Chapter 19 Flashcards
(295 cards)
1
Q
Blood must circulate continuously to maintain ____ in the body: It must do so whether you are resting in bed or participating in exercise.
A
homeostasis
2
Q
Circulation of the blood is accomplished by the _________, which is composed of both the heart and the blood vessels.
A
cardiovascular system
3
Q
The general function of the cardiovascular system is to transport blood throughout the body to allow the exchange of _____ between the blood of capillaries and the body’s ___.
A
substances (respiratory gases, nutrients, wastes)
cells
4
Q
The “goal” of the cardiovascular system is to provide adequate perfusion of all _____.
A
body tissues
5
Q
____ is the delivery of blood per unit time per gram of tissue.
A
perfusion
6
Q
Perfusion is typically expressed in mililiters per minute per gram. _____ perfusion involves delivering sufficient blood to maintain the health of all body cells.
A
Adequate
7
Q
The continual pumping action of the heart and health , unblocked vessels are essential to maintain good blood _____ and ample ____.
A
circulation
perfusion
8
Q
If the heart fails to pump sufficient volumes of blood, or the vessels become hardened or occluded (blocked), then an adequate amount of blood may not reach ____. Thus the tissues will be deprived of need oxygen and nutrients, waste products accumulate, and ____ may occur.
A
the body’s cells
cell death
9
Q
The three types of blood vessels
A
arteries
veins
capillaries
10
Q
____ carry blood away from the heart.
A
arteries
11
Q
____ carry blood back to the heart.
A
veins
12
Q
_____ serve as the sites of exchange, either between the blood and the air sacs (alveoli) of the lungs or the blood and systemic cells.
A
capillaries
13
Q
Blood low in O2 and high in CO2
A
deoxygenated
14
Q
Blood high in O2 and low in CO2
A
oxygenated
15
Q
The ___ is the center of the cardiovascular system.
A
heart
16
Q
A hollow, four chambered organ,, serving to pump blood throughout the body.
A
heart
17
Q
Three anatomical features are significant in the normal function of the heart: 1 the two sides of the heart 2: the great vessels attached to the heart 3: the _____ that are located within the heart.
A
two sets of valves
18
Q
The heart is composed of two sides: the right side and the ___ side.
A
left
19
Q
Each side of the heart has two chambers: a superior chamber for _____ blood called an ___ and an inferior chamber for ____ blood away from the heart called a _____.
A
receiving
atrium
pumping
ventricle
20
Q
The two sides of the heart allow separation of circulating _____ and ____ blood.
A
dexoygenated
oxygenated
21
Q
The right side of the heart receives deoxygenated blood from the body and pumps it to the ___.
A
lungs
22
Q
The left side of the heart receives oxygenated blood from the lungs and pumps it to the ___.
A
body
23
Q
Blood is transported directly to and from the chambers of the heart by the ____ that are continuous with the specific chambers of the heart.
A
great vessels
24
Q
The great vessels include two large arteries or arterial trunks, _____ and ____, as well as 2 large veins, ___ and ____.
A
pulmonary trunk
aorta
SVC and IVC
pulmonary veins
25
The ____ which splits into pulmonary arteries carries blood from the right ventricle.
pulmonary trunk
26
The ___carries blood from the left ventricle.
aorta
27
Large veins deliver blood to the heart atrium via the _____ and the _____, which drain blood into the right atrium.
superior and inferior vena cava
28
The ___ drain blood into the left atrium
pulmonary veins
29
The ____ valves are between the atrium and ventricle of each side of the heart.
atrioventricular valves (AV)
30
The right AV valve, is also called the ____ valve, is located between the right atrium and right ventricle.
tricuspid valve
31
The left AV valve, is also called the ___ or ____ valve, is located between the left atrium and left ventricle.
mitral or bicuspid valve
32
The ____ valves, mark the boundary between a ventricle and its associated arterial trunk.
semilunar
33
The _____ valve is between the right ventricle and the pulmonary trunk.
pulmonary semilunar valve
34
The ___ valve is between the left ventricle and the aorta.
aortic semilunar valve
35
The valves open to allow blood to flow through the heart and then to close to prevent ____. This ensures one-way or unidirectional, flow of blood through the heart.
backflow
36
The two sides of the heart and the blood vessels are arranged in to circuits: the ____ circulation and the _____ circulation.
pulmonary circulation
| systemic circulation
37
The pulmonary circulation includes the movement of deoxygenated blood through the ____ of the heart, blood vessels to the ____ to pickup oxygen and the release of carbon dioxide, and blood vessels that ___ blood to the the left side of the heart.
right side of the heart
lungs
return
38
The systemic circulation includes the movement of oxygenated blood through the ____ side of the heart, blood vessels to the systemic cells such as those of the liver, skin, muscle, and brain for ______ and blood vessels that return blood to the ____ of the heart.
