Adult Cardio 1 (Normal anatomy and physiology of the cardiovascular system)

Question 1

What are the two purposes of the circulatory system?

Answer 1

-To deliver oxygen, nutrients, and other substances to all the body’s cells
-To remove the waste products of cellular metabolism

Question 2

Delivery of oxygen and nutrients, as well as the removal of waste, is achieved by a complex array of tubing (___ ___) and a pump (the ___)

Answer 2

Blood vessels, heart

Question 3

Cardiovascular function is ____ and ____, with cooperation from other systems, specifically the nervous system and endocrine system

Answer 3

Continuous; automatic

Question 4

Nutrients and oxygen are supplied by the ____ and ____ systems

Answer 4

Digestive; respiratory

Question 5

Gaseous waste is removed by the ____

Answer 5

Lungs

Question 6

Other waste products are removed by the ___ and ___

Answer 6

Liver and kidneys

Question 7

The heart structures are categorized by what 3 functions?

Answer 7

-Structures that support the circulation of pulmonary and systemic blood flow through the heart
-Structures that maintain the cells of the heart
-Structures that stimulate and control the heart action

Question 8

What structures support the circulation of pulmonary and systemic blood flow through the heart?

Answer 8

-Heart wall and fibrous skeleton
-Valves
-Great vessels

Question 9

What structures maintain the cells of the heart?

Answer 9

-Vessels of the coronary circulation
-Lymphatic vessels of the heart

Question 10

What structures stimulate and control the heart action?

Answer 10

Nerves and specialized muscle cells that direct rhythmic contraction and relaxation of heart muscles

Question 11

The heart is shaped as a quadrangular pyramid and is orientated as if the pyramid has fallen onto one of its sides so that its base faces the ___ ___ ___ and its apex is pointed towards the ___ ____ ____

Answer 11

-Posterior thoracic wall
-Anterior thoracic wall

Question 12

The anterior surface of the heart contains almost all of the ___ ___

Answer 12

Right ventricle

Question 13

The inferior surface of the heart is also known as the ____ surface

Answer 13

Diaphragmatic

Question 14

The inferior (diaphragmatic) surface of the heart contains…

Answer 14

Mostly right ventricle and some of the left ventricle

Question 15

The right lateral surface of the contains the ___ ___

Answer 15

Right atrium

Question 16

The left lateral surface of the heart contains…

Answer 16

The left ventricle and a small part of the left atrium

Question 17

The posterior surface of the heart contains…

Answer 17

The left ventricle and most of the left atrium

Question 18

The broad end of the heart (base) is _____, while the tip (apex) is ____

Answer 18

Superior; inferior

Question 19

Since the heart sits on the diaphragm, it can cause symptoms like ___ and ___

Answer 19

Nausea/vomiting

Question 20

The heart is rotated ___ and ___

Answer 20

Laterally, inferiorly

Question 21

The apex of the heart lies under the ___ ___

Answer 21

Left nipple

Question 22

Most of the left ventricle is back under the ___ and towards the ___

Answer 22

Arm, back

Question 23

The ____ is the membrane that separates the right and left ventricle

Answer 23

Septum

Question 24

The ____ is the outermost layer of the heart

Answer 24

Epicardium

Question 25

The ____ is the middle layer of the heart

Answer 25

Myocardium

Question 26

The ____ is the inner surface of the heart

Answer 26

Endocardium

Question 27

The ___ ____ ____ prevents friction from the heart beating (acts as lubricant)

Answer 27

Pericardial cavity fluid

Question 28

With too much pericardial cavity fluid, the heart would not be able to ____

Answer 28

Pump

Question 29

The ____ layer encapsulates the heart in the chest and separates it from the lungs

Answer 29

Parietal

Question 30

Layers of the heart (starting with the outermost layer):

Answer 30

-Fibrous pericardium
-Parietal layer of pericardium
-Pericardial cavity
-Epicardium
-Myocardium
-Endocardium
-Heart chamber

Question 31

The heart wall contains what layers?

Answer 31

-Epicardium
-Myocardium
-Endocardium

Question 32

A heart contains how many chambers?

