LYMPHATIC Flashcards
The Lymphatic System
Consist of two semi-independent parts:
1.Lymphatic vessels
2.Lymphoid tissues and organs
Semi independent parts that
- consist of excess tissue fluid and plasma proteins carried by lymphatic vessels
- If fluids are not picked up, edema occurs as fluid accumulates in tissues
- also pick up excess fluid (lymph) and return it to the blood
Lymphatic Vessels
Weave between tissue cells and blood capillaries Walls overlap to form flaplike minivalves
Fluid leaks into this
also anchored to connective tissue by filaments
Higher pressure on the inside closes minivalves Fluid is forced along the vessel
Lymphatic capillaries
It collect lymph from lymph capillaries
Carry lymph to and away from lymph nodes
Return fluid to circulatory veins near the heart Right lymphatic duct drains the lymph from the right arm and the right side of the head and thorax
Thoracic duct drains lymph from rest of body
Lymphatic collecting vessels
Lymphatic vessels are similar to veins of the
cardiovascular system
Thin-walled
Larger vessels have valves
Low pressure, pumpless system
Lymph transport is aided by: Milking action of skeletal muscles
Pressure changes in thorax during breathing Smooth muscle in walls of lymphatics
Lymphatic vessels are similar to veins of the
cardiovascular system
Thin-walled
Larger vessels have valves
Low pressure, pumpless system
Lymph transport is aided by: Milking action of skeletal muscles
Pressure changes in thorax during breathing Smooth muscle in walls of lymphatics
Lymphatic nodes filter lymph before it is returned to the blood
Harmful materials that are filtered:
Bacteria
Viruses
Cancer cells
Cell debris
Lymphatic nodes filter lymph before it is returned to the blood
Harmful materials that are filtered:
Bacteria
Viruses
Cancer cells
Cell debris
WHAT
Defense cells within lymph nodes:
it - engulf and destroy bacteria, viruses, and other foreign substances in lymph
Macrophages
Defense cells within lymph nodes
It - respond to foreign substances in lymph
Lymphocytes
Most lymph nodes are kidney-shaped, less than 1 inch long, and buried in connective tissue
Surrounded by a capsule
Divided into compartments by trabeculae
Most lymph nodes are kidney-shaped, less than 1 inch long, and buried in connective tissue
Surrounded by a capsule
Divided into compartments by trabeculae
PART OF LYMPHATIC NODES
(outer part)
•Contains follicles - collections of lymphocytes
•Germinal centers enlarge when antibodies are released by plasma cell
Cortex
PART OF LYMPHATIC NODES
Contains phagocytic macrophages
Medulla (inner part)
Flow of lymph through nodes
Lymph enters the convex side through afferent lymphatic vessels
Lymph flows through a number of sinuses inside the node
Lymph exits through efferent lymphatic vessels
Flow of lymph through nodes
Lymph enters the convex side through afferent lymphatic vessels
Lymph flows through a number of sinuses inside the node
Lymph exits through efferent lymphatic vessels
Several other lymphoid organs contribute to lymphatic function (in addition to the lymph nodes)
what are these organs?
Spleen
Thymus
Tonsils
Peyer’s patches
Appendix
WHAT LYMPHOID ORGAN
- it is Located on the left side of the abdomen
Filters and cleans blood of bacteria, viruses, debris
Provides a site for lymphocyte proliferation and immune surveillance
Destroy worn-out blood cells
Forms blood cells in the fetus
Acts as a blood reservoir
Spleen
WHAT LYMPHOID ORGAN:
Found overlying the heart
Functions at peak levels only during youth
Thymus
WHAT LYMPHOID ORGAN
-Small masses of lymphoid tissue deep to the mucosa surrounding the pharynx (throat)
Trap and remove bacteria and other foreign pathogens
Tonsillitis results when the tonsils become congested with bacteria
Tonsils
WHAT LYMPHOID ORGAN:
Found in the wall of the small intestine
Similar lymphoid follicles are found in the appendix
Macrophages capture and destroy bacteria in the intestine
Peyer’s Patches
Mucosa-associated lymphoid tissue (MALT)
Includes:
Peyer’s patches
Tonsils
Appendix
Acts as a sentinel to protect respiratory and digestive tracts
Mucosa-associated lymphoid tissue (MALT)
Includes:
Peyer’s patches
Tonsils
Appendix
Acts as a sentinel to protect respiratory and digestive tracts
What are the wo mechanisms that make up the immune
system defend us from foreign materials
- Innate (nonspecific) defense system
- Adaptive (specific) defense system
- specific resistance to disease
Immunity
is a functional system rather than an organ system in an anatomical sense
Immune system
TYPE OF DEFENSE SYSTEM
Mechanisms protect against a variety of invaders Responds immediately to protect body from foreign materials
Innate (nonspecific) defense system