left
exchange of nutrients, respiratory gases, and wastes
right
39
Blood flow through the pulmonary circulation
1. deoxygenated blood enters the right atrium from the SVC and IVC as well as the coronary sinus
2. passes through the right av valve (tricuspid)
3. enters the right ventricle
4. passes through the pulmonary semilunar valve
5. enters the pulmonary trunk
6. blood continues through the right and left pulmonary arteries to both lungs
7. the blood enters the pulmonary capillaries of both lungs for gas exchange
8. this blood is now oxygenated, enter the right and left pulmonary veins and is returned to
9. the left atrium of the heart
40
Blood flow through the system circulation
1. oxygenated blood enters the left atrium
2. the blood passes through the left av valve (mitral or bicuspid)
3. the blood enters the left ventricle
4. the blood passes through the aortic semilunar valve
5. enters the aorta
6. the blood is distributed by the systemic arteries
7. enters systemic capillaries for nutrient and gas exchange
8. this blood which is now deoxygenated, ultimately drains into the SVC and IVC, and coronary sinus
9. enters the right atrium
41
The heart is located within the ___ cavity and is enclosed within a fibroserous sac called the ____; both of these structures have roles in protection and support of the heart.
thoracic
| pericardium
42
The heart is located ____ to the sternum left of the body midline between the lungs within the _____.
posterior
| mediastinum
43
The ___ side of ___ border of the heart is located more anteriorly, whereas its ___ side or ___ border is located more posteriorly.
right
| left
44
The postero-superior surface of the heart is called the ___.
base
45
The inferior, conical end of the heart is called the ___.
apex
46
The heart is enclosed in three layers, collectively called the ____.
pericardium
47
The _____ which is composed of tough, dense irregular connective tissue that encloses the heart, but does not attach to it
fibrous peridcardium
48
The ____ of the serous pericardium is composed of simple squamous epithelium and an underlying delicate layer of ___ connective tissue, adheres to the inner surface of the fibrous pericardium. (walls of cavity)
parietal layer
| aerolar connective tissue
49
The ___ layer of the serous pericardium (also called the ____) is also composed of a simple squamous epithelium and underlying delicate layer of areolar connective tissue. This layer adheres directly to the heart.
visceral layer
| epidcardium
50
The two serosal layers of the heart are continuous with one another and separated by a potential space called the ____.
pericardial cavity
51
The tough fibrous pericardium serves to both ___ the heart within the thoracic cavity and prevent the heart chambers from _____ with blood.
anchor
| overfilling
52
_____ is an inflammation of the pericardium typically caused by viruses, bacteria, or fungi. The inflammation is associated with an increase in permeability of capillaries within the pericardium, which become more "leaky" resulting in excess fluid leaving the blood and accumulating within the pericardial cavity.
Pericarditis
53
_____ is a helpful physical finding in diagnosing pericarditis. This is a crackling or scraping sound heard with a stethoscope that is caused by the movement of the inflamed pericardial layers against each other.
friction rub
54
The heart is a relatively small, conical, muscular organ approximately the size of a ____.
person's clenched fist
55
In the average normal adult heart, it weights about ___ grams, but certain diseases may cause heart size to increase dramatically.
300 grams or 0.7 pounds
56
The atria are separated from the ventricles externally by a relatively deep groove called the ____ that extends around the circumference of the heart.
coronary sulcus or atrioventricular sulcus
57
An ____ sulcus is a groove between the ventricles that extends inferiorly from the coronary sulcus toward the the heart apex and delineates the superficial boundary between the right and left ventricles.
interventricular
58
The ____ sulcus is located on the anterior side of the heart. Located within are the coronary vessels associated with supplying blood to the heart.
anterior interventricular sulcus
59
The ____ sulcus is located on the posterior side of the heart. Located within are the coronary vessels associated with supplying blood to the heart.
posterior interventricular sulcus
60
The portion of the right atrium that is most noticeable is its wrinkled, flaplike extension called the _____.
right auricle
61
The portion of the left atrium that is wrinkled and flaplike extension called ____.
left auricle
62
The walls of the ventricles are ____ then the walls of the atria; this is because the ventricles are the "_______."
thicker
| pumping chambers
63
The wall of the left ventricle is typically ____ times thicker than the right ventricular wall because the ____ ventricle must generate enough pressure to force the blood through the entire systemic circulation.
three times
| left
64
The right ventricle has to pump blood to the ___.
nearby lungs
65
There are three distinctive layers that compose the wall of each chamber: an external epicardium, a thick middle myocardium, and an internal ____.
endocardium
66
The ____ is the outermost heart layer and is also called the _____.
epicardium
| visceral layer
67
The epicardium or ____ layer is composed of ____ epithelium and an underlying layer of areolar connective tissue.
visceral layer
| simple squamous
68
As we age, the epicardium thickens as it becomes more invested with ____.
adipose connective tissue
69
The ____ is the middle layer of the heart wall. It is composed of ____ tissue and is the thickest of the three heart wall layers.
