Transcript Chapter 1 Intro

Pathophysiology
Cramming is a sure path to
failure !
It will blow up in your face!
Terminology
• 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 (interuption, 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.
Categories of etiology
• 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)
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
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
Eukaryotic 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:
•
melanin
•
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
• 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
We'll see this in heart, kidney (and others) w/
pathology
NOT due to increased cell volume or fluid
Rather, due to increased protein synthesis within
the cell, or decreased protein breakdown
Result is increased protein in organelles
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
Reversible
An example: ciliated columnar epithelium
replaced by
stratified squamous epithelium
Dysplasia = change in cell resulting in abnormal cell
size, shape or organization
We'll see this in respiratory tract, cervix w/ pathology
In mature cells only
Immature cells would be expected to change
in size, shape as they grow and mature
Considered a reversible change
Neoplasia = associated with a malignant tumor
Intracellular accumulations
• 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
• 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.
Free radicals :
uncharged atom or group of atoms with an
unpaired electron
Formed by radiation, redox reactions, chemicals
Atom is unstable
needs to gain or lose an electron
can alter chemical bonds in proteins,
lipids, carbohydrates and nucleic acids
can cause chain reaction in cell
Apoptosis
•
•
•
•
•
“fallen apart”
Regulated cell death
During development
Worn out cells
Diseased cells (tumor suppressor p53
gene, natural killer or Tc cells)
Necrosis
• Messy cell death
• Initiates inflammation
• Gangrene – large mass of tissue
undergoes necrosis
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
• Programmed change theories
• Error theories
• Telomerase