Chapter 5: Resident Flora and Pathogens

Vocabulary flashcards covering key terms related to resident flora, various types of pathogens (bacteria, viruses, rickettsiae, mycoplasms, chlamydiae, fungi, protozoa), and their characteristics and mechanisms of action, based on Chapter 5 lecture notes.

Bias

Influencing or interpreting information in a particular way.

Resident Flora

Organisms that live inside the body without harm in non-sterile areas like skin, mucous membranes, bowel, vagina, and rectum, binding to specific human cell receptors.

Pathogen

An organism that causes disease by direct host cell destruction, interfering with host cell metabolic function, or exposing host cells to toxins, requiring binding to specific host receptors to cause harm.

Pathogenicity

The qualities or characteristics that promote the production of disease.

Virulence

The potency of a pathogen, measured by the number of cases it causes in a population exposed to it.

Infectivity

The proportion of exposures to an infecting agent that result in infection and the ability of the pathogen to survive.

Toxigenicity

The ability of a pathogen to produce harmful toxins and cause tissue damage.

Antigenicity

The degree to which a pathogen is viewed as foreign by the host, with a higher degree leading to a stronger immune response.

Pathogenic defense mechanism

Ways a pathogen manages to avoid destruction by the host's immune system.

Coinfection

The presence of two or more different pathogens in a host at the same time.

Superinfection

An infection that arises when one infection is already present, often due to the overproliferation of compromised resident flora.

Obligate parasites

Organisms that strictly require a host for their metabolism and reproduction.

Facultative parasites

Organisms that may live on a host but can also be independent.

Bacteria

Single-celled microorganisms classified as prokaryotes.

Prokaryotes

Cells characterized by the absence of a distinct nucleus and the presence of rigid cell walls.

Aerobic

Requires oxygen to survive and thrive.

Anaerobic

Does not require oxygen and often thrives in deep tissue.

Cocci

Bacteria that are circle-shaped.

Bacilli

Bacteria that are rod-shaped.

Vibrio

Bacteria that are comma-shaped.

Spirochete

Bacteria that are spiral-shaped.

Cytoplasm (bacteria)

The gelatinous material within the cell that contains cytosol, the outer cytoplasmic membrane, a nucleoid, and a cell wall.

Cytosol

The liquid portion of the cytoplasm that dissolves ions, carbohydrates, proteins, lipids, and waste products.

Nucleoid

A nucleus-like area within a prokaryotic cell that contains the chromosome but lacks a nuclear membrane.

Human cells (eukaryotes)

Cells that possess a distinct nucleus and organelles but do not have a cell wall.

Antibiotic treatment

Medical therapy primarily aimed at targeting and disrupting the bacterial cell wall.

Bacterial cell walls

Structures made up of peptidoglycan, with thickness varying depending on the type of bacteria.

Gram positive bacteria

Bacteria characterized by a thick peptidoglycan layer in their cell wall, which stains purple during Gram staining.

Gram negative bacteria

Bacteria characterized by a thin peptidoglycan layer in their cell wall, which stains red during Gram staining.

Glycocalyx

A covering over the cell wall made of polysaccharides or polypeptides, which can be loose (slime layers) or firmly attached (capsule), and protects the cell from drying out.

Endotoxin

A complex phospholipid polysaccharide that forms a structural component of the gram-negative cell wall, released upon bacterial lysis and capable of inducing fever.

Endospores

Tough, resistant structures formed around bacteria to protect them from harsh conditions.

Exotoxins

Toxins produced and secreted by bacteria that result in dysfunction or lysis of host cells.

Viruses

Acellular, obligate intracellular parasites that require a host cell for reproduction.

Virions

Individual virus particles that can enter and infect other nearby cells.

Rickettsiae

Obligate intracellular, gram-negative parasites that produce energy and target human endothelial cells of blood vessels and capillaries.

Mycoplasms

Bacteria that lack a cell wall, cannot replicate outside of a host, and survive on a host.

Chlamydiae

Obligate intracellular parasites that reproduce through binary fission but use host metabolism for reproduction and do not enter host cells for replication.

Fungi

Common resident microbes that can be unicellular yeasts or multicellular molds.

Yeasts

Unicellular fungi that reproduce by budding and can form an elongated chain called pseudohyphae.

Molds

Multicellular fungi that form tubules called hyphae, which branch to form clusters known as mycelium.

Mycoses

Infections caused by fungi.

Opportunistic pathogens

Pathogens that cause disease in a host with a compromised immune system.

Maceration

The softening and breaking down of tissues, often due to prolonged exposure to moisture.

Protozoa

Unicellular organisms that can be irregular in shape, lack a cell wall, and are transmitted through sex, contaminated food/water, or insect/arthropod vectors; some are parasitic, while others can live independently.