Chapter 20 The Heart Flashcards Preview

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Flashcards in Chapter 20 The Heart Deck (207):
1

where is the heart located?

- in the mediastinum

2

what kind of region is the mediastinum?

an anatomical region

3

the mediastinum, an anatomical region, extends from what to what in the thorax cavity?

extends from the sternum to the vertebral column, from first rib to the diaphragm, and between the lungs

4

what does the medial cavity of the thorax also contain besides the heart?

also contains the great vessels (largest veins and arteries in the body), thymus, esophagus, trachea, lymph nodes, nerves and other tissues

5

the heart rests on the superior surface of the?

of the diaphragm

6

the heart extends or lays?

obliquely and measures about 5 in. from the base to apex; second rib to the diaphragm (5th intercostal space)

7

what is the PMI?

Point of Maximal Intensity; point of where the apex contracts the chest wall (easily feel heart beating)

8

what is the apical pulse?

heartbeat at the apex and is heard with a stethoscope (counted for a full min.)

9

what is the double walled sac of the heart called?

the pericardium

10

what does the pericardium do for the heart?

membrane that surrounds, protects and secures the position of the heart w/in the mediastinum

11

what does the pericardium consists of?

- fibrous pericardium (superficial layer)
- serous pericardium (deeper layer)

12

describe the difference of texture of the fibrous and serous pericardium?

- fibrous pericardium is tough, dense connective tissue layer
- serous pericardium is slippery, delicate, thinner, two-layer serous membrane

13

what does the fibrous pericardium (superficial layer) do for the heart?

anchors heart to surrounding structures and attaches to the diaphragm

14

what prevents the heart to overfill with blood; preventing the heart to overstretch?

the fibrous pericardium (superficial layer)

15

what are the two layers called that make up the serous pericardium (deeper layer)?

- parietal layer (parietal pericardium)
- visceral layer (visceral pericardium/epicardium)

16

what does the parietal pericardium (parietal layer) of the serous pericardium (deeper layer) line?

the internal surface of the fibrous pericardium

17

what is the parietal layer (parietal pericardium) of the serous pericardium (deeper layer) composed of?

mesothelium and underlying areolar connective tissue

18

the visceral layer (epicardium) of the serous pericardium (deeper layer) adheres tightly to what surface?

to the surface of heart; which is one of the layers of the heart wall

19

what is the visceral layer (epicardium) of the serous pericardium (deeper layer) composed of?

mesothelium, underlying areolar connective tissue, variable layers of fibroelastic connective tissue and adipose

20

where is the pericardial cavity of the serous pericardium located?

between the parietal and visceral layers, thin film of serous fluid

21

what are the 3 distinct layers of the heart wall that are all richly supplied with blood vessels?

- epicardium (visceral pericardium)
- myocardium (middle layer)(cardiac muscle)
- endocardium

22

what is the visceral layer of the serous pericardium that also covers the outer surface of the heart called?

the epicardium

23

what does the epicardium consists of and what does it attach to?

exposed mesothelium and an underlying layer of areolar connective tissue that is attached to the myocardium

24

where are the coronary blood vessels located?

in the epicardium (visceral layer of the serous pericardium)

25

what is the muscular wall of the heart that forms the bulk of the heart?

myocardium (the middle layer of the heart wall)

26

what is the myocardium composed of?

spiral bundles of cardiac muscle tissue, blood vessels and nerves

27

describe the cardiac muscle bundles?

branching cardiac muscle cells are tethered together by crisscrossing connective tissue fibers (collagen and elastin) that are arranged in spiral or circular bundles

28

what forms the fibrous skeleton of the heart (cardiac skeleton)?

the connective tissue that are especially thick and dense in some areas of the myocardium

29

what covers the inner surfaces of the heart including the heart valves?

endocardium (the inner surface of the heart wall)

30

what is the endocardium composed of?

simple squamous epithelium (endothelium)

31

what is continuous with the endothelial lining of the blood vessels leaving and entering the heart?

endocardium

32

cardiac muscle tissue forms what kind of layers that wrap around the what and what within the walls of the what?

