micro bio unit 3

When do humans become heavily colonized with microbiota?

Humans become heavily colonized with microbiota shortly after birth as they are exposed to various microorganisms from their environment.

What are the differences between parasitism, commensalism, mutualism, and synergism?

Parasitism benefits one organism at the expense of another, commensalism benefits one while the other is neither helped nor harmed, mutualism benefits both organisms, and synergism occurs when two organisms work together for a greater outcome.

What is an infectious dose?

The infectious dose is the minimum number of microbes required to cause an infection.

Differentiate between true pathogens and opportunistic pathogens.

True pathogens can cause disease in healthy individuals, while opportunistic pathogens can only cause disease in individuals with weakened immune systems or in unusual conditions.

What does it mean for a microbe to be contagious?

A contagious microbe is easily transmitted from one host to another.

What does it mean for a microbe to be communicable?

A communicable microbe can be transmitted from one person to another, either directly or indirectly.

What does it mean for a microbe to be noncommunicable?

A noncommunicable microbe cannot be transmitted from one host to another.

Describe a nosocomial infection.

A nosocomial infection is an infection acquired in a healthcare setting, such as a hospital, often due to the use of medical equipment.

What does it mean for a microorganism to be virulent?

Virulence refers to the degree of pathogenicity or the ability of a microorganism to cause disease.

What are some virulence factors?

Virulence factors include toxins, adhesion factors, invasiveness, and the ability to evade the host's immune response.

Differentiate between epidemic, endemic, and pandemic.

An epidemic refers to a sudden increase in disease cases within a specific area, endemic is constant presence in a specific region, and pandemic is an epidemic that has spread over multiple countries or continents.

Differentiate between signs and symptoms.

Signs are objective evidence of disease observable by others (e.g., rash, fever), while symptoms are subjective feelings reported by the patient (e.g., pain, fatigue).

Define and describe sequelae.

Sequelae are long-term consequences or complications that follow an infectious disease.

What is a reservoir?

A reservoir is any person, animal, or environment that harbors the pathogen and can serve as a source of infection.

What is a vector?

A vector is an organism, often an arthropod, that transmits pathogens from one host to another.

Describe microbial antagonism.

Microbial antagonism is the competition between microbes for resources, which helps to limit pathogenic growth.

Describe the different types of transmission: vertical, indirect, direct, droplet, fomite (vehicle), endogenous.

Vertical transmission occurs from parent to offspring, indirect transmission involves an intermediary, direct transmission is direct contact, droplet transmission involves respiratory droplets, fomite (vehicle) involves non-living objects, and endogenous transmission involves pathogens from the host's own microbiota.

Describe endotoxins.

Endotoxins are bacterial toxins that are part of the outer membrane of certain bacteria and can trigger an immune response.

Describe the route microbes take when causing infection.

Microbes typically enter the body through portals of entry such as mucous membranes, breaks in the skin, or the respiratory tract.

Describe the stages of infection.

The stages of infection typically include incubation, prodromal, illness, decline, and convalescence.

What concept explains the development of a yeast infection following antibiotics?

The concept of microbial antagonism explains how antibiotics can disrupt the normal microbiota, leading to overgrowth of opportunistic pathogens such as yeast.

How would you classify a disease pattern following an outbreak of influenza in a school?

The pattern of disease would be classified as epidemic due to the sudden increase in cases in a localized area.

What type of infection is pneumonia after being on a ventilator in the hospital?

This is a nosocomial infection because it was acquired in a healthcare setting.

Which strain of bacteria is more infectious: one requiring 10 cells to cause illness or another requiring 10,000?

The strain requiring 10 cells is more infectious because it has a lower infectious dose.

What does it mean for a host defense mechanism to be specific vs nonspecific?

Specific defense mechanisms target specific pathogens, while nonspecific defenses act against a broad range of pathogens.

List some examples of specific vs nonspecific defense mechanisms.

Specific examples include antibodies and T cells, while nonspecific examples include skin barriers and phagocytic cells.

What does it mean for a host defense mechanism to be induced vs uninduced?

Induced defenses are activated in response to an infection, while uninduced defenses are always present and ready to act.

List some examples of induced vs uninduced defense mechanisms.

Induced examples include the production of antibodies, while uninduced examples include anatomical barriers like skin.

Describe the steps of phagocytosis.

The steps of phagocytosis include chemotaxis, adherence, ingestion, digestion, and elimination.

What are pyrogens?

Pyrogens are substances that induce fever by acting on the hypothalamus to raise body temperature.

What part of the body do pyrogens act on?

Pyrogens act on the hypothalamus in the brain.

What are interferons?

Interferons are signaling proteins that help to coordinate the body's antiviral defenses.

How do interferons help in the second line of defense?

Interferons help by enhancing the immune response and activating neighboring cells to increase their antiviral defenses.

Describe the purpose and function of antimicrobial peptides.

Antimicrobial peptides function to disrupt microbial cell membranes and inhibit the growth of pathogens.

What are cytokines?

Cytokines are signaling molecules that facilitate communication between immune cells.

What is the function of cytokines?

