Exercise Phys Exam 3

heart rate

each rotation of systole and diastole is one cardiac cycle or one beat of the heart

systole

is the contraction phase

diastole

is the relaxation pr filling phase

stroke volume

the blood forces out of the heart during each beat

end diastolic volume

blood in the left ventricle at the end

end systolic volume

blood in the left ventricle of at the end

ejection fraction

the percentage of edv that is ejected

factors influencing stroke volume

preload, contractility, and afterload

preload

volume of blood returning to the heart, increase in edv

venous return

influenced by venoconstriction (reduced volume capacity of the veins and muscle pumps)

contractility

the force of the heart contraction, decrease in esv

End-systolic volume (esv)

the blood remaining in the ventricle after contraction

afterload

the resistance presented to the ventricle, increase in esv

cardiac output (q)

the quantity of the blood pumped per minute

normal resting heart rate

60-90 bpm

normal resting stroke volume

50-90 ml per min

vasodialtion

the arterioles allow us to redistribute blood flow

blood flow distribution

at rest, only 1 out of 30-40 capillaries are open in he skeletal muscle

parasympathetic and sympathetic

these pathways must receive info in order to do their jobs to help control q

baroreceptors

pressure sensors in the aorta and carotid bodies

increase in pressure, tells the body to decrease pressure and increase parasympathetic stimulation

stretch receptors

in the heart, sense an increase in venous return

increase in return will occur during exercise, signaling sympathetic activation and parasympathetic deactivation

increase heart rate, increase force of contraction

both changes q

chemoreceptors monitor

PO2, CO2, and pH (H+)

what do muscle/joint receptors do

sense muscle specific contractions and metabolic products

what do muscular contractions do

signal for increases blood via sympathetic activation

what do temp changes signal

parasympathetic and sympathetic

cardiovascular response

the changes to the cardiovascular system from rest

you are on the treadmill, increasing from low to maximal

increase in O2 consumption

increase in CO2 production (via krebs)

increase in H+/lactate (change in pH and more CO2)

increase joint movement

venous muscle pump

SBP during exercise

increases because cardiac output goes up

DBP during exercise

stays about the same, maybe a slight decrease

cardiovascular adaptions

higher exercise intensities SV is maxed out

this exercise stress to increase Q, creates a volume overload

Increase ventricular diameter

Increase ventricular mass

coronary blood flow

the heart is working harder during higher intensity exercise

increased myocardial capillarization

increase the ability for the coronary arteries to dilate

endurance training increases stroke volume by

increase cardiac dimensions

increase blood volume, increase venous return

increase preload, increase sv

increase contract, increase sv

blood pressure adaptations

minimal in healthy individuals

since q has increased, at maximal exercise, one may see slight elevations in systolic pressure

endurance training helps reduce BP if hypertensive

detraining

vo2 max, sv, q, a-vo2 diff all decrease

largest changes were within 12 days of stopping

thermoregulation

balance/regulation of body temp

balancing of core temp (96.8-99.5)

failing to maintain core temp

heat cramps/exhaustion/stroke (105)

frostbite, hypothermia (95)

heat loss + gain= thermal balance

body gains heat from environmental sources

environmental sources

radiant, conductive, convective

radiant

infrared radiation directly acts on the body

conductive

transfer of heat through direct contact

convective

air around the body

metabolic

bmr, thermogenic effect of food, physical activity

body gives away heat

radiant, conductive, convection, evaporation

evaporation

conversion of liquid into vapor. warmed liquid (sweat) turning into vapor and removing heat from the body

relative humidity

impacts evaporative

air movement/wind speed

impacts evaporative and convection

degree of direct sunlight

impacts radiant

clothing

can impact all forms

best places for measuring thermoregulation

gastrointestinal, rectal, esphageal

testing heat chambers

air temp, humidity, elevation

heat during exercise

metabolic rate may increase 15-20 times resting during exercise

increase in sweat rate

increase evaporative heat loss

vasodilation at the skin

increase radiant, conductive, and/or convective heat loss

vasodilation

Dilating the subcutaneous blood vessels allows a greater portion of the blood nearer to the skin

exercise in the heart and/or humidity creates a stressful scenario

heat gained from atp

heat loss is limited due to air temps or humidity

heat does what

creates competition for blood flow between skin and working muscle

because of sweating, reduction in plasma volume (less blood overall)

SV increase and HR increase (compensation)

but not enough to help q

improving heat tolerance via acclimatization

lower resting core temp

larger plasma volume

earlier swear onset (lower temp) and greater rate

results in smaller decrease in plasma volume during exercise