heart parts, layers, pathway Flashcards

1
Q

what is the heart enclosed in?

A
  • pericardium (double walled sack with 3 layers)
  • 3 layers:
    1. fibrous pericardium
    2. parietal pericardium
    3. visceral pericardium (epicardium)

1 and 2 are attached
3 is actually on the heart

2 and 3 are serous membranes for friction

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2
Q

pericardium

A
  • serous
  • parietal layer lines internal surface of the fibrous pericardium
  • visceral layer (epicardium) on external surface of heart
  • separated by fluid pericardinal cavity
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3
Q

layers of the heart wall

A
  1. epicardium: visceral layer of serous pericardium
  2. myocardium:
    - spiral bundles of cardiac muscle cells (to make it more efficient at pushing fluid out)
    - fibrous skeleton of the heart crisscrosses, interlacing layer of connective tissue (anchors, supports great vessels and valves, and limits spread of action potential to specific paths)
  3. endocardium:
    - continuous with endothelial lining of blood vessels, made of simple squamous
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4
Q

4 chambers of the heart: atria

A

2 atria:
- where blood enters FIRST
- separated internally y by interatrial septum
- coronary sulcus (atrioventricular groove) encircles the junction of the atria and ventricles
- auricles increase atrial volume

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5
Q

4 chambers of the heart: ventricles

A

2 ventricles:
- separated by interventricular septum (super thick wall of muscle)
- anterior and posterior interventricular sulci mark the position of septum externally

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6
Q

atria

A
  • receiving chambers
  • walls are ridged by pectinate muscles
  • vessels entering right atrium: superior and inferior vena cavas
  • vessels entering left atrium: right and left pulmonary veins
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7
Q

veins

A

low pressure, to the heart

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8
Q

arteries

A

high pressure, away from heart

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9
Q

ventricles

A
  • discharging chambers
  • walls are ridged by trabeculae carnae
  • papillary muscles project into ventricular cavities
  • vessel leaving right ventricle: pulmonary trunk
  • vessel leaving left ventricle: aorta
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10
Q

pathway of blood through heart

A
  • the heart= 2 side by side pumps
  • RT side: pump for pulmonary circuit (vessels that carry blood to and from LUNGS)
  • left side: pump for systemic circuit (vessels that carry blood to and from all body tissues)
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11
Q

equal volumes of blood are…

A

pumped to the pulmonary systemic circuits

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12
Q

pulmonary circuit

A

short, lower pressure

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13
Q

systemic circuit

A

blood encounters a lot of resistance in the long pathways, lots of pressure

(left ventricle thicker because of more pressure)

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14
Q

pathway of blood: steps

A
  1. RT ventricle
  2. passes through pulmonary semilunar valve
  3. into pulmonary trunk
  4. pulmonary arteries
  5. lungs
  6. back into heart through pulmonary veins
  7. left atrium
  8. atrial ventricular valve (bicuspid)
  9. left ventricle
  10. pumped past aortic semilunar valve
  11. aorta
  12. out to other systems of the body
  13. superior/inferior vena cava
  14. back to the right atrium
  15. right atrial ventricular valve (tricuspid)
  16. right ventricle (start)
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15
Q

coronary circulation

A
  • blood supply to heart muscle itself
  • arterial supply varies and contains many anastomoses (junctions) in branches
  • collateral routes give more ways to deliver blood
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16
Q

hemostatic imbalances

A
  • angina pectoris:
    “tight chest” caused by loss of blood flow to myocardium
    cells are weakened
  • myocardial infarction:
    prolonged coronary blockage
    areas of cell death are repaired with noncontractile scar tissue
17
Q

myocardial infarction vs ischemia

A

ischemia: decrease in blood supply, leading to angina pectoris

infarction: end point of ischemia

both: heart failure