Answer 32

4 (2 upper, 2 lower)

Question 33

The upper chambers contain…

Answer 33

-Right atrium
-Left atrium

Question 34

The role of the upper chambers is to…

Answer 34

Recieve incoming blood

Question 35

The lower chambers are more muscular and contain…

Answer 35

-Right ventricle
-Left ventricle

Question 36

The role of the lower chambers is to…

Answer 36

Pump blood out of the heart

Question 37

The role of the right atrium:

Answer 37

Receives oxygen-poor blood from the body and pumps it to the right ventricle

Question 38

The role of the right ventricle:

Answer 38

Pumps oxygen-poor blood to the lungs

Question 39

The role of the left atrium:

Answer 39

Receives oxygen-rich blood from the lungs and pumps it to the left ventricle

Question 40

The role of the left ventricle:

Answer 40

Pump oxygen-rich blood to the body

Question 41

The ___ ventricle is thicker than the ____

Answer 41

Left; right

Question 42

The left ventricle is a ___-___ system

Answer 42

High-pressure

Question 43

The left ventricle has ____ contractions

Answer 43

Concentric (more round)

Question 44

The right ventricle is a ___-___ system

Answer 44

Lower-pressure

Question 45

The right ventricle has ____ contractions

Answer 45

Bellows

Question 46

The ____ ventricle has more workload because it has to pump blood further/harder

Answer 46

Left

Question 47

The left ventricle is more ____, so it will generate a strong pressure even with little effort

Answer 47

Circular

Question 48

The right ventricle is more ____ and causes a bellow contraction

Answer 48

Angular

Question 49

The left ventricle pumps blood to the rest of the body, so it needs more ____

Answer 49

Pressure

Question 50

If you want blood to pump from left to right, we need to have more pressure on the ____

Answer 50

Left

Question 51

Blood flows in circulation not only because of the beating of the heart, but because it is a continuous cycle of ___ ____ on one side and ___ ___ on the other side

Answer 51

High pressure; low pressure

Question 52

Heart ____ are parts of your heart that act like doors by opening and closing to let blood flow from one area of the heart to another

Answer 52

Valves

Question 53

Valves help ensure that blood moves at the right ___ and in the correct ____

Answer 53

Time; direction

Question 54

What are the four valves of the heart?

Answer 54

-Aortic valve
-Mitral valve
-Pulmonic valve
-Tricuspid valve

Question 55

Step 1 in the route of blood:

Answer 55

Blood that needs oxygen flows from your body into the right atrium

Question 56

Step 2 in the route of blood:

Answer 56

The blood flows through the tricuspid valve to the right ventricle

Question 57

Step 3 in the route of blood:

Answer 57

The right ventricle pumps the blood through the pulmonary valve and into your lungs, where it picks up oxygen

Question 58

Step 4 in the route of blood:

Answer 58

The oxygen-rich blood then flows to the left atrium

Question 59

Step 5 in the route of blood:

Answer 59

The heart pumps through the mitral valve into the left ventricle

Question 60

Step 6 in the route of blood (last step)

Answer 60

From the left ventricle, the blood flows through the aortic valve to the rest of your body

Question 61

The Tricuspid valve has 3 leaflets, which are:

Answer 61

-Anterior
-Posterior
-Septal

Question 62

The tricuspid valve and its leaflets allow blood to flow from the ___ ___ to the ___ ___

Answer 62

Right atrium to right ventricle

Question 63

The tricuspid valve also prevents blood from flowing ____

Answer 63

Backward

Question 64

What are the three leaflets of the pulmonary valve?

Answer 64

-Right
-Left
-Anterior

Question 65

The pulmonic valve and its leaflets allow blood to pump from the ___ ____ to the ___ ____

Answer 65

Right ventricle; pulmonic artery

Question 66

The pulmonic artery leads to the ____ where the blood picks up oxygen

Answer 66

Lungs

Question 67

The pulmonic valve also prevents blood from flowing ____

Answer 67

Backward

Question 68

What are the two leaflets of the mitral valve?

Answer 68

-Anterior
-Posterior

Question 69

The mitral valve and its leaflets allow blood to flow from the ____ into the ___ ___

Answer 69

Lungs; left atrium

Question 70

The mitral valve and its leaflets also prevent blood from flowing ___

Answer 70

Backward

Question 71

What are the three leaflets of the aortic valve?

