Unit 1 Section 5: The heart basics Flashcards Preview

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Flashcards in Unit 1 Section 5: The heart basics Deck (13)
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1
Q

atria ventricular valves (AV)

A

link the atria to the ventricles

2
Q

semi-lunar valves (SL)

A

link the ventricles to the pulmonary artery(right) & the aorta(Left)

3
Q

tendons

A

valves are prevented from being inverted because of tendons.

4
Q

valves and pressure

A

Higher pressure behind a valve it’s forced open

Higher pressure in front of the valve it’s forced shut.

5
Q

thickness of chamber walls

A

the left ventricle has a thicker muscle than the rest of the heart because it needs to contract more powerfully to pump blood around the whole body.

  • The right side only needs to force blood to the lungs
  • The atria just have to pump blood into the ventricles
6
Q

(NOT IMPORTANT BUT JUST IN CASE) heart chamber wall measurements

A

atrium - 2mm
right ventricle - 4-5mm
left ventricle - 8-15mm

7
Q

hydrostatic pressure

A

blood leaving heart in arteries is under high pressure from ventricle contraction

8
Q

The cardiac cycle

A

an ongoing sequence of contraction and relaxation of the atria and ventricles that keeps blood continuously circulating around the body.

9
Q

The cardiac cycle - 1.DIASTOLE

A
  • blood enters the atria of the heart through the pulmonary vein and the vena cava.
  • Pressure in atria rises forcing open the Atrioventricular valves allowing blood to move into the ventricles
  • all cardiac muscles are relaxed at this point.
  • this causes the pressure in the ventricles to reduce to lower than that of the aorta and pulmonary artery so the semi-lunar valves close maintaining a one way flow.
10
Q

The cardiac cycle - 2.ATRIAL SYSTOLE

A
  • atria muscle contracts forcing the remaining blood into the ventricles
  • during this the ventricle walls remain relaxed (ventricular diastole)
11
Q

The cardiac cycle - 3.VENTRICULAR SYSTOLE

A
  • after a short delay the ventricles contract, increasing their blood pressure, forcing shut the AV valves preventing back-flow
  • This causes the pressure to rise further forcing open the semi-lunar valves allowing blood into the pulmonary artery and aorta.
12
Q

The cardiac cycle - 3.VENTRICULAR SYSTOLE

A
  • after a short delay the ventricles contract, increasing their blood pressure, forcing shut the AV valves preventing back-flow
  • This causes the pressure to rise further forcing open the semi-lunar valves allowing blood into the pulmonary artery and aorta.
13
Q

Pocket (SL) valves in veins

A

ensure that when the vein is squeezed blood flows back to the heart rather than away from it.