A&p 2 Saladin 6Th Ed. Chapter 19 - The Heart

Front 1

Cardiovascular system

Back 1

Heart and blood vessels

Front 2

Circulatory system

Back 2

Heart, blood vessels, and the blood

Front 3

Pulmonary circuit

Back 3

Carries blood to lungs for gas exchange and back to heart

Front 4

Systemic circuit

Back 4

Supplies oxygenated blood to all tissues of the body and returns it to the heart

Front 5

Pericardium

Back 5

double-walled sac (pericardial sac) that encloses the heart
Allows heart to beat without friction, provides room to expand, yet resists excessive expansion
Anchored to diaphragm inferiorly and sternum anteriorly

Front 6

Parietal pericardium

Back 6

—outer wall of sac
Superficial fibrous layer of connective tissue
Deep, thin serous layer

Front 7

Epicardium

Back 7

Visceral pericardium
heart covering
Serous lining of sac turns inward at base of heart to cover the heart surface
Adipose in thick layer in some places
Coronary blood vessels travel through this layer

Front 8

Pericardial cavity

Back 8

cavity—space inside the pericardial sac filled with 5 to 30 mL of pericardial fluid

Front 9

Endocardium

Back 9

Smooth inner lining of heart and blood vessels
Covers the valve surfaces and is continuous with endothelium of blood vessels

Front 10

Myocardium

Back 10

Layer of cardiac muscle proportional to work load
Muscle spirals around heart which produces wringing motion

Front 11

What are the four chambers?

Back 11

Right and left atria
Right and left ventricles

Front 12

Interatrial septum

Back 12

Wall that separates atria

Front 13

Interventricular septum

Back 13

Muscular wall that separates ventricles

Front 14

How many valves and what are they?

Back 14

Pulmonary Semilunar
Aortic semilunar
Tricuspid
Bicuspid

Front 15

Atrioventricular (AV) valves

Back 15

control blood flow between atria and ventricles

Front 16

Right AV valve

Back 16

has three cusps (tricuspid valve)
no oxygen

Front 17

Left AV valve

Back 17

has two cusps (mitral or bicuspid valve)

Front 18

Chordae tendineae

Back 18

cords connect AV valves to papillary muscles on floor of ventricles
Prevent AV valves from flipping inside out or bulging into the atria when the ventricles contract

Front 19

Semilunar valves

Back 19

control flow into great arteries; open and close because of blood flow and pressure

Front 20

Pulmonary semilunar valve

Back 20

in opening between right ventricle and pulmonary trunk

Front 21

Aortic semilunar valve

Back 21

in opening between left ventricle and aorta

Front 22

Myocardial infarction

Back 22

heart attack
Interruption of blood supply to the heart from a blood clot or fatty deposit (atheroma) can cause death of cardiac cells within minutes

Front 23

Cardiocytes

Back 23

striated, short, thick, branched cells, one central nucleus surrounded by light-staining mass of glycogen

Front 24

Interdigitating folds

Back 24

folds interlock with each other, and increase surface area of contact

Front 25

Desmosomes

Back 25

weldlike mechanical junctions between cells
Prevents cardiocytes from being pulled apart

Front 26

Gap junctions

Back 26

allow ions to flow between cells; can stimulate neighbors
Entire myocardium of either two atria or two ventricles acts like single, unified cell

Front 27

The Conduction System

Back 27

Coordinates the heartbeat
Composed of an internal pacemaker and nervelike conduction pathways through myocardium

Front 28

Sinoatrial (SA) node

Back 28

modified cardiocytes
Pacemaker initiates each heartbeat and determines heart rate
Pacemaker in right atrium near base of superior vena cava
Signals spread throughout atria

Front 29

Atrioventricular (AV) node

Back 29

Located near the right AV valve at lower end of interatrial septum
Electrical gateway to the ventricles
Fibrous skeleton—insulator prevents currents from getting to ventricles from any other route

