Microbio Exam 4: Chapter 16 Innate Immunity

the ability to ward off disease

immunity

lack of resistance to a disease

susceptibility

defenses against any pathogen; rapid; present at birth, no memory, non-specific immunity

innate immunity

immunity or resistance to a specific pathogen; slower to respond, has a memory component

adaptive immunity

involves physical barriers, chemicals like salt in sweat, cells that can phagocytize, inflammation, fever, and molecules like interferon and complement which are all non-specific for the pathogen.

innate

What type of immune response involves antibody-producing cells?

Adaptive

Which cells help B-cells and T cells in the adaptive immune response?

Phagocytes

What type of immune response responds specifically to a pathogen?

Adaptive

What is the role of cells in the innate immune system?

They respond to pathogens and activate adaptive immunity.

What activates the responses of the innate immune system?

Protein receptors in their plasma membranes.

What are Toll-like receptors (TLR)?

Receptors that attach to various pattern recognition receptors (PRRs) on pathogens.

What are pathogen-associated molecular patterns (PAMPs)?

Commonly found patterns on pathogens recognized by PRRs.

What is an example of a PAMP found in gram-negative bacteria?

LPS (lipopolysaccharide) of the outer membrane.

What is flagellin?

A PAMP found in the flagella of motile bacteria.

What is peptidoglycan?

A PAMP found in the cell wall of gram-positive bacteria.

What types of DNA are recognized as PAMPs?

DNA of bacteria and DNA and RNA of viruses.

What do TLRs induce defensive cells to release upon encountering PAMPs?

Cytokines.

What is the first line of defense in the immune system?

Physical factors

What is the role of the skin in the immune system?

Barrier to entry

What are the two layers of the skin?

Dermis and epidermis

What is the dermis?

The inner, thicker portion of the skin made of connective tissue

What is the epidermis?

The outer portion of the skin made of tightly packed epithelial cells containing keratin

How does shedding of the top layer of skin help prevent infections?

It helps remove microbes

What is the function of mucous membranes?

They line the gastrointestinal, respiratory, and genitourinary tracts

What do mucous membranes secrete to trap microbes?

Viscous glycoproteins (mucus)

What is the function of the lacrimal apparatus?

Drains tears and washes the eye

What is the ciliary escalator?

A mechanism that transports microbes trapped in mucus away from the lungs

What happens if the ciliary escalator is inhibited?

It can lead to a buildup of mucus and debris in the respiratory tract, increasing the risk of infections

What is the function of the epiglottis?

Covers the trachea during eating to prevent microorganisms from entering the lower respiratory tract

How does earwax contribute to the immune system?

It prevents microbes from entering the ear

How does urine contribute to the immune system?

Cleans the urethra via flow

What role do vaginal secretions play in immunity?

They move microorganisms out of the vaginal tract and can have an unsuitable pH for microbes

What are some physical processes that help eliminate microbes from the body?

Peristalsis, defecation, vomiting, and diarrhea

How does saliva help prevent microbial colonization?

It dilutes the numbers of microorganisms and washes them from the surface of teeth and mucous membranes

What is the role of sebum on the skin?

Sebum forms a protective film and lowers the pH (3-5) of the skin.

What is lysozyme and where is it found?

Lysozyme is an enzyme capable of breaking down cell walls of gram-positive bacteria and is found in perspiration, tears, saliva, and urine.

What does lysozyme break down?

Lysozyme breaks the peptidoglycan layer of bacteria.

What is the pH range of gastric juice and its effect on bacteria?

The low pH (1.2-3.0) of gastric juice destroys most bacteria and toxins.

How does the pH of vaginal secretions affect microbes?

The low pH (3-5) of vaginal secretions inhibits microbes.

What is microbial antagonism?

The competition between normal microbiota and pathogens for colonization sites.

How do normal microbiota prevent the overgrowth of harmful microbes?

By competing for space and nutrients and producing substances harmful to pathogens.

What role do normal microbiota play in the immune system?

They play an important role in the development of the immune system.

What is commensalism?

A relationship where one organism benefits while the other (host) is unharmed.

Which organisms are considered opportunistic pathogens among the normal microbiota?

E. coli, S. aureus, S. epidermidis, Enterococcus faecalis, Pseudomonas aeruginosa.

What beneficial substance does E. coli provide to humans?

Vitamin K.

What are probiotics?

Live microbial cultures administered to exert a beneficial effect to restore microbiota.

What are prebiotics?

Chemicals (nutrients) that selectively promote the growth of beneficial bacteria and are not regulated.

What is the second line of defense in the immune system?

