Human Physiology Ch 14 Cardiovascular System

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Chapter 14: Cardiovascular Physiology

Cardiovascular Physiology
 Chapter 14 "
Heart anatomy " Cardiac muscle cells " Autorhythmic cells " Cardiac cycle " Cardiac output " 1

Functions of Circulatory System "
  Transportation"
–  Respiration"
  Transport 02 and C02."

–  Nutrition"
  Absorbed digestion products delivered to liver and tissues"

–  Excretion"
  Carry metabolic wastes to kidneys"

–  Hormonal: "
  Carry hormones to target tissues"

2

The cardiovascular system circulates blood to tissues "
  Pulmonary circulation"   Coronary circulation"   Systemic circulation"

Fluid Mechanics "
  Blood flow rate (vol/min) = Cardiac Output"   5 L/min at rest = total blood volume per minute"   Pressure produced by heart pushes blood through vessels"   Vessels become successively smaller"   Blood pressure drops as blood moves away from heart" 3

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Fig. 14.1, pg. 465"

Bio5, Denise Lim

1

Chapter 14: Cardiovascular Physiology

Pressure is measured in 
 mm Hg "
  Units refer to the force required to push mercury (Hg) up a barometer" 5

Pressure is greatest at aorta, lowest at vena cava "

Fig. 14.2, pg. 466"

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Pressure drops over distance "

Drop in pressure over distance keeps blood moving "
  Change in pressure over distance produces a pressure gradient"   Without difference in pressure, blood would stop flowing"

  Hydrostatic pressure: no flow"   Pressure is constant"

  Hydraulic pressure: fluid in motion"   Pressure decreases" 7

Fig. 14-3a&b, pg. 468"

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Bio5, Denise Lim

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Chapter 14: Cardiovascular Physiology

Flow depends on the pressure gradient "

Resistance (friction)
 opposes flow "
  Peripheral resistance = resistance in vessels (not in heart itself)"   Resistance is determined by:" –  Viscosity = v" –  Vessel length = l" –  Vessel radius = r"

" R ∝ vl " r4"

Fig. 14.3, pg. 468"

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Resistance decreases to the 4th power as radius increases"

Blood flow dependent on pressure changes and resistance "
Fig. 14.3e" pg. 469"
  Pressure and resistance are opposing forces"   Total peripheral resistance = sum of all vascular resistances"   Arteries and arterioles produce resistance by vasoconstriction" 12

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Bio5, Denise Lim

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Chapter 14: Cardiovascular Physiology

Rate of flow is not the same as velocity of flow"
  Rate of flow = volume/time (mL/ min)"
– Volume of fluid moving past a point in a given time"

Velocity is dependent on flow rate and cross-sectional area of vessel "   Velocity = flow rate! cross-sectional area"

  Velocity = distance/time"
– Distance a fixed volume of fluid travels in a given time" 13

  Cross-sectional area ∞ radius"
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Velocity of flow is faster at point X than point Y, even though flow rate is the same "

Velocity increases when diameter decreases because pressure increases "   Example: garden hose"

Fig. 14.4, pg. 471"

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Bio5, Denise Lim

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Chapter 14: Cardiovascular Physiology

Heart Chambers"
  Right heart – pulmonary circulation"
– Right atrium: blood enters from vena cava, carrying deoxygenated blood" – Right ventricle: blood sent to lungs for oxygen" Fig. 14-5f, pg. 473"

Left heart – systemic circulation "
  Left atrium: blood enters from lungs, carrying oxygenated blood"   Left ventricle: blood sent to body to feed tissues" 17

Fig. 14-5g, pg. 473"

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Left ventricle wall is thicker "
  Left side must produce enough force to move blood through systemic circulation" 19

Heart valves insure one-way flow "
  Atrioventricular (AV) valves: between atrium and ventricles" – Tricuspid valve: right side" – Bicuspid or mitral valve: left side" 20

Bio5, Denise Lim

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Chapter 14: Cardiovascular Physiology

Semilunar valves: between ventricles and arteries"
  Pulmonary semilunar valve: Right side"  ...
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