Homeostasis
Reflects a tendency to stabilize an organism's functional systems, despite changes both internally and
... [Show More] externally
Allostasis
Intricate regulatory processes orchestrated by the brain and the ability to successfully adapt to changes
‣ Dynamic process that maintains or re-establishes homeostasis in light of environmental and lifestyle changes
Clinical Manifestations
Signs and symptoms or evidence of disease
Specificity
The probability that a test will be negative when applied to a person who does not have a given condition
Sensitivity
The probability that the test will be positive when applied to a person with the condition
Exacerbation
A relatively sudden increase in the severity of a disease or any of its signs/symptoms
Remission
An abatement or decline in severity of signs/symptoms of a disease
‣ If a remission is permanent (>5 yrs) the person is said to be cured
Convalescence
The stage of recovery after a disease, injury, or surgical operation
Etiology
The study of the causes or reasons for phenomena
Risk Factors
Characteristics or behaviors that increase the likelihood of developing a medical disorder or disease
‣ Modifiable
‣ Non-Modifiable
Modifiable Risk Factor
A behavioral risk factor that can be reduced or controlled by intervention, thereby reducing the probability of disease
‣ Drug/alcohol use, weight, stress management
Non-Modifiable Risk Factor
A risk factor that cannot be reduced or controlled by intervention
‣ Age, race/ethnicity, genetics
Stress/Stressor
Physical, chemical, or emotional factor that result in tension of body or mind
‣ Actual physical and mental state that tension produces
‣ Real or perceived state to homeostasis
General Adaptation Syndrome (GAS)
Selye's concept of the body's adaptive response to stress in three phases:
1. Alarm
2. Resistance/adaptation
3. Exhaustion.
Catecholamine
Secreted by the sympathetic nervous system (SNS) and adrenal medulla when hypothalamus senses a stressful stimulus in internal or external environment
‣ Epinephrine
‣ Norepinephrine
‣ Play integral roles in allostasis
Corticosteroid
Secreted by the adrenal cortex when hypothalamus senses a stressful stimulus in internal or external environment
Epinephrine (E)
Neurotransmitter secreted by the adrenal medulla in response to stress. Also known as adrenaline.
Norepinephrine (NE)
‣ Constricts blood vessels and raises blood pressure
• alpha receptor
‣ Enhances myocardial contractility, increases heart rate, and increases cardiac output
• beta 1 receptor
‣ Causes bronchodilation
• beta 2 receptor
‣ Increases the release of glucose from the liver (glycogenolysis) and elevates blood glucose levels
‣ Reduces gastric secretions
‣ Increases night/far vision
Adrenocortical Steroids
Critical to maintain homeostasis and may synergize/antagonize effects of catecholamines
‣ Cortisol and aldosterone
Cortisol (Steroid)
Primary glucocorticoid that affects protein metabolism, promotes appetite and food-seeking behaviors
‣ Results in immune suppression
‣ Has anti-inflammatory effects
Aldosterone
Primary mineralocorticoid that promotes reabsorption of sodium and water
‣ Increases blood pressure (BP)
Cellular Injury Mechanisms
• Hypoxic Injury
• Free radical injury (oxidative stress)
• Physical agents of injury
• Chemical Injury
• Infectious Injury
• Immunologic and Inflammatory Injury
• Nutritional injury
Ischemia and Hypoxic Injury
Tissue hypoxia is most often caused by ischemia; causes power failure in the cell
‣ Ischemia is the most common cause of cell injury and injures cells faster than hypoxia alone
‣ Combination of disruption of oxygen supply with accumulation of metabolic waste
Ischemia
Cellular events that lead to lactic acidosis
‣ Cellular proteins and enzymes become more dysfunctional
‣ Reversible, but cell death occurs when plasma, mitochondrial, and lysosomal membranes are critically damaged (irreversible)
Reversible Cell Injury
Hydropic swelling and intracellular accumulations [Show Less]