Ap 2 - Ch 20 - Heart

Front 1

What structures form the cardiovascular system?

Back 1

Blood, heart, blood vessels.

Front 2

What cavity does the heart lie in & what are the boundaries of this cavity? What does it rest on?

Back 2

Mediastinum - b/w sternum, vertebral column & 1st rib, diaphragm. It rests on diaphragm.

Front 3

The heart is enclosed & held in place by the ___ which also protects it.

Back 3

Pericardium

Front 4

Outer layer of heart composed of tough, inelastic, dense irregular CT which prevents ___ of heart, protects & anchors heart to mediastinum.

Back 4

Fibrous pericardium. Overstretching.

Front 5

Inner layer of heart composed of parietal, visceral layer.

Back 5

Serous pericardium.

Front 6

Outer layer of serous pericardium fused to fibrous pericardium vs. inner layer AKA ___ adhered to heart surface.

Back 6

Parietal. Visceral (epicardium).

Front 7

Slippery substance in pericardial cavity that reduces friction b/w membranes.

Back 7

Pericardial fluid

Front 8

What are the 3 layers of the heart from superficial to deep?

Back 8

Epicardium, myocardium, endocardium.

Front 9

Heart layer consisting of mesothelium & CT which gives a smooth, slippery texture to heart.

Back 9

Epicardium

Front 10

Heart layer consisting of cardiac mm that makes up 95% of heart. Striated, involuntary.

Back 10

Myocardium

Front 11

Heart layer consisting of endothelium & CT which provides smooth inner heart lining. Continuous w/ endothelial lining of large blood vessels attached to heart.

Back 11

Endocardium

Front 12

Inflammation of pericardium, including acute/chronic.

Back 12

Pericarditis

Front 13

Inflammation of myocardium that usually occurs as complication of viral infection.

Back 13

Myocarditis

Front 14

Inflammation of endocardium usually involving heart valves.

Back 14

Endocarditis

Front 15

Small pouches on anterior surface of each atrium that increaes capacity of each atrium.

Back 15

Auricle (L/R)

Front 16

Grooves on heart surface containing blood vessels, fat & separate chambers. Each one marks external boundary b/w 2 chambers of heart.

Back 16

Sulcus

Front 17

Sulcus that encircles most of heart & marks boundary b/w atria & ventricles.

Back 17

Coronary sulcus

Front 18

2 sulcus that separate R/L ventricles.

Back 18

Anterior/posterior interventricular sulcus

Front 19

The R atrium receives deoxygenated blood from what 3 veins?

Back 19

Superior/inferior vena cava, coronary sinus

Front 20

R atrium forms R border of heart & has smooth posterior, rough anterior wall due to muscular ridges called ___ that aid in contraction.

Back 20

Pectinate mm

Front 21

Structure dividing R/L atria is called ___ containing an ovale depression called ___, remnant of foramen ovale (closes after birth).

Back 21

Interatrial septum. Fossa ovalis.

Front 22

Blood passes from R atrium to R ventricle through ___ valve, AKA R ___ valve. R ventricle forms most of anterior surface of heart.

Back 22

Tricuspid valve. R atrioventricular valve.

Front 23

Raised bundles of myocardium that are part of conduction system of heart. Found in L/R ventricles.

Back 23

Trabeculae carneae

Front 24

Tricuspid/bicuspid valves connected to ___ which are tendons of ___. Found in L/R ventricles.

Back 24

Chordae tendinae. Papillary mm.

Front 25

Internal partition that divides L/R ventricles.

Back 25

Interventricular septum

Front 26

Blood passes from R ventricle to large artery called ___ via ___ valves.

Back 26

Pulmonary trunk. Pulmonary semilunar valve.

Front 27

L atrium forms heart base. Has smooth anterior/posterior walls. Receives blood from 4 ___.

Back 27

Pulmonary veins

Front 28

Blood from L atrium flows through L ventricle through ___ valve.

Back 28

Bicuspid (mitral, L atrioventricular) valve

Front 29

L ventricle is thickest chamber forming heart apex. Like R ventricle it also has ___, ___, ___.