Answer 71

-Right
-Left
-Posterior

Question 72

The aortic valve and its leaflets open to let blood flow from your heart’s ___ ____ to the ___

Answer 72

Left ventricle; aorta

Question 73

The ____ is the largest blood vessel in your body

Answer 73

Aorta

Question 74

The aorta brings ____ ____ from your heart to the rest of the body

Answer 74

Oxygenated blood

Question 75

The aortic valve prevents blood from flowing ___

Answer 75

Backward

Question 76

When the heart is enlarged, the muscles are going to stretch and pull the leaflets open which causes blood to squeeze back and cause a ____ by moving backward

Answer 76

Leak

Question 77

Both the left coronary artery and the right coronary artery start at the ___ ____

Answer 77

Aortic arch

Question 78

The right coronary artery supplies blood to the ___ ___ and ___ ___

Answer 78

Right atrium and right ventricle

Question 79

Branches of the right coronary artery supply the ____ node and the ____ node

Answer 79

-Sinoatrial (SA)
-Atrioventricular (AV)

Question 80

The sinoatrial and atrioventricular nodes send ___ ___ through your heart

Answer 80

Electrical signals

Question 81

Branches of the right coronary artery also deliver blood to 1/3 of the _____ ____, which is the wall between the heart’s 2 chambers

Answer 81

Interventricular septum

Question 82

The left coronary artery supplies blood to your ___ ___ and ___ ____

Answer 82

Left atrium and left ventricle

Question 83

The left coronary artery is where ___ ___ arrives from your lungs before your heart pumps it out to the rest of the body

Answer 83

Oxygenated blood

Question 84

Branches of the left coronary artery supply blood to the other 2/3 of your ___ ___

Answer 84

Intraventricular septum

Question 85

The coronary veins return deoxygenated blood from the myocardium back to the ____ ____

Answer 85

Right atrium

Question 86

Coronary venous anatomy is highly variable, but it is generally comprised of what three groups?

Answer 86

-Cardiac veins
-Anterior cardiac veins
-Venae cordis minimae

Question 87

Cardiac veins drain into the ___ ___

Answer 87

Coronary sinus

Question 88

Cardiac veins that drain into the coronary sinus include…

Answer 88

-Great cardiac vein
-Middle cardiac vein
-Small cardiac vein
-Posterior vein of the left ventricle
-Vein of Marshall

Question 89

Anterior cardiac veins drain directly into the ___ ___

Answer 89

Right atrium

Question 90

The venae cordis minimae are the smallest cardiac veins and they drain directly into all four chambers, but are more frequent int the ___ ___

Answer 90

Right atrium

Question 91

Takeoff of coronary arteries is immediately beyond the ___ ___ in the aorta

Answer 91

Aortic valve

Question 92

The ___ ___ has minimal blood flow during systole (when aortic valve leaflets open)

Answer 92

Coronary Ostia

Question 93

The coronary artery fills with blood during ____

Answer 93

Diastole

Question 94

___ ____ peaks during diastole

Answer 94

Coronary circulation

Question 95

____ occurs when the heart contracts to pump blood out to the rest of the body

Answer 95

Systole

Question 96

Diastole is when the heart relaxes after ____ and blood comes back to the heart to refill it before it contracts again

Answer 96

Contraction

Question 97

Coronary blood flow is approximately ____ cc/min (4-5% of total CO)

Answer 97

225

Question 98

Coronary blood flow ____ in systole

Answer 98

Decreases

Question 99

Coronary blood flow ____ in diastole

Answer 99

Increases

Question 100

Coronary blood flow is greatest during ___ ___

Answer 100

Early diastole

Question 101

If diastolic time is shortened, coronary flow is ____

Answer 101

Decreased

Question 102

Coronary artery blood flow moves from ____ to ____ surfaces

Answer 102

Epicardial to endocardial

Question 103

Epicardial coronary artery blood flow is impinged by ___ ___, affecting subendocardial vessels the greatest

Answer 103

Cardiac contraction

Question 104

____ is where the most work happens within the heart

Answer 104

Systole

Question 105

We want blood to flow from the ___ down to the ___

Answer 105

Myocardium, epicardium

Question 106

Blood flows on the surface first, and then through the arteries to get to the epicardium, meaning that the epicardium is ____ last

Answer 106

Oxygenated

Question 107

If we do not have enough oxygen, the epicardium will get oxygenated before the ____, leaving it with no oxygen

Answer 107

Endocardium

Question 108

In ____, there is low pressure with maximum blood flow in intra-myocardial vessels

Answer 108

Diastole

Question 109

In ____, there is a circumferential squeeze around intra-myocardial vessels

Answer 109

Systole

Question 110

Tachycardia is harmful because you are spending more time in ___

Answer 110

Systole

Question 111

___ ____ are given to those with tachycardia to slow heart rate

Answer 111

Beta-blockers

Question 112

What are the two main mechanisms in which coronary blood flow is controlled?

