Circulatory & Respiration Flashcards

0
Q

Increase in venous return results in an increase in _____, which lengthens cardiac fibers, which improves the force of contractility, resulting in an increase in _____.

A
  1. End-Diastolic BP

2. Stroke Volume

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1
Q

End-Diastolic Volume

A

(Preload)

How much blood is in the left ventricle before it squeezes

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2
Q

Factors of Venous Return

A
  1. Venoconstriction
  2. Muscle Pump
  3. Respiratory Pump
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3
Q

Venoconstriction

A

Reduces the volume capacity of the veins to store blood –> blood moves toward heart

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4
Q

Muscle Pump

A

When muscles contract during exercise, they compress veins & push blood back toward the heart

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5
Q

Respiratory Pump

A

During inspiration, pressure in the thorax decreases & the abdominal pressure increases. This creates a flow of venous blood from the abdominal region into the thorax = venous return

Predominant factor of venous return.

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6
Q

Stroke Volume

A

Volume per beat

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7
Q

Stroke Volume is regulated by?

A
  1. End-Diastolic Volume
  2. Afterload (Aortic BP)
  3. Strength of ventricular contraction (Contractility)
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8
Q

Preload

A

The pressure on the wall of the heart

**more blood = more pressure

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9
Q

Afterload

A

The pressure on the aortic semilunar valve (Diastolic BP)

Overcoming the pressure to open the semilunar valves

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10
Q

Stroke Volume in relation to Afterload

A

SV is inversely proportional to the Afterload; increase in aortic pressure produces a decrease in SV

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11
Q

Contractility

A

How hard the heart squeezes

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12
Q

Mechanisms of Contractility

A
  • the effect of epinephrine & norepinephrine
  • direct sympathetic stimulation by cardiac accelerator nerves

Both increase the Calcium available to the myocardial cell

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13
Q

Ejection Fraction

A

The percentage of blood pumped out of a filled ventricle during contraction.

The greater the EF, the greater the Stroke Volume which increases Cardiac Output.

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14
Q

Cardiac Output

A

Volume of blood pumped to the body per minute

Q= HR * SV

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15
Q

Heart Rate

A

Beats per minute

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16
Q

Isovolumic Contraction

A

The pressure increases while volume stays the same

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17
Q

Surfactant

A

Lowers the surface tension of the alveoli & prevents its collapse

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18
Q

Purpose of the Cardiovascular System

A
  1. The transport of O2 to the tissues & removal of wastes
  2. The transport of nutrients to tissues
  3. Regulation of body temperature
19
Q

Myocardium

A

“Heart Muscle”

-responsible for contracting & forcing blood out of the heart

20
Q

Cardiac Muscle Fiber vs. Skeletal Muscle Fibers

A
  1. They’re shorter & connected in a tight series; branched & contraction is involuntary
  2. They’re interconnected via intercalated discs (permit the transmission of electrical impulses from one fiber to another)
  3. Fibers cannot be divided into different fiber types (type similar to SO Type I)
21
Q

Systole

A

Contraction phase of the cardiac cycle

22
Q

Diastole

A

Relaxation period of the cardiac cycle

23
Q

Heart 2-Step Pumping Action

A
  1. Right & Left Atria contract together, which then empties atrial blood into the ventricles.
  2. Then ventricular contraction occurs, delivering blood into systemic & pulmonary circuits.
24
Q

Blood Distribution During Rest

A

Systole ejects 2/3s of the blood in the ventricles, leaving 1/3 in the ventricles. Ventricles then fill with blood during the next diastole (longer time in diastole)

25
Q

The effects of rising heart rate on Diastole & Systole

A

Rising heart rate results in a greater time in reductionism diastole, whereas systole is less affected. (Diastole is reduced greatly)

26
Q

Pressure Changes During the Cardiac Cycle

A

70% of the blood entering the atria during diastole flows directly into the ventricles through the atrioventricular valves before contraction. Contraction then forces the remaining 30% into the ventricles.

The rise in pressure closes the AV Valve & prevents backflow.

27
Q

Pressure Changes During the Cardiac Cycle (continued…)

A

When the ventricular pressure exceeds the pressure of the pulmonary artery & the aorta, the pulmonary & aortic valves open & blood is forced into both pulmonary & systemic circulations.

28
Q

Heart Sounds

A

1st- closing of the AV valve

2nd- closing of the aortic & pulmonary valves

29
Q

Systolic BP

A

Pressure generated as blood is ejected from the heart during ventricular systole

30
Q

Diastolic BP

A

Time during ventricular relaxation (diastole) & the arterial blood pressure decreases

31
Q

Mean Arterial Blood Pressure (MAP)

A

Average pressure during the cardiac cycle at REST

-determines the rate of blood through the systemic circuit

32
Q

Pulse Pressure

A

Difference between systolic & diastolic blood pressure

33
Q

Hypertension

A

High blood pressure

Rise above 140/90mmHG

34
Q

Mean Arterial BP is determined by:

A
  1. Cardiac Output
  2. Total Vascular Resistance

Increase in determents = increase of MAP

35
Q

Blood Pressure Factors

A
  • Cardiac Output
  • Blood Volume
  • Resistance to Flow
  • Blood Viscosity
36
Q

What regulates BP?

A

Acute: sympathetic NS
Long-Term: kidneys

-kidneys regulate BP by controlling blood volume

37
Q

Total Vascular Resistance

A

Sum of resistance to blood flow provided by ALL systemic blood vessels

38
Q

Increase in Arterial BP

A

Baroreceptors send impulses to the cardiovascular control center, which responses by decreasing sympathetic activity

39
Q

Decrease in Arterial BP

A

Reduction of baroreceptor activity to the brain, resulting in Cardiovascular Control Center increasing sympathetic outflow

40
Q

Sinoatrial Node (SA Node)

A

Pacemaker of the heart; electrical activity occurs

Modified by:

  • parasympathetic NS
  • sympathetic NS
41
Q

Heart Rate Breakdown

A

HR increases at the beginning of exercise due to withdrawal of parasympathetic tone.

At higher work rates, the increase in HR is achieved via an increased sympathetic outflow to the SA Nodes.

42
Q

Hemodynamics

A

The study of pressure, resistance, & flow of blood

43
Q

Blood Flow Resistance Factors

A
  • length of the blood vessel
  • viscosity of the blood
  • RADIUS OF THE VESSEL

Resistance = (length * viscosity) / Radius^4

44
Q

Greatest vascular resistance to blood flow

A

Occurs in the arterioles.

45
Q

Increased Oxygen Delivery to Exercising Skeletal Muscles is Accomplished by:

A
  1. Increase in Cardiac Output

2. Redistribution of blood flow from inactive organs to working muscle