Back 29

Trabeculae carneae, chordae tendinae, papillary mm.

Front 30

Blood passes from L ventricle through ___ valve into ___.

Back 30

Aortic valve. Ascending aorta.

Front 31

During fetal life, a temporary blood vessel ___ shunts blood from ___ into ___. At birth this closes & becomes ___.

Back 31

Ductus arteriosus. Pulmonary trunk. Aorta. Ligamentum arteriosum.

Front 32

Atrial walls are (thick/thin) b/c they deliver blood to ventricles.

Back 32

Thin

Front 33

Ventricle walls are (thick/thin) b/c they pump blood greater distances.

Back 33

Thick

Front 34

R ventricle wall is (thicker/thinner) than L ventricle wall b/c it pumps blood to ___ whereas L ventricle pumps blood to ___.

Back 34

Thinner. Lungs. Whole body.

Front 35

What are 4 functions of the fibrous skeleton of the heart?

Back 35

Foundation for which heart valves attach, attach points for cardiac mm bundles, prevents valves overstretching, electrical insulator preventing action potential spread from atria to ventricles.

Front 36

Valves open/close in response to ___ to ensure one-way flow of blood.

Back 36

Pressure changes

Front 37

When AV valve is open, pointed ends of cusps project into ___.

Back 37

Ventricle

Front 38

Blood back flow is prevented by contraction of ___ tightening chorda tendinae which prevent valve cusps from everting.

Back 38

Papillary mm

Front 39

___ valves (include aortic & pulmonary) pass blood from heart to arteries but prevent back flow of blood into ventricles.

Back 39

Semilunar valves

Front 40

What closes the semilunar valves?

Back 40

As ventricles relax, blood backflow fills valves cusps, pushing them closed.

Front 41

What are 2 areas in the heart where there are no valves?

Back 41

B/w R atrium & superior vena cava, L atrium & pulmonary vein.

Front 42

Failure of a valve to close completely.

Back 42

Insufficiency/incompetence

Front 43

Valvular narrowing that restricts blood flow.

Back 43

Stenosis

Front 44

Caused by acute rheumatic fever & congenital bicuspid valve associated w/ early valvular calcification.

Back 44

Aortic stenosis

Front 45

Scar formation or congenital defect causing narrowing of mitral valve.

Back 45

Mitral stenosis

Front 46

Condition where 1 or both cusps of abnormally thickened mitral valve protrude into L atrium during contraction. Blood backflow from L ventricle to L atrium increases risk of sudden death.

Back 46

Mitral valve prolapse

Front 47

Which side of the heart is the pump for pulmonary vs. systemic circulation?

Back 47

R - pulmonary. L - systemic.

Front 48

Trace the pathway of blood flow through the heart.

Back 48

Superior/inferior vena cava, coronary sinus, R atrium, tricuspid valve, R ventricle, pulmonary valve, pulmonary trunk/arteries, lungs, pulmonary vein, L atrium, bicuspid valve, L ventricle, aortic valve, aorta/systemic arteries.

Front 49

Blood flow supplying myocardium is called ___.

Back 49

Coronary circulation

Front 50

2 principle arteries branching from ascending aorta carrying oxygenated blood are ___.

Back 50

R/L coronary arteries

Front 51

Branch of L coronary artery that supplies both ventricle walls & sits in anterior interventricular sulcus.

Back 51

Anterior intraventricular aa/branch

Front 52

Branch of L coronary artery that supplies L atrium/ventricle & lies in L coronary sulcus.

Back 52

Circumflex branch

Front 53

Branch of R coronary artery that supplies both ventricle walls & sits in posterior interventricular sulcus.

Back 53

Posterior intraventricular aa/branch

Front 54

Branch of R coronary artery that supplies R ventricle & sits in R side of coronary sulcus.

Back 54

Marginal branch

Front 55

Connection of 2 or more arteries supplying same region called ___ provide alternate route called ___.

Back 55

Anastomoses. Collateral circuits.

Front 56

Deoxygenated blood returns to R atrium primarily via principal vein, ___ located in ___.