myocardium
| cardiac muscle
70
Contraction of cardiac muscled composing the myocardium generates the force necessary to ____.
pump blood
71
The internal surface of the heart and the external surfaces of the heart valves are covered by ____.
endocardium
72
The endocardium is composed of ______ and an underlying layer of areolar connective tissue. The epithelial layer of the endocardium is continuous with the ___ layer of the endothelium, which lines the _____.
simple squamous epithelium
epithelial layer
blood vessels
73
The right and left atrial chambers are separated by a thin wall called the ______ .
interatrial septum
74
The right and left ventricles are separated by a thick wall called the _____.
interventricular septum
75
The interventricular septum is delineated on the heart's superficial surface with the _____.
interventricular sulci
76
The internal wall of the right atrium is smooth on its posterior surface, but exhibits muscular ridges, called ___ on its anterior wall and within the aricle.
pectinate muscles
77
The interatrial septum reveals an oval depression called the ____. It occupies the former location of the fetal _____, which shunted blood from the right atrium, bypassing the lungs during the fetal life.
fossa ovalis
| foramen ovale
78
Immediately inferior to the fossa ovalis is the opening of the _____, which drains deoxygenated blood from the heart wall.
coronary sinus
79
Openings at the top and bottom of the chamber for the ___ and ____ are also visible in the right atrium.
IVC and SVC
80
Separating the right atrium from the right ventricle is the AV opening that contains the AV valve, also called the ____.
tricuspid valve
81
The internal wall surface of the right ventricle displays characteristic large, smooth, irregular muscular ridges, called the ____.
trabeculae carnea
82
Extending from the internal wall of the right ventricle are typically three cone shaped, muscular projections called ____.
papillary muscles (the number can range from 2 to 9)
83
Papillary muscles anchor thin strands of collagen fibers called _____ or _______ which are attached to the right atrioventricular valve.
tendinous cords or chordae tendineae
84
The superior portion of the right ventricle narrows into a smooth-walled region leading into the _____.
pulmonary trunk
85
The _____ valve is positioned between the right ventricle and pulmonary trunk.
pulmonary semilunar valve
86
Like the right atrium, the left atrium has pectinate muscles in its _____.
auricle
87
The internal wall surface of the left ventricle also displays thin strands of collage fibers called _____ or ____ that anchor two papillary muscles.
tendinous cords or chordae tendineae
88
The entrance into the ____ is located at the superior aspect of the left ventricle.
aorta
89
The ______ valve is positioned at the boundary of the left ventricle and ascending aorta.
aortic semilunar valve
90
Effective blood flow requires valves to control blood flow and ensure it is _______.
one way
91
Each valve consists of _____ lined fibrous connective tissue flaps called cusps.
endothelium-lined
92
The right AV valve (tricuspid) covers the right ____ opening, and it has ___ cusps.
atrioventricular
| three
93
The left AV valve (mitral or bicuspid) covers the left atrioventricular opening, but has only ___ cusps.
two
94
____ is one term used to indicate an increase in the thickness of the heart muscle wall (hypertrophy) or an obvious increase or enlargement in heart size due to stress applied to the heart.
Cardiomegaly
95
The enlargement of the heart seen in young athletes is caused by a condition called _______. This condition involves both an enlargement of the heart walls and a narrowing of the openings for the blood to pass through, which results in a decrease in cardiac output.
hypertrophic cardiomyopathy
96
When the ventricles contract, blood is forced superiorly as ventricular pressure rises. This causes the AV valves to ___.
close
97
The papillary muscles secure the chordea tendineae that attache to the lower surface of each AV valve cusp which prevents the valve from inverting and being ____ into the atrium when the valve is closed.
pushed open
98
By being properly held in place, the cusps of the AV valves prevent blood flow back into the ___.
atrium
99
The semilunar valves are composed of _________, pocketlike semilunar cusps.
half moon shaped
100
Neither papillary muscles or chordeae tendineae are associated with ___.
semilunar valves
101
The semilunar valves open when the ____ contract and the force of he blood pushes the semilunar valves open and blood enters the arterial trunk.
ventricles
102
The semilunar valves close when the ventricles ____ and the pressure in the ventricle becomes less than the pressure in an arterial trunk.
relax
103
Blood in the arteries begins to move backward toward the ventricle and is caught in the cusps of the semilunar valves, and they ____. This prevents backflow into the ventricle.
close
104
Both ____ and elasticity of connective tissue composing heart valves decrease with aging or ____ which may cause the heart valves to become ____.
flexibility
disease
inflexible
105
When the heart valves become inflexible, blood flow through the heart may be altered, and a ______ may be detected.
heart murmur
106
The lub or S1 sound represent the _____ of the atrioventricular valves.
closing
107
The dupp or S2 sound represent the _____ of the semilunar valves.
closing
108
An abnormal heart sound, generally called a ___, is the first indication of heart valve problems. It is usually the result of turbulence of the blood as it passes through the heart, and may be caused by valvular leakage, decreased valve flexibility, or a misshapen valve.
