Exam 2

Lymphatic system

Network of lymphatic vessels and organs that absorb interstitial fluid, transport fats from the digestive tract, and defend the body with lymphoid tissue and white blood cells.

Lymph

Fluid (interstitial fluid) that circulates in lymphatic vessels.

Lymphatic capillaries

Blind-ended vessels in tissues that absorb excess interstitial fluid and dietary fats.

Primary lymphatic organs

Red bone marrow and thymus; sites where lymphocytes develop.

Secondary lymphatic organs

Lymph nodes, spleen, tonsils; sites where immune responses are organized.

Spleen

Largest lymphatic organ that filters blood; has white pulp (immune) and red pulp (pathogen removal).

White pulp

Lymphoid tissue in the spleen involved in immune responses.

Red pulp

Part of the spleen where macrophages remove pathogens and old red blood cells.

Lymph node

Filtration point for lymph; contains macrophages and lymphocytes; encapsulated and compartmentalized.

Lymphatic nodules

Concentrations of lymphoid tissue without a capsule (e.g., tonsils, Peyer’s patches).

Peyer's patches

Lymphoid tissue in intestinal walls that fights infections from the digestive tract.

Tonsils

Lymphatic nodules in the pharynx that help defend against inhaled pathogens.

Innate immunity

Nonspecific defense present at birth; includes barriers, inflammatory response, phagocytes, NK cells, and protective proteins.

Adaptive immunity

Specific, acquired immunity that develops after exposure and involves B and T lymphocytes with memory.

Antigen

Substance recognized as foreign by the immune system; can be a protein or fragment.

Antigen-presenting cell (APC)

Cells (e.g., macrophages, dendritic cells) that process and present antigens to T cells.

B cell

Lymphocyte that mediates antibody-mediated (humoral) immunity; matures in bone marrow.

T cell

Lymphocyte that mediates cell-mediated immunity; matures in the thymus and requires antigen presentation.

B-cell receptor (BCR)

Antigen-binding receptor on a B cell; binds a specific antigen to activate the cell.

Antibody

Y-shaped protein produced by plasma cells that binds specifically to an antigen.

Immunoglobulin classes

Five antibody classes: IgG, IgM, IgA, IgD, IgE; each has distinct roles and distributions.

Plasma cell

Antibody-secreting daughter cell produced during B cell clonal expansion.

Memory B cell

Long-lived B cell that responds rapidly upon re-exposure to the same antigen.

Cytotoxic T cell

CD8+ T cell that destroys infected or abnormal cells via perforins and granzymes.

Helper T cell

CD4+ T cell that secretes cytokines to regulate and amplify immune responses.

Clonal selection

Process by which a lymphocyte with a receptor for an antigen is chosen for activation.

Clonal expansion

Proliferation of activated lymphocytes bearing the same receptor.

Cytokines

Signaling proteins that regulate immune cell development and activity.

Interferon

Cytokine with antiviral properties and immune-modulating effects.

Vaccination

Administration of antigens to induce active immunity and memory against a pathogen.

Active immunity

Immunity in which the body produces antibodies after infection or vaccination.

Passive immunity

Immunity acquired by receiving antibodies from another source; temporary.

HIV

Human immunodeficiency virus; infects helper T cells and macrophages, weakening immunity.

AIDS

Acquired immunodeficiency syndrome; advanced HIV infection with severe immune failure.

Hypersensitivity

Exaggerated immune response causing tissue damage; includes allergies and transplant rejection.

Allergy

Hypersensitivity to harmless substances; typically IgE-mediated with histamine release.

Anaphylactic shock

Severe, rapid allergic reaction causing dangerous drop in blood pressure; treated with epinephrine.

Autoimmune disease

Immune system attacks the body’s own tissues (e.g., rheumatoid arthritis, SLE, MS).

Transplant rejection

T cells attack transplanted tissue; immunosuppressants and MHC matching help prevent.

Memory T cell

T cells that persist after an immune response to provide faster future responses.

Thymus

Primary lymphatic organ where T cells mature.

Red bone marrow

Primary lymphatic organ where B cells mature and all blood cells originate.

Humoral immunity

Antibody-mediated immunity driven by B cells and antibodies.

Cell-mediated immunity

T cell-mediated immunity that targets infected or abnormal cells.

CD4 protein

Surface receptor on helper T cells; target for HIV infection.

MHC proteins

Proteins that present antigen fragments to immune cells; important in transplant compatibility.

HAART

Highly active antiretroviral therapy; combination drugs to suppress HIV replication.

