BIOS 213 Exam 6

Innate Immunity

First line of defense against pathogens; epithelial membranes, high acidity in stomach, etc.

Toll-like receptors

Stimulate the release of chemokines and cytokines.

NOD-like receptors

Stimulate formation of inflammasomes and cytokines; lead to apoptosis.

Complement System

Integrates innate and adaptive immune responses; consists of proteins in the plasma that become activated when antibodies bind to antigens. Promotes phagocytosis, lysis of target cells and inflammation. Part of nonspecific immunity.

Phagocytic cells

Neutrophils, mononuclear -- cells, and organ-specific --.

Neutrophils

Phagocytose in blood and all tissues - 1st to arrive at an infection.

Monocytes

Phagocytose in blood (mononuclear phagocytic cell). (Arrive 2nd).

Tissue Macrophages (histiocytes)

Phagocytose in all tissues (including spleen, lymph nodes, bone marrow). (mononuclear phagocytic cells). Arrive 2nd.

Kupffer Cells

Phagocytose in liver

Alveolar macrophages

Phagocytose in lungs.

Microglia

Phagocytose in CNS.

Diapedesis (extravasation)

The process of neutrophils and monocytes squeezing through gaps in post-capillary venue walls to enter tissues.

Fever

Regulated by the hypothalamus; endogenous pyrogens increase the body's thermostat.

Endogenous Pyrogens

Produced as cytokines by leukocytes in response to endotoxins from some bacteria; induce sleepiness and decreased iron concentration in plasma.

Interferons

Antiviral polypeptides produced by infected cells; three types. Stimulate macrophage phagocytosis, activity of cytotoxic T cells, activity of NK cells, and production of antibodies while inhibiting cell division tumor growth, maturation of adipose cells and erythrocytes.

Alpha and Beta interferons

Help fight viral and bacterial infections

Gamma Interferons

Help fight infections and cancer

Adaptive Immunity

The acquired ability. to defend against specific pathogens after exposure to these pathogens.

Antigens

Cell surface molecules that stimulate the production of specific antibodies and combine with those antibodies.

Haptens

Smaller, non antigenic molecules that can become antigens when bound to other proteins.

Lymphocytes (B and T cells)

Derived from stem cells in the bone marrow that seed the thymus, spleen and lymph nodes.

Primary Lymphoid Organs

Thymus and bone marrow.

T Lymphocytes

Lymphocytes that seeded the thymus, then move on to the blood, lymph nodes and spleen. Attack host cells that have become infected with a virus or fungus, transplanted human cells and cancer cells. These do not produce antibodies and must be in close proximity to the victim cell in order to destroy. Cell-mediated immunity.

Cell-Mediated Immunity

Cells killing cells.

B Lymphocytes

Lymphocytes that come directly from bone marrow to seed other organs; combat bacterial and some viral infections. Secrete antibodies into blood and lymph. Humoral or antibody-mediated immunity.

Secondary Lymphoid Organs

Lymph nodes, spleen, tonsils and Peyer's patches. Capture and present pathogens to macrophages and house lymphocytes. Will migrate between lymphoid organs to sample blood and lymph.

Opsonization

Antigen-antibody complex that amplifies phagocytosis with neutrophils, monocytes and macrophages.

PGE2

Lowers pain threshold

IgG

Main form of antibodies in circulation: production increased after immunization; secreted during secondary response.

IgA

Main antibody type in external secretions, such as saliva and mother's milk.

IgE

Responsible for allergic symptoms in immediate hypersensitivity reactions.

IgM

Function as antigen receptors on lymphocyte surface prior to immunization; secreted during primary response.

IgD

Function as antigen receptors on lymphocyte surface prior to immunization; other functions unknown.

C1

Recognition protein in complement system.

C2, C3 and C4

Serve as activators in complement system.

C5 - C9

Attack by attaching to a cell membrane and destroying it in complement system.

Classic Pathway

IgG or IgM antibodies bind to antigens. Complement system activation.

Alternate Pathway

Unique polysaccharides on bacterial membranes activate complement system.

