Microbiology > Ch 14 > Flashcards

Ch 14 Flashcards

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1
Q

What are the primary functions of a healthy immune system?

A
  • Surveillance of the body
  • Recognition and differentiation of normal versus foreign material
  • Attack against and destruction of entities deemed to be foreign

These functions are essential for maintaining health and responding to pathogens.

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2
Q

What are Pattern Recognition Receptors (PRRs)?

A
  • Receptors on WBC membranes for PAMPs
  • Detect foreign molecules
  • Examples: kinases, lectins, mannose-binding receptors

PRRs act like ‘feelers’ to identify pathogens.

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3
Q

What do Toll-like Receptors (TLRs) recognize?

A
  • Broad microbial features
  • Not specific pathogens

TLRs are a type of PRR located on phagocytes and other immune cells.

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4
Q

What are PAMPs?

A
  • Shared molecular structures found on many microbes
  • Act as ‘red flags’ that alert immune cells
  • Recognized by PRRs and TLRs

Examples of PAMPs include peptidoglycan and lipopolysaccharide.

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5
Q

What are the four major immune compartments?

A
  • Reticuloendothelial System (RES)
  • Extracellular Fluid (ECF)
  • Bloodstream
  • Lymphatic System

These compartments are crucial for effective immune responsiveness.

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6
Q

The Reticuloendothelial System (RES) is primarily composed of what type of cells?

A

Phagocytic cells (e.g., macrophages)

The RES is found in tissues and organs, providing structural support and connectivity.

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7
Q

What constitutes whole blood?

A

Blood cells (formed elements) + plasma

Whole blood can be separated into cells and plasma using a centrifuge.

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8
Q

What are the two main types of agranulocytes?

A
  • Lymphocytes
  • Monocytes

Agranulocytes are key immune cells without prominent granules.

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9
Q

What is the role of macrophages?

A
  • Phagocytosis of pathogens and debris
  • Antigen presentation to lymphocytes
  • Secretion of signaling molecules

Macrophages are derived from monocytes and play a crucial role in the immune response.

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10
Q

True or false: The first line of defense in the immune system is nonspecific.

A

TRUE

The first line includes physical barriers like skin and mucus membranes.

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11
Q

What is the function of dendritic cells?

A
  • Trap pathogens in peripheral tissues
  • Phagocytose bacteria and viruses
  • Present antigens to lymphocytes

Dendritic cells are crucial for initiating adaptive immune responses.

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12
Q

What is the normal range of leukocytes per mm³ of blood?

A

5000 – 9000 cells

This count is essential for assessing immune function.

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13
Q

What does lymph consist of?

A
  • Water
  • Dissolved salts
  • 2 to 5% proteins

Lymph is a plasma-like liquid carried by lymphatic circulation.

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14
Q

Fill in the blank: MHC I markers are found on every cell surface except __________.

A

red blood cells

MHC I markers play a key role in immune recognition.

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15
Q

What are the three lines of defense in the immune system?

A
  • First line: Physical and genetic barriers
  • Second line: Protective cells and fluids
  • Third line: Acquired immunity with exposure

These lines of defense work together to protect the body.

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16
Q

What is the function of thin walls in lymphatic vessels?

A

Easily permeated by extracellular fluid

This fluid is moved through contraction of skeletal muscles.

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17
Q

The flow of lymph in the lymphatic system is unidirectional toward the _______.

A

heart

Lymph eventually returns to the bloodstream.

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18
Q

Name the primary lymphoid organs.

A
  • Bone marrow
  • Thymus gland

These organs serve as nurseries for developing lymphocytes.

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19
Q

What is the role of the thymus gland?

A

T cells mature here

It is essential for T cell development and is largest in childhood.

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20
Q

What are the secondary lymphoid organs?

A
  • Lymph nodes
  • Spleen
  • MALT
  • GALT
  • SALT

These organs are sites for immune responses and pathogen encounters.

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21
Q

The spleen is primarily responsible for what function?

A

Filters blood

It removes old red blood cells and plays a role in phagocytosis of blood-borne pathogens.

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22
Q

What does MALT stand for?

A

Mucosal-Associated Lymphoid Tissue

Found in tonsils, GI tract, respiratory tract, and urinary tract.

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23
Q

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

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A
  • Genetic resistance
  • Physical barriers
  • Chemical defenses

These defenses block the entry of microbes and foreign agents.

24
Q

What are the four main characteristics of inflammation?

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A
  • C_____
  • R_____
  • T_____
  • D_____

These characteristics describe the body’s response to injury or infection.

