A + P Lymphatic and Immune Systems Flashcards
immune system
-what is it?
collection of biological structures and processes within the body that protect against disease by identifying and killing pathogens and tumor cells
pathogens
microscopic organisms, such as viruses, bacteria, fungi, parasites, and toxins that cause disease in a specific way
lymphatic system
-what is it?
part of the immune system and is comprised of a network of conduits called lymphatic vessels that carry a clear fluid called lymph unidirectionally toward the circulatory system
important structures of the lymphatic system
lymph lymphatic capillaries lymphatic vessels lymph nodes bone marrow thymus gland spleen appendix tonsils
lymph
- originates
- some plasma
- most of this tissue fluid
- the rest
originates as plasma in the blood
some plasma from arterial circulation seeps out into the surrounding tissues where it becomes tissue fluid that delivers nutrients, O2, and hormones to the cells
most of this tissue fluid (90%) absorbs cellular waste products and protein cells before entering the venous circulation as plasma
remaining tissue fluid (10%) is now known as lymph
lymphatic capillaries
- lymph leaves body tissues via
- -most are
- -the rest
- lymphatic capillaries join
lymph leaves body tissues via specialized lymphatic capillaries
-most are superficial capillaries located just below the skin
-the rest are known as deep lymphatic capillaries, which surround most of the body’s organs
lymphatic capillaries join together to form a mesh-like network of tubes, which eventually give rise to the lymphatic vessels
lymphatic vessels
- lymphatic vessels and body depth
- separated into function units called
- -characteristics
deep within the body the lymphatic vessels become progressively larger and are located near major veins
lymphatic vessels are separated into functional units called lymphangions, which have walls lined with smooth muscle and one-way valves to prevent backward lymph flow
lymph nodes
- what are they?
- contain
- function
small, spherical structures connected to lymphatic vessels that contain sinuses that house lymphocytes (mature B and T cells) and macrophages
lymph nodes filter the lymph before it returns to the circulatory system
lymphatic flow/drainage
- how does it flow?
- lymph passes through
lymph only flows upward through the body traveling from the extremities through the body toward the neck
as it travels through the body, lymph passes through lymph nodes where it is filtered
lymphatic flow organization
-organized into two separate
organized into two separate and very unequal left and right drainage areas
normally lymph does not drain across the “invisible lines” that separate these areas
structures within each area carry lymph to the base of the neck, where lymph enters the subclavian veins and once again becomes plasma in the venous circulation
bone marrow
-what is produced there?
macrophages and lymphocytes (B cells and T cells) are produced in the bone marrow
thymus gland
- what happens?
- -in response to
T cells mature in the thymus in response to thymosin release
spleen
-function
helps purify blood that passes through it by removing bacteria and worn-out or damaged red blood cells
appendix
- connected to
- houses
- with regard to immune function
connected to the cecum of the LI
houses several types of bacteria that are helpful for digestion
with regard to immune function, it is supposedly rich in lymphocytes and may release antigens during fetal development that elicit antibody production
tonsils
-function
specialized lymphatic tissues that represent the body’s first line of defense against ingested or inhaled pathogens
important components of the immune system
antibodies (immunoglobins)
antigens
leukocytes
interleukins
antibodies (immunoglobins)
- produced from
- what makes them useful?
- what happens to “marked” pathogens
proteins produced from B cells that are designed to protect against pathogens
ability to recognize specific pathogens makes them useful for defense against foreign invaders
pathogens that are “marked” with antibodies are phagocytized or removed from the body
5 classes of human antibodies
IgA IgD IgE IgG IgM
antigens
- what are they
- usually
molecules that antibodies are capable of recognizing
usually a protein or carbohydrate chain bound to a pathogen
leukocyte
- what is it?
- types
WBC that come in several variants types -neutrophils -eosinophils -basophils -monocytes -lymphocytes
neutrophils
- what are they?
- function
microphages that phagocytize pathogens
eosinophils
- what are they?
- function
microphages that phagocytize pathogens
basophils
-function
release histamine, which contributes to the inflammatory response at a site of injury or infection
monocytes
- what are they?
- in response to
- function
macrophages
in response to inflammation signals, they move to the site of injury or infection and divide/differentiate into macrophages for phagocytosis
lymphocytes
-produced in
produced in red bone marrow, lymphatic tissues (e.g. tonsils) and lymphatic organs (e.g. spleen, thymus)
lymphocyte types
B-cells
T-cells
Natural Killer (NK) cells
B-cells
- mature in
- contain
- function
mature in the bone marrow and lymph nodes
have specific antibodies attached to their surface, which function to detect specific antigens in their native form
T-cells
- mature in
- like B cells
mature in the thymus
like B cells, they have specific antibodies attached to their surface, which function to detect specific antigens in their processes form (antigen+MHC)
types of T-cells
cytotoxic T cells
helper T cells
suppressor T cells
memory T cells
cytotoxic T cells
-function
attack foreign cells or cells infected by viruses
helper T cells
-function
stimulate the activation and function of B cells and T cells
suppressor T cells
-function
inhibit the activation and function of B cells and T cells
memory T cells
-formed in response to
formed in response to a pathogen and remain in body for long period, just in case…
natural killer (NK) cells -function
attack foreign cells, virus-infected cells, and cancer cells
interleukins
- what are they?
