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 bilayerPhospholipids have hydrophobic tailPhospholipids have hydrophilic headsAlso contains embedded proteins

proteins are important for cell-cellcommunication:

receptors for hormonescell recognition

also important for metabolic processes inside the cell:

channelspumpsenzymes

CytoplasmCytosol – aqueous gel-like medium

Important metabolic processes occur here

Organelles – membrane bound structuresMembranes provide compartments forseparation of chemical reactions

NucleusDNA codes for proteins

Rough Endoplasmic ReticulumContains ribosomes – make proteins

Smooth ERsynthesizes phospholipids

detoxifies

Golgi ApparatusPackages protein for export

MitochondriaThe cell’s power plant

Cellular respiration

Vesicles“sacs” that hold molecules within a cell

lysosomes –digestive enzymesmolecules to be exported

InclusionsTemporary structures

• ribosomes

• filaments – cytoskeleton – protein strands

• other molecules without membranes:

• melanin

• lipids, etc.

TissuesMade up of cells with common function

Four major tissue types:

1. Epithelial covering and lining

interacts with the body’s environmentglandular tissue

2. Connective tissue

Important to structure , support and protection

3. Nervous tissueMade up of neurons and supporting (glial) cells

receives info from outside (or inside) the bodyprocesses informationacts 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 supplydecreased nutrition

Of tissues or organs may be due to cell shrinkage or due to cell death.

Hypertrophy = increase in cell sizeWe'll see this in heart, kidney (and others) w/ pathologyNOT due to increased cell volume or fluidRather, due to increased protein synthesis within the cell, or decreased protein breakdownResult is increased protein in organelles

Hyperplasia = increase in cell numberDue to increased cell division

Uterus and breast tissueParathyroid gland in kidney failureLiver (compensatory hyperplasia)

Metaplasia = replacement of one cell type with anotherReversible

An example: ciliated columnar epithelium replaced by

stratified squamous epithelium

Dysplasia = change in cell resulting in abnormal cell size, shape or organizationWe'll see this in respiratory tract, cervix w/ pathologyIn 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 cellDue to :

Decreased oxygen in airDecreased hemoglobin or decreased oxygen transported to cellsDiseases 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 hypoxiaDecreased 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 systemCO -- deprives body of oxygenEthanol -- 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 electronFormed by radiation, redox reactions, chemicals

Atom is unstable needs to gain or lose an electroncan alter chemical bonds in proteins, lipids, carbohydrates and nucleic acidscan 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 agentsMicroorganisms can invade and harm cells

Cell injury can have effects on the entire bodyExamples: fever, pain, increased heart rate

Cell aging

• Programmed change theories

• Error theories

• Telomerase