Transcript Lecture 1 - Introduction Chap1

Pathophysiology
Bio 395
Terminology
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Pathology – focus on physical changes in
diseased organs and tissues
Pathophysiology – abnormal functioning
of diseased organs and how it applies to
medical treatment and patient care
Disease – loss of homeostasis, or when
physical or mental capacities cannot be
fully utilized (interruption, cessation or
disorder in the function of an organ or
system).
Etiology = cause of the disease
When the etiology is unknown, the disease
is said to be idiopathic.
Iatrogenic: disease and/or injury as a result
of medical intervention
Categories of etiology
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Genetic disease– genes are responsible for a
structural or functional defect
Congenital disease– genetic information is
intact, but the intrauterine environment
interferes with normal development
Acquired disease – disease is caused by
factors encountered after birth (biological
agents, physical forces, and chemical agents)
Nosocomial – diseases acquired as a result of
being in the hospital
Clinical manifestations – indications that
the person is sick
Symptoms – unobservable effects of a
disease reported by the patient
Signs – observable or measurable traits
Syndrome - a characteristic combination of
signs and symptoms associated with a
particular disease.
Pathogenesis - sequence of events in the of
development of a disease
Sequelae – lesions or impairments resulting from
a disease
Acute conditions – rapid onset, develop quickly,
usually of short duration
Chronic conditions – longer duration
onset may be sudden or insidious
Remission – periods when clinical
manifestations disappear or diminish
significantly
Exacerbation – periods when clinical
manifestations become worse or more
severe
Distribution of lesions may be:
Local – confined to one area of the body
Systemic – widely distributed throughout
the body
Within an organ damage can be:
Focal if there are only one or more
distinct sites of damage
Diffuse if the damage is uniformly
distributed
Diagnosis – identification of the specific
disease
Therapy – the treatment of the disease to
either effect a cure or reduce the patient’s
signs and symptoms
Prognosis – prediction of a disease’s
outcome
Normal Functioning of
Cells
Boundary – Cell membrane
(plasma membrane)
Composed of lipid molecules in bilayer
Phospholipids have hydrophobic tail
Phospholipids have hydrophilic heads
Also contains embedded proteins
proteins are important for cell-cell
communication:
receptors for hormones
cell recognition
also important for metabolic
processes inside the cell:
channels
pumps
enzymes
Cytoplasm
Cytosol – aqueous gel-like medium
Important metabolic processes occur here
Organelles – membrane bound structures
Membranes provide compartments for
separation of chemical reactions
Nucleus
DNA codes for proteins
Rough Endoplasmic
Reticulum
Contains ribosomes – make
proteins
Smooth ER
synthesizes phospholipids
detoxifies
Golgi Apparatus
Packages protein for export
Mitochondria
The cell’s power plant
Cellular respiration
Vesicles
“sacs” that hold molecules within a cell
lysosomes –digestive enzymes
molecules to be exported
Inclusions
Temporary structures
 ribosomes
 filaments – cytoskeleton – protein strands
 other molecules without membranes:
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melanin
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lipids, etc.
Tissues
Made up of cells with common function
Four major tissue types:
1. Epithelial
covering and lining
interacts with the body’s environment
glandular tissue
2. Connective tissue
Important to structure , support and protection
3. Nervous tissue
Made up of neurons and supporting (glial) cells
receives info from outside (or inside) the body
processes information
acts on the information through muscles, glands,
etc.
Muscle
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Important to movement
Three types
– Skeletal
– Smooth
– Cardiac
Cells change to adapt to
their environment
Atrophy = shrinkage = decrease in cell size.
Due to :
decreased use
decreased blood supply
decreased nutrition
Of tissues or organs may be due to
cell shrinkage or due to cell death.
Hypertrophy = increase in cell size
Result is increased protein in
organelles, but number of cells staty the
same
Hyperplasia = increase in cell number
Due to increased cell division
Uterus and breast tissue
Parathyroid gland in kidney failure
Liver (compensatory hyperplasia)
Metaplasia = replacement of one cell type with
another, still normal cells
Reversible
An example: ciliated columnar epithelium
replaced by stratified squamous epithelium
Dysplasia = change in cell resulting in abnormal cell
size, shape or organization
in respiratory tract, cervix w/ pathology
Considered a reversible change
Neoplasia = associated with a malignant tumor
Normal
Tissue
Abnormal
Tissue
Intracellular
accumulations
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Buildup of substances the cell can’t
use or dispose of.
– Normal body substances
– Abnormal products from inside the body
(inborn errors of metabolism)
– Substances from outside the body
(transient or permanent)
Cellular injury – cell unable
to maintain homeostasis
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Causes of cell injury:
Deficiency – lack of a substance
necessary to the cell
Intoxication or poisoning –
presence of a toxin or substance that
interferes with cell functioning
Trauma – physical injury and loss of
cell’s structural integrity
Deficiencies:
Deficiency in oxygen most important
Hypoxia = deficiency in oxygen at cell
Due to :
Decreased oxygen in air
Decreased hemoglobin or
decreased oxygen transported to cells
Diseases of the respiratory and/or
cardiovascular system
Important to cell because of
oxidative phosphorylation, which results
in the production of ATP
Oxidative: need oxygen to produce ATP
ATP: needed by cell for metabolism, cell life
Cellular response to hypoxia
Decreased mitochondrial reactions 
decreased ATP produced 
decreased energy
Ion pumps cease, so can't regulate ions
into/out of cell (ATP needed for this)
Can't pump Na+ and water out of cell, so get
cell swelling  organelle swelling 
cell death
Ischemia is inadequate blood supply to a cell or
tissue.
Ischemia can cause hypoxia.
Intoxication (or introduction of toxins
into the cell)
Effect on cell depends on toxin and on
cell
Some examples:
Lead -- injures nervous system
CO -- deprives body of oxygen
Ethanol -- effects central nervous
system
Trauma -- physical disruption of cells
Ex: abrasion, cutting, burns,
microorganisms etc.
Apoptosis
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“fallen apart”
Regulated cell death
During development
Worn out cells
Diseased cells (tumor suppressor p53
gene, natural killer or Tc cells)
Necrosis
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Messy cell death
Initiates inflammation
Gangrene – large mass of tissue
undergoes necrosis
Coagulative Necrosis - Kidney
Necrosis
Fatty Necrosis - pancreas
Necrosis
Dry Gangrene
Wet Gangrene 2º to diabetes
Necrosis
w/ liquefactive
component
Infections agents
Microorganisms can invade and harm
cells
Cell injury can have effects on the entire
body
Examples: fever, pain, increased heart
rate
Cell aging
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Programmed change theories
Error theories
Telomerase