Translational Physiology Block 8 Flashcards
How can someone reverse obesity and diabetes?
Roux en Y bypass; pharmacotherapy, and lifestyle modifications (diet and exercise)
What gene is involved in muscle growth and remodeling? negative regulator of muscle mass?
Fn14; myostatin
Describe euglycemic-hyperinsulinemic clamp.
The amount of glucose needed to maintain euglycemia provides a measure of insulin-mediated glucose uptake, or insulin resistance.
T/F: healthy aging is associated with a decline in glucose tolerance and insulin sensitivity?
T
When does aging (senescence) begin?
puberty
Define homeostenosis.
Older persons have limited physiologic reserves with which to maintain the internal physiologic milieu
What is frailty?
is a pathologic syndrome that results in a constellation of signs and symptoms, and is characterized by high susceptibility, impending decline in physical function and high risk of death.
Describe heat stroke.
Excessive cutaneous vasodilation can lead to a fall in arterial pressure and therefore to a decrease in brain perfusion
High body temperature can cause fibrinolysis and consumption of clotting factors and thus disseminated intravascular coagulation
Heat-induced damage to the cell membranes of skeletal and myocardial muscle leads to rhabdomyolysis (in which disrupted muscle cells release their intracellular contents, including myoglobin, into the circulation) and myocardial necrosis.
Cell damage may also cause acute hepatic insufficiency and pancreatitis
Renal function, already compromised by low renal blood flow, may be further disrupted by the high plasma levels of myoglobin
Describe training regimens for diabetic patients.
Goal of exercise in treating diabetic patients is not to improve maximal oxygen uptake but rather to improve insulin sensitivity (GLUT4 translocation)
Requires a training regimen that limits muscle stress and TNF alpha
What is frailty?
is a pathologic syndrome that results in a constellation of signs and symptoms, and is characterized by high susceptibility, impending decline in physical function and high risk of death.
anorexia, sarcopenia, immobility, atherosclerosis, balance impairment, depression, cognitive impairment
“loss of functional reserve”
3/5 criteria: unintentional weight loss, muscle weakness, slow walking speed, exhaustion, and low physical activity
etiology: other disease and/or aging
Describe acclimatization to altitude.
adaptive processes of acclimatization reduce, as much as possible, the size of each step in the oxygen cascade (the process of declining oxygen tension from atmosphere to mitochondria; throughout the cascade oxygen is either extracted or lost) resulting in a final partial pressure (mixed-venous blood) at high altitude that is not greatly different from the sea level value (HYPERVENTILATION)
After 20 days, at altitude, sea level values of alveolar carbon dioxide partial pressure produce a massive increase in ventilation (hypercapnic ventilatory response)
What happens in conditions of mild hypoxia?
Exposure to even mild hypoxia stimulates the peripheral chemoreceptors (increase in carotid sinus nerve)
No change in minute ventilation up to an altitude of around 3000 meters
hypoxia increases cerebral blood flow and decreases cerebral extracellular partial pressure of carbon dioxide, which increases the pH around the central medullary chemoreceptors causing them to exert an equal and opposite inhibitory effect opposing any increase in ventilation
What is the result of respiratory alkalosis?
Respiratory alkalosis stimulate production of 2,3-diphosphoglycerate shifting the oxygen-hemoglobin dissociation curve to the right (affinity for hemoglobin for oxygen is decreased)
How is diffusion capacity change at high altitude?
At extreme altitude, even at rest, marked diffusion limitation occurs because of the feeble oxygen partial pressure gradient which does not permit equilibration of oxygen between the alveoli and capillary in the time that it takes for a red cell to traverse the alveolar capillary (also occurs with exercise at altitude)
T/F: Exposure to hypobaric hypoxia produces pulmonary vasoconstriction resulting in pulmonary hypertension
T
