The cardiovascular system Flashcards

1
Q

What are the purposes of the cardiorespiratory system?

A
  • Transport O2and nutrients to tissues.
  • Removal of CO2wastes from tissues.
  • Regulation of body temperature.
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2
Q

What are the 2 major adjustments of blood flow during exercise?

A
  • Increased cardiac output.
  • Redistribution of blood flow from inactive organs to active muscle.
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3
Q

Describe the pulmonary circuit

A
  • Right side of the heart.
  • Pumps deoxygenated blood to the
    lungs via pulmonary arteries.
  • Returns oxygenated blood to the left
    side of the heart via pulmonary veins.
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4
Q

Describe the systemic circuit

A
  • Left side of the heart.
  • Pumps oxygenated blood to the
    whole body via arteries.
  • Returns deoxygenated blood to
    the right side of the heart via
    veins.
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5
Q

Physical characteristics of blood - plasma

A
  • Liquid portion of blood.
  • Contains ions, proteins, hormones.
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6
Q

Physical characteristics of blood - cells

A
  • Red blood cells erythrocytes.
  • Contain haemoglobin to carry oxygen.
  • White blood cells.
  • Important in preventing infection.
  • Platelets.
  • Important in blood clotting.
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7
Q

Physical characteristics of blood - hematocrit.

A

Percentage of blood composed of erythrocytes (red blood cells).

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8
Q

Why does the right hand side of the heart not have a lot of pressure?

A

In order for slow blood flow for efficient gas exchange

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9
Q

Define resistance.

A

Resistance = measure of hindrance or opposition to blood flow through a vessel, caused by friction between the blood in the vessel wall.

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10
Q

What is total peripheral resistance?

A

Total peripheral resistance =
Sum of resistances to flow in all individual organs.

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11
Q

What does Darcy’s Law state?

A

That blood flow is inversely proportional to resistance:
Blood flow = change in pressure/resistance

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12
Q

What does resistance depend on?

A

*Length of the vessel.
*Viscosity of the blood.
*Radius of the vessel (greatest influence on resistance).

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13
Q

What is the resistance equation?

A

Resistance = (length x viscosity)/ Radius(power of 4)

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14
Q

What is local vascular resistance?

A

The resistance to blood flow in an organ or tissue calculated from pressure and local organ/tissue flow.

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15
Q

TPR is calculated when MAP and CO are known, what equation links these together?

A

MAP = CO x TPR

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16
Q

What is the oxygen consumption equation?

A

Oxygen consumption = cardiac output x A-V oxygen difference

17
Q

What is AVO2 difference?

A

*Amount of O2that is taken up from 100 ml of blood.
*↑ during exercise due to ↑ O2uptake in tissues.
*Used for oxidative ATPproduction

18
Q

What is Fick equation?

A

Describes relationship between CO (Q), a-VO2 difference, and VO2:
VO2 = Q x a-VO2 difference

19
Q

Where does the initial ‘drive’ of the CV system come from?

A

higher brain centres.
* Due to centrally generated motor signals at the onset of exercise (rapid adjustments).

Fine-tuned by afferent feedback from:
*Heart mechanoreceptors.
*Muscle chemoreceptors [sensitive to metabolites (K+, lactic acid)] &
mechanoreceptors
*Pressure sensitive receptors (baroreceptors)

20
Q

Given baroreceptors work to rapidly maintain BP homeostasis why do we see a continued increase in systolic BP with exercise?

A

Baroreflex is reset during exercise.

  • Central command and exercise pressor reflex both play an active role in resetting the arterial baroreflex during exercise.