special topics exam 2

inflammatory response typically activated by

1. invasion of pathogens (ie. infections, by outside organism)

2. physical tissue damage (ie. trauma, tissue broken or ruptured)

after activiation

1. pain (dolor)

2. redness (rubor)

3. heat (calor)

4. swelling (tumor)

characteristics of inflammation were first described by Celsus around BC-AD

pain is the result of…

pain-inducing substance releases from damaged tissue

______ , _____, and _____ are due to changes in the vasculature of the affected region

redness, heat, and swelling

the signaling compounds released into the bloodstream are…

causing the blood vessel s in the area of the injury to change. pushes immune cells into the damaged tissue to help protect the rest of the tissue

increased permeability of the vasculature…

sends fluid into the injured region. It’s why injuries swell with fluid

why do pain and inflammation occur together?

general theory is that persistent hyperalgesia promotes immobility

pain helps control…

the physical activity of an animal so that the inflammatory response can take place and so that healing can occur

local vasculature becomes…

dilated and more permeable. It is driven by the production of histamine, serotonin, kinins, lipid mediators, prostaglandins, and chemotactic leukotriene B4

leukocytes are…

white blood cells

recruitment of leukocytes

mast cells and tissues macrophages in the area of the tissue damage release Tumor Necrosis Factor a. (TNFa).

TNFa promotes the release of…

interleukins (IL-2, IL-6, and IL-8)

interleukins induce formation of…

adhesion receptors which make the white blood cells ‘stick’ to the endothelium (lining) of the vasculature and ‘roll’ toward the site of tissue damage

interleukins are also…

signaling molecules that will amplify the inflammatory response

adhesion molecules are like…

magnets. they allow white blood cells to stick. the flow of blood through that area is what prompts the white blood cells to roll along the surface until they reach the point where there is a break in the tissue or until there is enough permeability to allow them to move into the tissue. They are responsible for protecting the tissue.

So white blood cells provide…

immune protection for the body,

when the vasculature becomes leaky or when there is a break in the tissue…

the surrounding tissue is protected by the release of white blood cells

onset of pain

the pain response begins at the site of the tissue damage with the activation of tissue macrophages

at the time of tissue damage…

plasma and tissues kallikrein (enzymes) are activated → prompts the conversion of of kininogens to bradykinin and kallidin

bradykinin and kallikin are classified as…

kinins

kinins

produce pain, vasodilation, increased vasculature permeability, and prostogladin release

macrophages are cells responsible for…

chewing up unwelcome cells like pathogens or chewing up pieces of broken cells

since the 1950s, bradykinin has been identified as…

the major contributor to pain development following tissue damage

hyperalgesia

increased pain sensitivity associated with damaged tissues

hyperalgesia is modulated by two inflammatory mediator groups…

prostoglandins and sympathomimetic amines

prostoglandins

increase afferent neuronal sensitivity by promoting the partial depolarization of neuron membrane potentials. this is accomplished by modulating the passage of sodium and potassium across the membrane

sympathomemetic amines

activated by the sympathetic nervous system and believed to be triggered by norepinephrine and dopamine (catechlamine) release from sympathetic neurons

these inflammatory mediator groups can…

increase or decrease the intensity of hyperalgesia and increased pain intensity by changes in their respective concentrations

C fibers

• non-myelinated

• slow conduction

• velocity < 1m/sec

• stimulation results in dull aching with not well defined borders

AO fibers

• fine-myelinated

• conduction velocity of ~15m/sec

• stimulation results in intense, well localized pain

NSAIDs

inhibit the functionality of cyclooxygenase (COX), an enzyme that connects arachidonic acid to prostoglandins and thromoboxane

first documented use of NSAID use was…

3,500 years ago through the use of plant extracts containing salicylate. willow bark contains salicylate

algometry

the amount of pressure applied to a surface

algometry is…

a procedure that can be defined as the measurement of pain by means of an algometer, an instrument for determining sensitivity to pain produced by pressure

algometry history

algometry appears to have gained clinical acceptance in human medicine beginning in the 1980s

method of function

tool consists of a load cell attached to a small rubber-coated disc called a pressure algometer

MNT is

mechanical nociceptive threshold

process to collect mechanical nociceptive threshold (MNT)…

• callibrate device

• appropriately restrain animal

• apply the algometer probe to area of interest, pushing at a Force of 1 kg force increase/sec

restraint is important because…

improper restraint may give false positives

in some species…

the threshold is 10 kg of force, which should take 10 seconds to reach maximum force

mechanical nocicpetive threshold is…

the maximum amount of pressure that is applied to the animal before they withdraw. it is considered to be an indication of pain sensitivity in that region of the body

sensory receptors are present throughout the body, and especially in the skin, that are capable…

of transmitting information about the intensity of physical contact

these receptors emit…

graded potentials. other receptors are present for nociception. they emit an “all or none” action potential

a graded potential is…

a potential where a partial depolarization of the membrane has occurred on a cell. they vary in the amount of force that’s developed when they’re triggered

if there’s a painful stimulus present…

the nociceptive receptors are going to fire, however the sensory receptors would have to be overloaded in order to induce pain

algometry values are expressed…

in units of force (usually kg)

it Is most appropriate to take…

multiple measurements and average them to develop a more robust indication of Mechanical Nociceptive Threshold

where can algometry be used?

• identification of deep tissue injury and monitoring the effects of therapy

• assessment of claw status in lameness cases

• research regarding the impact of painful procedures and pain management in animals

thermography

capture of infrared energy in the form of an image that we can analyze identify differences in temperature gradients over a specific area

there is never a…

direct measure of animal welfare

the quantification of animal welfare requires…

the collection of of information from multiple sources that can be assembled to bring our view of an animal’s welfare state into focus

what to look for when assessing welfare

• acute stress

  • hormone and metabolite concentrations, behavior

• chronic stress

  • behavior, changes in body condition, and health status

• pain

  • hormone concentrations, behavior, response to stimulus, heat emission

any time a tissue becomes more inflamed, it….

emits heat

inflammatory response has two primary phases…

vascular phase and cellular phase

heat is a…

excitement of molecules and atoms

objects emit…

heat energy until absolute zero is reached

heat energy that is released occurs…

in the form of infrared radiation

what is a thermograph?

• a graphic or visual record produced by thermography

• a picture of heat emission

how does an infrared sensor work?

• it consists of arrays of thermally-sensitive semiconductor materials

• changes in infrared wavelength cause the semiconductors on the sensor to heat to different temperatures

• semiconductors are primarily made from pyroelectric materials

pyroelectric materials are…

materials that display varying electrical potential dependent on very minute changes in temperature