Exercise Phys exam 3 chp 23 & 24

3 purposes of the cardiorespiratory system

1. deliver oxygen and remove waste from body tissues

2. transport nutrients

3. aid in temperature regulation

The difference in oxygen demand between rest and exercise increase how many fold

15 to 25 fold

Two ways the 15-25 fold increase in oxygen demand during exercise met

1. Increase in cardiac output

2. Redistributing blood flow from inactive organs to active skeletal muscle through careful use of blood pressure

Resistance vessels

arterioles

squeeze them to limit flow or open to cause lots of flow

Capacitance vessels

Venules, veins, vena cava

where blood is stored that mobilizes during exercise (all veins) (why you pump pump do calf raises on planes to pump blood

Cardiac muscle- structural

No satellite cells- no can’t repair this

The endocardium is not wrapped around a single cell because we want them all to contract at the same time

Mono or binucleate

have sliding filaments but cardiac muscle is shorter

intercalated discs

just endocardium

Cardiac tissue- functional

Highly aerobic

involuntary

Cardiac cycle at rest

large amount of time in diastole

The cardiac cycle during exercise

During heavy exercise, diastole drops significantly more than systole- has high venous return

Mean arterial Pressure equation

MAP= DBP+ 0.33 x pulse pressure

the .33 represent the % time spent in systole out of time spent in both systole and diastole

P wave

Depolarization of the atria

QRS wave

depolarization of ventricles

(repolarization of the atria)

T wave

ventricular repolarization

Acute BP regulation

sympathetic nervous system

Long term BP regulation

kidneys through adjusting blood volume

Five factors that increase blood pressure

Blood volume increases

heart rate increases

stroke volume increases

blood viscosity increases

peripheral resistance increases

Q

cardiac output

Q equation

Q= heart rate x stroke volume

HR is monitored by what

The vagus nerve uses ach to hyperpolarizes- like a car brake

Parasympathetic tone keeps the heart beating constantly

cardiac stimulator nerve stimulates HR with NE

100 is base HR but modified by these effectors

Beta blockers function

Beta Blockers can slow down the sympathetic NS telling the heart to go fast- blocks epinephrine

Heart rate variability indicates good

sympathovagal balance

Predictors of low HR variability

Advancing age

Various diseases

Risks of low HR variability

Cardiovascular disease

• heart failure

• myocardial infarction

• hypertension

Stroke volume is regulated by what three factors

• end diastolic volume

• aortic pressure

• strength of contraction

Stroke volume is regulated by 1. end diastolic volume

EDV= the volume of blood in the ventricles

Frank starling law

Frank starling law

increases the strength of contraction with greater stretch of the ventricle (greater EDV) more actin myosin interactions

Filling from venous influenced by 3 things

venoconstriction

Muscle pump

respiratory pump- movement of dipahragm down changes pressure gradient and pushes blood back oto the heart

Stroke volume regulated by aortic pressure (MAP)

Stroke volume is inversely proportional to afterload

arteriole dilation limits afterload

(afterload is pressure from system pushing back on the heart)

Stroke volume regulated by strength of contraction

Circulating epi and ne and direction stimulation by cardiac accelerator nerves increase contractility by increasing ca+++

Chart