Cytokines regulate immune responses, inflammation, and hematopoiesis.

Describe the difference(s) between PAMPs and PRRs.

PAMPs (Pathogen-Associated Molecular Patterns) are molecules found on pathogens, whereas PRRs (Pattern Recognition Receptors) are host receptors that recognize PAMPs.

What are the 4 cardinal signs of inflammation?

The four cardinal signs of inflammation are redness (rubor), swelling (tumor), heat (calor), and pain (dolor).

Know the Latin versions of the cardinal signs of inflammation.

Rubor (redness), tumor (swelling), calor (heat), dolor (pain).

Describe macrophages, monocytes, neutrophils, basophils, and eosinophils.

Macrophages are large phagocytic cells, monocytes are precursors to macrophages, neutrophils are the most abundant white blood cells, basophils release histamines during allergic reactions, and eosinophils are involved in fighting parasitic infections.

Define edema.

Edema is the accumulation of fluid in tissues, often causing swelling.

Define diapedesis.

Diapedesis is the process by which white blood cells move out of blood vessels and into tissues.

Describe the characteristics of a fever that we discussed.

Fever is characterized by an elevated body temperature, often resulting from infection, that can enhance immune responses.

Are fevers good? Bad?

Fevers can be good as they help fight infections, but extremely high fevers can be dangerous.

Describe the steps of the inflammatory response.

The inflammatory response includes vascular changes, recruitment of immune cells, and the release of signaling molecules.

How would a reduced number of helper T cells affect a patient with HIV?

A reduced number of helper T cells impairs both specific and nonspecific immune defenses, making the patient more susceptible to infections.

Why might a fever following a viral infection be beneficial?

A fever can help inhibit viral replication and enhance immune cell activity.

Which step of phagocytosis is impaired if neutrophils can engulf bacteria but fail to destroy them?

The digestion step of phagocytosis is impaired due to defective lysosomes.

Why would corticosteroids weaken the inflammatory response?

Corticosteroids suppress the immune response, reducing inflammation and the activity of immune cells.

Which molecule is responsible for increasing antiviral defenses in neighboring cells during a viral infection?

Interferons are responsible for increasing antiviral defenses in neighboring cells.

Describe the types of immunity associated with B cells and T cells.

B cells are primarily responsible for antibody-mediated immunity, while T cells are involved in cell-mediated immunity.

Describe MHC I markers.

MHC I markers are molecules on cell surfaces that present endogenous antigens to cytotoxic T cells.

Describe APCs (antigen presenting cells).

APCs are cells that process and present antigens to T cells, initiating an immune response.

Which cells secrete antibodies?

Plasma cells are the cells that secrete antibodies.

Describe the structure of an antibody.

An antibody consists of two heavy chains and two light chains with variable regions that bind to specific antigens.

Where does an antibody bind to an antigen?

An antibody binds to the specific epitope on an antigen.

What is a secondary response vs a primary response vs a latent response?

A primary response is the initial immune response to an antigen, a secondary response is a faster and stronger response upon re-exposure, and a latent response has no symptoms for a period following infection.

Differentiate between neutralization, opsonization, and agglutination.

Neutralization blocks the pathogen's action, opsonization enhances phagocytosis, and agglutination clumps pathogens together for easier elimination.

Know the roles of IgA, IgE, IgG, IgM and when they would be present in larger numbers in the body.

IgA is found in mucosal areas, IgE is involved in allergic responses, IgG is the most abundant in serum, and IgM is the first responder to an infection.

Know the functions of Helper T cell, Plasma cell, Memory T cell, Natural Killer Cell, and Cytotoxic T cell.

Helper T cells assist other immune cells, Plasma cells secrete antibodies, Memory T cells provide long-term immunity, Natural Killer Cells target infected or cancerous cells, and Cytotoxic T cells destroy infected cells.

Describe the different types of immunity: active natural, active artificial, passive natural, and passive artificial.

Active natural immunity occurs from infection, active artificial from vaccination, passive natural from maternal antibodies, and passive artificial from antibody transfer through medical intervention.

Describe clonal deletion and selection.

Clonal deletion is the elimination of self-reactive lymphocytes, whereas selection ensures the survival of those that can effectively respond to pathogens.

How are attenuated viruses different from inactivated viruses?

Attenuated viruses are live but weakened and capable of replication, while inactivated viruses are killed and cannot replicate.

What should an immunocompromised patient do regarding vaccination?

An immunocompromised patient should consult with a healthcare provider to determine appropriate vaccination options.

Which type of immunity is induced after a flu vaccine, and which immune cells are primarily activated?

The flu vaccine induces active artificial immunity primarily activating B cells.

Why does a person recovering from chickenpox usually not get it again?

This is due to the development of immunological memory facilitated by memory cells.

Which type of immunity protects a newborn from infection through breast milk?

This is passive natural immunity.

Which antibody and immune cells are most involved during a severe allergic reaction to a bee sting?

IgE antibodies and mast cells are most involved in a severe allergic reaction.

Why do MHC markers play such an important role during an organ transplant?

MHC markers help determine compatibility between donor and recipient, influencing acceptance or rejection of the transplant.