Cell Injury Adaptive Response Flashcards
Symptoms
patient’s subjective observations/descriptions, usually not quantifiable
Signs
abnormalities on physical exam, usually quantifiable; what you detect on physical exam
Syndrome
cluster of related symptoms &/or signs typically due to a single cause in an individual patient
Etiology
the “cause” of a disease; overly simplistic to think that a disease can have one single cause;
example: measles-> several causes such as lack of immunizations, poverty, the disease itself, etc.
Pathogenesis
sequence of events by which the disease develops
Pathognomonic
a particular sign/abnormality is found only in one condition or disease; example: forme fruste- very mild variant of a more serious disease
Example: Gilbert’s disease
Incidence
number of new cases per unit time; usually expressed as “new cases per 100,000 people per year“
Prevalence
number of cases at any one time; usually expressed as “cases per 100,000 people”
Risk
how much your particular situation increases your chance of getting a disease compared with everyone else
Diagnosis
name given to the particular disease once identified
Prognosis
expected outcome for a particular case of a disease;
Influenced by diagnosis, the age & general health of the patient, available treatments.
Hypoxia- #1, prototype for cell injury
-Poor nutrition (lack of nutritious substrates); Cells respond in different ways
-Infectious agents: several mechanisms depending on agent; viruses multiple in host cell and cause cell to explode
-Immune injury (overly responds)
4-5 types, antibody- or T cell-mediated
-Chemical agents (poisons, toxins, too much water, too much salt); Noxious stuff or too much good stuff
-Physical agents: trauma, radiation, etc.
Ischemia (ischemic hypoxia)
Involves lack of arterial blood flow (arterial occlusion, venous occlusion); Pump failure
*Lack of oxygen due to a clot or blockage; shunts
Hypoxemia (hypoxic hypoxia)
Low oxygen in the blood
- Failure to ventilate or perfuse the lungs
- Failure of lungs to oxygenate blood
- Inadequate RBC mass
- Inability of hemoglobin to carry or release oxygen
Histotoxic hypoxia
the inability of cells to take up or use oxygen from the bloodstream, despite physiologically normal delivery of oxygen to such cells and tissues.
Examples: cyanide, carbon monoxide, and dinitrophenol
Different cells tolerate hypoxia differently. Which lasts longer between the brain and a leg?
A leg can last longer than the brain
Lack of ___ stops oxidative phosphorylation/ETC, which results in the ____ failing.
O2, which results in the Na+/K+ ATPase failing
What is an early sign of cell injury?
- Na+ & H2O enter cell, causing acute cellular edema
- cellular leakage
- example: if liver enzymes are high after/during a vigorous workout, it can damage skeletal muscle cells
Anaerobic metabolism leads to _______ & ______, which denatures proteins.
lactic acid accumulation and pH drop
If the Ca+2 ATPase fails, then what occurs?
- Ca+2 enters the cytoplasm from ECF and ER
- transition from reversible to irreversible injury
Ca+2 entry is key step leading to ____ ____.
cell death
What transpires after Ca+2 entry?
-Activates enzymes that damage membranes, proteins, and DNA.
-Opens pores in outer mitochondrial membrane (shuts down oxidative phosphorylation,
mitochondria release free radicals, and mitochondria release caspases that induce apoptosis)
-Rigor mortis due to Ca+2 -induced sarcomere shortening of muscle
____ is the key link between depolarization and muscle contraction.
Calcium
Free radical injury
- Common mechanism of cell injury (radiation, poisons, normal metabolism)
- Unpaired electron in outer (valence) orbital, typically O2 derivatives. Examples: Superoxide (O2-), hydroxyl (.OH), hydrogen peroxide (H2O2)
- Having an unpaired electron can damage other molecules that try to pair to he lonely electron
- Damage cell membranes, cause DNA mutations, aging?
- Limited ability to dispose of free radicals (Superoxide dismutase & catalase; antioxidants-vitamin E, vitamin C)
Examples of chemical injury
-Depends on nature of poison (acids/alkalis destroy membranes, formaldehyde crosslinks proteins & DNA)
Other poisons:
- Cyanide-blocks ETC
- Mushrooms (toadstools)-destroy ribosomes
- Chemotherapy-damages DNA to disrupt cell replication (cancer cells)
- Strychnine-motor neuron synapses
- Carbon monoxide-replaces O2 on hemoglobin, blocks ETC
What cell accumulations and deposits indicate cellular injury
or systemic disease?
- Triglycerides (fatty change, steatosis)
- Glycogen
- Complex lipids or carbohydrates
- Pigments
- Calcium