- concentric layers around the atria (atrial musculature)
- spiral layers within the walls of the ventricles (ventricular musculature)

33

In addition to cardiac muscle tissue, the heart wall also contains a dense connective tissue network forming what?

the fibrous skeleton of the heart

34

what does the fibrous skeleton (cardiac skeleton) of the heart reinforce and what does it anchor?

- the fibrous skeleton of the heart reinforces the myocardium internally and anchors the cardiac muscle fibers

35

what is thicker in some areas than others in of the fibrous skeleton of the heart (cardiac skeleton)?

the network of collagen and elastin fibers of the cardiac skeleton

36

what consists of 4 dense connective tissue rings surrounding all the 4 cardiac valves like handcuffs?

the fibrous skeleton (cardiac skeleton) of the heart

37

what are the 4 important functions of the fibrous skeleton, four dense connective tissue rings?

- anchors the valve cusps
- prevents over dilation of the valve openings
- provides the point of insertion for the bundles of heart muscle
- blocks the direct spread os electrical impulses from atrial to ventricular muscles

38

what are the four chambers of the heart?

- right atrium
- left atrium
- right ventricle
- left ventricle

39

which chambers of the heart are superior and are receiving chambers?

the right and left atrium

40

what is the right and left atrium separated by?

the interatrial septum

41

what is an auricle of the left and right atrium?

a small, wrinkled protruding pouch-like appendage that sits externally of the right and left atrium

42

what are pectinate muscles of the right atrium only?

muscle bundles that are smooth-walled posterior part, in anterior part in the internal of the right atrium only

43

which chambers of the heart are relatively thin-walled chambers (thin layer of myocardium)?

the right and left atrium

44

what encircles most of the heart and externally marks the junction of the atria and ventricles?

atrioventricular groove (coronary sulcus)

45

what are inferior and discharging chambers?

the right and left ventricles

46

what separates the right and left ventricles?

the interventricular septum

47

what are the internal, irregular ridges of muscles called and what are the muscle bundles that play a role in valve function called?

- trabeculae carneae

- papillary muscles

48

which chambers of the heart has relatively thick-walled chambers (thicker layer of myocardium)?

the right and left ventricles

49

what marks the external boundary between the ventricles?

interventricular sulcus (anterior and posterior)

50

which chamber of the heart receives blood from 3 veins?

the right atrium

51

what are the three veins called in the right atrium?

- superior vena cava
- inferior vena cava
- coronary sinus

52

what does the superior vena cava do for the right atrium?

returns blood from body regions superior to the diaphragm

53

what vein returns blood to the right atrium from body regions inferior to the diaphragm?

the inferior vena cava

54

the coronary sinus collects blood from where and drops it off to the right atrium?

the myocardium

55

what kind of muscles are found in the internal anterior wall of the right atrium that extends into the auricle?

pectinate muscles (musculi pectinati)

56

what is a prominent feature found in the interatrial septum of the right atrium?

the fossa ovalis (remnant of the foramen ovale)

57

where does the blood drain to from the right atrium and through what?

into the right ventricle through the right atrioventricular valve (tricuspid)

58

true or false? the right and left atrium are the same thickness.

true

59

the left atrium receives blood from how many and which veins?

4 pulmonary veins (2 right pulmonary veins from the right lung and 2 left pulmonary veins from the left lung)

60

where are the pectinate muscles found in that is associated with the left atrium?

found only in the auricle

61

where does the blood drain to from the left atrium and through what?

drains into the left ventricle through the left atrioventricular valve (bicuspid/mitral)

62

which chamber forms most of the anterior surface of the heart?

the right ventricle

63

describe the difference in the cavity shape of the ventricles of the heart.

the right ventricle is a flat crescent shape and the left ventricle is nearly circular.

64

what are chordae tendineae and what do they do?

they are tendon like cords that connects the cusps of the tricuspid valve in the right ventricle and the bicuspid valve in the left ventricle to the papillary muscles.

65

where is the blood from the right ventricle pumped to and through what?

to the pulmonary trunk through pulmonary semilunar valve

66

where is the blood from the left ventricle pumped to and through what?

to the aorta through the aortic semilunar valve

67

how many valves are in the heart and what are they called?

