Cardiovasular Lecture (Exam 3)

Question 1

Nitric Oxide (NO)

Answer 1

cellular signaling molecule involved in many physiological processes, including dilation or arterioles
-1 of 3 endothelium-derived vasodilators blood flow regulators at rest and during exercise

Question 2

Cardiovascular Drift

Answer 2

an increase in heart rate during exercise to compensate for a decrease in stroke volume. This compensation helps maintain a constant cardia output
-decrease in SV and a parallel increase in HR

Question 3

Endothelium

Answer 3

innermost layer of the intima

Question 4

For cardiovascular drift, when SV decreases:

Answer 4

skin blood flow increases
plasma volume decreases (sweating)
venous return/preload

Question 5

Maximal Heart Rate (HRmax)

Answer 5

the highest heart rate value attainable during an all-out effort to the point of exhaustion

• 1 beat per year decreases
• estimated HRmax = 208 - (0.7 x age in years)

Question 6

Normal RHR

Answer 6

• the heart rate at rest, averaging 60 to 80 beats/min
• Trained RHR: as low as 30 to 40 beats/min
• Due to an increase in vagal tone for PSNS

Question 7

Steady-State HR

Answer 7

the optimal heart rate for meeting circulatory demands at a submaximal intensity

• point of plateau
• if intensity increases, so does steady-state HR
• adjustment to new intensity takes 2 to 3 minutes
• is the basis for simple exercise tests hat estimate aerobic fitness and HRmax

Question 8

Systolic blood pressure (SBP)

Answer 8

highest arterial blood pressure, resulting from ventricular systole

• top number : 110/*
• ~110 - 120 mmHg

Question 9

Ventricular Systole

Answer 9

contraction of the heart muscles

Question 10

SBP normal response to exercise

Answer 10

increase in SBP is proportional to exercise intensity

• 120 mmHg at rest
• > 200 mmHg in trained individuals
• 240-250 mmHg in highly trained individuals

Question 11

Diastolic blood Pressure (DBP)

Answer 11

lowest arterial pressure, resulting from ventricular diastole
-bottom number: */70
~70 - 80 mmHg

Question 12

Ventricular Diastole

Answer 12

resting phase of the heart

-heart refills with blood

Question 13

DBP normal response to exercise

Answer 13

slight decrease or slight increase at max exercise

Question 14

Sympathetic Nervous System relationship to the heart

Answer 14

-increases HR and force contraction because of stress by releasing of norepinephrine (neurotransmitter)
-carries impulses to SV, AV nodes to increase:
rate of depolarization of SA node
conduction speed
-Increases HR above intrinsic HR
determines HR during physical activity and emotional stress
max HR: 250 bpm

Question 15

Parasympathetic Nervous System relationship to the heart

Answer 15

-reaches heart through the vagus nerve (vagal tone)
-decrease HR and force of contraction by release acetylcholine
-can slow it as low as 20-30 bpm
-carries impulses to SV, AV nodes to:
cause hyperpolarization of cells, resulting in slower depolarization and decreased HR and contraction
-Decreases HR below intrinsic HR
intrinsic HR: 100 bpm
normal RHR: 60-100 bpm
elite endurance athletes: 35 bpm

Question 16

Stroke Volume

Answer 16

volume of blood pumped in 1 heartbeat
-most blood ejected during systole
-end-diastolic volume
-end-systolic volume
SV(mL/bpm) = EDV - ESV

Question 17

End Diastolic Volume (EDV)

Answer 17

volume of blood in ventricle before contraction

Question 18

End Systolic Volume (ESV)

Answer 18

volume of blood in ventricle after contraction

Question 19

Ejection Fraction

Answer 19

proportion of blood pumped out of the left ventricle each beat
Total Volume of Blood per min: EF (%) = SV / EDV

Question 20

Contractility

Answer 20

the strength and vigor of the heart’s contraction during systole

Question 21

Cardiac Output

Answer 21

the volume of blood pumped out by the heart per minute
Q• = HR x SV
-increases with increased intensity

Question 22

Normal Values for Cardiac Output

Answer 22

resting: Q ~5 L/min
untrained: Qmax ~20 L/min
trained: Qmax 40 L/min

Question 23

Resting a-vO2diff value

Answer 23

~6 mL O2 / 100 mL blood

Question 24

Max exercise a-vO2diff value

Answer 24

~16 to 17 mL O2/100 mL blood

Question 25

a-vO2diff (mL O2 / 100 mL blood)

Answer 25

represents the extent to which oxygen is extracted from the blood as it passes through the body
VO2 = Q• x (a-v- )O2 difference
VO2 = HR x SV x (a-v- )O2 difference

Question 26

Fick Equation

Answer 26

represents the relationship of the body’s oxygen consumption (VO2) to the arterial – venous oxygen difference (a-vO2diff) and cardiac output (Q)

Question 27

Sinoartrial (SA) node

Answer 27

Initiates contraction signal (pacemaker)

• contracts w/o neural stimulation with an intrinsic HR of ~ 100 bpm
• pacemaker cells on posterior wall of right atrium (RA)
• stimulates RA, LA contraction

Question 28

Atrioventricular (AV) node

Answer 28

Built in delay of .13 seconds allowing atria to contract before ventricles

• located in right arterial wall near center of heart
• contracts w/o neural stimulation with an intrinsic HR of ~40 bpm

Question 29

AV bundle (bundle of his)

Answer 29

relays signals to right and left ventricles

• travels along interventricular septum
• sends signals towards apex of heart

Question 30

Pirkinje Fibers

Answer 30

sends signals throughout right and left ventricles with 6x faster transmission
stimulate LV, RV contraction

Question 31

Estimating HRmax equation

Answer 31

208 - (0.7 x age in years)