exam 3: cardiac cycle

Question 1

what contracts first because of an AV delay?

then ventricles contract at the same time as the artium

then the ventricles relax

Answer 1

atria

atrium relaxes

Question 2

cardiac cycle events for a single heartbeat:
1. between beats-
2. artrial systole-
3. atrial diastole/early ventricular systole-
4. late ventricular systole-
5. early ventricular diastole-
6. late ventricular diastole

Answer 2

1. between beats- passive filling
2. artrial systole- active filling
3. atrial diastole/early ventricular systole- isovolumetric contraction
4. late ventricular systole- ejection phase
5. early ventricular diastole- isovolumetric relaxation
6. late ventricular diastole

Question 3

between beats,
pressure atria _____pressure veins
pressure atria ___pressure ventricles (causes what to happen)
pressure ventricles ____ pressure arteries attached (causes what to happen)

Answer 3

pressure atria < pressure veins
pressure atria >pressure ventricles
-AV valves open
pressure ventricles< pressure arteries
-keeps semilunar valves closed

Question 4

80% of blood for contraction loaded into ventricles at this time
-between beats

Answer 4

period of passive filling

Question 5

2. atrial systole (atria contracts)
   causes pressure in atria to

Answer 5

increase

Question 6

2. atrial systole
   pressure atria____ pressure veins
   pressure atria ____ pressure of ventricles (causes what)
   pressure ventricle ___ pressure arteries

Answer 6

pressure atria> pressure veins
pressure atria>pressure ventricles
-causes av valves to open
pressire ventricles<pressure arteries
-causes semilunar valves to stay closed

Question 7

20% of blood for contraction loaded into ventricles at this time
-atrial systole

Answer 7

period of active filling

Question 8

atrial begins to relax as ventricles begin to contract:

pressure of atria=
pressure of ventricles=

Answer 8

atrial diastole/early ventricular systole

pressure of atria= decreases
pressure of ventricles=increases

Question 9

3. atrial diastole/early ventricular systole
   pressure atria ___ pressure veins
   pressure artia ___ pressure ventricles (causes)
   pressure ventricles ___ pressure arteries (causes)

Answer 9

pressure atria < pressure veins
pressure artia < pressure ventricles
-causes av valves to close
pressure ventricles < pressure arteries
-causes semilunar valves to stay closed

Question 10

rapid rise of pressure in ventricles increases
3. atrial diastole/early ventricular systole

Answer 10

period of isovolumetric contraction

Question 11

4. late ventricular systole
   pressure atria ___ pressure veins
   pressure atria ___ pressure ventricles (cause)
   pressure ventricles ___ pressure arteries (cause)

Answer 11

pressure atria < pressure veins
pressure atria < pressure ventricles
-causes av valves to close
pressure ventricles > pressure arteries
-causes semilunar valves to open and blood flow out

Question 12

5. early ventricular diastole
   (getting into ventricular relaxation)

causes pressure of ventricles to=

Answer 12

decreases

Question 13

5. early ventricular diastole
   (getting into ventricular relaxation)
   pressure atria ___ pressure veins
   pressure atria ___ pressure ventricles (causes)
   pressure ventricles ___ pressure arteries

Answer 13

pressure atria < pressure veins
pressure atria < pressure ventricles
-causes av valves to stay closed
pressure ventricles < pressure arteries
-causes semilunar valves to close

Question 14

6. late ventricular diastole

pressure atria __ pressure veins
pressure atria ___ pressure ventricles (causes)
pressure ventricles ___ pressure arteries (causes)

Answer 14

pressure atria < pressure veins
pressure atria > pressure ventricles
-av valves open
pressure ventricles < pressure arteries
-semilunar valves closed

Question 15

vol of blood in ventricle before it contracts

Answer 15

EVD (135)

Question 16

vol of blood in the ventricle before it relaxes/after it contracts (after ventricular systole)

Answer 16

ESV (65)

Question 17

volume of blood ejected per beat

Answer 17

SV- stroke volume
EDV-ESV=~70

Question 18

ejection fraction=
fraction of EDV ejected/beat

Answer 18

SV/EDV

Question 19

heart sounds (lub dub) due to

Answer 19

valve closure

Question 20

-abnormal heart sounds
-failure of valves to open completely=
-failure of valves to close properly=

Answer 20

heart murmurs
-failure of valves to open completely=stenosis
-failure of valves to close properly=insufficiency or prolapse

Question 21

what causes 1st heart sound?

Answer 21

closure of AV valve

Question 22

what causes 2nd heart sound?

Answer 22

closure of semilunar valves

Question 23

amount of blood pumped out of each ventricle in 1 minute

Answer 23

cardiac output
CO=HR x SV (heart rate x stroke volume)

Question 24

CO regulated to match demands of tissues.
increased by:
decreased by:

Answer 24

increased: physical activity, metabolic status, drugs
decreased: blood loss, heart disease

Question 25

factors that increase HR are called factors that decrease HR are called

Answer 25

increase= + chronotropic decrease= - chronotropic

Question 26

SNS increases HR (___ and ___ cells)

Answer 26

AR and contractile cells

Question 27

PNS decreases heart rate ( ___ cells only)

Answer 27

AR cells only

Question 28

which is which: (SNS and PNS) 1. + dromotropic and + chronotropic 2. - dromotropic and - chronotropic

Answer 28

SNS + dromotropic and + chronotropic PNS - dromotropic and - chronotropic

Question 29

3 ways SV is altered: SV=EDV-ESV

Answer 29

1. preload (changing EDV) 2. afterload (Blood Pressure) 3. contractility (force of contraction)

Question 30

at rest, cardiac muscle sits at a length that is LESS than optimum. by increasing EDV:

Answer 30

this increases stretch of myocardium moves resting cardiocytes length towards optimum increases SV (stroke volume)

Question 31

what is EDV directy related to

Answer 31

venous return (VR)

Question 32

rate at which blood is returned to the heart from veins

Answer 32

VR (venous rate)

Question 33

veins are what kind of vessels? they can hold up to 60% of the total blood volume

Answer 33

flaccid Peripheral Venous Pool

Question 34

the pressure to return blood back to the heart from capillaries is very large/small

Answer 34

small

Question 35

increase in venous return (VR) by: (all dependent on one-way valves)

Answer 35

1. increase in skeletal muscle pump 2. increase in breathing in and out (thoracic pump) 3. increase venoconstriction via SNS (a1 adrenergic receptor)

Question 36

decrease in venous return (VR) by:

Answer 36

1. tachycardia (extreme high heart rate)= decrease CO by decrease EDV 2. valsalva maneuver (increasing thoracic pressure against closed epiglottis)

Question 37

what is SV (stroke volume) increase related to? what is CO (cardiac output) related to?

Answer 37

SV/HR CO=HR (at normal HR)