Answer 112

1. Coronary supply
2. Myocardial demand

Question 113

Coronary supply is regulated almost exactly in proportion to the need of ___ ____ (supply=demand)

Answer 113

Cardiac musculature

Question 114

Even in a resting state, __-__% of oxygen is extracted from blood in coronary circulation

Answer 114

65-75%

Question 115

To increase oxygen availability, blood flow must ___

Answer 115

Increase

Question 116

What must happen to increase delivery of oxygen?

Answer 116

-Increase heart rate
or
-Increase arterial diameter
or both

Question 117

Possible mechanisms for coronary artery dilation in response to increased oxygen needs:

Answer 117

-Release of adenosine by myocardial cells
-Release of other vasodilator substances (K+, H+, CO2, bradykinin, PGE)
-Relaxation of vessel walls in response to oxygen deficiency
-Nervous control of coronary blood flow

Question 118

The parasympathetic nervous system has ___ inflence on coronary blood flow

Answer 118

Negligible

Question 119

The sympathetic nervous system can heavily influence coronary blood flow by causing what two things?

Answer 119

-Epicardial vessel preponderance of alpha receptors
-Intramuscular vessel preponderance of beta receptors

Question 120

___ ___ is determined more by intraventricular pressure than by work of the heart

Answer 120

Myocardial demand

Question 121

____ ____ is not as closely related to the work of the heart as it is to the increase in pressure

Answer 121

Oxygen consumption

Question 122

___ ____ ____ is the primary determinant of oxygen consumptions

Answer 122

Peak muscle tension

Question 123

Heart chamber ____ (even in diastole) results in increased muscle tension

Answer 123

Dilation

Question 124

La Place’s Law states that wall tension is ____ related to the product of intraventricular pressure and internal radius, and ____ related to wall thickness

Answer 124

Directly, inversely

Question 125

La Place’s Law Formula:

Answer 125

(Pressure x radium)/(2 x wall thickness)

Question 126

A network of specialized muscle cells found in the heart’s walls send signals to the rest of the heart to cause contraction; this group of muscle cells is known as the ___ ____ ____

Answer 126

Cardiac conduction system

Question 127

What are the 5 main parts of the cardiac conduction system?

Answer 127

-SA node
-AV node
-Bundle of HIS
-Bundle branches
-Purkinje fibers

Question 128

Within the cardiac conduction system, the ___ ___ starts the sequence by causing the atrial muscle to contract

Answer 128

SA Node

Question 129

Since the SA node starts the contraction, many times it is referred to as the ___ ___

Answer 129

Anatomical pacemaker

Question 130

After the SA node causes contraction of the atrial muscles, where does the signal continue to travel?

Answer 130

-To the AV node
-Through the bundle of HIS
-Down the bundle branches
-Through the Perkinje fibers (causing the ventricles to contract)

Question 131

Cardiac myocytes are composed of myofibrils that contain ____

Answer 131

Myofilaments

Question 132

Myofibrils have distinct, repeating units called ____ which represent the basic contractile units of the myocyte

Answer 132

Sarcomeres

Question 133

The sarcomere is defined as the region of microfilament structures between two ___-___

Answer 133

Z-lines

Question 134

The sarcomere is composed of thick and thin filaments called ___ and ___

Answer 134

Actin and myosin

Question 135

Chemical and physical interactions between the actin and myosin cause the sarcomere length to shorten, and therefore the myocyte to ____ during the process of excitation-contraction coupling

Answer 135

Contract

Question 136

The interactions between actin and myosin serve as the basis for the ___ ___ theory of muscle contraction

Answer 136

Sliding filament

Question 137

Electricity in the heart comes from what three things?

