Exercise bullSHIT Flashcards
ECG changes with exercise
exercise activates beta-1 receptors in the SA node, increasing the frequency of impulse generation and in the AV node, increasing the rate of impulse conduction from the atria to the ventricles; on ECG there is increasing frequency of P waves and shortening of the PR interval and RR interval (sinus tachycardia)
Exercise-associated collapse (EAC)
typically occurs after intense exercise in well-conditioned athletes; characterized by loss of postural tone or syncope immediately following cessation of exercise and occurs due to impaired venous return to the heart
Exercise-associated collapse (EAC) overview
ATP production during exercise
intense exercise creates a high demand for ATP and the primary method of ATP production varies with the duration of exercise; the phosphocreatine shuttle is the primary source of ATP at the beginning of exercise, followed sequentially by anaerobic glycolysis and then oxidative phosphorylation
ATP production during exercise
the phosphocreatine shuttle is the primary source of ATP at the beginning of exercise, followed sequentially by anaerobic glycolysis and then oxidative phosphorylation
limitations of hemoglobin A1c interpretations
Hemoglobin A1c is produced by non enzymatic glycosylation of the hemoglobin molecule; provides an estimate of chronic glycemic control over the span of 3 months (circulating RBCs 120 days); rapid RBC turnover (hemolytic anemia) can give misleading low readings
Acromegaly
caused by an excessive production of GH, usually due to a pituitary somatotropin adenoma; manifests as bony hypertrophy (frontal bossing, enlarged jaw, hands and feet) and osteoarthritis; LV hypertrophy is often common and may progress to HF
Congenital hypothyroidism tx
treated w prompt initiation of levothyroxine in early infancy, late or inadequate tx is associated w cognitive and neurological dysfunction
Postpartum thyroiditis histology
occurs within 12 months of pregnancy and is characterized by autoimmune destruction of thyroid follicles; beings w a hyperthyroid phase due to release of preformed antibodies and then followed by a transient hypothyroid phase due to depletion of thyroid hormone; histology shows lymphocytic infiltration, sometimes w formation of germinal centers
BPH tx
5-alpha reductase inhibitors (ex: finasteride) reduce conversion of testosterone to DHT, in men w BPH reduction in prostate volume alleviates obstruction of urinary flow
physiologic age-related cardiovascular changes
aortic compliance progressively decreases w age, especially those over 65 yrs; this leads to an increase in pulse pressure, a slight decrease in diastolic pressure and the characteristic isolated systolic HTN commonly seen in the elderly population
