healing Flashcards
7
what initiates healing
tissue damage (any type)
what is the main goal of repairing damaged tissue?
return the tissue to its normal anatomy and normal function
during tissue repair what cells are proliferated?
fibroblasts
endothelial cells
roll of fibrous tissue
gives substance and strength to healing tissue
what are fibroblasts
specialized cells that can produce fibrous tissue (which gives substance and strength to healing tissue)
healing by the first intention
- takes place after an injury in which there has been minimal tissue damage and ideally no bacterial contamination (eg, surgical incision)
- good tissue apposition, no tissue loss
- endothelial cells increase in size and number, forming capillary loops
- the capillary loops join across the injured area and form functioning blood vessels
- fibroblasts begin laying down fibrous tissue
- the repair will resemble new tissue in 2-3 weeks with minimal scaring
healing by secondary intention
- in tissues with considerable tissue loss and damage
- initially, a blood clot temporarily fills the tissue loss, protecting the region
- endothelial cells and fibroblasts grow into the space, producing much more fibrous tissue than healing by first intention
- the capillary loops are extensive and give the healing tissue a granular appearance
- the epithelium grown under the clot.
- eventually, the clot falls off (scab) the damaged area, leaving the epithelium to protect the repaired tissue
- more scaring
what is vaccination
a procedure that helps the immune system to become even more effective in fighting off invaders
are allergies an immune system malfunction?
yes
most common
variolation
- precursor to vx
- from ancient Chinese practices
- rubbing the puss of an individual with smallpox into the scratch wounds of a healthy individual
- most individuals recovered but some died so the practice became unfavoured
cross-protection
when the antibodies made for one virus (cowpox) can protect against a different virus (smallpox)
developed by Edward Jenner
immunology
the study of the defense mechanism of the body
antibodies
proteins produced by the body in response to a foreign substance that protects the animal from disease
how can we develop immunity to a disease?
- from having the disease and recovering
- vaccination
both are due to the production of antibodies
treatment for viruses
Generally no treatment
What is the most important method of disease control for all animals in the world?
vx
species/natural resistance
- some sp never get some diseases
- characterized by a complete resistance by all members of the species
- mechanisms of resistance not fully understood but we know it is not dependent on specific antibodies
- natural immunity occurs without medical (human) intervention
artificial immunity
medically induced immunity
innate immune system
- non-specific immunity (immunity we are born with)
- includes physical and chemical barriers (intact skin, stomach acid, commensal organisms, mucus production, cilia, lysozyme in tears, body temperature)
- involves humoral and cell-mediated systems
- include inflammatory responses (particularly phagocytes)
- eg, wound healing
if the innate immune system is successful, the adaptive immune response will not be activated and antibody production will not occur - occurs immediately after antigen entry
- no specificity
what is the body’s first line of defense?
phagocytes
when does innate immunity begin?
Immediately after an antigen enters
how long does antigen production take?
a few days
why is it good/important that the innate immune system takes place immediately?
because antibody production takes a few days
why is the innate immune system more rapid?
because it treats all antigens the same way
does your innate immune system work faster on antigens that it has seen before?
no, treats everything the same way
what are the clinical signs of the innate immune system?
- histamine release
- many of the cardinal signs of inflammation
(swelling or edema from movement of plasma from circulation to the tissue)
(redness and excess heat from vasodilation and increased blood flow)
(occasionally release of excess mucus for protection)
what factors affect natural immunity?
innate immunity
interferon
interferon
- an antiviral agent
- present in the serum of certain animals that have been infected with a virus
- species specific
- is released from virus infected cells
- stop the formation of viral nucleic acid (this stops replication)
- produced in small amounts
acquired/adaptive/specific immunity
- occurs after birth
- is the response of the body’s defenses to an antigen
- results in the production of antibodies
- highly specific
- remembers so the body’s response becomes more rapid and stronger with each encounter with the same antigen
what is a unique component of the immune system?
ability to remember
how is adaptive immunity faster?
there is a greater number of B-cells (memory cells) allowing for a fast response
what does specificity allow for?
increased speed and strength of the immune system when encountering the same antigen for a subsequent time
how and when is immunity created?
- created during the adaptive response
- involves T lymphocytes and phagocytes (neuts, monos, and macrophages)
- the antibody will bind and neutralize the antigen by providing a physical barrier between the antigen and the host cells
individual level of immunity reached depends on:
- genetics
- general health status
- dosage of antigen
- the antigen’s portal entry
- antigens persistence (rate of clearance)
- number of times it has been encountered previously
active immunity
- produced by the host animal’s immune system to produce antibodies
- long term immunity occurs
- the body has learned through exposure to a disease or vx how to make antibodies to a disease
- not immediate
what does active immunity follow?
stimulation from an antigen through disease or vx
does long-term immunity occur in active immunity
yes
serenoconservation
the changeover from a nonexistent or low antibody titer to an elevated one
how long does it usually take for active immunity to kick in?
2-3 weeks after virus introduction
how long does active immunity last?
can last a long time, years to life
passive immunity
immunity that is produced in another animal in response to virus stimulation.
the antibodies are transferred to the passively immunized animal
can acquire this type of immunity either by acquiring it or artificially
two types of passive immunity
acquired passive immunity
artificial passive immunity
how is acquired natural passive immunity achieved
when antibodies are passed from the mom to the fetus
can occur by antibodies passing through the placental barrier or colostrum
acquired artificial passive immunity
- when antibodies produced in one animal are infused into another animal
- the individual immune system is not stimulated (no antibody or memory cell creation)
- immediate protection
what are the antibodies taken for acquired passive immunity used for?
- may be used to produce antiserum (this can be given to other animals, short-term immunity)
- used to create a toxoid
if vx are given to a bitch too soon what may the maternal antibodies do?
they may block the neonate’s immune system from responding resulting in no immunity
if vx are given to the bitch too late (far in the past) what may the maternal antibodies do?
- maternal antibodies may be gone
- Young will not get antibodies
what determines how much IgG antibody can cross the placental barrier?
the number of layers of tissue comprising the placenta
IgG antibody
protects against bacterial and viral infections
how much IgG crosses the 3 layers of the placenta
100%
is in humans and primates
protects from systemic infections
which antibody do the neonates still require and how do they get it?
IgA antibody
colostrum
conveys immunity to the GI tract to help prevent neonatal diarrhea
how many layers are the cat and dog placenta?
4
how do kittens and puppies get most of their maternal immunity?
colostrum
how many layers is the ruminant placenta
5
blocks all antibody crossing
how many layers is the donkey, pig, and horse placenta?
6
blocks all antibody crossing
antigen
a foreign substance that is introduced into the body
- usually protein in structure and have a high molecular weight
what makes different antigens unique?
(antigenic determinant)
peculiarities on the surface of the antigen unique to that antigen
antibody
- natural product of the body in response to antigen stimulation
- are proteins
- has a SPECIFIC reaction with the antigen that causes their formation
- part of the immunoglobulin group