Answer 137

-Sodium
-Potassium
-Polarity (more sodium outside, more potassium inside)

Question 138

The inside of the cell is negatively charged so the membrane has ___ ____

Answer 138

Action potential

Question 139

What two ions mainly exist in the extracellular space (outside of the cells)?

Answer 139

-Sodium
-Calcium

Question 140

When the membrane of a cell becomes permeable, sodium and calcium rush into the cell and give it a large ____ charge (potassium has the opposite effect)

Answer 140

Positive

Question 141

Once the ventricle is stimulated, there is an impulse that would cause a ___-___ ion channel to open and sodium to rush in

Answer 141

Voltage-gated

Question 142

When sodium rushes in, it ____ the cell and causes a positive charge inside the cell and a negative charge on the outside of the cell

Answer 142

Depolarizes

Question 143

____ recognizes the change in polarity of the cell (caused by sodium) and will come into the cell and send potassium out to bring the membrane potential/polaity closer to resting (negative)

Answer 143

Calcium

Question 144

The calcium controls everything and is a ____

Answer 144

Messenger

Question 145

Once inside the cell, calcium goes to the ____ ____ to tell it to release its stores of calcium which causes lots of calcium in the cytoplasm

Answer 145

Sarcoplasmic reticulum

Question 146

Calcium acts on actin as a messenger which opens the gate and causes the ____ and ____ to get shorter

Answer 146

Myosin, sarcomere

Question 147

Once the sarcomere has contracted, the sarcoplasmic reticulum basically collects the ____ back

Answer 147

Calcium

Question 148

The cardiac muscle tissue is also known as the ____

Answer 148

Myocardium

Question 149

When a cardiac muscle cell contracts, the ___ filaments pulls the ____ filament toward each other, causing the cell to shrink

Answer 149

Myosin; actin

Question 150

A single myosin filament connects to ___ actin filaments on either side; this unit is what makes up a sarcomere

Answer 150

2

Question 151

Intercalated discs connect cardiac muscle cells and ____ ____ relay electrical impulses from one cardiac muscle cell to another

Answer 151

Gap junctions

Question 152

____ are structures present within intercalated discs that hold cardiac muscle fibers together

Answer 152

Desmosomes

Question 153

The ____ is the cell membrane of muscle cells and is made up of longitudinal units

Answer 153

Sarcolemma

Question 154

___ ___ are extensions of cell membranes into cells and allow for the transmission of action potential into the depths of cells

Answer 154

Transverse tubules

Question 155

The ___ ____ is located around the myofibrils; when an action potential is transmitted through the transverse tubules, this releases its stored calcium which activates actin and myosin

Answer 155

Sarcoplasmic reticulum

Question 156

Actin and myosin filaments are composed of ____ protein molecules

Answer 156

Polymerized

Question 157

Actin and myosin lie __ by ___, with approximately 1500 myosin and 3000 actin filaments per myofibril

Answer 157

Side by side

Question 158

Actin filaments are very ___

Answer 158

Thin

Question 159

Myosin filaments are thicker and contain ___ ___ ___

Answer 159

Hinged cross bridges

Question 160

Actin and myosin partially interdigitate, causes the myofibril to have alternate ___ and ___ bands

Answer 160

Light and dark

Question 161

Actin filaments are attached to a ___ ___/___

Answer 161

Z membrane/disk

Question 162

Z membranes pass from myofibril to myofibril, attaching them to each other and forming __ ___

Answer 162

Z bands

Question 163

The ___ filaments reside between the actin filaments

Answer 163

Myosin

Question 164

The potion of the myofibril that lies between two successive Z bands is a ___

Answer 164

Sarcomere

Question 165

In the relaxed state, the ends of the actin filaments from two successive Z membranes barely ____, while at the same time completely covering the myosin filaments

Answer 165

Overlap

Question 166

In the contracted state, the actin filaments are pulled inward along the ___ ___ so that they overlap each other to a major extent, and the Z membranes are pulled inward until they touch the myosin filaments

Answer 166

Myosin filaments

Question 167

Each myosin filament is a coil of 2 chains wrapped around each other; at the end of each chain is a ___ ___ that looks like a two-headed golf club (called the head)

Answer 167

Globular region

Question 168

Myosin molecules are combined into ____, which are stalks of myosin from which the heads protrude at regular intervals

