Chapter 1 - Introduction to Pathology Flashcards
Pathology
Study of changes in structure and function as a result of disease including:
- Cause, nature and course of disease
Disease
Unhealthy state caused by the affects of injury
- Structural changes: result in abnormal function
- Abnormal function: result in structural changes
Acute disease
Arises rapidly.
- Distinct symptoms
- Short duration
Chronic disease
Begins slowly.
- Signs/symptoms difficult to interpret
- Long duration
- Not prevented by vaccine or cured with medication
Etiology
The cause of a disease
Idiopathic
Unknown cause
Pathogenesis
Sequence of events leading from causes to manifestations of the disease
Pathophysiology
Mechanism by which the abnormal function is spread
Sign
Manifestation of a disease seen by an observer
- Vomitting
Symptom
Manifestation of a disease reported by the patient
- Nausea
Syndrome
Collection of signs and symptoms
Lesion
Structural changes in a tissue or organ (change in morphology)
Localize change representing a wound or injury
Morbidity
Short term or long term disability due to a disease “illness”
Mortality
Outcome of a disease is death
Incidence
The frequency of a disease over a period of time in a given population
Incidence = # of new cases per year/
# of persons in the population
“Rate”
Prevalence
The number of cases present in a given population at any one time
Prevalence = # of persons with disease at
any moment in time/
# of persons in the population
”%”
Anatomic pathology
Structural.
Involves examination of solid tissues using:
- Naked eye: “gross exam” “macroscopic”
- Microscope: light and electron
Surgical pathology
Includes:
- All material removed at surgery
- Biopsies
- Frozen sections
Cytology
The study of cells. Includes:
- Cervical and vaginal smears: pap smear
- Sputum smears: material coughed up
- Urine and body fluid – bladder cells are shed during urination
- Fine needle aspirates
- Cellular materials obtained during endoscopic exams
Autopsy pathology
Necropsy
Routine hospital autopsy
- Requires family’s permission
- Quality control mechanism that evaluates clinical impressions of disease and results of treatment
- Teaching and research tool: becomes data
Clinical pathology
– Functional
– Involves laboratory study of fluid tissues
Clinical chemistry
Blood levels of:
- Electrolytes
- Enzymes: released into the blood from damage cells
- Hormones
- Drugs
Infections
Virology, microbiology, parasitology
- Identification of microorganisms
- Evaluation of sensitivity of antibiotics
Immunology
Study of antibodies and antigens
Blood banking
Immunohematology
- Blood types
- Cross matches
- Processing of blood components for transfusion
Hematology
Evaluation of blood cells and coagulation
Urinalysis
- Dissolved substances: sugar, protein, drugs
- Crystals
- Cells (blood, bacteria)
- Casts: coagulated clusters of protein formed in the kidney – kidney stones
Forensic pathology
Disease and death as they are related to law
Coroners autopsy
Jurisdiction of coroner defined by law
Includes:
- Accident victims
- Suicides, homocides
- Sudden death without prior medical attention
- Patients who die within 24 hours of admission
- Patients who die on the operating table
*** Coroner may release body for private autopsy or burial without autopsy
Laboratory evaluation
Material from rape victims or alcohol and drug levels
Heredity or congenital abnormalities
Present at birth
- Genetic defects: - ranging from chromosome abnormality to single gene defects
- may result in a metabolic abnormality at a cellular level or in the gross malformations - Developmental abnormalities: without definite genetic changes
Physical injury
- Trauma: fractures, cuts, crush, stretch
- Thermal: burns, freezing, radiation, electricity
Chemical injury
- Poison: soaps, bleach, insecticides, plants, venom
- Drugs: aspirin, tranquilizers, narcotics, vitamins
- Environmental hazards
Inflammatory diseases
- Infection: viruses, bacteria, fungi, protozoan, worms
- Non-infection inflammations
Vascular diseases
- Ischemia: too little blood to the tissues
- Hypoxia: decreased oxygen (#1 cause ofcellular injury)
- often cause of other disease
- no oxygen > no ATP
- no ATP > no function
Neoplasia
Tumor production
- Benign or malignant
- Often named by presumed cell of origin