4 valves: the right atrioventricular (tricuspid) valve; the left atrioventricular (bicuspid/mitral) valve; the pulmonary and the aortic semilunar valve

68

blood returning to the heart fills what?

the atria, pressing against the atrioventricular (AV) valves.

69

what forces the atrioventricular (AV) valves to open?

the increased pressure

70

as ventricles fill with blood, how are the atrioventricular (AV) valve flaps? what does this mean about the the blood drainage?

the AV valve flaps hang limply into the ventricles which means that blood drains passively from atrium to ventricle

71

after blood drains passively from the atrium to ventricle, what would force additional blood into the ventricles?

atria contraction

72

when the AV valves open, which pressure is greater?

atrial pressure is greater than ventricular pressure

73

if the pressure is high what does this mean for the volume and vice versa?

when the pressure is high, the volume is low; when the pressure is low, the volume is high

74

when does the atrioventricular (AV) valves close?

when the ventricles contract, forcing blood against the AV valve cusps

75

what happens when ventricles contract?

forces blood against the atrioventricular (AV) valve cusps

76

what prevents the valve flaps from everting into the atrium when the ventricles contract?

the papillary muscle contraction and the chordae tendineae tightening

77

when the atrioventricular (AV) valves are closed, which pressure is greater?

atrial pressure is less than ventricular pressure

78

what forces the semilunar valves to open?

as ventricles contract and the intraventricular pressure rises, blood is pushed up against the semilunar valves, forcing them open

79

what forces the semilunar valves to close?

as ventricles relax and the intraventricular pressure falls, blood flows back from arteries , filling the cusps of semilunar valves and forcing them to close

80

what is the pulmonary circuit?

blood vessels that carry blood to and from the lungs, which allow for gas exchange at the lungs

81

the right side of the heart is what kind of circuit pump?

the pulmonary circuit pump

82

what is the systemic circuit?

blood vessels that carry blood to and from all body tissues

83

the left side of the heart is what kind of circuit pump?

the systemic circuit pump

84

where does the blood gain oxygen and loses carbon dioxide and vice versa?

blood loses carbon dioxide and gains oxygen in the pulmonary capillaries; blood loses oxygen and gains carbon dioxide in the systemic capillaries

85

does both sides of the heart pump at the same time?

yes

86

oxygen poor blood returns from the body tissues back to the heart through what?

superior vena cava (SVC), inferior vena cava (IVC), and the coronary sinus

87

oxygen poor blood is carried to the lungs to get oxygenated in what?

two pulmonary arteries

88

oxygen rich blood returns to the heart by what?

four pulmonary veins to the left atrium

89

what is the functional blood supply of the heart called?

the coronary circulation

90

what is the shortest circulation in the body?

the coronary circulation, which is to and from the heart

91

where does the right coronary artery branch to?

to the posterior interventricular artery and the marginal artery

92

where does the left coronary artery branch to?

anterior interventricular artery and the circumflex artery

93

what are branches of more than one artery supplying the same region that eventually fuse called?

anastomosis (junction of vessels)

94

where does the major cardiac veins drain to?

into the coronary sinus

95

what is striated and contracts by the sliding filament mechanism (just like skeletal muscle)?

cardiac muscle fibers

96

what are short, flat (less circular than skeletal muscle), branched, and usually has one centrally located nucleus?

the cardiac muscle fibers

97

which muscle fiber has intercellular spaces filled with loose connective tissue matrix (endomysium) and numerous capillaries (more than in skeletal muscle)?

the cardiac muscle fibers

98

which muscle fiber has large and numerous mitochondria (25% of volume)?

the cardiac muscle fiber

99

which muscle fiber's plasma membrane of adjacent cells interlock at junctions called intercalated discs, which contains desmosomes and gap junctions?

the cardiac muscle fiber

100

which muscle fiber's myofibrils vary greatly in diameter and branch extensively (less dramatic banding patterns)?

the cardiac muscle fiber

101

which muscle fiber's T tubules are wider and fewer (enter cells once/sarcomere at Z discs)?

the cardiac muscle fiber

102

which muscle fiber's sarcoplasmic reticulum is simpler and lacks large terminal cisternae (no triads)?

the cardiac muscle fiber

103

what are the two types of cardiac muscle fibers?

