NRS 313 Study Guide - Midterm Guide: Cortisol, Lipid Bilayer, Crush Injury
27 May 2018
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W1:Cellular Function and Dysfunction
• Crush injury increases serum potassium levels.
o SERUM = a component of the intravascular compartment.
o POTASSIUM = major intracellular cation.
o HYPERKALEMIA = excess potassium in the vascular space.
o Calcium stabilizes the cell membrane permeability = preventing calcium and
sodium from entering healthy cells
o Avoid LR because it has potassium chloride in it. LR = LACTATED RINGERS
a type of IV fluid.
• Cell Membranes
o Control physiological function by controlling transport of substances in and out of
cell
o Types of membranes:
▪ Organelle membranes: higher percentage of proteins due to enzymatic
activity going on within the organelle
▪ Plasma membrane: lipid bilayer: integral and peripheral proteins,
phospholipids, cholesterol, glycoproteins.
• What can harm the plasma membrane itself?
o Hypoxia
o Impaired Calcium Homeostasis
o Free Radicals AKA Reactive Oxygen Species (ROS)
• Hypovolemia: Low blood volume
o 4 liters are circulating in your bloodstream.
o When someone loses 900ml, they are at risk for ischemia
• Stroke Volume: blood amount pumping from heart. 60-80ml
• Ischemia
o Decreased blood flow. Caused by crush injury, tourniquet application, low blood
volume. In other people, ischemia may be caused by anything that impairs blood
flow including atherosclerosis and arteriosclerosis or even thrombus.
o Hemorrhage
o Cardiac dysfunction
• Hypoxemia
o Decreased O2. Caused by suffocation, drowning, anemia, any condition that
impairs ventilation and exchange of O2 and Co2
o Tachypnea: fast breathing
o Anemia: decreased size or hemoglobin on cell
o Pneumothroxic= air is coapsing lung. COPD
• Hyperkalemia
o Decreases Stroke Volume
• Hypoxia
o insufficient oxygen to cells
▪ cell death
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o Most common cause of cellular injury
▪ Local hypoxia caused by “ischemia” - decreased blood flow to certain
cells/tissues/organs
▪ Systemic hypoxia caused by “hypoxemia”: decreased oxygen carrying
capacity of the blood
o No ATP = failure of Na+/K+ pump causing changes in membrane permeability,
leads to hydropic swelling and cell injury.
o NOTE: end products of cellular hypoxia are lactic acid, hydropic swelling, and
chromatin clumping.
▪ Tightly coiled DNA becomes dysfunctional and cell dies
▪ Lysosomes in cell:pH is 5.0
• Sodium/ Potassium Pump
o ATP is required to effectively activate the sodium/potassium pump. ATP is
required for Active Transport!
o ATP: made by mitochondria – O2 and glucose are needed.
o Active transport
o If it fails there is a higher polarity. Serum in extra cellular will increase=
Hyperkalemia
• Calcium Dysregulation
o Calcium lines protein membrane channels, stabilizing ion flow across cell
membranes.
o Signs of Hypocalcemia
▪ Convulsions
▪ Arrhythmias
▪ Tetany
▪ Spasms and stridor
• Difficult breathing pattern that effects the diaphragm
•
▪ Numbness in the fingers
• Injurious Agent
o 02-, H2O2, OH+
▪ Free Radical Formation
• Oxidation of cell structures and nuclear and mitochondrial DNA
o Hypxia/Ischemia
▪ Mitochondrial depletion -> ATP depletion
• Decrease in Na+/K+ ATPase pimp ->Influx of NA+ and H2O
o Accumulation of intracellular fluids, dilation of
endoplasmic reticulum, increased membrane permeability,
decreased mitochondrial function
• Increase in Anaerobic metabolism
o Decrease in glycogen stores and intracellular pH
▪ ACIDOSIS
• Other effects
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Caused by crush injury, tourniquet application, low blood volume. In other people, ischemia may be caused by anything that impairs blood flow including atherosclerosis and arteriosclerosis or even thrombus: hemorrhage, cardiac dysfunction, hypoxemia, decreased o2. Caused by suffocation, drowning, anemia, any condition that impairs ventilation and exchange of o2 and co2: tachypnea: fast breathing, anemia: decreased size or hemoglobin on cell, pneumothroxic= air is coapsing lung. Atp is required for active transport: atp: made by mitochondria o2 and glucose are needed, active transport, if it fails there is a higher polarity. Increase in anaerobic metabolism: decrease in glycogen stores and intracellular ph, acidosis, other effects, detachment of ribosomes decreased protein synthesis and, increase in intracellular ca++ lipid deposition. Initiation of inflammatory response: wound may get larger before it starts healing, eschar: necrotic dead tissue. Wash it away with medical grade leeches: purulent: puss smells bad. Sign of phagocytosis: ischemic brain injury, 1.