TYPE OF DEFENSE SYSTEM
Fights invaders that get past the innate system
Specific defense is required for each type of invader
The highly specific resistance to disease is immunity
Adaptive (specific) defense system
Innate body defenses are mechanical barriers to
pathogens (harmful or disease-causing
microorganisms) and include:
Body surface coverings
•Intact skin
•Mucous membranes
Specialized human cells
Chemicals produced by the body
Innate body defenses are mechanical barriers to
pathogens (harmful or disease-causing
microorganisms) and include:
Body surface coverings
•Intact skin
•Mucous membranes
Specialized human cells
Chemicals produced by the body
Surface membrane barriers, such as the skin and
mucous membranes, provide the first line of
defense against the invasion of microorganisms
Protective secretions produced by these membranes
Acidic skin secretions inhibit bacterial growth
Sebum is toxic to bacteria
Mucus traps microorganisms
Gastric juices are acidic and kill pathogens
Saliva and tears contain lysozyme (enzyme that destroy bacteria)
Surface membrane barriers, such as the skin and
mucous membranes, provide the first line of
defense against the invasion of microorganisms
Protective secretions produced by these membranes
Acidic skin secretions inhibit bacterial growth
Sebum is toxic to bacteria
Mucus traps microorganisms
Gastric juices are acidic and kill pathogens
Saliva and tears contain lysozyme (enzyme that destroy bacteria)
Cells and chemicals provide a second line of
defense
Natural killer cells and phagocytes Inflammatory response
Chemicals that kill pathogens
Fever
Cells and chemicals provide a second line of
defense
Natural killer cells and phagocytes Inflammatory response
Chemicals that kill pathogens
Fever
SECOND LINE OF DEFENSE
Lyse (burst) and kill cancer cells, virus-infected cells
Release chemicals called perforin and granzymes to degrade target cell contents
Natural killer (NK) cells
SECOND LINE OF DEFENSE
Triggered when body tissues are injured
Four most common indicators (cardinal signs) of acute inflammation
1. Redness
2. Heat
3. Pain
4. Swelling (edema)
Inflammatory response
SECOND LINE OF DEFENSE
Damaged cells release inflammatory chemicals Histamine
Kinin
These chemicals cause:
Blood vessels to dilate
Capillaries to become leaky
Phagocytes and white blood cells to move into the area (called positive chemotaxis)
Inflammatory response (continued)
Process of the inflammatory response
Neutrophils migrate to the area of inflammation by rolling along the vessel wall (following the scent of chemicals from inflammation)
Neutrophils squeeze through the capillary walls by diapedesis to sites of inflammation
Neutrophils gather in the precise site of tissue injury (positive chemotaxis) and consume any foreign material present
Process of the inflammatory response
Neutrophils migrate to the area of inflammation by rolling along the vessel wall (following the scent of chemicals from inflammation)
Neutrophils squeeze through the capillary walls by diapedesis to sites of inflammation
Neutrophils gather in the precise site of tissue injury (positive chemotaxis) and consume any foreign material present
DEFENSE CELL
Cells such as neutrophils and macrophages engulf foreign material by phagocytosis
The phagocytic vesicle is fused with a lysosome, and enzymes digest the cell’s contents
Phagocytes
DEFENSE CELL/ CHEMICAL
Enhance innate defenses by:
Attacking microorganisms directly Hindering reproduction of microorganisms
Most important types
Complement proteins
Interferon
Antimicrobial proteins
Complement refers to a group of at least 20 plasma proteins that circulate in the plasma
Complement is activated when these plasma proteins encounter and attach to cells (known as complement fixation)
Antimicrobial proteins: complement proteins
DEFENSE CELL/ CHEMICAL
are small proteins secreted by the virus- infected cells
bind to membrane receptors on healthy cell surfaces to interfere with the ability of viruses to multiply
Antimicrobial proteins: interferons
DEFENSE CELL / CHEMICAL
Abnormally high body temperature is a systemic response to invasion by microorganisms Hypothalamus regulates body temperature at 37°C (98.6°F)
The hypothalamus thermostat can be reset higher by pyrogens (secreted by white blood cells)
High temperatures inhibit the release of iron and zinc (needed by bacteria) from the liver and spleen
Fever also increases the speed of repair processes
Fever
Adaptive body defenses are the body’s specific defense system, or the third line of defense
Immune response is the immune system’s response to a threat
Antigens are targeted and destroyed by antibodies
