Module 5: The Lymphoid and Immune Systems

Chapter 21 Lymphoid (Lymphatic) and Immune Systems

immune system

Not an organ system, but a cell population that inhabits all organs and defends the body from agents of disease

pathogens

Organism capable of causing illness

immunity, lipid absorption, fluid recovery

functions of lymphoid (lymphatic) and immune system

lymph

Clear, colorless fluid, similar to plasma but much less protein

lymphatic capillaries (terminal lymphatics)

Penetrate nearly every tissue of the body; Cells tethered to surrounding by protein filaments

lymphatic vessels

Transport the lymph

lymph

The recovered fluid

Lymphoid (lymphatic) tissues

Composed of aggregates of lymphocytes and macrophages that populate many organs in the body

lymphoid (lymphatic) organs

Defense cells are especially concentrated in these organs; Separated from surrounding organs by connective tissue capsules

tunica interna,media,externa

what are the names of the 3 lymphatic vessel layers

lymphatic collecting vessels

Course through many lymph nodes (similar to medium size veins)

lymphatic trunks

Drain major portions of body

Right lymphatic duct

Receives lymph from R arm, R side of head and thorax; empties into R subclavian vein

Thoracic duct

Larger and longer, begins as a prominent sac in abdomen called the cisterna chyli; receives lymph from below

thoracic pump

aids flow from abdominal to thoracic cavity

neutrophils

antibacterial

natural killer (NK) cells

Lymphocytes that attack and destroy infected host cells and cancerous cells; Responsible for immune surveillance

T lymphocytes (T-cells)

Mature in thymus

B lymphocytes (B-cells)

Activation causes proliferation and differentiation into plasma cells that produce antibodies

Macrophages

develop from monocytes: are the man APC’s

lymphoid tissue

aggregations of lymphocytes in the connective tissues of mucous membranes and various organs

diffuse lymphoid tissue

lymphocytes are scattered (not densely clustered)

lymphoid nodules (follicles)

lymphocytes and macrophages gather in dense masses

aggregated lymphoid nodules

large clusters of nodules in the small intestine

lymphoid organs

have connective tissue capsule that separates lymphatic tissue from neighboring tissues

primary lymphoid organs

red bone marrow and thymus; Site where T and B cells (bone marrow) become immunocompetent

secondary lymphatic organs

Lymph nodes, tonsils, and spleen; Location where immunocompetent cells migrate and populate

lymph nodes

most numerous lymphatic organs; cleanse the lymph, alerts immune system to pathogens

afferent

sensory/going up

efferent

leaving/exciting

cervical lymph nodes

Deep and superficial group in the neck

axillary lymph nodes

what lymph nodes are found in the Concentrated in armpit

thoracic lymph nodes

what lymph nodes are found In thoracic cavity (chest), especially embedded in mediastinum

abdominal lymph nodes

what lymph nodes are found in Abdominopelvic wall

intestinal and mesenteric lymph nodes

what lymph nodes are found in Found in mesenteries

inguinal lymph nodes

what lymph nodes are found In the groin

popliteal lymph nodes

what lymph nodes are found in the back of the knee

lymphadenitis

Swollen, painful lymph node responding to foreign antigen

metastasis

Cancerous cells break free original tumor, travel to other sites in the body, and establish new tumors

tonsils

Patches of lymphatic tissue located at the entrance to the pharynx

palatine tonsils

Most often infected; Pair at posterior margin of oral cavity

lingual tonsils

Pair at root of tongue

pharyngeal tonsil (adenoids)

Single tonsil on wall of nasopharynx

spleen

The body’s largest lymphatic organ

red pulp

Sinuses filled with erythrocytes

white pulp

Lymphocytes, macrophages surrounding small branches of splenic artery

spleen

erythrocyte graveyard

innate immunity

Defenses we are born with; protects us from a broad spectrum of disease agents; no prior exposure

adaptive immunity

Defenses against specific pathogens, develops only upon exposure, and maintains immune memory; Results from prior exposure, protects against only a particular pathogen

1st line of defense

skin and mucous membranes

neutrophils

Phagocytize bacteria

eosinophils

Antiparasitic effect

basophils

Aids mobility action of WBCs by release of histamine and heparin

histamine

Increases blood flow to infected area

heparin

Prevents immobilization of phagocytes

monocytes

Circulating precursor to macrophages

macrophages

widely distributed in loose connective tissue

dendritic (langerhan) cells

Oral mucosa, lymphatic organs, esophagus, vagina

microglial cells

Neuroglial cells of CNS

alveolar macrophages

Lungs

hepatic (Kuffer) macrophages

liver

natural killer (NK) cells

continually patrol body looking for pathogens and diseased host cells

perforins

proteins that destroy infected host cells

interferons

Secreted by certain cells infected by viruses; Alert neighboring cells and protect them from becoming infected

fever

An abnormal elevation of body temperature

2nd line of defense

fever

fever benefits

promotes accelerating metabolic rate and tissue repair; inhibiting pathogen reproduction

inflammation

Local defensive response to tissue injury of any kind, including trauma and infection

cellular immunity

Cell-mediated (T cells)

humoral immunity

Antibody mediated (B cells)

antigens

Any molecule that triggers an immune response

haptens (incomplete antigens)

Too small to be antigenic by themselves, but can combine with proteins that render them antigenic

Antibodies, immunoglobulins

Defensive proteins that play a variety of defensive roles

natural active immunity

Production of one’s own antibodies or T cells as a result of infection or natural exposure to antigen

artificial active immunity

Production of one’s own antibodies or T cells as a result of vaccination

natural passive immunity

Temporary immunity that results from antibodies produces by another person

artificial passive immunity

Temporary immunity that results from the injection of immune serum (antibodies) from another personal or animal

IgM

in the process of having it

IgG

you have prior exposure to it

B lymphocytes

develop into Plasma Cells - Produce Antibodies

antigen presenting cells

what cells function as Dendritic cells, macrophages, reticular cells, and B cells

major histocompatibility (MHC) complex

proteins that label every cell of your body as belonging to you

interleukins

Used by lymphocytes and APC’s to communicate

cytotoxic T cells

Carry out attack of enemy cells

helper T cells

Help promote activities of other immune cells

memory T cells

Descend from the cytotoxic cells and are responsible for memory in cellular immunity

recognition

what stage of humoral immunity is when B cell receptors bind antigen; Differentiate into plasma cells, produce antibodies specific to that antigen

attack

what stage of humoral immunity is when antibodies bind to antigen, render it harmless, ‘tag it’ for destruction

memory

what stage of humoral immunity is when some B cells differentiate into memory cells

autoimmune diseases

Immune system does not correctly distinguish self-antigens from foreign ones

immunodeficiency diseases

Vulnerability to opportunistic infection and must live in protective enclosures

aids

Caused by infection with the human immunodeficiency virus (HIV): Invades helper T cells, macrophages, and dendritic cells by “tricking” them to internalize viruses by receptor-mediated endocytosis

aids

can be transferred through sex, contaminated blood products and needles