What are the chemicals of inflammation? 3

1. histamine 2. kinins 3. prostaglandins

immune system physiology Flashcards by Ericka Shane Santiaguel

How many body defenses are there? Explain briefly

1.first line of defense= physical barriers & secretions

2.second line of defense = phagocytes, NK cells, inflammation

3.third line of defense= specific immune response

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What are the major components of the first line of defense?

4 components

Physical barriers
* skin (keratin)
* mucous membranes

Skin secretions (chemical)
* acidity & sebum (oil)

Mucous membrane secretions
* gastric secretions –> HCl & proteolytic enzymes
* acidic vaginal secretions
* mucus

Exocrine secretions
* saliva
* tears
* perspiration

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What type of effect do skin secretions/chemical barriers have?

name examples

bacteriostatic effect
* acidity & sebum (oil)

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What effect do acidic vaginal secretions have?

mucuous membrane secretion - 1st line

bacteriostatic

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How does mucus act as a first line of defense?

mucuous membrane secretion - 1st line

it traps microrganisms
* prevents it from entering the deeper & internal systems

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How do gastric secretions contribute to the first line of defense?

mucuous membrane secretion - 1st line

they contain proteolytic enzymes & HCl
* inactivates swallowed microorganisms
* inhibitins infectious agents from reaching the intestine

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How do exocrine secretions contribute to the first line of defense?

mucuous membrane secretion - 1st line

they contain lysozymes
* bactericidal effect

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What are the major components of the second line of defense?

Phagocytes
* macrophages
* lysosomes

NK cells (natural killer cells)
* MHC proteins

Inflammation
* non-specific response triggered when tissues are injured

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How do phagocytes aid in the second line of defense?

macrophages - 2nd line of defense

Macrophages
* uses pseudopodia to engulf the bacteria
* lysosomes surround the bacteria –> has lysozymes (low pH)
* creates a phagolysosome
* releases bacterial debris out to be removed

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How do NK cells contribute to the second line of defense ?

2nd line of defense

NK cells are always circulating the blood
searches for MHC proteins = major histocompatibility complex
if present = NK cells bypasses it
if not present = NK cells release bactericidal enzymes & chemical –> kills organism

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What are the purposes of inflammation?

2nd line of defense

prevent spread of infection
eliminate cell debris & noxious agents
mark for tissue repair

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What are the chemicals of inflammation?

histamine
kinins
prostaglandins

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How does histamine contribute to inflammation?

2nd line of defense

initiates inflammation
* released by mast cells
* promotes vasodilation, and increases capillary permeability

rationale = allows more blood to get to site of injury or infection

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How do kinins contribute to inflammation?

2nd line of defense

stimulates neutrophils to release lysosomal enzymes
* chemotactic = migrate to area of infection due to high levels of chemicals
* induces pain
* same action as histamines

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What are kinins?

2nd line of defense

kininogen (plasma protein) is activated by enzymes from lysosomes
transformed into active kinin peptides

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What is chemotaxis?

2nd line of defense

migration of immune cells to source of chemical stimulus (cite of infection)
immune cells can detect the direction and intensity of an extracellular chemical gradient

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How do prostaglandins (PGs)contribute to inflammation?

2nd line of defense

induces pain
* result = increases pain sensitivity
* fatty acids synthesized from cell membrane phospholipids

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What are the events of inflammation?

briefly explain each (3)

1.Cell Injury
* infection, physical injury, autoimmune reactions

2.Vascular response
* vasodilation = bring more blood & immune cells to the area
* initiates and maintains the inflammatory response by providing immune cells and nutrients to the site of injury or infection

3.Cellular response
* migration of immune cells to the site of injury or infection
* tissue repair & elimination of harmful cells
* neutrophils, macrophages, lymphocytes,

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What occurs during the vascular response?

inflammation - 2nd line of defense

Hyperemia = increased blood flow to organ
1.vasodilation = increases blood flow

2.increased capillary permeability = allows immune cells to move closer to site of infection

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What occurs when capillary permeability is increased during the vascular response?

inflammation - 2nd line of defense

exudation of fluid & albumin (protein) into the interstital space
leads to edema (swelling)

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What is the role of protein/albumin in the vascular response?

inflammation - 2nd line of defense

maintain blood pressure and prevent excessive fluid loss from the bloodstream –> leads to edema
contains the infection
helps recruit more proteins & immune cells to site of infection

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What is the difference between erythema & edema?

erythema = redness
edema = swelling

What occurs during the cellular response ?

inflammation - 2nd line of defense

diapedesis of leukocytes
* immune cells move from the blood vessels into the surrounding tissue at the site of inflammation
* attracted by cheomtactic factors to site of cell injury

What phagocytes are involved in inflammation?

inflammation - 2nd line of defense

neutrophils
macrophages
mast cells

What are the **cardinal signs of inflammation**? | inflammation - 2nd line of defense

* pain (dolor) * redness (rubor or erythema) * impaired function * swelling (tumor) * heat (calor)

