Pathophysiology Bio 395

Terminology Pathology – focus on physical changes in diseased organs and tissues 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 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 Genetic disease– genes are responsible for a structural or functional defect 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 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) 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 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 ribosomes filaments – cytoskeleton – protein strands filaments – cytoskeleton – protein strands other molecules without membranes: other molecules without membranes: melanin melanin lipids, etc. 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 Important to movement Three types 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 Buildup of substances the cell can’t use or dispose of. 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: Causes of cell injury: Deficiency – lack of a substance necessary to the cell Deficiency – lack of a substance necessary to the cell Intoxication or poisoning – presence of a toxin or substance that interferes with cell functioning Intoxication or poisoning – presence of a toxin or substance that interferes with cell functioning Trauma – physical injury and loss of cell’s structural integrity 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 “fallen apart” “fallen apart” Regulated cell death Regulated cell death During development During development Worn out cells Worn out cells Diseased cells (tumor suppressor p53 gene, natural killer or Tc cells) Diseased cells (tumor suppressor p53 gene, natural killer or Tc cells)

Necrosis Messy cell death Messy cell death Initiates inflammation Initiates inflammation Gangrene – large mass of tissue undergoes necrosis 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 Programmed change theories Programmed change theories Error theories Error theories Telomerase Telomerase