Adaptive body defenses are the body’s specific defense system, or the third line of defense
Immune response is the immune system’s response to a threat
Antigens are targeted and destroyed by antibodies
Three aspects of adaptive defense
Antigen specific - the adaptive system recognizes and acts against particular foreign substances
Systemic - immunity is not restricted to the initial infection site
Memory - the adaptive defense system recognizes and mounts a stronger attack on previously encountered pathogens
Three aspects of adaptive defense
Antigen specific - the adaptive system recognizes and acts against particular foreign substances
Systemic - immunity is not restricted to the initial infection site
Memory - the adaptive defense system recognizes and mounts a stronger attack on previously encountered pathogens
Two arms of the adaptive defense system are:
Humoral immunity = antibody-mediated immunity Provided by antibodies present in body fluids
Cellular immunity = cell-mediated immunity Targets virus-infected cells, cancer cells, and cells of foreign grafts
Antigens are any substance capable of exciting the
immune system and provoking an immune
response
Examples of common nonself antigens
Foreign proteins provoke the strongest response
Nucleic acids
Large carbohydrates
Some lipids
Pollen grains
Microorganisms (bacteria, fungi, viruses)
Antigens are any substance capable of exciting the
immune system and provoking an immune
response
Examples of common nonself antigens
Foreign proteins provoke the strongest response
Nucleic acids
Large carbohydrates
Some lipids
Pollen grains
Microorganisms (bacteria, fungi, viruses)
TYPE OF ANTIGEN
Human cells have many protein and carbohydrate molecules
- do not trigger an immune response in us
The presence of our cells in another person’s body
can trigger an immune response because they are
foreign
Restricts donor for transplants
Self-antigens
TYPE OF ANTIGEN
, incomplete antigens, are not antigenic
by themselves
When they link up with our own proteins, the immune system may recognize the combination as foreign and respond with an attack
Found in poison ivy, animal dander, detergents, hair dyes, cosmetics
Haptens
Cells of the Adaptive Defense System:
respond to specific antigens
B lymphocytes (B cells) produce antibodies and oversee humoral immunity
T lymphocytes (T cells) constitute the cell-mediated arm of the adaptive defenses; do not make antibodies
lymphocytes
CELLS OF ADAPTIVE DEFENSE SYSTEM
help the lymphocytes but do not respond to specific antigens
. Antigen-presenting cells (APCs) -
CELLS OF ADAPTIVE SYSTEM
Arise from hemocytoblasts of bone marrow
Whether a lymphocyte matures into a B cell or T cell depend on where it becomes immunocompetent
Lymphocytes
CELLS OF THE ADAPTIVE SYSTEMS
The capability to respond to a specific antigen by binding to it with antigen-specific receptors that appear on the lymphocyte’s surface
Immunocompetence
Lymphocytes (continued)
T cells develop immunocompetence in the thymus
and oversee cell-mediated immunity
Identify foreign antigens
Those that bind self-antigens are destroyed Self-tolerance is important part of lymphocyte “education”
B cells develop immunocompetence in bone marrow and provide humoral immunity
Lymphocytes (continued)
T cells develop immunocompetence in the thymus
and oversee cell-mediated immunity
Identify foreign antigens
Those that bind self-antigens are destroyed Self-tolerance is important part of lymphocyte “education”
B cells develop immunocompetence in bone marrow and provide humoral immunity
Cells of the Adaptive Defense system: An Overview
Immunocompetent T and B lymphocytes migrate to the lymph nodes and spleen, where encounters with antigens occur
Differentiation from naive cells into mature lymphocytes is complete when they bind with recognized antigens
Mature lymphocytes ( especially T cells ) circulate continously throughout the body
Cells of the Adaptive Defense system: An Overview
Immunocompetent T and B lymphocytes migrate to the lymph nodes and spleen, where encounters with antigens occur
Differentiation from naive cells into mature lymphocytes is complete when they bind with recognized antigens
Mature lymphocytes ( especially T cells ) circulate continously throughout the body
Antigen-presenting cells (APCs)
Engulf antigens and then present fragments of them on their own surfaces, where they can be recognized by T cells
Major types of cells behaving as APCs
Dendritic cells
Macrophages
B lymphocytes
Antigen-presenting cells (APCs)
Engulf antigens and then present fragments of them on their own surfaces, where they can be recognized by T cells
Major types of cells behaving as APCs
Dendritic cells
Macrophages
B lymphocytes