Answer 168

Filaments

Question 169

In the resting muscle, the myosin binding sites are covered by ____ and ____

Answer 169

Troponin and tropomyosin

Question 170

When the action potential reaches the muscle cell, ___ ___ carry the message deep into the sarcoplasm where the sarcoplasmic reticulum releases calcium

Answer 170

Transverse tubules

Question 171

Once calcium is released, it binds to ____ which makes tropomyosin move to uncover the myosin binding site

Answer 171

Troponin

Question 172

Then, the myosin heads bind to actin filaments to create ___-___ between the myosin and actin binding sites to cause contraction

Answer 172

Cross bridges

Question 173

The combined effects of actin-myosin interactions within all of the myofibrils produce muscle ____

Answer 173

Contraction

Question 174

5 steps of actin-myosin interactions leading to contraction:

Answer 174

-Calcium binds to troponin, leading to a conformational change that displaces tropomyosin from the actin binding sites
-Crossbridge formation occurs with ATP hydrolyzed into ADP+P
-Power stroke moves actin filament toward the center of the sarcomere; ADP+P are now released from the myosin heads
-Actin released with ATP binding to myosin. Myosin heads cocked back into firing position, ready to make crossbridges further downstream
-The cycle continues until calcium levels decrease, allowing calcium to dissociate from troponin. Tropomyosin returns to original conformation that blocks actin binding site.

Question 175

During contraction, there is progressively ___ overlap of the actin and myosin which causes the dark bands tp get darker

Answer 175

More

Question 176

____ is the main regulator of contraction

Answer 176

Calcium

Question 177

How does calcium initiate muscle contraction?

Answer 177

-Calcium enters the cell and goes to the sarcoplasmic reticulum
-Calcium-induced calcium release from sarcoplasmic reticulum
-Calcium binds to troponin to cause tropomyosin to move away from actin binding site

Question 178

How does calcium cause muscle relaxation?

Answer 178

-Cessation of inward flow of calcium
-Uptake and storage of calcium into the sarcoplasmic reticulum (active transport)
-Drop in intracellular calcium

Question 179

The composition of ___ and ____ ions in myocardial cells is different

Answer 179

Intracellular, extracellular

Question 180

At rest, the internal cellular environment is more ____ charged as compared to the external environment

Answer 180

Negatively

Question 181

Substances can travel through the cell membrane by what two methods?

Answer 181

-Assisted diffusion (mediated transport)
-Active transport

Question 182

With assisted diffusion, you can have either ___ or __ __ ___ __

Answer 182

Pores, voltage-gated ion channels

Question 183

What are two examples of active transport?

Answer 183

-Sodium potassium pump
-Sodium calcium pump

Question 184

At baseline, the sodium-potassium pump maintains a ___ charge inside the myocardial cell

Answer 184

Negative

Question 185

The ____ of the membrane to the ions determines the electrical environment of the cell

Answer 185

Permeability

Question 186

At rest, the membrane integrity is such that only a slight movement of the ions is permitted, so the relative ___ charge of the internal environment is preserved

Answer 186

Negative

Question 187

Upon stimulation, the voltage-gated pores on the cell membrane are activated such that the permeability to ___ and ___ are changed; this causes assisted-diffusion to occur, resulting in elctropositivity in the cell

Answer 187

Sodium and potassium

Question 188

Next, the ___ ___ ___ will be activated

Answer 188

Active transport pumps

Question 189

Upon stimulation, the influx of sodium through the inward sodium channels reverses the ____ of the cell

Answer 189

Polarity

Question 190

The reverse polarity triggers the influx of potassium through the outward potassium channels, which ____ polarity

Answer 190

Restores

Question 191

What are the 4 phases of an action potential?

Answer 191

-Depolarization
-Plateau
-Final Repolarization
-Return to RMP

Question 192

What happens during the depolarization phase of an action potential?

Answer 192

-Sodium influx
-Cell interior becomes more positive
-At threshold, fast channels open causing a rush of sodium inward with briefly allows the cell to become more positive than the outside

Question 193

What happens during the plateau phase of an action potential?

Answer 193

-Rapid influx of sodium is terminated
-Sodium-potassium and sodium-calcium pumps become active
-Calcium entering the cell stimulates further release of calcium from sarcoplasmic reticulum causing contraction

Question 194

What happens during the final repolarization phase of an action potential?

