exercise Flashcards
outline the pathway of exercise to dilation of skeletal muscle arterioles via epinephrine
- exercise
- increase sympathetic outflow to adrenal medulla
- release of epinephrine
- acts on B-2 receptors
- dilation of skeletal muscle arterioles
what is central command and what initiates it
central command is a series of responses by the motor cortex initiated by the anticipation of exercise
what processess does central command initiate
- sympathetic outflow to the heart and BV
- decreased PNS outflow to the heart
- increased muscle sympathetic nerve activity
- allows for graded increases in ventilation
stimulation of exercise pressor reflex afferent fibers has what affect?
increases sympathetic nerve acitivity to:
- induces elevation in HR
- elevation of BP
stimulation of exercise pressure reflex receptors generates somatosensory signals which are transmitted to CNS via which afferent fibers
- thinly myelinated group III
- unmyelinated group IV
increase in CO is met by increases in both HR and SV up to what capacity?
- 50 capacity (VO2max)
- at near maximal workloads, HR is still on the rise, where as SV levels off and begins to drop
what is the equation to approximate maximal HR
HR max = 220 - age (years)
why does stroke volume increase with exercise?
- increased venous return
- enhanced LV filling
- heightened contracitility by sympathetic stimulation
what affect does exercise have on EDV and ESV
- increases end-diastolic volume
- decreases end systolic volume
what is VO2 max
maximal capacity for oxygen consumption during exercise
what is the equation for VO2 max
VO2max = HR x SV x arterial venous difference
oxygen uptake is proportional to work performed, up to what?
maximal work capacity (VO2 max)
what is dynamic exercise
repeated voluntary muscle movements in which there is alternate contraction and relaxation of the muscle
- aerobics, swimming, cross country skiing
what is static exercise
refers to state in which the muscle is kept in continued contraction
- bench press, lifting
what happens to systolic BP, diastolic BP, and pulse pressure in dynamic exercise
- systolic pressure increases
- diastolic pressure decreases
- pulse pressure increases