Back 56

Coronary sinus. Coronary sulcus.

Front 57

Vein that supplies coronary sinus & drains anterior side of R/L ventricles.

Back 57

Great cardiac v.

Front 58

Vein that supplies coronary sinus & drains posterior side of R/L ventricles.

Back 58

Middle cardiac v.

Front 59

Vein that supplies coronary sinus & drains R atrium/ventricle.

Back 59

Small cardiac v.

Front 60

Vein that supplies coronary sinus & drains R ventricle & empties directly into R atrium.

Back 60

Anterior cardiac v.

Front 61

Partial obstruction of coronary arteries usually accompanied by angina pectoris.

Back 61

Myocardial ischemia

Front 62

Reduced oxygen supply

Back 62

Hypoxia

Front 63

Complete obstruction to blood flow in coronary artery commonly called a heart attack.

Back 63

Myocardial infarction

Front 64

Compared to skeletal mm fibers, cardiac mm is ___ in length, ___ in diameter, & ___ in transverse section.

Back 64

Shorter length. Larger diameter. Less circular.

Front 65

Cardiac mm exhibit ___ giving fibers a "stair step" appearance.

Back 65

Branching

Front 66

Cardiac mm fibers connected by thickening of sarcolemma called ___. ___ allow action potentials to spread & contract as a single, coordinated unit.

Back 66

Intercalated discs. Gap junctions.

Front 67

Cardiac mm have same actin/myosin, band arrangements but more ___ than skeletal mm fibers. Also have smaller ___ & therefore smaller reserve of Ca+2.

Back 67

Mitochondria. Sarcoplasmic reticulum.

Front 68

Specialized cardiac mm cells are ___ b/c they are self-excitable. They generate spontaneous ___ that trigger heart contractions.

Back 68

Autorhythmic. Action potentials.

Front 69

Autorhythmic fibers act as a ___ to set rhythm of electrical excitation for heart contraction.

Back 69

Pacemaker

Front 70

Autorhythmic fibers form ___, the route for spreading action potential in heart. This pathway ensures cardiac chambers contract in coordinated manner.

Back 70

Conduction system

Front 71

What are the 5 components of the conduction system?

Back 71

Sinoatrial node (SA, pacemaker), Atrioventricular node (AV), atrioventricular bundle (bundle of His), R/L bundle branches, Purkinje fibers.

Front 72

Signals from ___ system & ___ ie, epinephrine, modify rate/strength heartbeat but not fundamental rhythm.

Back 72

Nervous system. Hormones.

Front 73

Time interval when a 2nd contraction can't be triggered. Longer than contraction itself.

Back 73

Refractory period

Front 74

For ATP, cardiac mm cells rely on mitochondria performing (aerobic/anaerobic) respiration. Also produce ATP from ___.

Back 74

Aerobic cellular respiration. Creatine phosphate.

Front 75

Recording of electrical signals that accompany each cardiac cycle.

Back 75

Electrocardiogram (ECG)

Front 76

What are 4 things the ECG can help determine?

Back 76

If conducting pathway is abnormal, heart is enlarged, regions are damaged, cause of chest pain.

Front 77

Time on ECG when ventricular contractile fibers are depolarized during plateau phase of action potential.

Back 77

S-T segment

Front 78

Time on ECG from ventricular depolarization to end of ventricular repolarization.

Back 78

Q-T segment

Front 79

Contraction phase

Back 79

Systole

Front 80

Relaxation phase

Back 80

Diastole

Front 81

Describe the relation of the ECG waves w/ atrial/ventricular systole.

Back 81

See p737 Tortora. Pg18 AP2 notes.

Front 82

ECG wave associated w/ atrial depolarization - spread of impulse from SA node over atria, & atrial systole.

Back 82

P wave

Front 83

ECG wave associated w/ ventricular depolarization involving AV bundle, AV branches, Purkinje fibers.

Back 83

QRS complex

Front 84

Why is action potential slower at AV node?

Back 84

Here fibers have smaller diameters & fewer gap junctions, giving atria time to contract.

Front 85

ECG wave associated w/ ventricular repolarization & diastole.

