what is the number of pathogens that kills 50 percent of hosts within a specifdied period of time/ associated with toxin production
Infetious dose (id50)
number of pathogens that infect 50 pecent of hosts within a specified period of time
abiliity of microorganisms to establish an infection
ability of microorganisms to spread to adjacent tissues or other anatomical areas
What is disease?
any deviation of the host from a healthy state to an unhealthy state (health vs. unhealthy).
abnormal state where part or all of the host is unable to perform the normal functions of the body
morbid state (indicating diseased or unhealthy condition)
this change is manifested by signs and symptoms
- evidence of disease
- characteristics of a disease that can be observed by someone else in addition to the patients
redness, runny nose, swelling, rash, couphing, pus formation,fever, vomiting, diarrhea
characteristics of disease that can only be determined by the patient.
pain, shortness of breath, nausea, sore throat, headache, malaise (discomfort)
What is inflamation?
What is it characterized by?
a nonspecific defense mechanism by the body in response to infection, injury or chemical irritation.
- dolor, soreness or tenderness from injury to local nerve.
- calor: heat (warmth generated from the blood due to vasoconstriction)
- tumor: swelling (edema, from the accumulation of fluid in surrounding tissue)
- Rubor: redness from blood accumulation
What are the stages of inflamation?
- vascular changes (vasoconstriciton)
- increase in vacular permeability (results in edema)
- Leukocyte migration
- Chronic inflamation
What happens at the second stage of inflamation?
- Extravasation: movement of cells out of blood vessels (neutrophils)
- local swelling caused by the accumulation of plasma nad blood components in extracellular spaces (white blood cells come for attack)
What is the third stage of inflamation?
- Leukocyte migration
- Macrophages and neutrophils are the primary leukocytes that infiltrate the damaged area.
- remove dead and damaged cells
- allows for the growth of new cells and thereby aiding in tissue repair
- leukocytes aid in tissue repair
What happens at stage four of the stages of inflamation, chronic inflamation?
- pus formation
- purulent or suppurative
Granuloma and abscess
What happens at the fifth stage of inflamation (resolution/healing)?
Collagenation: deposition of collagen matrix to allow for the building of new tissue
Angiogenesis: new glood vessels are formed
Proliferation: sustained collagen building and revasularization.
remodeling: newly generated cells cells must be structurally arranged to perform the function of the tissue of organs.
What are the bennefits of inflamation?
vasolilation delivers more oxygen and nutrients to injured tissue.
edema delivers more phagocytes to tiddues and organs
- kills invading pationgens
- clears away tissue debris
repairs damaged/injured tissue
What is the disadvantage of swelling?
swelling of protective membrans (brain or spinal cord) can interfere with function.
swelling in the lungs can constrict airwayse and interefere with breatining.
What is a disadvantage of vasodilation?
can help pathogens to thrive by bringing increased oxygen and nutrients.
What is a disadvantage of clotting?
can restrict access of white blood cells to infected sites.
What are the two additonal signs and symptoms of inflammation?
granuloma small mass or nodule of inflamed tissue; due to the action of phagocytes and the subsequent accumulation of pus
abscess a collection of pus in a tissue, cavity or confined area surrounded by inflamed tissue
is what occurs when the immune system's response to an infection hurts the host cells and tissues
is damage to the host, mediated by the immune system in response to the pathogen.
What are the signe of infection in the blood?
What is pathology?
The study of diseased states.
the study of the structural and functional manifestations of disease
a branch of medicine that examines the nature of disease, how the disease is manifested, and changes to the body that occur as a result of disease
What are the characteristics of Necrosis?
Premature cell death
cell death, due to trauma or injusry to the cell
damage to the plasma membrane; cell rupture.
What is apoptosis?
programmed cell death
cell membrane remains intact; cell blebbing occurs
What are viral pathogenic effects referred to as?
What are the three ways that viral pathogenic effects occur?
- Viral overload
- Cytocidal effects
- non-cytocidal effects
What is viral load and how does it infect other cells?
the virus multiplies rapidly within the cell
number of viruses (virus overload) exceeds the dimensions of the cell causes cell lyses
then the virus infects surrounding cells, starting a new growth cycle.
How does cytocidal effects occur?
- when host immunwhen host immune cells identify virally-infected cells and kills them.
- cytotoxic t-cells
- natural killer cells
cell death then occurs by apoptosis.
When does non-cytocidal effects occus?
when the virus inhibits the metabolic functions of the host cell
- dna replication
What is syncytia that is a microscopic damage?
is giant, multinucleated cells
resulting from fusing of several virally-infected cells
What are negri bodies?
are inclusion bodies; ovservable viral particles
What is a syndrome?
combination of signs and symptoms, occur together and are indicative of a diseased or abnormal condition
complex of symptoms indicative of a morbid state.
What is sequela?
permanent damage to tissues as a result of infection and disease
What is diagnosis?
process of determining the cause of disease
commonly involves the use of chemical or immunological tests
What is prognosis?
What is the recovery success is based on?
projected outcome of a diseas, prospect of recovery from a disease.
based on the nature (pathology) of the disease.
What is prophylaxix?
What are the measures used to prevent?
what is it based on understanding and what does it include?
prevent the spread and development of disease
based on understanding the etiology and mode of transmission
includes the vaccination, improving hygiene and sanitation, standards of living, and education.
relieving or soothing the symptoms of a disease or disorder without affecting a cure
providing relief from pain and other distressing symptoms
What is an itiopathic disease?
a disease with an unknown etiology, pathology, and prognosis
What is etiology?
what are the various factors that cause disease?
- study of how diseases are caused.
- factors include:
- pathogens (infection)
- Genetics (genetic disordera)
- immune dysfuntion (autoimmune diseases)
- Biochemical/physiological deficiencies or changes
- psychological dysfunciton
What is epidemiology?
the study of the frequency and distribution (spread) of disease and other health-related problems within human populations.