Front 30

Atrioventricular (AV) bundle (bundle of His)

Back 30

Bundle forks into right and left bundle branches
Branches pass through interventricular septum toward apex

Front 31

Purkinje fibers

Back 31

Nervelike processes spread throughout ventricular myocardium
Signal passes from cell to cell through gap junctions

Front 32

Sympathetic nerves

Back 32

Increase heart rate and contraction strength
Dilates coronary arteries to increase myocardial blood flow

Front 33

Parasympathetic nerves

Back 33

Parasympathetic stimulation reduces the heart rate

Front 34

Systole

Back 34

atrial or ventricular contraction

Front 35

Diastole

Back 35

atrial or ventricular relaxation

Front 36

Sinus rhythm

Back 36

normal heartbeat triggered by the SA node
Set by SA node at 60 to 100 bpm
Adult at rest is 70 to 80 bpm (vagal tone)

Front 37

Nodal rhythm

Back 37

if SA node is damaged, heart rate is set by AV node, 40 to 50 bpm

Front 38

Intrinsic ventricular rhythm

Back 38

if both SA and AV nodes are not functioning, rate set at 20 to 40 bpm
Requires pacemaker to sustain life

Front 39

Ectopic focus

Back 39

another part of heart fires before the SA node
Caused by hypoxia, electrolyte imbalance, or caffeine, nicotine, and other drugs

Front 40

Arrhythmia

Back 40

any abnormal cardiac rhythm
Failure of conduction system to transmit signals (heart block)
Bundle branch block
Total heart block (damage to AV node)

Front 41

P wave

Back 41

SA node fires, atria depolarize and contract
Atrial systole begins 100 ms after SA signal

Front 42

QRS complex

Back 42

Ventricular depolarization
Complex shape of spike due to different thickness and shape of the two ventricles

Front 43

T wave

Back 43

Ventricular repolarization and relaxation

Front 44

Pressure

Back 44

causes a fluid to flow (fluid dynamics)
Pressure gradient—pressure difference between two points
Fluid flows down its pressure gradient from high pressure to low pressure

Front 45

Resistance

Back 45

opposes fluid flow
Great vessels have positive blood pressure
Ventricular pressure must rise above this resistance for blood to flow into great vessels

Front 46

Auscultation

Back 46

listening to sounds made by body

Front 47

First heart sound (S1

Back 47

louder and longer “lubb,” occurs with closure of AV valves, turbulence in the bloodstream, and movements of the heart wall
occurs at the beginning of Isovolumetric contraction

Front 48

Second heart sound (S2),

Back 48

softer and sharper “dupp,” occurs with closure of semilunar valves, turbulence in the bloodstream, and movements of the heart wall
occurs as blood rebounds from the closed semilunar valves and the ventricle expands...Isovolumetric relaxation

Front 49

Phases of the Cardiac Cycle

Back 49

Ventricular filling
Isovolumetric contraction
Ventricular ejection
Isovolumetric relaxation
All the events in the cardiac cycle are completed in less than 1 second!

Front 50

Pulse

Back 50

surge of pressure produced by each heart beat that can be felt by palpating a superficial artery with the fingertips

Front 51

Tachycardia

Back 51

resting adult heart rate above 100 bpm
Stress, anxiety, drugs, heart disease, or fever
Loss of blood or damage to myocardium

Front 52

Bradycardia

Back 52

resting adult heart rate of less than 60 bpm
In sleep, low body temperature, and endurance-trained athletes

Front 53

Preload

Back 53

the amount of tension in ventricular myocardium immediately before it begins to contract
Increased preload causes increased force of contraction

Front 54

Frank–Starling law of the heart

Back 54

SV  EDV
Stroke volume is proportional to the end diastolic volume
Ventricles eject as much blood as they receive
The more they are stretched, the harder they contract

Front 55

Afterload

Back 55

blood pressure in the aorta and pulmonary trunk immediately distal to the semilunar valves
Opposes the opening of these valves
Limits stroke volume