Back 85

T wave

Front 86

What does a cardiac cycle consist of?

Back 86

Systole/diastole of both atria, systole/diastole of both ventricles = one heart beat.

Front 87

What 2 measurements change during the cardiac cycle?

Back 87

Pressure, volume

Front 88

Study cardiac cycle.

Back 88

p739 Tortora, p19 AP2 notes.

Front 89

0.05 sec when all valves are closed. MM contracting but not yet shortening.

Back 89

Isovolumetric contraction

Front 90

Period when SL valves are open.

Back 90

Ventricular ejection

Front 91

What is stroke volume & how is it calculated?

Back 91

Volume ejected per beat. SV = end diastolic volume - end systolic volume.

Front 92

How much blood remains in each ventricle at end of ventricular diastole in a resting person? What is this volume called?

Back 92

End diastolic volume is 130 mL.

Front 93

Wave on aortic pressure curve caused by rebound of blood off closed cusps of aortic valve.

Back 93

Dicrotic wave

Front 94

Heartbeat sound comes from ___ in blood flow caused by ___ not from ___ of heart mm.

Back 94

Turbulence. Valves closing. Contraction.

Front 95

What causes the 1st heart sound (lubb)?

Back 95

Blood turbulence associated w/ AV valves closing after ventricular systole.

Front 96

What causes the 2nd heart sound (dubb)?

Back 96

SL valves closing close to end of ventricular systole.

Front 97

What is cardiac output & how is it calculated?

Back 97

Blood volume ejected from L ventricle into aorta each min. CO = stroke volume x heart rate.

Front 98

Ratio b/w max cardiac output & cardiac output at rest.

Back 98

Cardiac reserve

Front 99

What are the 3 factors that regulate stroke volume?

Back 99

Preload (degree of stretch before heart contracts), contractility (forcefulness of contraction of individual ventricular mm fibers), afterload (pressure that must be overcome before SL valve can open).

Front 100

What is the Frank-Starling law of the heart?

Back 100

A greater preload (stretch) on cardiac mm before they contract increases their force of contraction during systole.

Front 101

Preload is proportional to ___, which is determined by length of ventricular diastole & venous return.

Back 101

End diastolic volume

Front 102

The stretch of contraction at any preload is affected by positive/negative ___.

Back 102

Inotropic agents (influence contractility of mm tissue)

Front 103

Are the following (positive/negative) inotropic agents that (increase/decrease) contractility? Increase Ca+2 inflow, NS stimulation, epinephrine/norepinephrine.

Back 103

Positive. Increase.

Front 104

Are the following (positive/negative) inotropic agents that (increase/decrease) contractility? ANS inhibitors, acidosis, anaesthetics.

Back 104

Negative. Decrease.

Front 105

Increased afterload (increases/decreases) stroke volume b/c more blood remains in ventricles at end of systole.

Back 105

Decreases

Front 106

Condition where blood begins to remain in ventricles, increasing EDV & eventually causing an overstretched heart & less forceful contraction. L ventricle failure results in ___ edema. R ventricle failure results in ___ edema.

Back 106

Congestive heart failure. L - pulmonary edema. R - peripheral edema.

Front 107

Cardiac output depends on heart rate & stroke volume. What is the body's principal mechanism of controlling cardiac output/blood pressure?

Back 107

Changing heart rate

Front 108

Nervous system regulation of heart originates in cardiovascular centre in ___.

Back 108

Medulla oblongata

Front 109

Sensory receptor that monitors limb movement, ie exercise. Stimulates rise in HR.

Back 109

Proprioceptor

Front 110

Sensory receptor that monitors chemical changes in O2/CO2 blood levels.

Back 110

Chemoreceptor

Front 111

Sensory receptor that monitors blood pressure - detects stretching in major arteries/veins. Located in ___ & ___.

Back 111

Baroreceptor. Arch of aorta. Carotid sinus.

Front 112

From thoracic level of spinal cord, ___ extend to SA/AV node, myocardium to trigger norepinephrine release.