- functions
cytokines produced from WBC
functions
-collectively increase T cell sensitivity
-stimulate B cell activity and antibody production
-help moderate/suppress the immune response
what do the four types of immunity represent?
represent body defenses and mechanisms that prevent or fight infection, illness, and disease
4 types of immunity
innate (non-specific) immunity
adaptive (specific) immunity
active immunity
passive immunity
innate (non-specific) immunity
mechanisms that are present at birth and generally effective against a variety of pathogens
adaptive (specific) immunity
generally acquired only after exposure to a pathogen
active (adaptive) immunity
antibodies acquired after exposure to a specific antigen (e.g. environmental exposure or vaccines
passive (adaptive) immunity
antibodies are acquired from another source (e.g. from mother or by injection)
innate (non-specific) immunity components
physical barriers phagocytes immunological surveillance interferons complement inflammatory response fever
physical barriers
keep hazardous materials outside the body
-include skin, skin oils, ciliary linings, low pH in the stomach, tears, and saliva
phagocytes
microphages (neutrophils an eosinophils) and macrophages (monocytes) that attack and remove dangerous pathogens
immunological surveillance
constantly monitors normal tissues for the presence of cancer cells or viral infections
when present, NK cells are activated, identify the pathogens, and act to destroy them
interferons
chemical messengers (cytokines) that trigger production of antiviral proteins in normal cells to interfere with viral replication (but do not destroy viruses)
complement
plasma contains 11 special complement (C) proteins that complement/assist antibodies with the destruction of pathogens
inflammatory response
a localized, tissue-level response that tends to limit the spread of injury or infection and facilitate the repair of damaged cells
fever
high body temperature (activated by pyrogens that travel to the hypothalamus)
- increases metabolism
- accelerates pathogen defenses
- inhibits the function of some pathogens, such as viruses and bacteria
adaptive (specific) immunity timeline
responds to specific antigens with coordinated action of T cells and B cells
T cells provide cell-mediated immunity, which is defense against abnormal cells and pathogens inside cells
B cells provide antibody-mediated immunity, which is defense against antigens and pathogens in body fluids
adaptive (specific) immunity cont.
once antigens bind to antibodies, they are subsequently “presented” to lymphocytes, which leads to
- initial (first exposure)
- secondary (subsequent exposures)
initial (first exposure)
antigens activate B and T cells, plasma B cells differentiate, and specific antibody levels increase
secondary (subsequent exposures)
activation of memory B and T cells, which elicits a more extensive and prolonged antibody defense
responses to bacterial vs. viral infections
bacterial
-neutrophils and NK cells begin killing bacteria
-cytokines draw phagocytes to the area of infection
-antigen presentation activates helper T cells and cytotoxic T cells
-B cells activate and differentiate
-plasma cells increase antibody levels
viral
-similar to bacterial infection, but cytotoxic T cells and NK cells are activated by direct contact with virus-infected cells
homeostatic imbalances
autoimmune diseases immunodeficiency diseases allergies lymphedema leukemia lymphadenopathy/lymphadenitis
autoimmune disease
- various diseases that result from a compromised ability to recognize and ignore “normal” antigens in the body
- consequently, activated B cells make “autoantibodies” against healthy body cells, which leads to their destruction
autoimmune disease examples
rheumatoid arthritis
multiple sclerosis
Grave’s disease
Type I diabetes
immunodeficiency diseases
-underactive or imparied immune function due to improper embryological development of lymphoid tissues, viral infections such as HIB, and/or immunosuppressive drugs and radiation treatments
immunodeficiency disease examples
AIDS
Severe Combined Immune Deficiency (SCID)
allergies
- overactive immune responses to allergens, which are specific antigens
- mast cells contain antibody receptors to allergens (antigens)
- when stimulated, they secrete histamine
- causes mucus secretion, bronchoconstriction, and inflammation
lymphedema
- a blockage of lymph drainage from a limb, which causes severe swelling and allows bacteria to thrive within the stagnant protein-rich lymph
- consequently, the likelihood of infections is dramatically increased
leukemia
- type of cancer of the blood or bone marrow characterized by large amounts of immature leukocytes (WBC), which are unable to form correctly functioning lymphocytes (B and T cells)
- consequently, immune system function is severely compromised
lymphadenopathy/lymphadenitis
chronic or excessive enlargement of lymph nodes due to various infections, endocrine disorders, or cancer