25
What is the purpose of **edema** during inflammation?
* Dilutes harmful substances * Brings plasma proteins to the site * Traps microbes ## Footnote It helps prevent the spread of infection.
26
What is **chemotaxis**?
Migration of WBCs in response to chemicals ## Footnote This process is crucial for immune response during inflammation.
27
True or false: The **spleen** filters lymph.
FALSE ## Footnote The spleen filters blood, not lymph.
28
What is the role of **pyrogens** in fever?
Reset the hypothalamus to a higher temperature ## Footnote They can be exogenous or endogenous.
29
What are the **stages of fever**?
* Low-grade: 100–101°F * Moderate: 102–103°F * High: 104–106°F ## Footnote These stages indicate the severity of the fever.
30
What is the **mechanism** of fever?
Controlled by the hypothalamus ## Footnote Pyrogens influence the body's thermostat.
31
What is the **function of cytokines** in the immune response?
* Coordinate immune responses * Regulate lymphocyte growth * Activate immune responses ## Footnote They are produced by various immune cells.
32
What is the **role of neutrophils** in the immune response?
* Migrate toward infection * Engage in phagocytosis ## Footnote They are key defenders against pyogenic bacteria.
33
What does **SALT** stand for?
Skin-Associated Lymphoid Tissue ## Footnote It plays a role in local immune responses.
34
What is the **definition of fever**?
Elevated body temperature ## Footnote Common in infections, allergies, and other illnesses.
35
What happens during **diapedesis**?
WBCs migrate out of blood vessels into tissues ## Footnote This occurs in response to chemotactic factors.
36
What is the **function of the lymphatic circulation**?
Collects foreign material and moves it through ducts ## Footnote It ultimately flows into the bloodstream.
37
Fill in the blank: Forces host to ______ (illness, pain) so body can fight infection!
suffer ## Footnote This highlights the body's response mechanism to infections.
38
What is a key concept of **genetic defenses** in hosts?
* Some hosts are genetically immune to diseases of other hosts * Humans can’t acquire distemper from cats * Cats can’t get mumps from humans ## Footnote Viruses have great specificity for their host receptors.
39
What are some examples of **physical or anatomical barriers** in the body?
* Built-in defenses in skin * Outermost layer of skin with epithelial cells * Flushing effect of sweat * Mucous membranes * Mucous coat impedes attachment of bacteria * Ciliary defense of respiratory tree * Nasal hair traps larger particles * Coating of digestive, genitourinary, and respiratory tracts * Blinking and tear production * Flow of saliva * Flushing effect of urination, defecation, vomiting ## Footnote These barriers help prevent pathogens from entering the body.
40
What are some **nonspecific chemical defenses** from skin and mucous membranes?
* Sebaceous secretions * Lysozyme in tears, saliva, and skin * Defensins that lyse bacteria and fungi * High lactic acid and electrolyte concentration in sweat * Skin’s acidic pH * Hydrochloric acid in stomach * Digestive juices and bile of intestines * Semen contains antimicrobial chemicals * Vagina has acidic pH maintained by microbiota ## Footnote These chemical defenses play a crucial role in protecting the body from infections.
41
What are the **four phases** of phagocytosis?
* Chemotaxis * Binding * Ingestion * Killing ## Footnote These phases describe the sequential events in the process of phagocytosis.
42
What is produced during **oxygen-dependent killing** in phagocytosis?
* H₂O₂ * O₂⁻ * OH• * OCl⁻ ## Footnote These reactive oxygen intermediates (ROIs) are crucial for destroying pathogens.
43
What are the **antimicrobial agents** involved in phagocytosis?
* Lactic acid * Lysozyme * Nitric oxide (NO) * Cationic proteins * Hydrolytic enzymes ## Footnote These agents contribute to the destruction of pathogens during phagocytosis.
44
What is the role of **myeloperoxidase** in phagocytosis?
Forms toxic halogen ions ## Footnote Myeloperoxidase is an enzyme that helps produce reactive substances to kill pathogens.
45
What is **interferon (IFN)**?
Small proteins produced by white blood cells and tissue cells ## Footnote Interferons function as antiviral agents, immune enhancers, and tumor suppressors.
46
Name the **three major types** of interferon.
* IFN-α (alpha) * IFN-β (beta) * IFN-γ (gamma) ## Footnote Each type is produced by different cells and has distinct roles in the immune response.
47
What stimulates **IFN production**?
* Viruses * Foreign RNA * Immune signals * Microbial molecules ## Footnote These stimuli trigger the production of interferons to enhance the immune response.
48
What are the **three primary defensive features** of the complement system?
* Membrane attack complex (MAC) * Opsonization * Recruitment of inflammatory cells ## Footnote These features work together to destroy pathogens and enhance the immune response.
49
What activates the **classical pathway** of the complement system?
Presence of antibody bound to microorganism ## Footnote This pathway is part of the complement system that helps in the immune response.
50
What is the **role of neutrophils** in the immune response?
* First responders in inflammation * Target bacteria, damaged tissue, and foreign material * Major component of pus ## Footnote Neutrophils are crucial for the initial immune response to infections.
51
What are **dendritic cells** derived from?
Monocytes ## Footnote Dendritic cells process antigens and present them to lymphocytes, playing a key role in adaptive immunity.
52
What is the purpose of **phagocytes**?
* Survey tissue spaces * Eliminate harmful substances * Extract immunogenic information ## Footnote Phagocytes are essential for detecting and responding to pathogens.
53
What is the **first step** in phagocytosis?
Chemotaxis ## Footnote This step involves phagocytes moving toward chemical signals from microbes or injury.
54
What happens during **phagolysosome formation**?
Fusion of phagosome with lysosome ## Footnote This process allows digestive enzymes and toxic chemicals to act on the engulfed pathogen.
55
What is the **function of the membrane attack complex (MAC)**?
Kills pathogen directly ## Footnote MAC creates holes in the pathogen's membrane, leading to its destruction.
56
True or false: **Eosinophils** play a major role in phagocytosis.
FALSE ## Footnote Eosinophils have a minor phagocytic role and are more active in parasitic infections.
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