C3a and C5a

Stimulate mast cells to release histamine to increase blood flow to the area.

Cytotoxic T Lymphocytes

Destroy body cells that harbor foreign antigens. Must touch victim cell. Secretes performs and granzymes. Surface molecule = CD8 (senses MHC-1).

Perforins

Secreted by cytotoxic T cells to create a large pore in the victim cell.

Granzymes

Secreted by cytotoxic T cells to trigger apoptosis in victim cell with caspase enzymes.

Helper T Lymphocytes

Surface molecule = CD4 (senses MHC-2); improves the ability of B lymphocytes to become plasma cells and enhance ability of cytotoxic T cells to kill targets. Secrete lymphokines.

Regulatory T Lymphocytes

Surface molecules = CD4 and CD25; inhibit response of B lymphocytes and cytotoxic T cells; activate FOXP3 gene.

FOXP3 Gene

Codes for transcription factor needed for development of T lymphocytes.

Lymphokines

Autocrine regulators. Cytokines specific to lymphocytes, aka interleukins. Stimulate B cell or cytotoxic T cell activity. Subtypes of helper T cells produce these. Responsible for costimulation/activation of cytotoxic T and B cells.

TH1

Produce IL-2 and gamma interferon; activates cytotoxic T cells and stimulates NO production in macrophages.

TH2

Produces IIL-4, IL-5, IL-13 and others; stimulates B cells and humoral immunity, recruits eosinophils and induces IgE production.

TH17

Secretes IL-17; fights infections in skin, lungs and mucous membranes; stimulates neutrophils.

Major Histocompatibility Complex (MHC/HLA)

Bind to antigens that get into our body and present them to WBCs.

Class 1 MHC

Made by all cells except RBCs. Presented with foreign antigens to activate cytotoxic T cells.

Class 2 MHC

Made by antigen-presenting cells and B cells. Presented with foreign antigens to helper T cells.

IL-1

Stimulates cell division and proliferation of T cells. Stimulates helper T cell mitosis.

Macrophage Colony-Stimulating Factor and Gamma Interferon

Secreted by helper T cells; promote macrophage activity.

Interleukin-2

Secreted by helper T cells; makes macrophages produce tumor necrosis factor and activates cytotoxic T cell activity and mitosis.

FAS

A surface receptor and protein ligand that active T cells produce; binding causes apoptosis and helps to maintain immunologically. privileged sites.

Primary Immune Response

Immune response the first time the body is exposed to a particular antigen. Does not peak until 10-17 days after exposure.

Secondary Immune Response

Immune response after the body has already been exposed to a specific antigen. Response is faster, of greater magnitude, and more prolonged.

Clonal Selection Theory

Explains how the secondary immune response works - a person inherits lymphocytes specific to almost every pathogen, but there are few of each type. When exposed to foreign antigens, immune cells respond by making copies of themselves.

Vaccine

Stimulates a primary response and active immunity without making the person sick.

Adjuvants

Molecules that boost immune response when delivered with the vaccine antigens; found to be PAMPs.

Immunological Competence

Ability to mount an immune response; develops during early postnatal life. Involves being able to distinguish self-antigens from foreign antigens.

Immunological Tolerance

Continued recognition and tolerance of self-cells.

Clonal Deletion

Lymphocytes that recognize self-antigens are destroyed.

Clonal Anergy

Lymphocytes are prevented from becoming active.

Central tolerance

Occurs in thymus and bone marrow

Peripheral tolerance

anywhere outside the thymus or bone marrow

Passive Immunity

Passing of antibodies from one individual to another; person does not make their own antibodies.

Monoclonal Antibodies

An animal injected with antigen produces antibodies; a B lymphocyte is extracted and fused with a cancerous myeloma in vitro, hybridoma, and produces clones that produce antibodies specific for the antigen.

Ventilation

Mechanic process that moves air into and out of the lungs.

External Respiration

Gas exchange in the lungs; O2 moves from alveoli to pulmonary capillaries and CO2 moves from pulmonary capillaries to alveoli via diffusion.

