Anatomy Of The Heart Flashcards

1
Q

What is the shape and primary function of the heart?

A

Cone-shaped, muscular pump

The heart functions to pump blood throughout the body.

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2
Q

Where is the heart located?

A

In the thorax between the lungs (region of mediastinum)

It is protected by the ribs and sternum.

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3
Q

What is the apex of the heart?

A

Lies in the 5th intercostal space in the midclavicular line

The apex indicates the lower tip of the heart.

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4
Q

What is the fibrous pericardium?

A

Inelastic, made of dense connective tissue (network of capillary fibres)

It fuses inferiorly with the diaphragm and superiorly with great vessels, preventing overfilling of the heart and anchoring it in position

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5
Q

What are the two layers of the serous pericardium?

A

Parietal layer (outer layer) and visceral layer (inner layer)

The visceral layer is also known as the epicardium.

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6
Q

What is the function of the pericardial cavity?

A

Contains pericardial fluid, prevents friction & allows heart to move smoothly

overproduction can cause inflammation

The pericardial cavity is a potential space between the parietal and visceral layers.

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7
Q

What are the three layers of the heart wall?

A
  • Endocardium: inner layer - endothelium (simple squamous epithelium)
  • Myocardium: middle layer - cardiac muscle (main layer, forms atria and ventricles)
  • Epicardium: outer layer - visceral pericardium
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8
Q

What chambers make up the heart?

A
  • Right atrium (RA)
  • Left atrium (LA)
  • Right ventricle (RV)
  • Left ventricle (LV)

These chambers are responsible for receiving and pumping blood.

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9
Q

What are the great vessels connected to the heart?

A
  • Superior vena cava - delivers blood to RA from head, neck and upper limbs
  • Inferior vena cava - carries blood to RA from trunk, viscera and lower limbs
  • Pulmonary trunk & arteries
  • Pulmonary veins (4 of them)
  • Aorta

These vessels are essential for blood circulation to and from the heart.

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10
Q

What is the function of heart valves?

A

Prevent backflow of blood

There are 4 heart valves:
- 2x Atrioventricular valves
- 2x Semilunar valves

Heart valves ensure unidirectional blood flow through the heart chambers.

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11
Q

Name the two types of atrioventricular (AV) valves.

A
  • Tricuspid (right AV valve) = has 3 cusps
  • Bicuspid/mitral (left AV valve) = has 2 cusps

These valves separate the atria from the ventricles.

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12
Q

What are the semilunar valves?

A
  • Pulmonary valve
  • Aortic valve

These valves guard the entrances to the aorta and pulmonary trunk.

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13
Q

What is the role of chordae tendineae and papillary muscles?

A

Anchors AV valves and prevents backflow

Chordae tendineae connect the valves to the papillary muscles.

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14
Q

What is the cardiac conducting system responsible for?

A

Coordinating effective heart contraction

It consists of non-contractile cells that initiate electrical impulses.

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15
Q

What are the shortcuts in fetal circulation?

A
  • Foramen ovale (window) = connects the right to the left atria, bypassing the right ventricle and pulmonary system
  • Ductus arteriosus = connects the pulmonary trunk to the arch of the aorta, bypassing the pulmonary system and left side of heart (goes to aorta instead of lungs)
  • Ductus venosus = connects the umbilical vein to the inferior vena cava (as processed by the mother), bypasses the liver
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16
Q

What happens to the foramen ovale at birth?

A

Closes to become fossa ovalis

This closure is due to increased left atrial pressure after birth.

17
Q

How is blood flow through the heart sequenced?

A

RA → RV → Lungs → LA → LV → Aorta

This sequence describes the pathway of blood circulation.

18
Q

What is the significance of the coronary circulation?

A

Supplies blood to the myocardium during ventricular relaxation

It consists of arteries and veins that specifically serve the heart muscle.

19
Q

What does an electrocardiogram (ECG) measure?

A

The electrical activity of the heart

ECGs are crucial for assessing heart function.

20
Q

What is the fibrous skeleton of the heart?

A
  • Bands of fibrous connective tissue between the atria and ventricles
  • Electrically separates the atria from the ventricles so they don’t contract at the same time
  • Encircles the pulmonary trunk and aorta (leaving the ventricles)
  • Heart valves suspended from it
21
Q

Describe atrioventricular valves

A
  • located between the atria and ventricles
  • opened by the blood flowing from atria to the ventricles
  • The cusps are anchored by chordae tendinae to papillary muscles (form part of heart wall)
  • Contraction of papillary muscles prevents eversion of the valves and therefore backflow of blood into the atria
22
Q

When do atrioventricular valves open/close?

A

Open when ventricular pressure is less than atrial pressure

Close when ventricular pressure is greater than atrial pressure

23
Q

Describe semilunar valves

A
  • Guards the entrances of the aorta and pulmonary trunk
  • Opened by the force of blood (when pressure increases) as the ventricles contract
  • Blood flows backwards in the aorta and pulmonary trunk during ventricular relaxation
  • This pools in the cusps and pushes them shut
  • Thus preventing backflow of blood into the ventricles
24
Q

Internal features of the heart

Fill in the blanks
A
25
Q

What arteries and veins does the coronary circulation consist of?

A

Left coronary artery (LCA)
- anterior interventricular = left anterior descending (down between ventricles)
- Circumflex = wraps around heart

Right coronary artery (RCA)
- marginal artery = runs along lower border of right ventricle
- posterior interventricular = runs down ventricles at the back

  • Great, middle and small cardiac veins drain into the coronary sinus which empties into the right atrium
  • The anterior cardiac veins (come from right ventricle) drain directly into the right atrium
26
Q

What is angiography?

A

Dye used to examine patency of coronary vessels

27
Q

What are the non contractile cells that initiate electrical impulses?

A
  • Sinoatrial (SA) node = in atrium
  • Atrioventricular (AV) node = between the 2 atria, next to the ventricles
  • AV bundle (bundle of His) = passes through septum, slows down passage of impulse
  • Right & left bundle branches
  • Purkinje fibres = spread backwards up the heart
28
Q

What positions are non contractile cells that initiate electrical impulses located in?

A
29
Q

How is foetal circulation different from usual circulation?

A
  • oxygen and nutrients are received from the placenta via the umbilical vein
  • needs to bypass non-functional lungs
30
Q

What are the changes in foetal circulation at birth?

A
  • Ductus venosus (causes bypassing of liver) becomes ligamentum venosum
  • Foramen ovale (gap between the right and left atria) becomes fossa ovalis
  • Ductus arteriosus (between pulmonary trunk and aorta) becomes ligamentum arteriosum