heart murmur
109
A type of heart murmur called ____, occurs when one or more of the cardiac valves leaks because the valve cusps do no close tightly enough.
valvular insufficiency
110
A type of heart murmur called ___ is due to scarring of the valve cusps so that they become rigid or partially fused and cannot open completely.
valvular stenosis
111
A primary cause of valvular stenosis is ____ which may follow a streptococcal infection of the throat.
rheumatic heart disease
112
The myocardium is composed of ____.
cardiac muscle tissue
113
The cardiac muscle tissue is made up of relatively short, branched cells that usually house ___ or ___ nuclei.
one or two
114
The cardiac muscle cells are supported by ___ connective tissue, called and _____, that surrounds the cells
areolar connective
| endomysium
115
Neighboring cardiac muscle cells have an extensively folded ____ that permits ajoining membranes to interconnect, increasing exposed surface areas between neighboring cells.
sarcolemma
116
The folded sarcolemma that permits adjoining membranes to interconnect increases structural stability of the myocardium and facilitates ____ between cardiac muscle cells.
communication
117
____ are found at these cell to cell junctions. They link cardiac muscle cells together both ____ and ____ and contain two distinctive structural features.
Intercalated discs
| mechanically and electrically
118
Intercalated discs have two distinctive structural features ____ and ___.
desmosomes and gap junctions
119
Protein filaments that anchor into a protein plaque located on the internal surface of the sarcolemma. They act as mechanical junctions to prevent cardiac muscle cells from pulling apart.
desmosomes
120
These are protein pores between the sarcolemma of adjacent cardiac muscle cells. They provide a low-resistance pathway for the flow of ions between cardiac cells. They allow an action potential to move continuously along the sarcolemma of cardiac muscle cells, resulting in synchronous contraction of that chamber. Thus a chamber functions as a single unit, or ___.
gap junctions
| functional syncytium
121
Cardiac muscle has features that support its great demand for energy, including an extensive blood supply, ______, and other structures such as myoglobin and creatin kinase.
numerous mitochondria
122
Cardiac muscle relies almost exclusively on ___ cellular respiration.
aerobic
123
Cardiac muscle has a large number of mitochondria, compromising approximately ___% of its volume compared to about 2% of the volume in skeletal muscle.
25%
124
Cardiac muscle is also versatile in being able to use ____ of fuel molecules, including fatty acids, glucose, lactate, amino acids, and ketone bodies.
different types
125
As a consequence of its reliance on aerobic metabolism, cardiac muscle is quite susceptible to ____ if ischemic (low oxygen) conditions prevail.
failure
126
Cardiac muscle has limited capability in using ____ or accruing an oxygen debt in its activities.
glycolysis
127
Any change that interferes with blood flow to the heart muscle, such as narrowing of the coronary arteries, can cause damage or ___ of the cardiac muscle cells composing the myocardium. (myocardial infarction, angina pectoris)
death
128
The heart is supported internally by a ___ composed of dense irregular connective tissue.
fibrous skeleton
129
The fibrous skeleton that supports the heart provides ____ at the boundary between the atria and the ventricles. It also forms _____ to anchor the heart valves. It provides a rigid ____ for the attachment of cardiac muscle tissue and acts as an ___ because it does not conduct action potential and thus prevents the ventricular chambers from contracting at the same time as the atrial chamber.s
structural support
supportive fibrous rings
framework
electric insulator
130
When the atria contract, they compress the wall of the chambers ____ to move the blood into the ventricles.
inward
131
When the ventricles contract, the action is similar to the wringing of a mop in that it begins at the apex of the heart and compresses superiorly, moving the blood into the ___.
great arterial trunks
132
Although the heart continuously pumps blood through its chambers, it cannot absorb the oxygen and nutrients it requires from this ___.
blood
133
The diffusion of oxygen and nutrients at the needed rates through the thick wall of the heart is not possible; instead, an intricate distribution system called the ____ handles the task.
coronary circulation
134
The vessels that transport oxygenated blood to the wall of the heart are called ____.
coronary arteries
135
_____ transport deoxygenated blood away from the heart wall.
coronary veins
136
Right and left coronary arteries are positioned within the ____ of the heart to supply the heart wall.
coronary sulcus
137
The coronary arteries are the first and only branches of the ascending ___ and originate immediately superior to the ____.
aorta
| aortic semilunar valve
138
The right coronary artery typically branches into the ___ artery to supply the lateral wall of the right ventricle, and the ____ to supply the posterior wall of both the left and right ventricles.
right marginal artery
| posterior interventricular artery
139
The left coronary artery typically branches into the ____ artery to supply the lateral wall of the left ventricle and the ______ artery to supply both the anterior wall of the left ventricle and most of the _____.
circumflex artery
anterior interventricular atery
interventricular septum
140
The anterior interventricular artery is nicknamed the ____ because if this artery becomes occluded, there is a very high risk of a fatal heart attack.
widow maker
141
Body tissues are generally served by ___ artery; it is called an ____.
one
| end artery
142
Some body tissues are served by two arteries; this is referred to as an ____.
arterial anastomosis
143
An arterial anastomosis provides ___ means of effectively delivering blood to a given region.
two
144
The left and right coronary arteries both provide blood to the myocardium, and are described by some as an ____. The coronary arteries are more accurately called ______.
arterial anastomosis
| functional end arteries
145
Coronary arterial blood flow to the heart wall is ____ because coronary vessels are patent when the heart is relaxes and blood flow is possible.
intermittent
146
Coronary vessels are ____ when the heart contracts, temporarily interrupting blood flow.
compressed
147
RaMP - major coronary arteries on the right side.
