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49 Cards in this Set
- Front
- Back
What provides the most fuel in metabolic reactions?
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- breaking P-bonds (phosphate)
ex. ATP --> ADP + P + energy ADP --> AMP + P + energy |
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What is ATP?
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ADP + P + e
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What is ADP?
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AMP + P + e
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Where is the energy stored in ATP?
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P-bonds
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How is energy released from ATP?
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ATPase is an enzyme that speeds the reaction of splitting ATP. When ATP splits, the phosphate energy is released
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How does the sodium pump work?
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ATPase speeds the reaction to split ATP, phosphate is released and provides energy to pump 3 Na+ OUT & 2 K+ IN (then ATP needs to be replenished)
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How is ATP synthesized?
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glucose --> pyruvate (by glycolysis) and begins anaerobic or aerobic metabolism
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What is anaerobic metabolism?
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- NO O2 present
- pyruvate becomes lactic acid which stimulates pain receptors - takes place in CYTOSOL (gel-like substance containing organelles) - yields: 2 ATP |
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What is aerobic metabolism?
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- O2 is present
- pyruvate --> Acetyl CoA --> enters Kreb's cycle --> high energy electrons enter electron transfer system - occurs in MITOCHONDRIA - yields: 30-38 ATP |
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What are some other sources of energy?
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- CHO - breakdown into glucose molecules
- Protein - breaks down into amino acids (amino acid group [NH3] is converted to urea and excreted in urine. Remaining organic acid enters Kreb's Cycle) - Glycerol in fat enters glycolysis - Fatty acid in fat converted to acetyl coA --> enter Kreb's Cycle |
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What are the most important requirements for energy production (ATP)?
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- Glucose
- O2 |
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What are 3 factors that can significantly reduce the production of energy (ATP)?
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1. lack of glucose
2. lack of O2 3. lack of circulating volume - O2 is carried in blood, attached to Hgb |
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What does the respiratory system do? (relating to O2)
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takes in O2
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What does the circulatory system do? (relating to O2)
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gets O2 to cells
- distributes O2 throughout the body and produces ATP within the cells which is then broken down for energy |
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What is hypoxia?
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insufficient O2
(lack of O2 to cells = less ATP) |
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What are the causes of hypoxia?
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many causes but they all relate to DEMAND > SUPPLY
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How can demand for O2 increase?
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- increased exercise
- increased metabolic rate (ex. increased HR, fever, hyperthyroidism) |
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How can supply for O2 decrease?
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1. decreased availability of O2 (decreased atmosphere O2 or pressure ex. altitude - higher = less O2; decreased ventilation (gas exchange in lungs ex. lung disease; decreased O2 carrying capacity of blood ex. anemia)
2. decreased delivery of O2 - ISCHEMIA - decreased blood supply ex. blocked blood vessels, closed vessels; decreased DISSOCIATION of O2 from Hgb; increased capillary-to-cell DIFFUSION distance ex. tissue edema; decreased CARDIAC OUTPUT ex. hypovolemia |
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What are some causes of decreased O2 availability?
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1. decreased ATMOSPHERE O2 or pressure ex. altitude - higher = less O2
2. decreased VENTILATION (gas exchange in lungs ex. lung disease 3. decreased O2 CARRYING capacity of blood ex. anemia) |
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What are some causes of decreased O2 delivery?
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1. ISCHEMIA - decreased blood supply ex. blocked blood vessels, closed vessels
2. decreased DISSOCIATION of O2 from Hgb 3. increased capillary-to-cell DIFFUSION distance ex. tissue edema 4. decreased CARDIAC OUTPUT ex. hypovolemia |
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How does hypoxia affect cells?
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insufficient O2 --> switch to anaerobic metabolism --> decreased ATP production and increased lactic acid --> both harm cell in slightly different ways (continue this by creating 2 arms on flow diagrams)
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How does lack of ATP affect cells?
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no ATP means no energy for sodium pump (therefore it will not function) --> Na+ is retained by cell --> water moves in with the Na+ --> cells become swollen --> cell can rupture
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What happens when cells swell?
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cell swells --> rER (rough endoplasmic reticulum) dilates --> ribosomes come off --> disrupts protein synthesis --> lack of protein for cell maintenance or function
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How does lactic acid affect cells?
