Lymphatic System Flashcards
Responsible for cleaning escaped fluid from the blood and maintains normal blood volume and pressure
Lymphatic system
2-semi independent parts
- Lymphatic vessels
- Lymphoid tissues and organs
Specifically lymph nodes, filtering and cleaning escaped fluid before being brought back to circulation
Lymphoid tissues and organs
Responsible for circulating lymph
Lymphatic vessels
Functions of lymphatic system
- Transports escaped fluids from the cardiovascular system back to the blood
- Plays essential roles in body defense and resistance to disease
Consists of excess tissue fluid and plasma proteins carried by lymphatic vessels
Lymph
Lymph-collecting vessels (6)
- 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 of the head and thorax
- Thoracic duct drains lymph from the rest of the body
- Have valve to prevent backflow
Pick up excess fluid and return it to the blood
Lymph
If fluid are not picked up, _________ occurs as fluid accumulates in tissues
Edema
Filter lymph before it is returned to the blood
Lymph nodes
Defense cells within lymph nodes:
- Macrophages
- Lymphocytes
Engulf and destroy bacteria, viruses, and other foreign substances
Macrophages
Respond to foreign substances in lymph
Lymphocytes
Surrounded by a capsule and divided into compartments by trabeculae
Lymph nodes
Contains follicles (collections of lymphocytes) and germinal centers enlarge when antibodies are released by plasma cells
Cortex
Antibodies attach to viruses and try to deactivate it
Humor-mediated
Contains phagocytic macrophages
Medulla
Direct interaction between cells
Cell-mediated
- Located on the left side of the abdomen
- Filters and cleans blood of bacteria, viruses, and debris
- Provides a site for lymphocyte proliferation and immune surveillance
- Destroys worn-out blood cells
- Forms blood cells in the fetus
- Acts as a blood reservoir
Spleen
Matures in thymus gland
T-lymphocytes
Matures in bone marrow
B-lymphocytes
- Found overlying the heart
- Functions at peak levels only during youth
Thymus
- Small masses of lymphoid tissue deep to mucosa surrounding the pharynx
- Trap and remove bacteria and other foreign pathogens
Tonsils
Results when tonsils become congested with bacteria
Tonsilitis
- Found in the walls of small intestine
- Similar lymphoid follicles are found in the appendix
- Macrophages capture and destroy bacteria in the intestine
Pyer’s patches
Physical barriers, chemical barriers, cellular defenses
Innate/non-specific body defense
First line of defense
Surface membrane barriers
Secrete protective substances
Surface membrane barriers
Second line of defense
Cells and Chemicals: Internal defenses
- Control several types of tumors and microbial infections by limiting their spread and subsequent tissue damage
- Release perforin and granzymes to degrade target cell contents
Natural killers
Neutrophils and macrophages engulf foreign material by phagocytosis
Phagocytes
Fused with a lysosome, and enzymes digest the cell’s contents
Phagocytic vesicle
Triggered when body tissues are injured
Inflammatory response
Cardinal signs of acute inflammation
- Redness
- Heat
- Pain
- Swelling
Inflammatory response release the inflammatory chemicals
- Histamine
- Kinin
- Prevents spread of damaging agents
- Disposes of cell debris and pathogens through phagocytosis
- Sets the stage for repair
Inflammatory response
Abnormally high body temperature as systemic response to microorganism invasion
Fever
Inhibits the release of iron and zinc from the liver and spleen
Temperature
Hypothalamus thermostat can be reset higher by?
