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Applied Physiology > cardiovascular system > Flashcards

cardiovascular system Flashcards

1
Q

What is the purpose of the cardiovascular system

A

Deliver oxygen and nutrients
Remove waste and CO2
Temperature and pH regulation
Works in conjunction with the respiratory system
Adjust during exercise by increase CO2 and redirecting blood from inactive tissue to active skeletal muscle

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2
Q

the pulmonic pump

A
  1. Blood enters from the vena cava (the superior vena cava and inferior vena cava) and dumps into the right atrium
  2. Then blood passes through the tricuspid valve (right AV valve) from the atria into the right ventricle
  3. Blood then flows out of the right ventricle through the pulmonary semilunar valve into the pulmonary artery to go to the lungs
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3
Q

Systemic pump

A
  1. Blood returning from the lungs come in from the pulmonary vein and into the left atrium
  2. The left atrium will push blood through the left AV valve/mitral valve into the left ventricle
  3. The left ventricle will push blood through the aortic semilunar valve and into the aorta to the rest of the body
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4
Q

what are the layers of the cavity wall that the heart sits in

A
  1. Fibrous pericardium: outermost layer of the pericardial cavity
  2. Serous pericardium: the middle layer of the pericardium
  3. Pericardial cavity: fluid filled to decrease friction between muscles and fibrous layer (without this the muscle would work harder)
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5
Q

what is the outer most layer of the heart
describe characteristics and functions

A

Epicardium (visceral pericardium): the most intimate layer of the pericardium
Characteristics: serous membrane including blood capillaries, lymph capillaries and nerve fibers
Function: serves as lubricative outer covering

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6
Q

what is the middle layer of the heart
describe its characteristics and functions

A

Myocardium: muscle (the left side is thicker to pump to body)
Characteristics: cardiac muscle tissue separated by CTs and including blood capillaries, lymph capillaries and nerve fibers
Functions: provides muscular contractions that eject blood from the heart chambers

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7
Q

What is the inner most layer of the heart describe its characteristics and functions

A

Endocardium: innermost
Characteristics: endothelial tissue and a thick subendothelial layer of elastic and collagenous fibers
Functions: serves as a protective inner lining of the chambers and valves; Protects what gets in blood/musculature and evaginates around the valves

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8
Q

what is the difference between cardiac and skeletal muscles

A

cardiac has shorter muscles fiber lengths with branches
they are single nucleated cells
that only use aerobic respiration
they are under involuntary control
Ca++ stores are in SR and extracellularly

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9
Q

describe a cardiac cycle

A

-Systole: atria and ventricles contract
-Diastole: relaxation of the atria and ventricles
-Right and left atria contract and relax together
-Right and left ventricles contract and relax together
-Approximately 0.1 seconds after atrial contraction
-About ⅔ of the blood in the ventricles is ejected from the ventricles (⅓ of residual volume)

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10
Q

describe what exercise does to the cardiac cycle

A

at rest (heart rate = 75 bpm): Systole: 0.3 seconds and Diastole: 0.5 seconds

Heavy exercise: (heart rate = 180 beats per minute)
Systole: 0.2 seconds and Diastole: 0.13 seconds

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11
Q

describe the electrical activity of the heart

A

-SA node → Atrial muscle → AV node → bundle of His → bundle branches → purkinje
-SA = pacemaker but the vagus nerve must slow this down
1. Action potentials originate from the SA node and travel across the wall of the atrium to the AV node
2. Action potentials pass through the AV node and along the AV bundle which extends from the AV node through the fibrous skeleton into the interventricular septum
3. The Av bundle divides into right and left bundle branches and action potentials descend to the apex of each ventricle along the bundle branches
4. Action potentials are carried by the purkinje fibers from the bundle branches to the ventricle walls

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12
Q

What does the P-wave represent on a normal EKG

A

the P wave represents atrial depolarization

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13
Q

what does the QRS complex represent

A

the ventricular depolarization (the atrial depolarization is masked by this)

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14
Q

what does the T-wave represent

A

ventricular repolarization

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15
Q

what is the purpose of the valves of the heart

A

AV valves prevent backflow of blood into the atria during ventricular contraction
Semilunar valves prevent backflow from aorta and pulmonary artery during diastole

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16
Q

S1

A
  • first heart sound makes the lub
    -Closing of mitral and tricuspid valve AV
    low -pitched
    Best heard with bell of stethoscope
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17
Q

S2

A

2nd heart sound makes the dup
-Semilunar valves snapping closed (after ventricular contraction)
Onset of diastole
Crisp, higher pitch, shorter duration
Best heard with diaphragm or stethoscope

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18
Q

S3

A

can be normal; occurs early in diastole
Ventricular gallop
Sometimes heard normally in young children
low-pitched , early diastolic sound
Vibrations due to rapid ventricular filling

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19
Q

S4

A
  • typically always pathological
    Heard in late diastole
    artial gallop
    Low-pitched, late diastolic or pre-systolic
    Usually ventricular dysfunction (non-compliance=muscle is stiff)
    PFO= patent foramen ovale
    a hole between the left and right atria (upper chambers) of the heart
20
Q

End diastolic volume

A

volume at the end of diastole before systole/the highest volume

21
Q

end systolic volume

A

least volume/residual volume and last 1/3

22
Q

what is parasympathetic tone

A

70 BPM (controlled by the vagus nerve)

23
Q

what is a negative chronotrope

A

effect (something that affects the rate by decreasing it)
Acetylcholine: parasympathetic NT that decreases heart rate

24
Q

what is a positive chronotrope

A

(something that affects the rate by increasing it_
Norepinephrine: sympathetic NT that increases heart rate