Right coronary artery
Right marginal artery
posterior interventricular artery
148
LAC - major coronary arteries on the left side.
left coronary artery
anterior interventricular artery
circumflex artery
149
The term infarction refers to ___ of tissue due to lack of blood supply.
death
150
Coronary arteries may become narrowed and occluded with plaques in a condition called ______.
atherosclerosis
151
______ is a poorly localized pain sensation in the left side of the chest, the left arm and shoulder, or sometimes the jaw and the back.
Angina pectoris
152
___, commonly called a heart attack, is a potentially lethal condition resulting from sudden and complete occlusion or a coronary artery.
Myocardial infarction, MI
153
Transport of deoxygenated blood from the myocardium occurs through one of several cardiac veins which include the _____ within the anterior interventricular sulcus, positioned alongside the posterior interventricular artery; the _____ within the posterior interventricular sulcus and a ____ positioned alongside the right marginal artery.
the great cardiac vein
the middle cardiac vein
the small cardiac vein
154
The cardiac veins that transport deoxygenated blood from the myocardium drain into the ____, a large vein that lies within the posterior aspect of the coronary sulcus. The ____ returns this deoxygenated blood directly into the right atrium of the heart.
coronary sinus
155
The heart pumps continuously and depends upon rhythmic stimulation of _____.
cardiac muscle cells
156
Precise electrical events are orchestrated by the heart's conduction system, beginning with stimulation by the ____ and then transmission of an action potential by specialized conduction fibers of the heart to ensure that the atria are stimulated to contract prior to the ventricles. These events are influenced by the activity of the ____.
sinoatrial node
| autonomic nervous system
157
Specialized cardiac muscle cells are found within the heart located internal to the endocardium; they are collectively called the heart's _______.
conduction system
158
The distinct cardiac cells of the heart's conduction system do not contract, but rather they initiate and ______.
conduct electrical signals
159
The conduction system includes 4 structures
sinoatrial node (SA node)
atrioventricular (AV node)
atrioventricular bundle (AV bundle)
Purkinje fibers
160
The ___ cells initiate the heartbeat and are commonly referred to as the pacemaker of the heart.
sinoatrial node or SA node
161
The ______ is located in the floor of the right atrium between the right AV valve and the opening for the coronary sinus.
AV node or atrioventricular node
162
The ____ extends from the AV node into and through the interventricular septum. It divides into left and right bundles.
atrioventricular bundle or AV bundle
163
The ____ extend from the left and right bundles beginning at the apex of the heart and then continue through the walls of the ventricles.
Purkinje fibers
164
While the heartbeat is initiated by the SA node, both the heart rate and the strength of contraction are regulated by the ______, specifically by the cardiac center within the _____.
autonomic nervous system
| medulla oblongata
165
Sensory input is relayed from receptors to the cardiac cardiac center. Parasympathetic and sympathetic axons extend from the _____ to the heart.
cardiac center
166
The cardiac center houses both the cardioinhibitory and _____ centers.
cardioacceleratory
167
The _____ from the cardiac center does not initiate the heartbeat, it merely modifies cardiac activity including both the heart rate and its ____.
innervation
| force of contraction
168
____ innervation comes from the cardioinhibitory center via the right and left vagus nerves (CN X).
parasympathetic
169
The ____nerve innervates the SA node, and the ____ vagus nerve innervates the AV node.
right vagus
| left vagus nerve
170
Parasympathetic stimulation ____ heart rate, but generally has no direct effect of the force of contraction because the vagus nerve does not innervate the _____.
decreases
| myocardium
171
____ innervation arises from the cardioacceleratory center.
Sympathetic
172
Neurons within the T1 - T5 segments of the spinal cord to the ____, _____, and the myocardium.
