Cardio 3

Question 1

Pulmonary Circulation Pressures (4)

Answer 1

1= ventricular filling 
2= isovolumetric ejection
3= ventricular ejection
4= isovolumentric ventricular relaxation

Question 2

Cardiac Output (CO)

Answer 2

The amount of blood pumped out of each ventricle in 1 minute.

Question 3

Cardiac Output (CO) equation

Answer 3

CO= HR x SV

Question 4

Normal resting CO

Answer 4

= 70 beats/min x 70 ml/beat

≈ 5 L/min

Question 5

During intense exercise CO can increase to

Answer 5

30 – 35 L/min

Question 6

CO regulated to match demands of tissues
o Increased by: (3)
o Decreased by: (2)

Answer 6

Physical activity, Metabolic status, Drugs

Blood loss, Heart Disease

Question 7

Control CO by changing (2)

Answer 7

HR and SV

Question 8

Factors that increase HR are called

Answer 8

+ chronotropic agents

Question 9

Factors that decrease HR are called

Answer 9

• chronotropic agents

Question 10

HR is mainly controlled by input from the nervous

system: (2)

Answer 10

 SNS increases heart rate (AR and Contractile
Cells)
 PSNS decreases heart rate (AR Cells only)

Question 11

Major Factors Influencing Heart Rate (3)

Answer 11

increase activity of sympathetic nerves to heart
decrease activity of parasympathetic nerves to heart
increase plasma epinephrine

Question 12

stroke volume equation

Answer 12

SV= EDV-ESV

Question 13

SV is altered by: (3)

Answer 13

o Δ preload (EDV)
o Δ afterload (Blood Pressure)
o Δ contractility (Force of Contraction)

Question 14

At rest, cardiac muscle sits at a length that is

Answer 14

less than

optimum

Question 15

Starling’s Law of the Heart (4)

Answer 15

↑ EDV
↑ stretch of myocardium moves resting cardiocyte length toward optimum
↑ SV

Question 16

VR =

Answer 16

Rate at which blood is
returned to the heart from
veins

Question 17

Veins

Answer 17

Flaccid vessels and can hold
up to 60% of total blood
volume (Peripheral Venous
Pool)

Question 18

Veins:
ΔP to return blood to the heart
from capillaries

Answer 18

very small

Question 19

Veins:

One-way Valves to facilitate

Answer 19

blood movement back to heart

Question 20

increase VR by: (3)

Answer 20

1. increase Skeletal muscle pump
2. increase Thoracic Pump
3. increase Venoconstriction via Sympathetic NS
   (1-3 Dependent on one-way valves in veins)

Question 21

decrease VR by: (2)

Answer 21

1. valsalva maneurver

2. *Extremely high HR (tachycardia) – decrease CO by decrease EDV

Question 22

SV α 1/–

Answer 22

HR

Question 23

CO α

Answer 23

HR (at normal HR)

Question 24

HR has greater affect on CO

than SV unless extremely

Answer 24

tachycardic

increase in HR results in decrease CO (decrease SV, decrease EDV)

Question 25

Afterload is the

Answer 25

pressure 
that the ventricles must 
overcome to force open the 
aortic and pulmonary 
valves.

Question 26

Anything that increases
systemic or pulmonary
arterial pressure can

Answer 26

increase afterload

hypertension

Question 27

↑afterload causes

Answer 27

↓SV

Question 28

after load is a NOT a major factor in

Answer 28

healthy subjects

Question 29

Contractility

Answer 29

Ability of heart to contract at any given resting

fiber length

Question 30

The ventricles are never completely empty of
blood (ejection fraction), so a more forceful
contraction will

Answer 30

expel more blood with each

pump.

Question 31

Contractility is varied by

Answer 31

controlling the amount of Ca++ that
enters contractile cell via L type voltage gated
Ca++ channels (Graded Contractions)

Question 32

+ inotropic agents

Answer 32

increase contractility and increase ejection
fraction
(ex. Sympathetic Stimulation, Epinephrine)

Question 33

• inotropic agents

Answer 33

decrease contractility decrease ejection
fraction
(ex. β1 Blockers, Ca++ channel blockers)

Question 34

At rest,
amount of
ACh ? NE

Answer 34

>

Question 35

Cardiac Muscle vs. Skeletal Muscle

Similarities (2)

Answer 35

 Sarcomeres = functional unit

 Length/Tension

Question 36

Cardiac Muscle vs. Skeletal Muscle

Differences: (4)

Answer 36

 Stimulus (Intrinsic: Extrinsic)
 Ca++ release from SR (10% ECF/90% SR : 
100% SR)
 Summation/tetanus (No: Yes)
 Muscle Twitch (Graded: All or None)