Phagocytes, inflammation, fever

What are the two main components of blood?

Blood plasma and formed elements

What are the formed elements in blood?

Erythrocytes, leukocytes, and platelets

Where are formed elements in blood created?

In red bone marrow by blood stem cells

What are granulocytes?

Leukocytes with granules in their cytoplasm that are visible with a light microscope

What are the four types of granulocytes?

Neutrophils, basophils, eosinophils, and mast cells

What is the function of neutrophils?

Phagocytic and motile; active in the early stages of infection

What do basophils release?

Histamine; they work in allergic responses

What is the role of eosinophils?

Phagocytic; toxic against parasites and helminths

What do mast cells do during an infection?

Release chemicals that activate neutrophils and eosinophils

What are agranulocytes?

Leukocytes with granules in their cytoplasm that are not visible with a light microscope

What are the three types of agranulocytes?

Monocytes, dendritic cells, and lymphocytes

What do monocytes mature into?

Macrophages in tissues

Where are dendritic cells abundantly found?

In the skin, mucous membranes, and thymus

What is the role of dendritic cells?

Phagocytic and initiate adaptive immune responses by presenting antigens to lymphocytes

What types of lymphocytes are there?

T cells, B cells, and NK cells

What does the lymphoid system consist of?

Lymph plasma, lymphatic vessels, and structures containing lymphoid tissue

What is the function of lymphoid tissue?

Where the interaction of pathogens with B/T cells occurs, carrying out an immune response

Which type of white blood cells dominate during the initial phase of bacterial infection?

Granulocytes, especially neutrophils

What type of white blood cells dominate as a bacterial infection progresses?

Macrophages

What is the first phase of phagocytosis?

Chemotaxis

What are chemotactic chemicals?

Microbial products, components of white blood cells, damaged cells, and peptides derived from complement

What do macrophages use to locate pathogens?

Chemical signals

What is the second phase of phagocytosis?

Adherence

What are Toll-like receptors (TLRs)?

Proteins on the phagocyte's surface that recognize specific proteins or carbohydrates in pathogens

What do PAMPs stand for?

Pathogen-associated molecular patterns

What is the role of PAMPs in phagocytosis?

They facilitate the attachment of microbes to TLRs on phagocyte surfaces

What happens when PAMPs bind to TLRs?

It initiates phagocytosis and induces the phagocyte to release specific cytokines

What is opsonization?

The coating of a microorganism with serum proteins to make adherence easier

What are opsonins?

Complement components and antibodies that decorate pathogens to attract macrophages

What is the third phase of phagocytosis?

Ingestion

What do pseudopods do during phagocytosis?

They extend from the phagocyte's plasma membrane to engulf the microorganism

What are the signs and symptoms of inflammation?

Pain, redness, immobility, swelling (edema), heat (PRISH)

What is one function of inflammation?

Destroys injurious agent or limits its effects on the body

What is another function of inflammation?

Repairs and replaces tissue damaged by the injurious agent

What initiates the process of inflammation?

Tissue damage from organisms penetrating deep into the tissue.

What are vasoactive mediators?

Chemicals released by damaged cells in response to injury that cause vasodilation and increased permeability of blood vessels.

What is the purpose of blood clotting during inflammation?

To prevent excessive bleeding and to contain the microbe or its toxins.

What is margination in the context of inflammation?

The process where phagocytes stick to the endothelium of blood vessels in response to local cytokines.

What is diapedesis?

The migration of phagocytes squeezing between endothelial cells to reach the damaged area.

How do phagocytes destroy invading microorganisms?

Through a process called phagocytosis.

What is the role of the stroma in tissue repair?

It is the supporting connective tissue involved in the repair process.

What is the role of parenchymal cells in tissue repair?

They are the functioning part of the tissue that, when active, can lead to perfect or near-perfect reconstruction.

What happens when repair cells of the stroma are more active than parenchymal cells?

Scar tissue is formed.

What forms at the site of injury during tissue repair?

A scab.

What is the term for abnormally high body temperature?

Fever

What is the normal temperature setting of the hypothalamus?

37°C

What do cytokines cause the hypothalamus to release to reset its temperature?

Prostaglandins

What happens to body temperature during the crisis phase of a fever?

Body temperature falls, leading to vasodilation and sweating

How does fever help the body defend against disease?

It enhances the effectiveness of phagocytes and T cells

What effect does higher body temperature have on antimicrobial substances?

It intensifies their effect or production

What is one way that higher temperatures affect pathogens?

They may slow the growth of pathogens

How does fever affect the body's repair processes?

Increased metabolic rate speeds up repair processes