SA node
| AV node
173
Stimulation by the sympathetic division ____ both heart rate and force of contraction.
increases
174
There is also some sympathetic innervation to the coronary arteries , causing _____ of these vessels to support increased blood flow to they myocardium.
dilation
175
The physiologic process associated with heart contraction are organized into two major events: ______ and ______.
conduction system
| cardiac muscle cells
176
Electrical activity is initiated at the SA node, and an action potential is then transmitted through the _____.
conduction system
177
The action potential spreads across the sarcolemma of the cardiac muscle, causing sarcomeres within __________ to contract. These events occur in twice in cardiac muscle cells during a heartbeat, first in the cells of the _____ and then in the cells of the ventricles.
cardiac muscle cells
| atria
178
____ cells in the SA node are the pacemaker cells that initiate a heart beat by spontaneously depolarizing to generate and action potential
Nodal Cells
179
One essential feature of nodal cells the ____ charge difference across the plasma membrane; the intracellular fluid (cytosol) just inside the plasma membrane is relatively _____ in comparison to the fluid outside of the cell (interstitial fluid).
electrical
| negative
180
The electrical charge difference when the nodal cell is at rest is called the _______.
resting membrane potential (RMP)
181
An RMP is established and maintained by ____ leak channels, ____ leak channels, and ____ pumps.
K+ leak channels
Na+ leak channels
Na+/K= pumps
182
The primary function of the Na+/K+ pumps is to maintain the _____ for Na+ (with more Na+ outside the cell) and K+ (with more K+ inside the cell).
concentration gradients
183
Nodal cells also contain calcium ion (Ca+) pumps that establish a Ca2+ concentration gradient with more ____ outside the cell than inside.
CA2+
184
Nodal cells (unlike other cells) do not have a stable ____.
RMP
185
Nodal cells contain specific ______, include slow voltage gated Na+ channels (which are __) and both fast voltage gated Ca2+ channels and voltage gated K+ channels (which are ___)
voltage gated channels
open
closed
186
SA nodal cells are unique in that they exhibit _____, meaning that they are capable of depolarizing and firing an action potential spontaneously without any external influence.
autorhythmicity
187
SA node cellular activity
1) reaching threshold
2) Depolarization
3) Repolarization
188
When slow voltage gated NA+ channels open (this is caused by repolarization from the previous cycle). The Na + flows ___ the nodal cells, changing the RMP from -60mv to ______ mV, which is the threshold value. The threshold is reached without outside stimulation.
-40 mV
189
The threshold value of nodal cells is _____.
-40mV
190
The resting membrane potential for nodal cells is ____mV.
-60
191
With nodal cells threshold is reached ______ outside stimulation.
outside
192
Changing of the membrane potential to the threshold triggers the opening of ____ Ca2+ channels, and Ca2+ entry into the nodal cell causes a change in the membrane potential from -40mV to a slightly positive membrane potential (just above ___mV). This reversal of polarity is called depolarization.
fast voltage gated
| 0mV
193
The reversal of polarity is called ____.
depolarization
194
Calcium channels ____ and voltage-gated K+ channels open; K+ flows ___ to change the membrane potential from a positive value to ____mV, which is the RMP. The process of reestablishing the RMP is called repolarization. Repolarization triggers the reopening of slow voltage-gated Na+ channels, and the process begins again.
close
out
-60mV
195
The SA nodal activity typically takes ___ second, at rest; this results in a resting heart rate of __ beats per minute.
.8
| 75 beats
196
Interestingly, the inherent rhythm that SA nodal cells spontaneously depolarize is a much faster rate of approximately ___ times per minute. This inherent rhythm is determined when excised cardiac muscle cells placed into cell culture; without ______ nerve innervation.
100
| autonomic
197
The normal resting heart rate of 75 beats per minute is due to continuous _____ stimulation of the SA node by the vagus nerve. This slowing of the heart rate is called ____.
parasympathetic
| vagal tone
198
Nodal cells are like neurons because they have an ___.
RMP
199
A significant difference between nodal cells and neurons is that neurons require ____ (in the form of neurotransmitters) whereas nodal cells do not because they do not have a stable RMP.
stimulation
200
The RMP of nodal cells gradually increases to threshold when ___ Na+ channels reopen. This ability to reach the threshold without stimulation is called a ____.
slow
| pacemaker potential
201
Another difference between neurons and nodal cells is that depolarization results from the entrance of Na+ into ___, whereas it results from the entrance of ____ into nodal cells.
neurons
| Ca2+
202
Cardiac muscle stimulation
1) Action potential is distributed through both atria and is relayed to the AV node
2) The action potential is delayed at the AV node
3) The action potential travels form the AV node through the AV bundle to Purkinje fibers.
4) The action potential spreads through both ventricles via gap junctions.
203
During cardiac muscle stimulation the action potential is distributed through both _____ and is relayed to the AV node.
atria
204
STEP 1: CARDIAC MUSCLE STIMULATION
The action potential initiated in the SA node is spread between _____ in the atria by gap junctions that allow almost instantaneous excitation of all muscle cell in the ___ walls. This electrical stimulation ultimately results in cardiac muscle cells of both atria contracting a ___.
cardiac muscle cells
atrial
the same time
205
STEP 2: CARDIAC MUSCLE STIMULATION
The action potential is delayed at the ____. AV nodal cells have both smaller fiber diameters and few numbers of ____, thus, they exhibit characteristics that slow the conduction rate of the action potential by serving as a bottleneck. This is facilitated by the insulating characteristics of the fibrous skeleton, which only allow the action potential to move through the ___. The delay in conduction (about 0.1) may seem very brief, but it is long enough to allow the atria to finish contracting and force blood into the ventricles to complete ventricular filling before the ____ are stimulated to contract.
