HSC-Class 1 Flashcards
Define etiology
- causes of disease
- could be physical forces, biological agents, nutritional excesses/deficits or chemical agents
Define Disease
study of a cellular and organ changes occurring with diseases, and their affects on body functions
-interruption, cessation, or disorder of a body system or organ structure that is characterized usually by a recognized etiologic agent or agents an identifiable group of signs and symptoms, or consistent anatomic alteration
Define Risk Factors
pre-disposers of the disease
Define Pathogenesis
-sequence of cellular and tissue events from time of contact with etiological event until expression of disease
Define Manifestation
signs and symptoms
Define Syndome
- signs and symptoms characteristics of a specific disease state
- usually Etiology unknown
Define Complication
possible/actual adverse extensions of disease or as a result of treatment
Define sequelae
-impairments that are caused by disease
Hematologic System comprise of
RBC WBC Platelets Coagulation Factors Bone Marrow Lymph nodes Spleen
What is atrophy and the conditions which these changes occur
-the decrease in cell size
Conditions - disuse, denervation, loss of endocrine stimulation, inadequate nutrition and ischemia
What is Hypertrophy and the condition which this occur
-is the increase in cell size and with it an increase in the amount of functioning tissue mass
Two types - physiologic and non-physiologic
Exercising is physiologic
myocardial hypertrophy is pathologic
What is Hyperplasia and what condition does this change occur
-increase in the number of cells in an organ or tissue
Physiologic
- Hormonal (breast and uterine enlargement)
- compensatory (regeneration of the liver)
Non-physiologic
-excessive hormonal or growth factors
What is Metaplasia and the conditions this occurs
-reversible change in which on cell type is replaced with another cell type
- occurs in response to chronic irritation and inflammation
eg. smoker
What is dysplasia and what are the conditions which this occurs
-characterized by deranged cell growth of a specific tissue that results in different size, shaped and organization.
- minor degree of dysplasia are associated with chronic irritation or inflammation
- strongly precursor of cancer
What is Intracellular Accumulation and cite 4 sources
-the buildup of substances that cells cannot immediately use or eliminate.
3 Categories
- normal body substances (lipids, proteins, carbs, melanin, and bilirubin that are present in abnormally large amounts
- abnormal endogenous products, such as those resulting from inborn error of metabolism.
- exogenous products, such as tattoo, lead, coal dust
Causes of cell injury
physical agents radiation chemical injury biologic agents nutritional imbalance
Describe the mechanism whereby physical agent such as mechanical forces produces cell injury
- injury or trauma due to mechanical forces as a result of body impact with another object
- split and tear tissues, fracture bones, injure blood vessels, and disrupt blood flow
Describe mechanism of extreme temp on cell injury
- burns and severe heat stroke causes injury by inducing vascular injury, accelerating cell metabolism, inactivating temperature sensitive enzymes and disrupting the cell membrane
- exposure to cold increases blood viscosity and induces vasoconstriction by direct action on blood vessels and through reflex activity of the sympathetic nervous system. The resultant decrease in blood flow may lead to hypoxic tissue injury.
Mechanism of electrical forces on cell injury
AC (alternating current) - causes violent muscle contractions, preventing the person from releasing the electrical source.
DC - in and out quick, early cataracts
What is radiation? Differentiate between the effects of ionizing and nonionizing radiation in terms of their ability to cause cell injury
-interferes with DNA synthesis and mitosis
Ionizing Radiation affects cells by causing ionization of molecules and atoms in the cell, by directly hitting the target molecules in the cell or by producing free radicals that interacts with critical cell components. It can immediately kill cells, interrupt cell replication or cause a variety of genetic mutations. EG: cancer treatment, occupational/accidental exposure
-UV (just above the visible range) interrupts cellular bonds
Nonionizing Radiation
- infrared lights, ultrasound, microwaves, and laser energy. Causes vibration and rotation of atoms and molecules =>thermal energy
- injury from these is mainly thermal involving dermal and subcu injury
What is chemical Injury
Drugs - alcohol, prescription, OTC, street drugs
Lead toxicity -paint, glazes, cosmetic (Absorbed via GI tract or lungs)(children more susceptible because their blood-brain barrier is more permeable), can inactivate enzymes, interferes with enzymes for hemoglobin formation. Damages nerves (demyelination). S&S - anemia, fatigue, abd pain, mentation changes
Mercury
- fish, amalgams in dentistry, and vaccines.
- depending on the form involving can affect the CNS and kidneys
Explain how the injurious effects of biologic agents differ from those produced by physical and chemical agents
Biologic agents differ in that they are able to replicate and can continue to produce their effects. They injure cell by diverse mechanism.
- Virus enter cell and become incorporated into its DNC.
- Bacteria secrete exotoxin that interfere with cellular production of ATP
How is nutritional imbalances contribute to cell injury
nutritional excesses and deficiencies predispose cell to injury
Describe the three major mechanisms whereby most injurious agents exert their effects
Free Radicals
- highly reactive chemical species with an unpaired electron in the outer orbit. The unpaired electron causes free radicals to be unstable and highly reactive, reacting to nonspecifically with molecules in the vicinity.
- reacts with proteins, lipids, and carbohydrate (damaging cell membrane, inactivating enzymes, and damaging nuclei acids in DNA)
- Antioxidants inhibits free radicals
Hypoxic Cell Injury
- deprives the cell of oxygen and interrupts metabolism and generation of ATP
- Damage 4-6 min
- hypoxia can result from air, respiratory disease, vasoconstriction, anemia, edema, or inability of cells to use oxygen
- hypoxia causes a power failure in the cell, with widespread effects on the cell’s structural and functional components = aerobic metabolism ceases, cell reverts to anaerobic metabolism, using glycogen stores to maintain cell functions, reduced ATP = cell swelling.
Impaired Calcium Homeostasis
-cell usually maintains low intracellular calcium
-when calcium is released into the cell it:
=acts as a “second messenger” inside the cell
=turns on intracellular enzymes, some of which can damage the cell
=can open more calcium gates in the cell membrane which lets in more calcium (calcium cascade)