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)
What is Reversible Cell Injury
-impaired cell function, does not result in cell death
Cellular Edema
-reversible when ATP pump reactivates
Fat Accumulation
- usually do to a disease process
- Can be partially reversible
What is Programmed Cell Death
Cell death occurs by necrosis or by programmed cell death called apoptosis
- Inhibitors of apoptosis are thought to contribute to cancer and autoimmune disease
- Apoptosis (cell suicide), controlled cell destruction to remove/replace cells in excess, improperly developed, genetically damaged, worn out
NECROSIS
-cell death and degradation (unregulated)
Cell may undergo
- liquefaction
- coagulation
- infarction
Cell contents are often released
triggers inflammation
Compare dry, wet, and gas gangrene in regards to pathophysiology and physical outcomes
-gangrene is applied when a considerable mass of tissue undergoes necrosis. May be classified as dry or moist
DRY
-dry and shrinks, wrinkles, and color dark brown or black
-interference with arterial blood supply to the part without interference with venous return and is a form of coagulation necrosis.
WET
- area is cold, swollen and pulseless. Skin is moise, black and under tension. Liquefaction occurs and a foul odour is caused by bacterial action.
- interference with venous return.
GAS
- special type that results from infection (clostridium)
- trauma, fractures in which dirt are embedded
- bacteria produce toxins that dissolve membrane, muscle cell death, edema, hemolysis, renal failure
- characteristics are bubbles of hydrogen sulfide gas that form in muscle
What are the five cardinal signs of acute inflammation, describe the physiologic mechanisms involved in the production of these signs
- redness, swelling, heat, pain, loss of function
- characterized by exudation of fluid and plasma proteins and emigration of leukocytes, predominantly neutrophils.
Compare vascular and cellular stages of the inflammatory response
Vascular
-increased blood flow (vasodilation)
=-increase in capillary blood flow, causing heat and redness.(cardinal sign)
-increased vascular permeability allowing plasma proteins to leave the circulation. This reduces capillary osmotic pressure and increases the interstitial osmotic pressure. In addition, increase in capillary pressure, causes a marked outflow of fluid and its accumulation in the tissue spaces produces
-swelling, pain, impaired function (cardinal signs)
Cellular Stage
-emigration of leukocytes (mainly neutrophils) and their accumulation at the site of injury
Margination + Adhesion (leukocytes accumulate and adhere to endothelium, cytokines released)
Transmigration (Leukocytes move through vessel wall to tissue)
Chemotaxis (Leukocytes are guided by a gradient called chemokines to the site of injury)
Activation and phagocytosis (neutrophils, monocytes, and tissue macrophages engulf and degrade the bacteria and cellular debris
Name and Describe the five types of inflammatory exudates
Serous - watery fluids low in protein content that result from plasma entering the inflammatory site
Hemorrhagic exudates- occur when there is severe tissue injury that causes damage to blood vessels or when there is significant leakage of red cells from the capillaries
Fibrinous exudate - contains large amounts of fibrinogen and form a thick and sticky meshwork.
Membranous - develop on mucous membrane surfaces and are composed of necrotic cells enmeshed in a fibropurulent exudate
Purulent - contains pus, which is composed of degraded white blood cells, proteins, and tissue debris.
Contrast acute and chronic inflammation
- in contrast to acute inflammation, which is usually self-limited and short duration, chronic inflammation is self-perpetuating and may last for weeks, months or even years
- characterized by infiltration with mononuclear cells (macrophages, lymphocytes, and plasma cells) and attempted connective tissue repair involving new vessel formation.
*begins insidiously, often asymptomatic (atherosclerosis, lung disease, rheumatoid arthritis, and Inflammatory bowel disease.
- macrophages accumulate and release inflammatory mediators
- fibroblasts proliferate
- scar tissue forms
- macrophages mass around foreign bodies
- connective tissue surrounds and isolates the mass
Causes of Chronic Inflammation
Foreign bodies - talc, silica, asbestos, and surgical suture materials
- Virus, bacteria, fungi, and parasites.
- diseases that cause excessive and inappropriate activation of the immune system
- presence of a injured tissue such as that surrounding a healing fracture
- Obesity, white adipose tissue is to be an active endocrine organ and a source of an inflammatory mediator
Define core temperature
- Core body temperature (36 to 37.5) temperature of the deep body tissue.
- reflection of the balance between heat gain and heat loss by the body
- intracranial, intrathoracic, intra-abdominal
- caused by cytokine induced upward displacement of the set point in the hypothalamus center
- temp body is almost entirely regulated by the nervous system
Mechanism of heat production
- shivering (hypothalamus impulse, general increase in muscle tone, oscillating rhythmic tremor, which results in heat
- Physical exertion
Mechanism of heat retention
-Vasoconstriction- closing of the arteriovenous shunt
Pilomotor muscle contraction - raises skin hair (goosebumps), traps air and decreases surface area available for heat loss
Mechanism of heat loss
RADIATION - transfer of heat through the air (opening of AV shunt)
CONDUCTION - direct transfer of heat from one molecule to another (cooling blanket)
CONVECTION - air currents
EVAPORATION - use of body heat to convert water on the skin to water vapor
EXHALATION
URINE/FECES
HEAT EDEMA
INCREASED HR
Pathogenesis of Pyrexia
- exogenous pyrogen enters body -> engulfed and digested by macrophages
- interleukin released and travel to hypothalamus
- prostaglandin binds to hypothalamus which increases the setpoint
Explain intermittent, remittent, sustained and relapsing fevers
Intermittent - temp returns to normal at least once every 24h
Remittent - never returns to normal and varies
Sustained - never returns to normal but varies (only minimal)
Recurrent/relapsing - episode of fever with episodes with normal temp, both lasting days at time