AV node
gap junctions
AV node
ventricles
206
STEP 3: CARDIAC MUSCLE STIMULATION
The action potential travels from the AV node through the ___ to Purkinje fibers. The action potential spreads from the AV node along the AV bundle to the bundle of branches to the ___.
av bundle
| Purkinje fibers
207
STEP 4: CARDIAC MUSCLE STIMULATION
The action potential is then spread between ventricular cardiac muscles cell by ____ that allow the almost simultaneous stimulation of all the cardiac muscle cells in the _____. Generally, these cells begin to contract within ___ to ___ milliseconds after the firing of the SA nodal cells.
gap junction
ventricular walls
120 to 200 milliseconds
208
Purkinje fibers are larger in diameter than other ______, so action potential propagation is extremely rapid to the ventricular myocardium. Thus, the cardiac muscle cells of both ventricles contract at the ____.
cardiac conduction fibers
| at the same time
209
Papillary muscles within the ventricles are stimulated to contract ____. These muscles anchor the tendinous cords to the ___ valve cusps; they tighten the relaxed cords and cause them to start to pull on the AV valve cusps just prior to the increasing pressure within the ventricles. Thus the valves are ___ and better able to prevent back flow of blood into the atria.
immediately
AV valve cusps
braced
210
The stimulation of the ventricles begins at the _____of the heart. This feature ensures that blood is efficiently ejected superiorly toward the arterial trunks.
apex
211
A pacemaker other than the SA node is called an _____, or ____.
ectopic pacemaker or ectopic focus
212
Cells of the conduction system other than the SA node and cardiac muscle cells also have the ability to spontaneously depolarize and serve as the ____. However, they depolarize at slower rates than the SA node.
pacemaker
213
The AV node has an inherent rhythm of __ to ___ beats per minute, and cardiac muscle cells have a rate of 20 to 40 beats per minute.
40 to 50 beats
214
If the SA node is not functioning, the Av node becomes the default ____, and the AV node then establishes the rhythm of the heart rate.
pacemaker
215
Survival is possible because a rhythm of 40 to 50 beats per minute pumps sufficient blood to sustain life. However, if both the SA node and the AV node are not functioning, cardiac muscle cells will attempt to establish the ___. The heart rate will be only 20 to 40 beats per minute, which is almost always too slow to support life.
rhythm
216
Two significant and interrelated events occur within cardiac muscle cells following their stimulation by the conduction system. These include propagation of an action potential at the sarcolemma and contraction of sarcomeres within the ____.
cardiac muscle cells.
217
The events of cardiac muscle cells occur twice per heart beat: first in the cardiac muscle cells of the atria, and then in the cardiac muscle cells of the ___.
ventricles
218
The sarcolemma of cardiac muscle cells, like nodal cells has K+ leak channels, Na+ leak channels and Na+/K+ pumps, to establish and maintain a RMP with a greater concentration of ____ outside of the cardiac muscle cells and a greater concentration of K+ ___.
Na+
| inside
219
The RMP value of cardiac muscle cells, is _____mV. Cardiac muscle cells also contain Ca2+ ____ that form a Ca2+ concentration gradient with more Ca2+ outside the cell than inside the cell.
-90mV
| pumps
220
The sarcolemma of cardiac muscle cells has both fast-voltage gated Na+ channels that participate in ______ at the membrane and K+ voltage gated channels that participate in repolarization of the membrane.
depolarization
221
Cardiac muscles have slow voltage gated Ca2+ channels within the sarcolemma. Slow-voltage-gated Ca2+ channels, when open, allow ____ into the cell. The movement of Ca2+ is significant in the normal function of cardiac muscle cells.
Ca2+
222
Electrical events at the Sarcolemma of Cardiac Muscle Cells
1) Depolarization
2) Plateau
3) Repolarization
223
ELECTRICAL EVENTS AT THE SARCOLEMMA OF CARDIAC MUSCLE STEP 1:
An action potential transmitted through the conduction system (or via gap junctions) triggers the opening of fast voltage gated Na+ channels in the _____. Sodium ion enter the cardiac muscle cell, causing ____. The resting membrane potential changes from -90mV to ___ mV. Voltage gated Na+ channels close to the inactivated state.
sarcolemma
depolarization
+30 mV
224
ELECTRICAL EVENTS AT THE SARCOLEMMA OF CARDIAC MUSCLE STEP 2:
Depolarization triggers the opening of voltage gated K+ channels, and K+ ___ the cardiac muscle cells. There is a slight change in the membrane potential. Almost immediately, slow voltage gated Ca2+ channels in the ____ open, and Ca2+ enters from the ICF in the cardiac muscle cells. The entering of Ca2+ stimulate the sarcoplasmic reticulum to release ____ Ca2+. The exit of positively charged K+ from the sarcoplasm and the simultaneous entrance of positively charged Ca2+ into the sarcoplasm results in no electrical change at the sarcolemma. Thus the sarcolemma of the cardiac muscle cell remains in a ____ state. This leveling off is referred to as the plateau.
leaves
sarcolemma
more
depolarized.
