Transcript Mechanisms of Disease

Objectives
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Define the vocabulary words
Define CDC and explain its function
Define the patterns of disease
List and describe the basic
mechanisms of disease and risk
factors associated with disease
• List and describe the five categories
of pathogenic organisms and explain
how they cause disease (Be able to
identify each example on handout)
• Know Common Aseptic Methods in
Table 5-6 on page 116
• Distinguish between the terms
benign and malignant as they apply
to tumors (Know Table 5-7 on page
118)
• Describe the pathogenesis of cancer
• Outline the events of the
inflammatory response and explain
its role in disease
Vocabulary Words
• Health – physical, mental, and
social well-being; not merely
absence of disease
• Disease – abnormality in body
function that threatens health
• Etiology – the study of factors
that cause disease
More vocabulary words
• Idiopathic – refers to a disease with
an unknown cause
• Signs – objective abnormalities that
can be seen or measured by
someone other than the patient
• Symptoms – subjective abnormalities
felt only by the patient
• Syndrome – a collection of different
signs and symptoms
Vocabulary (cont’d)
• Acute – signs and symptoms appear
suddenly, persist for a short time,
then disappear
• Chronic – develops slowly and lasts
for a long time
• Communicable – can be transferred
from one person to another
• Pathogenesis – the pattern of a
disease’s development
• Incubation – latent or “hidden”
stage, no signs of disease are
visible
• Convalescence – recovery
• Remission – reversal of a
chronic disease; when
permanent the person is
considered “cured”
CDC
• Centers for Disease Control and
Prevention
• Branch of U.S. Public Health Service
• Headquarters in Atlanta
• Morbidity – disease rates in specific
populations
• Mortality – number of deaths caused
by specific diseases
Patterns of Disease
• Epidemiology – study of occurrence,
distribution, and transmission of
diseases in human populations
• Endemic – native to a local region
• Epidemic – disease affects many
people at the same time
• Pandemic – widespread, perhaps
global, epidemic
Pathophysiology
the study of underlying
physiological aspects of
disease
Mechanisms of Disease
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Genetic mechanisms
Pathogenic organisms
Malnutrition
Tumors and cancer
Physical and chemical agents
Autoimmunity
Inflammation
Degeneration (when tissues break
apart)
Risk Factors
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Genetic factors
Age
Lifestyle
Stress – psychogenic (mind-caused),
ulcers, headaches, hypertension
• Environmental factors
• Preexisting conditions- example:
blisters from a burn break
open…..bacterial infection
Pathogenic Organisms
• Viruses invade cells and insert their
own genetic code into the host cell’s
genetic code causing the cell to
produce viral DNA or RNA and
protein coats
• Classified by shape, nucleic acid
type, and method of reproduction
• Know Table 5-1 on page 109
Viruses
• Bacteria secrete toxic substances
that damage human tissues, become
parasites inside human cells, or may
form colonies that disrupt normal
human function
• Spores - nonreproducing forms of
bacteria that resist unfavorable
environmental conditions
Classifying Bacteria
• Function: aerobic (require oxygen)
vs. anaerobic (no O2)
• Staining properties (composition of
cell wall):
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Gram-positive – stained purple by
Gram’s staining technique
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Gram-negative – no staining
• Shape and size
Fungi (Fun-jye)
• Fungi that are pathogenic parasitize
tissue on or near the skin or mucous
membranes; mycotic infections
(often resist treatment)
• Protozoa are one-celled organisms
that can infest human fluids and
cause disease by parasitizing cells or
directly destroying them
Pathogenic Fungi
A Scanning electron micrograph of yeast cells
B Infectious mold that forms “fungus balls”
Major Groups of
Protozoa
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Amoebas – pseudopodia
Flagellates
Ciliates
Sporozoa (coccidia) – enter cells
during one phase of a two part
life cycle; borne by vectors
(transmitters) during the other
phase
• Pathogenic animals are
sometimes called metazoa.
Large, multicellular organisms
cause disease by parasitizing
humans or causing direct injury
Prevention and Control
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Person-to-person contact
Environmental contact
Opportunistic invasion
Transmission by a vector
Vaccination
Chemicals – antibiotics (natural
compounds derived from living
organisms) and synthetic compounds
Tumors and Cancer
• Neoplasms (tumors) – abnormal
growths of cells
• Benign – remain localized
• Malignant – spread, forming
secondary tumors
• Metastasis – cells leave a primary
tumor and start a secondary tumor at
a new location
Classification of Tumors
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Benign, epithelial tumors:
Papilloma – finger-like projection
(wart)
Adenoma – glandular tumor
Nevus – small. Pigmented tumor
(mole)
• Benign, Connective Tissue
Tumors:
• Lipoma – adipose (fat) tumor
• Osteoma – bone tumor
• Chondroma – cartilage tumor
Carcinomas
• Malignant epithelial tissues:
• Melanoma – involves
melanocytes (pigment-producing
cells of the skin)
• Adenocarcinoma – glandular
cancer
Sarcomas
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Connective tissue cancer
Lymphoma – lymphatic cancer
Osteosarcoma – bone cancer
Myeloma – bone marrow tumor
Fibrosarcoma – cancer of
fibrous connective tissue
Causes of Cancer
• Hyperplasia – growth of too many
cells
• Anaplasia – development of
undifferentiated cells
• Genetics
• Carcinogens
• Age
• Injury (radiation)
• Viruses
Pathogenesis of Cancer
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Early detection
Methods of detection:
Self-examination
Diagnostic imaging
(Know pages 121-122)
Grading – assess likely pattern
Cachexia (Ka-Kek-see-ah) –
syndrome: appetite loss, weight loss,
general weakness
• Causes of death: secondary
infections, organ failure,
hemorrhage, undetermined
• Treatments: chemotherapy,
surgery, radiotherapy, laser
therapy, immunotherapy, new
strategies (vaccines)
Inflammation
• Response reduces injury to
tissues, homeostasis
• Signs- redness, swelling, heat,
pain
• Inflammation mediators
released from tissues–
histamine, prostaglandins,
kinins
Inflammation Mediators
• Some cause blood vessels to
dilate (widen), increasing blood
volume (redness,heat); white
blood cells travel quickly to site
• Some increase blood vessel
permeability (swelling (edema)
and pain); white blood cells
move easily out of vessels,
irritant is diluted, and exudate
(fluid in inflamed
tissue)accumulates
• Some attract white blood cells
to the site - chemotaxis
• Phagocytosis
• Pus – exudate becomes thick
with white blood cells, dead
tissue and bacterial cells
Inflammatory Diseases
• Local or systemic (body-wide)
• Fever – destroys pathogens and
enhances immunity
• Chronic inflammation – damages
tissues
• Arthritis, asthma, eczema,
chronic bronchitis