Monoclonal antibodies

Antibodies engineered to recognize a single antigen for therapies.

Antigen-binding site

Region of an antibody’s variable region that binds to the specific antigen.

Primary response

First exposure to an antigen; lag before antibody production begins.

Secondary response

Faster, stronger antibody response upon a subsequent exposure due to memory.

Pathogen

A disease-causing agent such as bacteria or viruses.

Prokaryotic cell

A single-celled organism that lacks a nucleus and other membrane-bound organelles.

Virus

An acellular infectious agent that requires a host cell to replicate.

Microbes

Microscopic organisms, including bacteria, viruses, and protists, found in various environments.

Peptidoglycan

A polymer that makes up the cell wall of bacteria, providing structural support.

Gram-positive bacteria

Bacteria with a thick peptidoglycan layer in their cell wall that stain purple.

Gram-negative bacteria

Bacteria with a thin peptidoglycan layer and an outer membrane, staining pink.

Flagella

Long, thin appendages that facilitate bacterial movement.

Binary fission

A method of asexual reproduction in bacteria where a single cell divides into two.

Plasmids

Small circular DNA molecules within bacteria that can carry genes for antibiotic resistance.

Infectious disease

A disease caused by pathogens that can spread from one individual to another.

Outbreak

An increase in cases of a disease within a confined area.

Epidemic

A sudden increase in the number of cases of a disease above what is normally expected in a specific area.

Pandemic

An epidemic that has spread over multiple countries or continents.

HIV

Human Immunodeficiency Virus, the virus that causes AIDS.

Nucleocapsid

The protein shell that encloses the genetic material of a virus.

Provirus

Viral DNA that has integrated into the host cell's DNA.

Malaria

A disease caused by Plasmodium parasites transmitted by mosquitoes.

Antibiotic resistance

The ability of bacteria to survive and proliferate despite the presence of antibiotics.

Emerging diseases

Diseases that are newly identified or have recently increased in incidence.

Vector

An organism, often an insect, that transmits a pathogen from one host to another.

Prion

Infectious protein particles that cause neurodegenerative diseases.

Respiratory System

A system that ensures oxygen enters the body and carbon dioxide leaves the body.

Inspiration

The process of inhalation where air moves from the atmosphere to the lungs.

Expiration

The process of exhalation where air moves from the lungs to the atmosphere.

Upper Respiratory Tract

Consists of the nasal cavity, pharynx, and larynx, responsible for filtering, warming, and moistening air.

Nasal Cavity

The cavity that filters, warms, and moistens air; separates by a septum.

Pharynx

The funnel-shaped cavity that connects the nasal and oral cavities to the larynx; serves as a passageway for air and food.

Larynx

Also known as the voice box; produces sound and contains the vocal cords.

Trachea

Commonly called the windpipe; carries air to the lungs.

Bronchioles

Small branches of the bronchi that lead to the alveoli for gas exchange.

Alveoli

Microscopic air sacs in the lungs where gas exchange occurs between air and blood.

Diaphragm

A skeletal muscle that functions in ventilation by contracting to allow air in and relaxing to push air out.

External Respiration

The exchange of gases between the lungs and blood.

Internal Respiration

The exchange of gases between blood and tissue fluid.

Chemoreceptors

Sensory receptors that respond to changes in blood CO2 levels and pH to regulate breathing.

Carbonic Anhydrase

An enzyme that speeds up the conversion of carbonic acid into bicarbonate and protons in blood.

Pulmonary Fibrosis

A restrictive pulmonary disorder characterized by the build-up of fibrous connective tissue in the lungs.

Emphysema

A chronic obstructive pulmonary disease where alveoli are damaged, reducing surface area for gas exchange.

Asthma

A condition where the bronchi and bronchioles constrict, causing wheezing and difficulty breathing.

Lung Cancer

A disease characterized by abnormal cell growth in the lungs, often related to smoking.

Respiratory System

The system that ensures oxygen enters the body and carbon dioxide leaves it.

Inspiration

The process of inhalation where air moves from the atmosphere into the lungs.

Expiration

The process of exhalation where air moves from the lungs to the atmosphere.

Alveoli

Microscopic air sacs in the lungs where gas exchange occurs between air and blood.

Trachea

Also known as the windpipe; it connects the larynx to the primary bronchi and carries air to the lungs.

Larynx

The voice box that produces sound and is located between the pharynx and trachea.

Bronchioles

Small passages of air that lead from the bronchi to the alveoli.

Diaphragm

A skeletal muscle that plays a crucial role in ventilation (breathing).