Back 112

Cardiac accelerator nerves

Front 113

Norepinephrine enhances entry of ___ through channels to increase ___ of myocardium, resulting in increased SV, CO. Offsets decrease in preload.

Back 113

Ca+2. Contractility.

Front 114

___ nerves release NT ___ to decrease HR by slowing rate of node depolarization. Parasympathetic impulses have little effect on ventricle contractility.

Back 114

R/L vagus nn. (CN 10). Acetylcholine.

Front 115

What 3 hormones affect HR?

Back 115

Epinephrine, norepinephrine, thyroid hormones

Front 116

What 3 cations affect HR? How does each affect HR?

Back 116

Na+, K+, Ca+2. Increase of these cations in blood: Na+ blocks Ca+2 inflow during action potential to decrease force of contraction. K+ blocks action potential generation. Ca+2 speeds HR, heart contractility.

Front 117

Elevated resting HR.

Back 117

Tachycardia

Front 118

What region of the heart is innervated by the sympathetic division but not parasympathetic?

Back 118

Ventricular myocardium

Front 119

Resting HR under 50 beats/min.

Back 119

Bradycardia

Front 120

How does regular exercise affect the body?

Back 120

Decrease anxiety/depression, controls weight, reduces blood clotting.

Front 121

Heart develops from mesodermal cells called the ___ which then form a pair of elongated strands called ___ when then form ___.

Back 121

Cardiogenic area. Cardiogenic cords. Primitive heart tube.

Front 122

What are the 5 regions (tail-head) that develop from the primitive heart tube?

Back 122

Sinus venosus, atrium, ventricle, bulbus cordis, truncus arteriosus.

Front 123

Fetal heart structure that forms part of R atrium, coronary sinus, SA node.

Back 123

Sinus venosus

Front 124

Fetal heart structure that forms part of R/L atria, auricles.

Back 124

Atrium

Front 125

Fetal heart structure that forms L ventricle, part of R ventricle.

Back 125

Ventricle

Front 126

Fetal heart structure that forms part of R ventricle.

Back 126

Bulbus cordis

Front 127

Fetal heart structure that forms pulmonary trunk, ascending aorta.

Back 127

Truncus arteriosus

Front 128

Mesodermal thickenings that divide primitive atrioventricular canal into R/L AV canals separating R/L atria from R/L ventricles.

Back 128

Endocardial cushions

Front 129

Opening in interatrial septum before birth vs. after birth.

Back 129

Foramen ovale. Fossa ovalis.

Front 130

When is the partitioning of the heart complete?

Back 130

End of 5th week

Front 131

Describe the 5 steps in the conduction system sequence.

Back 131

1) Sinoatrial node in R atrium spontaneously depolarize to threshold called pacemaker potential to trigger action potential (AP). AP travels to both atria via gap junctions in intercalated discs. Atria contract as result. 2) AP travels in atria mm until it reaches atrioventricular node in interatrial septum b/w R/L atria. 3) From AV node AP enters AV bundle. Only site where AP can conduct from atria to ventricles due to fibrous skeleton insulation. 4) From AV bundle AP enters R/L bundle branches which extend through interventricular septum towards heart apex. 5) From AV bundle branches, large diameter Purkinje fibers conduct AP from heart apex upward to rest of ventricular myocardium. Here ventricles contract & push blood through semilunar valves.

Front 132

Describe the 3 steps of a cardiac action potential - depolarization, plateau, repolarization.

Back 132

1) Contractile fibers have resting membrane potential of -90mV. When AP brings fiber to threshold, voltage-gated fast Na+ channels open. Na+ flows into cell causing depolarization. Na+ channels inactivate to decrease inflow. 2) Period of maintained depolarization due in part to opening of voltage-gated slow Ca+2 channels in sarcolemma. Ca+2 moves into cell from outside & Ca+2 released from sarcoplasmic reticulum both trigger contraction. Depolarization maintained b/c Ca+2 flows in, volt-gated K+ channels open to allow K+ out to balance Ca+2 influx. 3) Recovery of resting membrane potential. After delay, additional K+ open & Ca+2 close, allowing overall outflow of positive ions to restore membrane potential to -90mV.