Exercise Physiology Exam 1 (topic 1 and 2)

physiology definition

the study of the functions of cells, tissues, organs, and systems; the study of how the body works

ACSM exercise definition

physical activity consisting of planned, stuctured, and repetitive bodily movements done to improve or maintain one or more components of physical fitness

ACSM physical activity definition

any bodily movement produced by the contraction of skeletal muscle that results in a substantial increase in caloric requirements over resting energy expenditure; doing something with body to burn energy

stress definition

a disturbance in homeostasis (internal environment)

what are examples of a stressor

exercise, low stress would be just sitting

stress timeline

stressor exposure → homeostasis disruption → stress response

what happens when you are stressed

the body’s functions are altered

stress response predictibility

if something is too high, change function to lower; if something is too low, change function to raise

what changes to exert homeostatic control (prevent change in internal environment)

physiological functions

low challenge stressor

most critical aspects of internal environment are not changed (minimal stress, little stimulus for adaptation)

high challenge stressor

most critical aspects of internal environment are changed (greater disruption, stronger stimulus for adaptation)

examples of altered physiological functions and internal environments

heart rate, sweating, ventilation, glycogen breakdown

heart rate function

maintain adequate O2 availibility (pump more O2 to blood and muscles)

sweating function

maintain adequate core temperature (using more muscles produces more heat; ATP → ADP and heat)

ventilation function

maintian adequate gas levels in the blood (increase or decrease respiratory rate)

glycogen breakdown function

maintain adequate energy availible in muscle cells

is homeoestasis exact numbers

no, it is a stable but dynamic process; small fluctuation are normal (ex. resting heart rate and blood pressure)

Biking example: what is the stressor

biking

Biking example: what is the homeostasis perturbation (stress)

drop in PO2 and a rise in PCO2 levels

Biking example: what is the stress response

increase minute ventilation

Biking example: what is the result of the stress response

PO2 increases and PCO2 decreases to normal levels

two timepoints to evaluate stress effects

acute (short term - single exercise session) and chronic (long term - repeat exposure to similar acute stresses)

two considerations of acute

control over homeostatic disruption and signaling cascade for response and protein synthesis - the foundation of the chronic change

control over homestatic distruption examples

ATP low in cell → increase glycogen breakdown; blood gas exchanges → increase heart rate and ventilation; HR increases during exercise and delayed return to baseline

signaling cascade for response and protein synthesis - the foundation of the chronic change

the sensing of homeostatic disruption (initiate control response), secondary signaling (usually phosphorylation of kinase), transcription, translation, and protein synthesis (initiation of physical change)

signaling cascade for response and protein synthesis - the foundation of the chronic change example

begin curling 5lb weights and after time being able to curl 50lbs

why does one exercise session not show many results

mRNA increase does not always result in net protein synthesis; accumulation of protein synthesis will occur over time

what are two functional considerations of homeostasis maintinance

greater homeostatic control to given stress (less homeostatic perturbation to an absolute stressor, ex. HR = 145 → one month training → HR = 140), and accumulated net protein synthesis for physical change (hypertrophy, enzyme concentration, mitochondria numer and size, etc)

in what way does your body try to adapt

in a way that will reduce magnitude of homeostasis perturbation to same stressor - homeostatic control (specificity principle of exercise)

science is about evidence based prediction which means…

do specific physical activity, cause specific acute and chronic responses, promote specific adaptations

work equation

force (N) x displacement (m) - “what” you completed

power equation

work (J)/ time (s) - walking 10 ft in 5s versus 10s

energy (kcal) definition

potential to do work or cause a change

calorimetry definition

measurement of energy expenditure

2 types of calorimetry

direct (via body heat production), indirect (measuring gas exchange - relative vs absolute)

what can be viewed as the spark of homeostatic disruption for exercise

use of energy

what is external work related to

internal work (run faster, burn more kilocalories; oxygen consumption is related to our metablic rate)

what do the ACSM equations estimate

VO2 demand

steady state definition

constant environment and constant physiological function, but not necessarily at normal level

when can steady state not be reached

high intensities (ex. 75-80% of VO2 max)

body control systems

intracellular (protein breakdown and synthesis, energy production) and organ systems (pulmonary and circulatory system)

3 control system parts

sensor (setects changes), control center (assesses input and initiates response), effector (changes internal environment to normal)

biological control center definition

interconnected componenets that maintain a physical or chemical parameter at a near constant value

how do most control systems work

negative feed back (ex. blood glucose after eating)

gain definition

capability of the system - if you improve fitness you improve the gain (greater homeostatic control potential

gain equation

correction/error

what does a large gain mean

large magnitude of correction and small error while regulating

strain definition

how challenged your physiology in exerting control (strained at a high percentage of your capacity)

recovery adaptation process (improves homeostatic control)

recovery (gain what was lost), adaptation (change in structure and function), acclimation (improved homeostatic function)

what influences recovery adaptation

time, resource, and capacity based process

hormesis definition

exposure to low-moderate dose of potentially harmful stress that results in adaptation

general adaptation syndrome (GAS)

organism’s changing ability to adapt to stress over its lifetime

3 phases of GAS

alarm phase (diminished performance and temporarily reduced ability to overcome stress), resistance phase (positive adaptations), exhaustion phase (long term impairment and inability to overcome stress)

allostasis definition

stability through change

how does allostasis happen

achieve stability through acute and chronic changes

allostatic load definition

cumulative cost of long term, repeated adaptation (ex. physiological stressors, life stressors) - can chronically alter homeostasis

5 cell signaling pathways

intracrine, juxtacrine, autocrine, paracrine, endocrine

cell signaling pathways definitions

intracrine (chemical messenger inside triggers response), juxtacrine (chemical messenger passed between two connected cells), autocrine (chemical messenger acts on that same cell), paracrine (chemical messenger act on nearby cells), endocrine (hormones released into blood and acts on cells with specific receptor)

how do cellular signals regulate protein synthesis by turning on and off specific genes

1. exercise actives cell signaling pathways (sense and respond to homeostasis challenge)

2. transcriptional activator molecule

3. transcriptional activator binds to gene promotor region

4. DNA transcribed to mRNA

5. mRNA to ribosome

6. mRNA translated into protein