When they present antigens, dendritic cells and macrophages activate _____ which release chemicals
T cells,
Humoral (Antibody-Mediated) Immune Response
B lymphocytes with specific receptors bind to a specific antigen
The binding event sensitizes, or activates, the lymphocyte to undergo clonal selection
A large number of clones is produced (primary humoral response)
Humoral (Antibody-Mediated) Immune Response
B lymphocytes with specific receptors bind to a specific antigen
The binding event sensitizes, or activates, the lymphocyte to undergo clonal selection
A large number of clones is produced (primary humoral response)
Most of the B cell clone members (descendants)
become plasma cells
Produce antibodies to destroy antigens Activity last for 4 or 5 days
Plasma cells begin to die
Some B cells become long-lived memory cells capable
of mounting a rapid attack against the same antigen in
subsequent meetings (secondary humoral response) These cells provide immunological memory
Most of the B cell clone members (descendants)
become plasma cells
Produce antibodies to destroy antigens Activity last for 4 or 5 days
Plasma cells begin to die
Some B cells become long-lived memory cells capable
of mounting a rapid attack against the same antigen in
subsequent meetings (secondary humoral response) These cells provide immunological memory
TYPE OF Humoral (Antibody-Mediated) Immune Response
Occurs when B cells encounter antigens and
produce antibodies
can be:
Naturally acquired during bacterial and viral infections
Artificially acquired from vaccines
Active immunity
TYPE OF Humoral (Antibody-Mediated) Immune Response
Occurs when antibodies are obtained from someone else
Naturally acquired from a mother to her fetus or in the breast milk
Artificially acquired from immune sebum or gamma globulin (donated antibodies)
Immunological memory does not occur Protection is short-lived (2-3 weeks)
Passive immunity
Passive immunity (continued)
Monoclonal antibodies
Antibodies prepared for clinical testing for diagnostic services
Produced from descendants of a single cell line Exhibit specificity for only one antigen
Examples of uses for monoclonal antibodies
Cancer treatment
Diagnosis of pregnancy
Treatment after exposure to hepatitis and rabies
Passive immunity (continued)
Monoclonal antibodies
Antibodies prepared for clinical testing for diagnostic services
Produced from descendants of a single cell line Exhibit specificity for only one antigen
Examples of uses for monoclonal antibodies
Cancer treatment
Diagnosis of pregnancy
Treatment after exposure to hepatitis and rabies
Humoral (Antibody-Mediated) Immune Response
Antibodies (immunoglobullins, lgs)
Constitute gamma globullin part of blood proteins Soluble proteins secreted by activated B cells (plasma cells)
Formed in response to a huge number of an antigens
Humoral (Antibody-Mediated) Immune Response
Antibodies (immunoglobullins, lgs)
Constitute gamma globullin part of blood proteins Soluble proteins secreted by activated B cells (plasma cells)
Formed in response to a huge number of an antigens
Antibody Structure
Four polypeptide chains, two heavy and two light, linked by disulfide bonds to form a T- or Y-shaped molecule
Each polypeptide chain has a variable (V) region and a constant (C) region
Variable regions form antigen-binding sites, one on each arm of the T or Y
Constant regions determine the type of antibody formed (antibody class)
Antibody Structure
Four polypeptide chains, two heavy and two light, linked by disulfide bonds to form a T- or Y-shaped molecule
Each polypeptide chain has a variable (V) region and a constant (C) region
Variable regions form antigen-binding sites, one on each arm of the T or Y
Constant regions determine the type of antibody formed (antibody class)
Antibody classes
Antibodies of each class have slightly different roles and differ structurally and functionally
Five major immunoglobullin classes (MADGE)
1. IgM - can fix complement
2. IgA - found mainly in secretions, such as mucos or tears
3. IgD - important in activation of B cell
4. IgG - can cross the placental barrier and fix complement; most abundant antibody in plasma
5. IgE - involved in allergies
Antibody classes
Antibodies of each class have slightly different roles and differ structurally and functionally
Five major immunoglobullin classes (MADGE)
1. IgM - can fix complement
2. IgA - found mainly in secretions, such as mucos or tears
3. IgD - important in activation of B cell
4. IgG - can cross the placental barrier and fix complement; most abundant antibody in plasma
5. IgE - involved in allergies
Antibody function
Antibodies inactivate antigens in a number of ways
Complement fixation: chief antibody antibody ammunition used against cellular antigens