Answer 194

-Preventing further inflow of sodium and calcium
-Continues potassium efflux out of the cell
-Intracellular environment becomes more negative
-Reestablish resting membrane potential

Question 195

What happens during the 4th and final phase of an action potential?

Answer 195

-Final cleanup of sodium by the sodium-potassium pump
-Intracellular calcium restored by active transport to the sarcoplasmic reticulum (needs magnesium)

Question 196

What are the 4 steps of signal propagation?

Answer 196

1. Sinus node impulse
2. Impulse passes through atrioventricular node
3. Ventricular impulses
4. Recovery

Question 197

The ____ period is the period following depolarization during which no ew cardiac action potential can be initiated by a stimulus

Answer 197

Refractory

Question 198

The ____ (absolute) refractory period corresponds to the time needed for the reopening of channels that permit sodium and calcium influx (phase 0 through half of phase 3)

Answer 198

Effective

Question 199

The ____ refractory period occurs near the end of repolarization (following the effective refractory period); during this time, the membrane can be depolarized again, but only by a greater than normal stimulus

Answer 199

Relative

Question 200

The phases of depolarization and repolarization occur somewhat differently in the ___ and ____ nodes; this allows these cells to generate action potentials independently and automatically

Answer 200

SA and AV

Question 201

Depolarization begins with a less ___ resting membrane potential, then proceeds to a slow upstroke (Phase 0) and usually lack a plateau phase (phase 2)

Answer 201

Negative

Question 202

There is also a ___ ___ ___ mediated by calcium (transient and long-lasting channels) and sodium ions flowing through “slow channels” of the cell membrane are responsible for the action potential of the SA and AV nodes

Answer 202

Slow inward current

Question 203

A take home message is that cardiac output is the result of the synchrony between ___, ____, and ____ events of the heart

Answer 203

Cellular, electrical, mechanical

Question 204

Stroke volume is governed by what two things?

Answer 204

-Entropy
-Preload

Question 205

At a heart rate of 75 BMP, ___ seconds are spent in systole and ___ second in diastole for each minute

Answer 205

23; 37

Question 206

____ time is constant, therefore as heart rate increases, ____ decreases

Answer 206

Systolic; diastolic

Question 207

At heart rate of 120 BMP, there is ___ seconds spent in systole and ____ seconds spent in diastole

Answer 207

36; 24

Question 208

____ compromises diastolic time and reduces vascular circulation

Answer 208

Tachycardia

Question 209

___ ____ is the amount of blood ejected by the heart per beat (mL)

Answer 209

Stroke volume

Question 210

___ ___ is the total volume of blood ejected per minute (L/min)

Answer 210

Cardiac output

Question 211

___ ___ is the amount of blood ejected in relation to the total amount available (%)

Answer 211

Ejection fraction

Question 212

___ ____ explains how cardiac output is adjusted for body surface area (L/min/m^2)

Answer 212

Cardiac index

Question 213

Formula for calculating cardiac output:

Answer 213

CO= stroke volume x heart rate

Question 214

____ is the volume of blood in ventricles at the end of diastole (end diastolic pressure)

Answer 214

Preload

Question 215

What conditions can increase preload?

Answer 215

-Hypervolemia
-Regurgitation of cardiac valves
-Heart failure

Question 216

____ is the resistance that the left ventricle must overcome to circulate blood

Answer 216

Afterload

Question 217

What conditions may increase afterload?

Answer 217

-Hypertension
-Vasoconstriction

Question 218

An increased afterload causes an increased ___ ___

Answer 218

Cardiac workload

Question 219

Ventricular end-diastolic volume imposes stretch on the ____; the relationship between the length and tension of this indicates that when there is the right amount of stretch (not overstretched or understretched), there is the highest contractile strength

Answer 219

Sarcomeres

Question 220

Circulatory blood flow is ____ related to pressure and ____ related to resistance

Answer 220

Directly; indirectly

Question 221

Resistance is ____ proportional to fluid viscosity and length of the circuit and ___ proportional to vessel diameter

Answer 221

Directly; indirectly

Question 222

Formula for calculating volume flowrate:

Answer 222

F= (P1-P2)/R