The heart Flashcards

1
Q

What does the cardiovascular system consist of?

A

Heart, blood and blood vessels

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2
Q

Where is the heart situated?

A

Between the lungs in the thoracic cavity, between the vertebral column and the sternum.

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3
Q

What are the 4 compartments of the heart?

A
  1. right atrium
  2. left atrium
  3. right ventricle
  4. left ventricle
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4
Q

What is the membrane that surrounds and protects the heart called?

A

Pericardium

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5
Q

The pericardium is made up of two layers. What are they?

A
  1. fibrous pericardium - the dense outer layer that protects and anchors the heart
  2. serous pericardium - thin, delicate double layer that lubricates the heart
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6
Q

There are 3 major layers of the heart wall. What are they?

(EME OR ‘EMMY’)

A
  1. epicardium
  2. myocardium (cardiac muscle tissue)
  3. endocardium
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7
Q

Arteries always take blood in what direction (in relation to the heart)?

A

Away from the heart (oxygen rich blood)

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8
Q

The pulmonary trunk divides the right and left pulmonary arteries and carries blood to where?

A

The lungs

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9
Q

Blood passes from the left atrium into the left ventricle via which valve? (hint: two cusps)

A

Bicuspid valve

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10
Q

Which chamber of the heart is the thickest?

A

Left ventricle

(it needs to pump blood greater distances at higher pressure)

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11
Q

Blood passes from the left ventricle to the ascending aorta via which valve?

A

Aortic valve

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12
Q

Valves ensure a one-way flow of blood. They open and close in response to what?

A

Pressure changes

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13
Q

The tricuspid and bicuspid valves are together known as the atrioventricular valves. Why is this?

A

Because they are located between an atrium and a ventricle.

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14
Q

The aortic and pulmonary valves are together known as what?

A

Semilunar valves

(crescent moon-shaped cusps)

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15
Q

What are the two closed circulation circuits? Which sides of the heart are associated with each?

A
  1. Pulmonary (right is the pump)
  2. Systemic (left is the pump)
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16
Q

Deoxygenated blood returns to the heart (right atrium) via 3 main veins. What are they?

A
  1. Superior vena cava
  2. Inferior vena cava
  3. Coronary sinus
17
Q

Cardiac Myofibrils are bundles of fibre that make up specialised muscle cells of the heart.

They contain less sarcoplasmic reticulum and need WHAT from extracellular fluid for contraction?

A

Calcium

18
Q

What are autorhythmic fibres?

A

Cardiac muscle cells that are self-excitable

(i.e. generate spontaneous action potentials that then trigger heart muscle contractions)

19
Q

What are the two main functions of autorhythmic fibres?

A
  • They act as a pacemaker
  • Form the cardiac conduction system
20
Q

Order the main components of the conduction system.

  • Right and left bundle branches
  • Atrioventricular (AV) Node
  • The Sinoatrial (SA) Node
  • Purkinje Fibers
  • Bundle of His
A
  1. Sinoatrial node (SA)
  2. Atrioventricular node (AV)
  3. Bundle of His
  4. Bundle branches
  5. Prukinje Fibers

SABBP

21
Q

What are the 3 main steps in the action potential of a heart contractile fibre?

A
  1. Depolarisation (Na+ inflow)
  2. Plateau (Ca2+ inflow and K+ outflow)
  3. Repolarisation (Ca2+ channels close)
22
Q

Pressure and volume change throughout the cardiac cycle. During a cycle, atria and ventricles alternately contract and relax, forcing blood from high to low pressure areas.

A cardiac cycle consists of three phases. What are they?

A
  1. Atrial systole
  2. Ventricular systole
  3. Relaxation period (diastole)
23
Q

Cardiac output equals the stroke volume multiplied by the heart rate.

What is stroke volume?

A

The volume of blood ejected by the ventricle each contraction.

24
Q

Changing heart rate is the body’s principal short-term way of controlling cardiac output and blood pressure.

What are the main factors that affect heart rate?

A

> Neural Factors

E.g. Sympathetic/parasympathetic impulses; Baroreceptors detect changes in blood pressure and send information to the cardiovascular centre…

> Hormones and Ions

E.g. Epinephrine, norepinephrine…

> Other Factors:

E.g. Age, gender, physical fitness and temperature