Immunologic injury
- Deficiencies: acquired or congenital
- Hypersensitivities
- Autoimmune diseases
Degeneration
Often associated with aging
Metabolic or nutritional deficiencies
- Electrolyte imbalances
- Deficiencies: vitamins, minerals, protein, calories
- Excess: calories, glucose, lipid, vitamins, minerals
Structural hierarchy of the body
Cells > tissues > organs > organ systems
Cells
Smallest functional unit of the body
Tissues
Collection of similar cells
Organ
Several different tissues organized into a distinct functional structure
Organ system
Different organs performing similar or related functions
Cell membrane (plasma membrane)
– Maintain cell structure
- Participates in cell function:
- Metabolically active
- Transports substances across the membrane: active transport, phagocytosis
- Forms intercellular junction’s to bind it tissues together
- Contains receptor sites for active compounds (hormone receptors)
Nucleus
Control center
- Contains chromosomes: total genetic info for that individual
- Sends out the instructions for the functioning of the cell in the form of RNA
Organelles
Structural subunits of the cells found in the cytoplasm
Mitochondria
- Cylindr or oval membrane-bound structures
- Produce energy to run cell
Ribosomes
RNA protein complexes
- Protein manufacturing centers
- Often attached to the membrane of the endoplasmic reticulum
Endoplasmic reticulum
Network of interlacing membrane and tubules
- Manufacturing and packaging centers for the cell
- Smooth ER: lipid
- Rough ER: protein, due to fixed ribosomes
Lysosomes
Membrane-bound sax containing hydrolytic enzymes
- Digestion and storage organelles
Epithelium
Lining cells (protective) and glandular cells (secretion)
- Originating from: ectoderm, mesoderm, and endoderm
- Squamous cells urothelium, ciliated columnar cells, mucus secreting columnar cells, glandular cells
Squamous cells
Flattened, pancake like cells covering body surfaces
- Present as multiple layers or as a single layer of cells
- Skin, mouth, esophagus
Urothelium (transitional cells)
- Layers of oval or domb shaped cells
- Urinary tract
Ciliated columnar cells
Usually a single layer of tile cells with delicate feathery cilia at one end
- Trachea, bronchi
Mucus secreting columnar cells
- GI tracked and salivary glands
Glandular cells
Any cell which secretes or absorbs something
- Liver, pancreas, thyroid, adrenal, kidney
Mesenchyme
Structural cells: support and shape
- Originate from mesoderm
- Muscle, bone, cartilage, fibrous tissue, fat, blood cells, endothelium, mesothelium
Muscle
- Skeletal
- Smooth: G.I. tract, bronchi, blood vessels, uterus, bladder
- Cardiac muscle: heart
Bone
- Osteocyte: maintain mature bone
- Osteoblast: form new bone
- Osteoclast: erode bone
Cartilage
- Chondrocyte: maintain mature cartilage
- Chondroblast: form new cartilage
Fibrous tissue (CT proper)
- Fibrocyte: maintain mature CT
- Fibroblast call in form new CT
Fat
Adipose tissue
Lipoblast/lipocyte > adipocyte or fat cells
Blood cells
Hematopoietic cells
Endothelium
Epithelial lining of blood cells (exception to “linings)
- Epithelium derived from mesenchyme > mesoderm
Mesotheliom
Epithelial lining body cavities: serosae (exception to “linings”)
- Epithelium derived from mesenchyme > mesoderm
Nervous tissue
Histologically ectoderm, technically not mesenchyme
- Neuron
- Glia: support sells for neurons
Healthy-normal test
True negative: 99%
Healthy-abnormal test
False positive: 1%
Sick-normal test
False negative: 1%
Sick-abnormal test
True positive: 99%
Sensitivity
The ability of a test to be positive in the presence of a disease
- The test is 99% positive if it is positive in 99 of 100 persons known to have the disease
- There’s a 1% chance of a false negative
- Do this test 1st: will allow you to detect a lot of suspects (+) and won’t miss any sick patients
- Pap smears, PSA tests
Specificity
Ability of a test to be negative in the absence of disease
- It is 99% specific if it is negative in 99 of 100 persons known not to have the disease
- This allows you to sort out the true positives (actually sick) from those with false positives (healthy patients)
- Cervical or prostate biopsy
Note on Prevalence and Predictive Value
A test has high predictive value if the prevalence in the population is high