- the auto-rhythmic (non-contractile) fibers
- the contractile fibers

104

which cardiac muscle fibers are specialized and are self-excitable (generates action potential (AP) repeatedly)?

auto-rhythmic (non-contractile) muscle fibers

105

which cardiac muscle fibers account for 1% of the cardiac muscle fiber?

auto-rhythmic (non-contractile) fibers
brains and hormones controls rate

106

which cardiac muscle fibers forms the bulk of atrial and ventricular walls?

contractile fibers

107

which cardiac muscle fibers account for 99% of the cardiac muscle fibers?

contractile fibers

108

what causes the rapid depolarization in the action potential of contractile cardiac muscle fiber?

it is due to Na+ inflow (influx) when voltage-gated fast Na+ channels open
- from the sarcolomere

109

what causes the plateau (maintaining depolarization) in the action potential of contractile cardiac muscle fiber?

due to the influx of Ca++ when voltage-gated slow Ca++ (sarcolemma 20% - sarcoplasmisc reticulum 80%) channels open and K+ efflux when some K+ channels open

110

what causes the re-polarization of the action potential of the contractile muscle fiber?

due to the closure of Ca++ channels and the efflux of K+ when additional voltage-gated K+ channels open

111

depolarization leads to what and repolarization leads to what?

- contraction
- relaxation

112

which refractory period of the contractile muscle fiber does the action potential lasts about 200 msec?

the absolute refractory period

113

in which refractory period the membrane cannot respond at all (a second contraction cannot be triggered)?

the absolute refractory period

114

in the cardiac muscle cell, which refractory period does the action potential lasts longer than the contraction?

the absolute refractory period

115

which refractory period of the cardiac muscle lasts about 50 msec?

the relative refractory period

116

in which refractory period of the cardiac muscle does the membrane respond to a stronger than normal stimulus by initiating another action potential (AP)?

the relative refractory period

117

what does a pacemaker potential (prepotential) do?

initiates the action potential (AP) that spread throughout the heart to trigger its rhythmic contractions (spontaneous depolarization)

118

what are the steps of the action potential of autorhythmic cardiac muscle fiber?

- prepotential (pacemaker potential)
- depolarization
- repolarization

119

what are the steps of the action potential of contractile fibers?

- depolarization
- plateau
- repolarization

120

which channels open at -40mv (threshold) in the action potential of autorhythmicfibers?

fast Ca++ channels open

121

what causes the voltage gated Na+ channels open in the action potential of autorhythmic fiber?

the pacemaker potential (prepotential) at -60mv

122

the fast voltage gated Ca++ channels close at what membrane potential of the action potential of autorhythmic fiber?

+10mv then the voltage gated K+ channels open

123

why would you never have tetnis in cardiac?

b/c of the instability of the Na+ channels; action potential spontaneously occurs

124

what forms the cardiac conduction system?

the autorhythmic (noncontractile) fibers

125

name the five parts of the electrical conduction system of the heart?

- sinoatrial (SA) node
- atrioventricular (AV) node
- bundle of HIS (AV bundle of his)
- right and left bundle branches
- purkinje fibers

126

the sinus rhythm ( about 70 bpm) are set by the what?

pace/rhythm set by the SA node

127

the junctional rhythm (about 40-60 bpm) are set by what?

pace/rhythm set by the AV node

128

what is the electrocardiograph?

the instrument used to record the ECG/EKG

129

what are the 3 distinguishable waves (deflection waves) of the electrocardiogram?

- P wave lasts 0.8 sec
- QRS complex lasts about 0.08 sec
- T wave lasts about 0.16 sec

130

what is the electrocardiogram?

recording of the electrical conduction system

131

which wave of the electrocardiogram represents the atrial depolarization?

P wave lasts 0.8 sec

132

the P wave of the electrocardiogram is a result from what?

result from the movement of depolarization wave from SA node through the atria

133

what happens approx. 0.1 sec after the P wave begins?

the atria contracts

134

which wave of the electrocardiogram represents the rapid ventricular depolarization?

the QRS complex lasts about 0.08 sec

135

action potential spreads through ventricular contractile fibers during which wave of the electrocardiogram?