25
Q

What is cardiac output and what are the ways to calculate

A

volume of blood pumped per minute
Two ways of calculating
Qt = SV x HR
Fick equation: Qt = Vo2/(Cao2-Cvo2)
Volume of O2 (Vo2)
CaO2= arterial O2
CvO2= Venous O2

26
Q

what are the three factors that influence SV

A

Preload: load of blood that comes into the ventricles before being pumped out → end diastolic volume
Afterload: resistance the ventricles must overcome to pump blood
Contactility

27
Q

describe the pressure-volume loop

A

End-diastolic volume (mitral vales are closed)
Isovolumeric contraction (there is no change in contraction but pressure is increasing)
diastolic pressure: increased pressure causes aortic valve to open- the diastolic pressure is what is needed to overcome
Then pressure increases and volume decreases, the highest pressure is systolic blood pressure
Then both the volume and pressure start to drop and the aortic valve closes (both valves are closed)
With both valves close, the isovolumeric relaxation begins
Mitral valve opens to begin refiling

28
Q

Preload (factors)

A

frank starling relationship
EDV is the most important determinant of SV
Venous return is the primary factor influencing EDV (end diastolic volume depends on how much volume of blood is returned to the heart)
An increase in EDV causes lengthening in cardiac muscles and increase contraction to a certain point
Increase in preload increases SV if just the preload increase (direct relationship)
EDV is most important for SV

29
Q

what is the freak starling relationship

A

Describes relationship between SV and end diastolic volume
Increases in end diastolic volume causes lengthening of cardiac fibers which increase contraction

30
Q

describe afterload

A

This is the sum of factors that oppose ejection of blood during systole
Vascular resistance: plaque build up
Low compliance of the ventricles or great vessels (aorta → not pliable, rigid)
Stenosis of semilunar valves: harden (a non movable heart means the heart has to work harder
SV inversely related to the afterload
Minimized during exercise secondary to arteriole dilation: after load decreases

31
Q

describe Contractility:

A

Positive inotropes: sympathetic and increase contractility
Circulating catecholamines (E and NE)
Increase Ca in muscle fiber and increase rate of Ca reuptake
Negative Inotropes parasympathetic and decreased contractility (beta blockers)
Direct sympathetic stimulation
Increase SV at any level of EDV

32
Q

what is rate pressure product

A

how well the myocardium is oxygenated
HR (Rest) x SBP
Indirect measure of myocardial oxygen consumption

33
Q

what is Pulse pressure

A

Difference between systolic and diastolic BP

34
Q

what is the mean arterial pressure

A

Average pressure during a cardiac cycle
Determines rate of blood flow
MAP=DBP +0.33(pulse pressure)

35
Q

what is the normal range for mean arterial pressure

A

70-110 mmHg

36
Q

what is the normal range for pulse pressure

A

40-60 mmHg

37
Q

what is the fick relationship

A

computes relationship between CO and Oxygen uptake

38
Q

what happens to O2 delivery during exercises (different tissues)

A

Oxygen consumption increases because of CO and a-vO2 difference
80-85% of CO goes to contracting skeletal muscle
% of CO that goes to brain is reduced
Coronary blood flow increases but % that goes to myocardium remains that same
Skin blood flow increases during light and moderate exercises but deceases with maximal
Flow to abdominal organs decreases during maximal exercises

39
Q

exercise effects on SV
-upright exercises
-untrained/moderately trained
-endurance athletes
supine positions

A

-Upright exercises: CO increases due to increase in SV and HR
-Untrained or moderately trained: SV does not increase beyond 40-60% VO2max workload; CO solely due to increased HR
-Endurance Athletes: SV continues to increase up to VO2 max due to improved venous return and EDV
-Body position
Effects on SV greater in upright exercises (walking, biking) than in supine exercises (swimming)
-In supine resting SV and venous return is greater to start with

40
Q

what are the effects of exercise on HR
-low intensity
-high intensity
-effect of Beta blockers
-temperature

A

Low intensity exercise: increase up to 100 bpm due to withdrawal of parasympathetic tone
Higher intensity exercise: sympathetic nerves release norepinephrine
Act on Beta receptors that increase force and rate
Effect of Beta blockers during exercise → negates these effects
-temperature directly influences HR

41
Q

Venous return during exercise

A
  1. venoconstriction: decreases diameter and increaes pressure in vein due to sympathetic contraction
  2. muscle pump: rhythmic muscles contraction allow the body to maintain EDV and get blood back to the heart,
  3. respiratory pump: inspiration thorax pressure decreases and abdominal pressure increases (less pressure in the thorax to allow blood flow into the thorax from abdomen
42
Q

Interaction of vasodilators during exercise

A

vasodilators are released
these are inflammatory so the Body learns how to keep these types of substances under control

43
Q

examples of vasodilators

A

nitric oxide
prostaglandins
ATP
adenosine
Endothelium derived hyper polarization factors

44
Q

What happens during a prolonged endurance?

A

Cardiac output maintain throughout exercises
-SV decreases and HR increases to maintain CO
-due to dehydration and reduced plasma volume from increased in body temp
-exaggerated in hot/humid environments

45
Q

what happens during an intermittent workout

A

-depends on individual fitness level, environmental conditions and duration/intensity
-full recovery may not occur in hot/humid environment

46
Q

Arm vs Leg exercises

A

Arm:
-HR and BP are higher
-isometric increase more (resistance in vessels)
-vasoconstriction of inactive muscle groups

Legs:
-more arterioles dilated which lower peripheral resistance and therefore, pressure

47
Q

explain the central command theory

A

-motor signal from the brain
-suggests that initial CV changes from exercise are due to centrally generated motor signals
-influenced by afferent feedback from heart, mechanoreceptors, muscle chemoreceptors, and baroreceptors

Applied Physiology (15 decks)

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