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- lactic acid means there is a high [H+] and low pH --> change in pH --> protein shape is affected --> enzymes don't work (functional) & cell falls apart (structural)
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What are the effects of decreased pH?
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- changes protein shapes/ability to function
- causes LYSOSOMES to swell and release their contents that include lysozymes (enzymes that digest the cell ex. hydrolases) --> cellular digestion occurs by auto-digestion |
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What are lysozymes?
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enzymes that digest the cell
ex. hydrolases |
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What are the consequences of hypoxia?
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- cell death = infarction
- time of infarction depends on the severity of the lack of O2 (approximately 20 mins before there is IRREVERSIBLE injury) |
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What does infarction mean?
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cell death
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What does ischemic mean?
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decreased blood supply (ex. blocked blood vessels or closed vessels
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What is reversible injury?
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- recovery is possible
- function and/or structure can be restored |
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What is irreversible injury?
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- recovery is not possible
- cell death (infarction) will occur |
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At which point with hypoxia injury does damage become irreversible?
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- it depends on the cell and the person
(approx. 20 mins) |
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What are some effects of hypoxia at organism level?
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1. cell death - loss of tissue function if enough cells die
2. pGs (prostaglandins) synthesized from damaged CM - stimulates pain receptors and stimulates inflammation 3. lactic acid from anaerobic metabolism - stimulates pain receptors and causes metabolic acidosis if widespread |
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What are some effects of loss of ATP?
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- fatigue - lack of ATP production - decreased energy
- weakness - lack of ATP production - decreased energy - dizziness - decreased ATP production --> altered Na+ pump --> alters depolarization causing dizziness - numbness/tingling of peripheral nerves (PARASTHESIA) - decreased ATP production --> altered Na+ pump --> alters depolarization causing numbness/tingling - HPA activation!! |
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What is parasthesia?
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numbness/tingling of peripheral nerves
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What causes dizziness, weakness, numbness & tingling?
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decreased ATP production --> altered Na+ pump --> alters depolarization --> dizziness, numbness/tingling
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What are the cardiovascular effects associated with HPA axis? (also include how this relates to O2)
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CATACHOLAMINES cause:
- VSM (vascular smooth muscle) vasoconstriction --> blood O2 is shunted to core --> pale/cool periphery --> this will affect peripheral hypoxia - SA node stimulated by epinephrine to deliver O2 --> increases firing rate --> increased HR |
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What are the respiratory effects associated with HPA axis? (also include how this relates to O2)
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CATACHOLAMINES:
- BSM (bronchial smooth muscle): bronchodilation --> increases O2 - respiratory center stimulated --> increases respiratory rate & effort --> increases O2 |
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Do all the S&S of HPA help correct hypoxia?
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No. Only the cardiovascular and respiratory system are helping to address the problem. (other S&S of HPA are still present though ex. sweating)
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How can hypoxia be treated?
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- reverse the cause of hypoxia/ischemia
- give supplemental O2 (guided by O2 saturation level [>95%] and also guided by pO2 |
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Where do free radicals come from?
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- free radicals are contained in lysosomes
- also byproduct of metabolism |
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What are free radicals?
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- highly charged molecule
- very unstable molecule - it wants to bind with everything - initiates chain reactions |
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What are some examples of free radicals?
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superoxide, peroxide, hydroxyl
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What makes a cell more susceptible to free radicals?
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hypoxia can disrupt normal cell processes, making the cell more vulnerable to free radicals
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What are free radicals useful for?
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for WBCs to destroy targets
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What is the MOA of free radical damage?
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1. damages cell membranes by attacking their DOUBLE BONDS (peroxidation) --> cell membrane gets leaky (ex. mitochondrial membrane - more Ca+ enters and disrupts function)
2. Damages proteins - interferes with cross-linking of amino acids 3. Creates lesions in DNA |
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Explain reperfusion injury.
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- cells are damaged during ischemia (decreased blood flow) and this causes the cells to be more vulnerable to free radicals
- if reperfusion occurs, more O2 is produced but free radicals are also produced as a result of the changes - the cells cannot handle the free radicals and this causes cell membrane damage |
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What are some examples of antioxidants?
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vitamin C, vitamin E
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What are antioxidants?
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they neutralize free radicals
- can help to prevent reperfusion injury |