Lab quiz #5 Flashcards
blood pressure =
cardiac output (Q) x total peripheral resistance (TPR)
flow x resistance =
pressure
Q =
SV x HR
Increased Q or TPR =
increased blood pressure
decreased Q or TPR =
decreased blood pressure
two factors influencing blood pressure:
- capacitance
- compliance
resistance to flow or TPR
- atherosclerosis
- arteriosclerosis
capacitance
distensibility of the vessels (expand to accept blood)
- decreases with age
compliance
Two phases of cardiac cycle:
- systole
- diastole
work phase of cardiac cycle
systole (SBP)
rest/fill phase of cardiac cycle
diastole (DBP)
Blood pressure is written as _ over _
- 120 mm Hg/80 mm Hg
SBP/DBP
- primary, clinical: determine risk of CVD or stroke
- establish a baseline for health interventions
- establish a baseline to compare the effect of exercise on BP
- looking at different types, intensities, and durations
reasons to measure blood pressure
Two methods of measuring blood pressure:
- invasive
- non-invasive
_ method for measuring BP:
- more accurate
- expensive
- elaborate
- can be traumatic
invasive
invasive method for measuring BP:
- _ : catheter inserted into an artery; pressure transducer attached to measure BP
flow transducer
_ method for measuring BP:
- ultrasound doppler/automated
- cuff manometry – sphygmomanometer (“cuff method”)
non-invasive
use of a stethoscope to auscultate _ (“auscultatory method”)
- 0.85 correlation with flow transducer
korotkoff sounds
vibrations from vascular walls
korotkoff sounds
korotkoff sounds:
- no blood flow =
no vibrations/sounds
korotkoff sounds:
- with pressure cuff/tourniquet =
vibrations/sounds
korotkoff sounds:
- unobstructed =
no vibrations/sounds
phase 1: first recognition or “faint, clear” sounds or “sharp thuds” that increase in intensity
SBP
phase 5: sounds are no longer audible or “disappear”
DBP
- body arm positions
- no practical difference in BP when supine vs sitting
- statistically slightly higher SBP (6-7 mm Hg) and DBP (1 mm Hg) when supine
- BP is higher when arm is below the heart vs above
factor affecting blood pressure measurements
- cuffs
- too small – overestimated BP
- too large – underestimate BP
factor affecting blood pressure measurements
Effects of aerobic exercise on BP:
- _ increases linearly with increasing exercise intensities
- Q increases significantly during graded exercise
- increases in flow/pressure are “absorbed” by elasticity of vessels dampening the change in blood flow (TPR decrease slightly)
- If TPR did not decrease, pressures would be extremely high – busrting
systole blood pressure
Effects of aerobic exercise on BP:
- _: slightly increases, slightly decreases, or remains unchanged (~10 mm Hg)
diastole blood pressure
Effects of aerobic exercise on BP:
- within 5-8 minutes of exercise cessation, BP usually returns _
- Return depends upon:
- type
- intensity
- duration
to pre-exercise level
Effects of aerobic exercise on BP:
- SBP may drop slightly lower than pre-exercise SBP and remain _ following exercise
lower for several hours
Effects of aerobic exercise on BP:
- _: can lead to syncope
- passive recovery – cessation of muscle pump – venous pooling – reduced venous return and vasoconstriction
- loss of plasma volume (sweating)
recovery hypotension
age, muscle mass, fitness level, smoking
factors affecting BP during exercise
type of exercise and exercise protocol
- Resistance training produces > BP than rhythmic aerobic exercise
- some aerobic exercises (cycling) produce greater BP than other aerobic exercise (treadmill)
factors affecting BP during exercise
pulse pressure =
SBP-DBP
difference between SBP and DBP
- reflects vascular compliance in large arteries
- high PP = increased risk of MI
- 40 - normal
- > 60 - may be at risk
pulse pressure (PP)
average force against arterial walls during the cardiac cycle
- based on actual arterial pressure that would be sustained if blood flow was constant and not pulsating
- slightly lower than average value of SBP and DBP
mean arterial pressure (MAP)
Q =
MAP/TPR
MAP =
DBP + (0.333 [SBP-DBP])
- reflects how hard the heart is working depending on rate (HR) and resistance (SBP)
- believed to be related to physical fitness (healthy persons)
- lower at rest
- higher maximal
rate pressure product (RPP)
RPP =
HR (bpm) x SBP (mm Hg) / 100
rate pressure product:
- considering both HR and BP offers a better estimate of _ than HR alone
myocardial O2 consumption
- aka: postural hypotension
- move from supine to standing
- venous pooling occurs immediately (gravity); Q decreases
- baroreceptors sense a decrease in BP and sends a message to the medulla oblongata to increase BP – venous return
- vasoconstriction
- increase in HR and SV
orthostatic intolerance (orthostatic hypotension)
- high risk for future CV morbidity and mortality
- primary: cause of HT is not known (~90% of HT in adults)
- secondary: caused by known endocrine or structural disorders
hypertension (high BP)
- more likely to accelerate atherosclerosis
- may cause occlusions (blood clots) and ruptures ~20 years prior to normotensives
- BP can be affected by non-pathological factors; should not classify persons from a single reading
hypertension
Systolic = less than 120
AND
Diastolic = less than 80
Blood pressure - normal
Systolic = 120-129
AND
Diastolic = less than 80
Blood pressure - elevated
Systolic = 130-139
OR
Diastolic = 80-89
Blood pressure - high blood pressure (hypertension) stage 1
Systolic = 140 or higher
OR
Diastolic = 90 or higher
Blood pressure - high blood pressure (hypertension) stage 2
Systolic = higher than 180
AND/OR
Diastolic = higher than 120
Blood pressure - hypertensive crisis (consult doctor immediately)