What stimulates pain receptors? | cardinal signs of inflammation

* pressure exerted by edema can stimulate nerve endings

What causes redness? | cardinal signs of inflammation

**capillary dilation** * hyperemia = increases blood flow to the area

Why does impaired mobility happen? | cardinal signs of inflammation

* edema leads to **joint stiffness** * only occurs if joint is involved in cell injury

Why does impaired mobility happen? | cardinal signs of inflammation

How does swelling (edema) happen during inflammation? | cardinal signs of inflammation

* tissue permeability is increased * leads to **exudation of albumin** = **decreased osmotic pressure**

What cause heat during inflammation? | cardinal signs of inflammation

hyperemia * heat is more localized bc more blood is coming to the surface

What is the third line of defense? | characteristics

**immune response** * highly specific * systemic * has memory * dependent on **antigen-antibody interactions**

What is the antigen? | 3rd line of defense

**antibody generating** * *stimulates an immune response* * examples = proteins or sugars on cell membrane * represents the "non-self"

What is the antibody? | 3rd line of defense

**immunoglobulin/gamma globulin** * protein produced in response to an antigen * **highly specific** = neutralizes only the antigen that it's made for --> key and lock mechanism

How does an antigen bind to an antibody? | 3rd line of defense

key and lock mechanism * on the antibody, there are **2 antigen binding sites** * antigen will only bind if it has specific receptors = highly specific

What cells are initially immunoincompetent? What happens to them? | 3rd line of defense

**lymphocytes** become mature in: 1. Bone marrow = B-cells 2. Thymus = T-cells

What are the 2 types of immunity? | 3rd line of defense

1. Humoral immunity = B-cells 2. Cell mediated immunity = T-cells

What cells are active in humoral immunity? | humoral immunity - 3rd line of defense

**immunocompetent B-cells** * patrol lymph, blood, and interstitial fluid

How are B-cells activated? | humoral immunity - 3rd line of defense

**recognize specific pathogenic antigens** 1. recognizes pathogenic antigen 2. B-cells are activated 3. Activated B-cells multiple rapidly & differentiate Become: 1. plasma cells --> large cells that secrete 2000 antibodies/second 2. memory cells | activation = antigen exposure

How long do plasma cells live? | humoral immunity - 3rd line of defense

dies after 4-5 days

When does the primary immune response occur? | primary immune response - humoral immunity

* occurs following intial exposure to specific antigen * begins **5-7 days** following exposure

What happens during the primary immune response? | primary immune response - humoral immunity

* antibody titre falls usually within ____ * memory cells remain *rationale* = it takes time for immune system to generate sufficient amount of antibodies; memory B cells are still being generated

When does the secondary immune response occur? | secondary immune response - humoral immunity

occurs following **re-exposure to the same antigen** exposed in the primary immune response

What is the difference between the secondary & primary immune response? | secondary immune response - humoral immunity

secondary immune response is faster, more robust, and mroe efficient * due to the memory cells that remain fromt he previous, initial exposure

What are the types of immunity that can be developped? | 4 types

1. Natural active 2. Artificial active 3. Natural passive 4. Artificial passive

What is **natural, active immunity**? Give examples

Immunity developped from natural exposure to a infectious agent examples: 1.contracting a disease = flu, cold

What is **artificial, active immunity**? Give examples

Immunity developped from artificial exposure to an infectious agent examples: 1. vaccinations

What is **natural, passive immunity**? Give examples

Immunity acquired naturally through the transfer of antibodies from another individual (don't produce their own) examples: 1. breast milk 2. placental transmission 3. blood transfusions

What is **artificial, passive immunity**? Give examples

Immunity acquired through the transfer of pre-formed antibodies from another individual via medication interventions examples: 1. antiserum

What cells are active in cell-mediated immunity? | cell-mediated immunity - 3rd line of defense

**T-cells** 2 types: 1. cytotoxic T-cells (killer) 2. helper T-cells

How are cytotoxic (kiler) T-cells activated? | cell-mediated immunity - 3rd line of defense

T-cells recognize fragments of antigens presented on cells 1. Attaches to recognized antigen (infected cell) 2. releases **perforin** to perforate the membrane of host cell 3. water enters the cells 3. cell bursts leading to **cell death**

How are helper T-cells activated? | cell-mediated immunity - 3rd line of defense

T-cells recognize fragments of antigens presented on cells 1. Antigen presentation = attaches to recognized antigen 2. Activation, proliferation, and differentiation of helpter T-cells 3. secretes **chemotatic agents (cytokines) that attract/stimulate other immune cells** (B cells, to produce antibodies, and cytotoxic T cells) to the area | recruits other WBCs to area of infection

What cells do helper T-cells activate? | cell-mediated immunity - 3rd line of defense

B-cells & T-cells

What would happen if we had no helper T-cells? | cell-mediated immunity - 3rd line of defense

slower immune response * impaired/slow activation of B cells & T-cells * reduced memory response * impaired regulation of the immune response