Neutralization: antibodies bind to specific sites on bacterial exotoxins or on viruses that can cause cell injury Agglutination: antibody-antigen reaction that can causes clumping of cells
Precipitation: cross-linking reaction in which antigen- antibody complex settles out of solution
Antibody function
Antibodies inactivate antigens in a number of ways
Complement fixation: chief antibody antibody ammunition used against cellular antigens
Neutralization: antibodies bind to specific sites on bacterial exotoxins or on viruses that can cause cell injury Agglutination: antibody-antigen reaction that can causes clumping of cells
Precipitation: cross-linking reaction in which antigen- antibody complex settles out of solution
Main difference between two arms of the adaptive response
B cells secrete antibodies
T cells fight antigens directly
Main difference between two arms of the adaptive response
B cells secrete antibodies
T cells fight antigens directly
Different classes of effector T cells
Helper T cells
Cytotoxic T cells
T cells must recognize nonself and self through the process of antigen presentation
Nonself▬the antigen fragment presented by APC
Self▬coupling with a specific glycoprotein on the APC’s surface at the same time
T cells must recognize nonself and self through the process of antigen presentation
Nonself▬the antigen fragment presented by APC
Self▬coupling with a specific glycoprotein on the APC’s surface at the same time
Cellular (Antibody-Mediated) Immune Response
Specialize in killing infected cells
Insert a toxic chemical (perforin or granzyme)
The perforin enters the foreign cell’s plasma membrane Pores now appear in the target cell’s membrane Granzymes (protein-digesting enzymes) enter and kill the foreign cell
- detaches and seeks other targets
Cytotoxic (killer) T cells
Cellular (Antibody-Mediated) Immune Response
Recruit other cells to fight invaders
Interact directly with B cells bound to an antigen, prodding the B cells into clone production Release cytokines, chemicals that act directly to rid the body of antigens
Helper T cells
Cellular (Antibody-Mediated) Immune Response
Release chemicals to suppress the activity of T and B cells
Stop the immune response to prevent uncontrolled activity
A few members of each clone are memory cells
A summary of cells and molecules follows
Regulatory T cells
Major Types of transplants, or grafts
Autografts - tissue transplanted from one site to another on the same person
Isografts - tissue grafts from genetically identical person (identical twin)
Allografts - tissue taken from a person other than an identical twin (most common type of graft) Xenografts - tissue taken from a different animal species (never successful)
Major Types of transplants, or grafts
Autografts - tissue transplanted from one site to another on the same person
Isografts - tissue grafts from genetically identical person (identical twin)
Allografts - tissue taken from a person other than an identical twin (most common type of graft) Xenografts - tissue taken from a different animal species (never successful)
Blood group and tissue matching is done to ensure the best match possible
75% match is needed to attempt a graft Organ transplant is followed by immunosuppressive therapy to prevent rejection
Blood group and tissue matching is done to ensure the best match possible
75% match is needed to attempt a graft Organ transplant is followed by immunosuppressive therapy to prevent rejection
The most important disorders of the immune system
Allergies
Autoimmune disease Immunodeficiencies
Types of allergies
Immediate (acute) hypersensitivity
—Seen in hives and anaphylaxis
Due to lgE antibodies and histamine
Anaphylactic shock is systemic, acute allergic response and is rare
Delayed hypersensitivity
—-Reflects activity of T cells, macrophages, and cytokine Symptoms usually appear 1-3 days after contact with antigen Allergic contact dermatitis (poison ivy, cosmetics)
Occurs when the body’s self-tolerance breaks down The body produces auto-antibodies and sensitized T lymphocytes that attack its own tissue
Most forms of autoimmune disease result from the appearance of formerly hidden self-antigens or changes in the structure of self-antigens, and antibodies formed against foreign antigens that resemble self-antigens
Autoimmune disease
May be congenital or acquired
Severe combined immunodeficiency disease (SCID) is a congenital disease
AIDS (acquired immune deficiency syndrome) is caused by a virus that attacks and cripples the helper T cells
Result from abnormalities in any immune element Production or function of immune cells or complement is abnormal
Immunodeficiencies