Internal Respiration

Oxygen utilization and gas exchange in tissues; O2 moves from systemic capillaries to tissue cells and CO2 moves from tissue cells to systemic capillaries via diffusion.

Conduction Zone

Transports air to lungs; warms, moistens and filters the air; vocalization (sound production); mucus traps small particles.

Respiratory Zone

Site of gas exchange.

Alveoli

Air sacs in the lungs where gas exchange occurs. ~300 million present. Provide large surface area to increase diffusion rate.

Type I Alveolar Cell

Simple squamous epithelial cells; 95-97% total surface area where gas exchange occurs.

Type II Alveolar Cell

Secrete pulmonary surfactant and reabsorb sodium and water, preventing fluid buildup.

Mediastinum

Area of the thoracic cavity containing the heart, trachea, esophagus and thymus.

Parietal Pleura

Lines the thoracic wall; surrounds the lungs and stays attached to ribs.

Visceral Pleura

Covers the lungs.

Intrapleural Space

Space between the parietal and visceral pleura; contains a thin layer of fluid to serve as a lubricant.

Diaphragm

Dome-shaped skeletal muscle; separates thoracic and abdominal cavities. Responsible for 65-75% incoming air at rest. Contraction lowers, increasing volume and decreasing pressure; thoracic cavity and lungs increase vertically. Relaxation raises, decreasing volume and increasing pressure; decreases thoracic cavity and lungs vertically.

Atmospheric Pressure

Pressure of air outside the body; standard at sea level = 760 mmHg.

Intrapulmonary/Intraalveolar Pressure

Pressure in the lungs.

Intrapleural Pressure

Pressure within the intrapleural space; always lower than both atmospheric and intrapulmonary pressure; keeps lungs pushed up against thoracic wall - when thoracic wall expands, lungs expand.

Boyle's Law

The pressure of a gas is inversely proportional to its volume.

Inspiration (Inhalation)

Intrapulmonary pressure is lower than atmospheric pressure - air flows into lungs. -3 mmHg. Breath in. Thoracic and lung volume increase while intrapulmonary pressure decreases causing air flow in.

Subatmospheric (negative) pressure

Pressure below that of the atmosphere. Breathe out.

Expiration (exhalation)

Intrapulmonary pressure is greater than atmospheric pressure - air flows out of lungs. +3 mmHg. Passive process. Thoracic and lung volume decrease while intrapulmonary pressure increases causing air flow out.

Lung Compliance

The change in lung volume per change in trans pulmonary pressure: delta V/delta P. The ease with which lungs expand under pressure. Reduced by factors that produce a resistance to dissension such as the infiltration of connective tissue proteins in pulmonary fibrosis.

Elasticity

Lungs return to initial size after being stretched (recoil); stuck to the thoracic wall and are always under -- tension; tension increases during inspiration and is reduced by -- recoil during expiration.

Surface Tension

Exists at every water to air interface. Resists dissension (collapse). Exerted by fluid secreted on the alveoli (absorbed by active transport of Na+ and secreted by active transport of Cl-).

Surfactant

Surface active agent secreted by type II alveolar cells; made of hydrophobic protein and phospholipids. Reduces surface tension by reducing the # of H bonds between water molecules. More concentrated as alveoli get smaller during expiration. Prevents collapse. Allows residual volume of air to remain in lungs.

External Intercostal Muscles

Raises rib cage during inspiration to increase volume, causing the thoracic cavity and lungs to increase in diameter.

Parasternal Intercostal Muscles

Works with external intercostals during inspiration.

Scalenes

Raises ribs 1-2 during forced inhalation.

Pectoralis minor

Raises ribs 3-5 during forced inhalation.

Sternocleidomastoid

Raises sternum during forced inhalation.

Internal Intercostal Muscles

Lowers rib cage, decreasing volume in lungs and diameter in thoracic cavity during forced exhalation.

Abdominal Muscles of Forced Exhalation

Rectus abdominus, external and internal oblique, and transverses abdominus.