanisms of immunity
1st step-recognition of cells as foreign by its antigens
• Helper T cells help in the identification of foreign antigens
• Triggers 1 of 2 mechanisms of immunity: cell-mediated immunity or humoral immunity
IgG
Location: Blood and extracellular fluid
Functions: A monomer; the most abundant immune globulin; crosses the
placenta to provide passive immunity for newborns; provides long-term immunity to a disease following recovery or a vaccine
IgA
Location: External and internal secretions (tears, saliva, intestinal)
Functions: A dimer; present in breast milk to provide passive immunity for breastfed infants; found in secretions of all mucous membranes to provide local defense where pathogens enter
IgM
Location: Blood
Function: A pentamer; produced first by the maturing immune system of infants; produced first during an infection (IgG production follows); the antibodies of the ABO blood group
IgD
Location: B Lymphocytes
Function: A monomer; forms receptors on B lymphocytes
IgE
Location: Mast cells or basophils
Functions: A monomer, is important in allergic reactions (mast cells release histamine) and responses to parasites such as worms
Antibody responses
Antibodies are produced slowly and in small amounts
Antibodies neutralize viruses by bonding to them and preventing them from entering into cells
Bacterial toxins are neutralized when antibodies bond to them and change their shape
Agglutination
occurs when antibodies bind to bacterial cells, which makes it easier for the macrophages to phagocytize them
Vaccines
Contains antigens that the immune system will respond to
- Attenuated-weakened or killed antigen
• May contain toxoids (inactivated bacterial toxin)
Allergies
Hypersensitivity to a particular antigen, which causes an over response by the immune system
mass production of the lgE antibodies
Histamine increases the permeability of capillaries, which increases fluid formation and in influx of WBC to the damaged area
Genetic immunity
Does not involve antibodies; is programmed in DNA
Some pathogens affect certain host species but not others
Acquired ammunity
involves antibodies
Passive immunity
Antibodies from another source
Natural-placental transmission of igG antibodies from mother to fetus-transmission of IgA antibodies in breast milk
Artificial-Injection of preformed antibodies after presumed exposure
Active immunity
production of ones own antibodies
Natural-Recovery from a disease, with production of antibodies and memory cells
Artificial: A vaccine stimulates production of antibodies and memory cells