QRS complex lasts about 0.08 sec

136

which wave of the electrocardiogram represents ventricular repolarization?

T wave lasts about 0.16 sec

137

what is also called the P-R interval?

P-Q interval

138

what is the P-Q interval?

from beginning of atrial excitation to the beginning of ventricular excitation

139

which part of the electrocardiogram includes atrial depolarization and atrial contraction?

P-Q interval

140

where does the spread of the depolarization wave through the rest of conduction system happen on the electrocardiogram?

P-Q interval

141

what does the S-T segment represent on the electrocardiogram?

the action potential (AP) is in its plateau phase

142

where on the electrocardiogram shows that the entire ventricular myocardium is depolarized?

at the S-T segment

143

which part of the electrocardiogram shows the period from beginning of ventricular depolarization through ventricular repolarization?

Q-T interval

144

what is systole?

contraction

145

what is diastole?

relaxation

146

where is the lag time/a pause in the electrical conduction system?

at the atrioventricular (AV) node

147

what is auscultation?

the act of listening to sounds within the body usually done with a stethoscope

148

what are the 2 distinguishable sounds of the heart?

- first sound (S1) lubb sound
- second sound (S2) dubb sound

149

which sound of the heart is louder and longer?

the first sound (S1)

150

the S1 of the heart sound is associated with what?

the closure of atrioventricular (AV) valves

151

the S1 of the heart sound is associated with what?

the closure of semilunar valves

152

what is heart murmur?

abnormal heart sounds; clicking, rushing or gurgling sound

153

heart murmurs are fairly common in who?

in young children (2-4 yrs. old)

154

what may a heart murmur often indicate?

a heart valve problem

155

what are some examples of heart murmurs?

- incompetent/insufficient valve
- stenotic valve

156

what does it mean to have an incompetent/insufficient valve?

blood backflows or regurgitates meaning the valve doesn't fully close producing a swishing sound

157

what does it mean to have a stenotic valve?

the valve opening is narrowed (valve doesn't fully open) which means blood flow through valve is restricted producing a high pitched sound or click when valve should be wide open, but isn't

158

what does isovolumetric mean?

all valves are closed

159

when all the events associated with blood flow through the heart during one complete heartbeat is known as what?

cardiac cycle which involves successive changes in pressure and volume in the heart

160

depolarization then contraction equals?

systole

161

repolarization then relaxation equals?

diastole

162

what are the phases of the cardiac cycle/

- atrial systole
- atrial diastole
- ventricular systole
- ventricular diastole

163

what is End Diastolic Volume (EDV)?

amount of blood that collects in a ventricle during diastole (about 120-130 mL per beat)

164

what is End Systolic Volume (ESV)?

volume of blood remaining in a ventricle after it has contracted (about 50-60 mL per beat)

165

what is Stroke Volume (SV)?

volume of blood ejected by one ventricle with each beat

166

how would you calculate stroke volume (SV)?

EDV - ESV = SV (stroke volume)

167

how would get an increase in SV (stroke volume)?

usually, an increase in force of ventricular contraction

168

with each heart beat, each ventricle pumps about what % of blood?

about 60% (ejection fraction) = SV/EDV*100

169

describe the process of phase 1 of the cardiac cycle?

- ventricular filling (mid-to-late diastole)
- atrial contraction

170

describe the process of phase 2a of the cardiac cycle?

- isovolumetric contraction phase (EDV)
(ventricular systole) (atrial in diastole)

171

describe the process of phase 2b of the cardiac cycle?

- ventricular ejection phase
(ventricular systole) (atria in diastole)

172

describe the process of phase 3 of the cardiac cycle?

- isovolumetric relaxation (ESV)
(early diastole)

173

what has the ability to stretch and recoil?

arteries

174

what is the dicrotic notch representing?

aorta bulge out

175

what is cardiac output (CO)?

the amount of blood pumped out by each ventricle in 1 minute

176

what is the formula to get cardiac output (CO)?

stroke volume (SV) * heart rate (HR) = CO

177

what is the normal adult blood volume?

about 5L (a little more than 1 gallon)

178

what provides a useful indication of ventricular efficiency over time?

cardiac output (CO)

179

what is highly variable and increases dramatically in response to exercise?

cardiac output (CO)

180

what are the three factors that affect the stroke volume (SV)?