Pyrogens (secreted by WBC)
Attack directly, hinder the reproduction of microorganisms
Antimicrobial proteins
Group of at least 20 plasma proteins that circulate in plasma
Complement proteins
Activated when these plasma proteins encounter and attach to cells
Complement proteins
Enhances inflammatory response
Activated complement
Small proteins secreted by virus-infected cells
Interferons
Bind to membrane receptors on healthy cell surfaces to interfere with the ability of viruses to multiply
Interferons
3 aspects of adaptive/specific body defense
- Antigen-specific
- System
- Memory
Recognizes and acts against particular foreign substance
Antigen-specific
Not restricted to the initial infection site
Systemic
Recognizes and mounts stronger attack on previously encountered pathogens
Memory
2 arms of Artificial Immune System
- Humoral immunity (antibody-media immunity)
- Cellular immunity (cell-mediated immunity)
Provided by antibodies present in body fluids
Humoral immunity (antibody-media immunity)
Targets virus-infected cells, cancer cells, and cells of foreign grafts
Cellular immunity (cell-mediated immunity)
Any substance capable of exciting the immune system and provoking an immune response
Antigens
Foreign proteins, nucleic acids, large carbohydrates, some lipids, pollen grains, microorganisms
Non-self antigens
Provoke strongest response
Foreign proteins
Protein and carbohydrate molecules in human cells
Self-antigens
- Do not trigger an immune response within the own body
- Presence in another body can trigger an immune response
Self-antigens
Not antigenic by themselves
Haptens (Incomplete antigens)
When they link up with proteins, the immune system recognize the combination as foreign and respond with an attack
Haptens
Cells of the AIS
- Lymphocytes
- Antigen-presenting cells (APCs)
Arise from hemocytoblasts of bone marrow
Lymphocytes
Capability to respond to a specific antigen by binding to it with antigen-specific receptors that appear on lymphocyte’s surface
Immunocompetence
Produce antibodies, oversee humoral immunity
B lymphocytes (B cells)
Don’t produce antibodies, oversee cell-mediated immunity, identify foreign antigens
T lymphocytes (T cells)
Help lymphocytes but don’t respond to specific antigens
Antigen-presenting cells (APCs)
Humoral immunity is divided into
- Active
- Passive
Immunity developed after being exposed to an infection or from a vaccine
Active
Antibodies made after exposure to infection
Natural
Antibodies made after getting a vaccination
Artificial
Immunity you acquire from someone or something else
Passive
Antibodies transmitted from mother to baby
Natural
Antibodies made after getting an immune serum medicine
Artificial
- Secreted by activated B cells
- Formed in response to a huge number of antigens
Immunoglobulins (Igs)
Five major immunoglobulin classes (MADGE)
- IgM - can fix complement
- IgA - found in secretions
- IgD - important in B-cell activation
- IgG - can cross the placental barrier and fix complement; most abundant in antibody in plasma
- IgE - involved in allergies
Antibodies inactivate antigens by
- Complement fixation
- Neutralization
- Agglutination
- Precipitation
Chief antibody ammunition against cellular antigens
Complement fixation
Antibodies bind to specific sites on bacterial exotoxins or on viruses that can cause cell injury
Neutralization
Antibody-antigen reaction that causes clumping of cells
Agglutination
Cross-linking reaction in which antigen-antibody complex settles out of solution
Precipitation
Antibodies neutralize it and prevent it from infecting more cells
Virus
Antibody coats mark cells for destruction through several immune pathways
Bacteria/Target cells
Attraction immune cells like NK cells that can kill cells coated with antibodies
Antibody-dependent cell-mediated cytotoxicity
Engulfing of target cells, attraction of phagocytes
Phagocytosis
Activating the complement that causes pores to appear in the membrane of the pathogens allowing influx of water, resulting to the bursting of the cell
Complement-dependent cytotoxicity
Different classes of effector T-cells
- Cytotoxic
- Helper
- Regulatory
Produces toxic agents to kill their targets
Cytotoxic
Stimulate B-cells to produce antibodies, T-cells to become active
Helper
Suppress immune responses
Regulatory
Specialize in killing infected cells
Cytotoxic (Killer) T-cells
Tissue that is transplanted from one site to another on the same person
Autograft
Tissue that is transplanted from a genetically identical person
Isograft
Tissue is taken from a person other than an identical twin
Allograft
Most common organ transplant
Allograft
Tissue is taken from a different animal species
Xenograft
Immune system overreacts to a harmless antigen, and tissue damage occurs
Allergies (hypersensitivities)
2 types of allergies (hypersensitivities)
- Immediate (acute) hypersensitivity (allergic reaction)
- Delayed hyper sensitivity
- Due to IgE antibodies and histamine
- Anaphylactic shock is systemic and rare
Immediate (acute) hypersensitivity (allergic reaction)
- Activity of T-cells, macrophages, and cytokines
- Symptoms appear after 1 to 3 days after contact with antigen
- Allergic contact dermatitis
Delayed hypersensitivity
Body produces auto-antibodies and sensitized T-lymphocytes
Autoimmune Diseases
Destroys joints
Rheumatoid arthtritis
Impair communication between nerves and skeletal muscle
Myasthenia gravis
White matter of brain and spinal cord is destroyed
Multiple sclerosis
Thyroid produces excess thyroxine
Graves’ disease
Destroys pancreatic beta cells, resulting deficient insulin production
Type 1 diabetes mellitus
Affects kidney, heart, lung, and skin; usually characterized by butterfly rash that spreads out across the nose and cheeks
Systemic lupus erythematosus
Severe impairment of kidney function due to acute inflammation
Glomerulonephritis
May be congenital or acquired
Immunodeficiencies
Congenital disease, usually cocooned in bubble to protect them from the environment
Severe combined immunodeficiency disease (SCID) aka Bubble Boy Disease
Caused by a virus that attacks and cripples the helper T-cells
Acquired immune deficiency syndrome (AIDS)