anatomy 2020: chapter 21 lymphatic system

lymphatic and immune system

lymph

lymph

fluid that enters the lymphatic system

lymphatic capillary

blind pocket, close to arterioles, capillary, and venules, start of lymphatic vessels

lacteal

a lymph tubule located in the villus of the small intestine that absorbs fatty acids

right lymphatic duct

receives lymph from the right upper part of the body, drains into right subclavian vein

left lymphatic duct

drains the left side and lower right side of the body, empties into left subclavian vein

cisterna chyli

an enlarged pouch on the thoracic duct that serves as a storage area for lymph moving toward its point of entry into the venous system

lymphedema

swelling due to an abnormal accumulation of lymph fluid within the tissues, can be because lymphatic vessel is blocked due to parasite or another cause

lymph node

collection of stationary solid lymphatic tissue along lymph vessels, filters lymph, surrounded by tough capsule

lymphoid nodule

the lymphocytes are densely packed in an area of loose connective tissue, no capsule

bone marrow

location of hematopoiesis

thymus

Gland in the thoracic cavity above the heart where T lymphocytes mature.

spleen

An organ that is part of the lymphatic system; it produces lymphocytes, filters the blood, stores blood cells, and destroys old blood cells.

Mucosa-associated lymphoid tissue (MALT)

lymphoid follicles on GI tract, breast tissue, lungs, and eyes. Important for immune response

lymphocytes

A type of white blood cell that make antibodies to fight off infections, includes NK, T, and B cells

NK cells

natural killer cells, responsible for immunological surveillance

T cells

cell-mediated immunity, mature in thymus, 100 trillion different receptors to recognize nearly every pathogen

B cells

mature in bone marrow, antibody mediated immunity, become Plasma cells which release antibodies into body fluids,

innate defense

present at birth, doesn't distinguish between threats (nonspecific)

pattern recognition receptor

Type of receptor on macrophages and dendritic cells that is able to recognize the nature of the invader (bacteria, virus, or fungi) and release the appropriate cytokines to attract the right immune cells to the area.

physical barrier

innate defense created by epithelial tissue and glandular secretions

phagocytes

first line of cellular defense, includes macrophage, dendritic, neutrophil, and monocytes

immunological surveillance

destruction of abnormal cells (virus infected or cancerous) by NK cells in peripheral tissues

fas ligand

released by NK cells triggers apoptosis in abnormal cells

perforin

released by NK cells to lyse abnormal cells

granzyme

released by NK cells to digest abnormal cells

cytokines

Hormone-like, "local" chemicals facilitating communication in the immune system.

interferon

one of a group of proteins that help cells resist viral infection

gamma interferon

released by NK and T cells to stimulate/attract macrophage

beta interferon

released by fibroblasts to slow inflammation in damaged area

alpha interferon

produced by virally infected cells to attract/stimulate NK cells

opsonization

coating antigen with antibody enhances phagocytosis

complement system

proteins in the blood that help antibodies kill their target, actions include opsonization, release of chemotactic chemicals, cell lysis

inflammation

increase in heat and blood flow to damaged tissue

mast cells

Cells that release chemicals (such as histamine) that promote inflammation.

histamine

vasodilation involved in inflammation

leukotrienes

attract neutrophils

prostaglandins

vasodilation, detected as pain

Fever

elevated body temperature greater than 37 degrees C or 99 degrees F

pyrogenes

released by bacteria, fungi, virus to reset the hypothalamus' temperature control center triggering fever

adaptive immunity

targets and disables particular threats (specific)

cytotoxic T cells

attack foreign or virus-infected cells, direct contact

helper T cells

stimulate T cells and B cells

regulatory T cells

inhibit T and B cell activity to keep immune response in check

Plasma cells

cells that produce and release antibodies into body fluids

acquired active natural immunity

exposure to antigens causing sickness, leads to production of antibodies (immunity)

acquired active artificial immunity

exposure to antigens via vaccinations, leads to production of antibodies (immunity)

acquired passive natural immunity

receive antibodies from mother via breast milk

acquired passive artificial immunity

receive antibodies via injection

properties of immunity

specific, versatile, memory, tolerant

antigen presentation

first step to initiating an immune response, occurs when cells are infected or when phagocytes have engulfed pathogens, "present" foreign antigen using MHC proteins

Major Histocompatibility complex

MHC, glycoprotein markers present on all cells, used in self-recognition

Class I MHC

found on all cells, if presenting an antigen indicates the cell is infected (compromised)

Class II MHC

found on "professional" antigen presenting cells (APC), if presenting an antigen indicates these cells found an invader

CD8 T cells

recognize and bind to class I MHC

CD4 T cells

recognize and bind to class II MHC

costimulation

the "go ahead" given by either the infected cell or the APC to activate the T cell

Activated CD8 T cell divides to make

Cytotoxic, Memory Tc, and Suppressor T cells

Active Cytotoxic T cells

release perforins or lymphotoxin or trigger apoptosis in the infected cell = cell death

Activated CD4 T cell divides to make

helper T cells and Memory Helper T cells

sensitized B cells

are presenting the antigen with Class II MHC AND have the antigen bound to their IgD antibody

Activated B Cells produce

Memory B cells and Plasma Cells

antibodies

large proteins (immunoglobulins) circulating in body fluids, bind to specific antigens at the antigen binding sites

IgG

80% of all antibodies, resistance to many viruses, bacteria, and bacterial toxins

IgE

attaches to basophils and mast cells, involved in allergy response

IgD

found on the B cell, involved in B Cell sensitization

IgM

released 1st with initial exposure declines with the release of IgG

IgA

found in glandular secretions such as mucous, tears, saliva, semen

antibody effects

neutralization, prevent pathogen adhesion, activation of complement, stimulate inflammation, opsonization, attract phagocytes, and precipitation and agglutination of pathogen cells