Heart and cardiovascular system Flashcards

1
Q

Location of heart

A

Thorax between the lungs in the inferior mediastinum

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2
Q

Size of heart

A

size of fist

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3
Q

Layers of the heart wall

A

epicardium, myocardium, endocardium

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4
Q

surface of the heart

A

visceral pericardium

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5
Q

Four valves of the heart

A

tricuspid, bicuspid, pulmonary, aortic

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6
Q

Flow of blood through the heart

A

Deoxygenated blood enters into the heart through the superior and inferior vena cava.

Blood travels into the right atrium and flows through the tricuspid valve into the right ventricle.

Blood is pushed through the pulmonary valve into the

pulmonary artery and lungs when the right ventricle contracts and pick up oxygen.

Oxygenated blood is then carried back to the heart by the pulmonary veins into the left atrium through the mitral valve and into the left ventricle.

Contraction of the left ventricle forces the blood through the aortic valve, through the aorta, and out to the entire body.

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7
Q

arteries that supply the myocardium

A

right and left coronary arteries

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8
Q

veins that drain the myocardium

A

cardiac veins

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9
Q

cardiac muscle tissue

A

specialized muscle tissue found only in the heart, striated, involuntary

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10
Q

Pacemaker of the heart

A

SA node

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11
Q

Normal EKG waves

A

-P Wave - caused by depolarization of atria
-QRS Complex - caused by depolarization of ventricles
-T Wave - caused by repolarization of ventricles

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12
Q

Stroke Volume (SV)

A

The volume of blood pumped forward with each ventricular contraction.

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13
Q

normal stroke volume

A

70 ml/beat

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14
Q

Left side of heart

A

-Fully oxygenated blood arrives from lungs via pulmonary veins

-Blood sent to all organs of the body via aorta

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15
Q

Right side of the heart

A

-Oxygen-poor blood arrives from inferior and superior venae cave

-Blood sent to lungs via pulmonary trunk

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16
Q

Right and left atria

A

-Two superior chambers
-Receive blood returning to heart
-Auricles (seen on surface) enlarge chamber

17
Q

Right and left ventricles

A

-Two inferior chambers
-Pump blood into arteries

18
Q

Atrioventricular (AV) valves

A
  • control blood flow between atria and ventricles
  • Right AV valve has three cusps (tricuspid valve)
  • Left AV valve has two cusps (mitral valve, formerly ‘bicuspid’)
19
Q

Semilunar valves

A
  • control flow into great arteries; open and close because of blood flow and pressure
  • Pulmonary semilunar valve: in opening between right ventricle and pulmonary trunk
  • Aortic semilunar valve: in opening between left ventricle and aorta
20
Q

First heart sound (S1)

A

louder and longer “lubb,” occurs with closure of AV valves

21
Q

First Heart sound (S2)

A

softer and sharper “dupp,” occurs with closure of semilunar valves

22
Q

The entire cardiac cycle

A

Ventricular filling (during diastole)
Isovolumetric contraction (during systole)
Ventricular ejection (during systole)
Isovolumetric relaxation (during diastole)

23
Q

define cardiac output and explain its importance

A

Cardiac output is the amount of blood pumped by the heart per minute. It is determined by the stroke volume and heart rate,

24
Q

functional significance of the intercellular junctions between
cardiac muscle cells

A

Intercalated discs are small connections that join cardiac muscle cells (cardiomyocytes) to each other. Gap junctions are part of the intercalated discs. When one cardiac muscle cell is stimulated to contract, a gap junction transfers the stimulation to the next cardiac cell. This allows the muscle to contract in a coordinated way.

25
Q

describe the heart’s pacemaker and internal electrical conduction system

A
  • Your atria (top heart chambers), telling them to contract.
  • The atrioventricular (AV) node, delaying the signal until your atria are empty of blood.
  • The bundle of His (center bundle of nerve fibers), carrying the signal to the Purkinje fibers.
  • The Purkinje fibers to your ventricles (bottom heart chambers), causing them to contract.
26
Q

describe the nerve supply to the heart and explain its role

A

The heart is innervated by sympathetic and parasympathetic fibers from the autonomic branch of the peripheral nervous system. The network of nerves supplying the heart is called the cardiac plexus. It receives contributions from the right and left vagus nerves, as well as contributions from the sympathetic trunk.

27
Q

describe the unusual action potentials of cardiac muscle and relate them to the
contractile behavior of the heart

A

action potential form SA nodes cause the atria to depolarize and contract forcing blood into the ventricles.

28
Q

describe in detail one complete cycle of heart contraction and relaxation.

A
  1. Ventricular filling
    Ventricles expand and their pressure drops below that of the atria AV valves open and blood flows into the ventricles

Filling occurs in three phases:
A. Rapid ventricular filling: first one-third
B. Diastasis: second one-third; slower filling
P wave occurs at the end of diastasis
C. Atrial systole: final one-third; atria contract
End-diastolic volume (EDV) achieved in each ventricle (about 130 mL of blood)

  1. Isovolumetric contraction
    a. Atria repolarize, relax and remain in diastole for rest of cardiac cycle
    b. Ventricles depolarize, causing QRS complex, and begin to contract
    c. AV valves close (as ventricular blood surges back against the cusps)
    Heart sound S1 occurs at the beginning of this phase
    “Isovolumetric” because although ventricles contract, they do not eject blood
    Pressures in aorta and pulmonary trunk are still greater than pressures in the ventricles
    Cardiocytes exert force, but with all four valves closed, the blood cannot go anywhere
  2. Ventricular ejection
    a. Begins when ventricular pressure exceeds arterial pressure and semilunar valves open

b. Pressure peaks in left ventricle at about 120 mm Hg and 25 mm Hg in the right
First: rapid ejection: blood moves out of ventricles quickly
Then: reduced ejection: slower flow with lower pressure
Ejection lasts about 200 to 250 ms
(T wave of ECG occurs late in this phase)
Stroke volume (SV) is about 70 mL
“Ejection fraction” is about 54% of EDV (130 mL)
60 mL remaining blood is end-systolic volume (ESV)

29
Q

relate the events of the cardiac cycle to the volume of blood entering and leaving the
heart

A

As volume increases, pressure decreases. As pressure increases, volume decreases.

30
Q

define cardiac output and explain its importance

A

Cardiac Output- Amount ejected by each ventricle in 1 minute.

Cardiac output = heart rate x stroke volume

  • CO=75 beats/min x 70mL/beat= 5250mL/min
  • Athletes 20L/min

Cardiac Reserve—The difference between a person’s maximum and resting CO

  • Disease diagnostic
31
Q

explain how the right and left ventricles achieve balanced output

A

. Right ventricular output exceeds left Ventricular output
2. Pressure backs up
3. Fluid accumulates in pulmonary tissue

  1. Left ventricular output exceeds right ventricular output
  2. Pressure backs up
  3. Fluid accumulates in systemic tissue
32
Q

Identify the Four Valves of the Heart

A

Valves ensure one-way flow of blood through heart

The Atrioventricular Valves
* Controls blood flow between atria and ventricles
* Right AV valve has three cusps (tricuspid valve)
* Left AV valve has two cusps (mitral valve, formerly ‘bicuspid’)

The Semilunar Valves (Pulmonary and Aortic Valve)
* Controls flow into pulmonary artery and aorta; open and
close because of blood flow and pressure