- preload: degree of stretch of heart muscle (EDV)
- contractility: degree of the force (ESV)
- afterload: back pressure by arterial-aorta blood (ESV)

181

what is the typical resting adult heart?

SV=70 ml/beat
HR=75 beats/min

182

what is preload?

the degree of stretch of cardiac muscle cells before they contract proportional to the EDV

183

what is the Frank-Starling Law of Heart?

the more the heart fills with blood, the greater force of contraction

184

what exhibits a length-tension relationship?

the cardiac muscle

185

what is shorter than optimal length at rest?

the cardiac muscle cells

186

what are the two factors that determine EDV?

- duration of ventricular diastole: filling time
- venous return: amount of blood returning to the heart

187

duration of ventricular diastole: the filling time depends entirely on the what?

the heart rate

188

the venous return: amount of blood returning to the heart depends on what?

- cardio output (CO)
- skeletal muscle activity
- blood volume
- HR

189

what is contractility?

contractile strength at given muscle length independent of muscle stretch and EDV

190

what are the agents that increase contractility called?

- positive inotropic agents
- thyronxine, glucagon, NE, epinephrine, drugs, stimulates Ca++ influx
- sympathetic stimulation - increased Ca++ influx - more cross bridges

191

what are the agents that decrease contractility called?

- negative inotropic agents
- acidosis, increased extracellular K+, calcium channel blockers

192

what is the afterload?

- the pressure ventricles must overcome to eject blood
- back pressure exerted on the aortic and pulmonary semilunar valves by arterial blood

193

what would increase the afterload?

- hypertension
- resulting in increased ESV (more blood left behind) and reduced SV (stroke volume)
- atherosclerosis (narrowing of the arteries)

194

what is the EDV and stroke volume like at rest?

- EDV is low
- myocardium stretches less
- stroke volume is low

195

what is the EDV and stroke volume like with exercise?

- EDV increases
- myocardium stretches more
- stroke volume increases

196

what are the two most important regulations of the heart rate?

- ANS regulation
- chemical regulation

197

what is the ANS (autonomic nervous system) Regulation?

- cardiac centers (cardiovascular Center)
- adjusts cardiac activity
- located in the Medulla Oblongata

198

what does the cardioacceletory center in the medulla oblongata control?

- controls the sympathetic neurons
- increases heart rate (HR)

199

the postganglionic sympathetic fibers (T1-T5 levels of spinal cord) innervates what through the cardiac plexus?

- SA and AV nodes
- myocardia
- coronary arteries
- increases HR and force of contraction

200

what does the cardioinhibitory center in the medulla oblongata do?

- sends inhibitory impules via the Vagus nerve (CN X)
- decreases the HR (heart rate)

201

postganglionic parasympathetic neurons; ganglia near the heart wall; heavily innervates what?

-SA and AV nodes
-decreases the HR (vagus nerve)

202

the cardiac centers (cardiovascular centers) receives input from what?

- sensory receptors (part of cardiac reflex pathway)
- higher brain centers (cerebral cortex, hypothalamus and limbic system)

203

what are the factors that increase heart rate?

positive chronotropic agents (NE, Epi)

204

what are the factors that decrease the heart rate?

negative chronotropic agents (ACh)

205

what does proprioceptors monitor of the cardiac reflexes?

- monitors position of limbs and muscles
- physical activity results in a quick rise in heart rate at onset

206

what does baroreceptors monitor of the cardiac reflexes?

- monitors changes in systemic blood pressure (stretching os major vessels: aortic arch, carotid arteries)
- a decrease in systemic blood pressure results in an increase in cardiac activity

207

what does chemoreceptors monitor of the cardiac reflexes?

- monitors changes in chemical composition of blood (Ph, dissolved Oxygen)
- a decrease in blood Ph can result in an increase in cardiac activity