225
ELECTRICAL EVENTS AT THE SARCOLEMMA OF CARDIAC MUSCLE STEP 3:
Voltage gated Ca2+ channels then close, and K+ channels remain open to complete _____ as K+ exits the cardiac muscle cell. The membrane potential reverses, and the RMP of -90mV is reestablished. This allows a muscle cell to propagate a new action potential when the cardiac muscle is ___.
repolarization
| stimulated again
226
Then entry of Ca2+ into the sarcoplasm from both the ICF and Sarcoplasmic Reticulum initiates the internal mechanical event of ___. Calcium ions now bind to ____ to begin cross-bridge cycling within a sarcomere, similar to the way in which skeletal muscle contracts. The closing of voltage gated Ca2+ channels reuptake of Ca2+ into the sarcoplasmic reticulum by Ca2+ pumps, and removal of Ca2+ from the cell by plasma membrane Ca2+ ____ decrease the calcium levels in the sarcoplasm. Calcium is released from troponin with the subsequent decrease in crossbridges between the thin and thick filaments. Sarcomeres return to their resting ___ as the cardiac muscle cell now relaxes.
muscle contraction
troponin
pumps
length
227
Caridac muscle cells (unlike skeletal muscle fibers) cannot exhibit ___, which is a sustanined muscle contraction without relaxation.
tetany
228
Review graphs pg 756 - differences in skeletal muscle vs cardiac muscle
?
229
Electrical changes within the heart can be detected during a routine physical exam using monitoring electrodes attached tot he skin. These electrical signals are collected and charted as an ______ also called an ECG or EKG.
electrocardiogram
230
An ECG provides a composite tracing of all cardiac action potentials generated by ____.
myocardial cells
231
The ____ reflects electrical changes of atrial depolarization that originates in the SA node. This event typically lasts .08 to .1 seconds.
P wave
232
The ___ usually lasts between .06 and .1 second, represents the electrical changes associated with ventricular depolarization. The atria are simultaneously repolarizing; however, this repolarization signal is masked by the greater electrical activity of the ventricles.
QRS complex
233
The ___ is the electrical change associated with ventricular repolarization.
T wave
234
The P-Q segment is associated with the atrial plateau at the sarcolemma when the cardiac muscle cells within the ___ are contracting.
ventricles
235
The ____ is the ventricular plateau when the cardiac muscle cells within the ventricles are contracting.
S-T segment
236
The flat line between cycles on an ECG represents when the heart is ___ between beats.
resting
237
The ___ reflects electrical changes of atrial depolarization originating in SA node.
P wave
238
The ____ is the electrical changes associated with ventricular depolarization. Atria is also simultaneously repolarizing.
QRS complex
239
The ___ is the electrical change associated with ventricular repolarization.
T wave
240
The ___ interval represent the conduction of the action potential through the entire conduction system.
p-r interval
241
P-R intervals lasting longer than ___ seconds indicates impaired conduction within the ventricles.
.2 seconds
242
The ___ intervl represents teh time required for teh action potential to move through the action potential to move through teh ventricles.
q-t interval
243
The q-t interval changes depending on ____ (0.2 - 0.4 seconds)
heart rate
244
Q-T intervals faster than 0.2 to 0.4 seconds increases heart rate and is called ______.
tachycardia
245
The changes within the heart from the start of one heartbeat until the start of another (one contraction/relaxation cycle)
the cardiac cyle
246
contraction of heart chamber, increases pressure within the heart chamber
systole
247
relaxation of heart chamber, decreases pressure within heart cahmber
diastole
248
Atria and ventricles contract/relax at ____ times (double pump)
opposite
249
Alternating pressure changes in the cardiac cycle are responsible for ____ movement of blood and ____ of heart valves.
unidirectional
| opening/closing of heart valves
250
In the unidirectional movement of blood in the heart, blood moves from ___ pressure to ___ pressure.
greater pressure
| lesser pressure
251
In the opening/closing of heart valves it is ensured that blood continues to move ____.
forward
252
The most important driving force to continually move blood through the heart and to open and close heart valves during the cardiac cycle is the contraction and relaxation of the ___.
ventricles
253
Before the cardiac cycle begins all chambers are ____, the AV valves are open, and blood entering atria passively fill the ____.
relaxes
| ventricles
254
Start of the cardiac cycle is initiated by the ___.
SA node
255
the cardiac cycle
1) atria contract, completely filling ventricles
2) Isovolumetric contraction - as atria relax, ventricles contract causing no movement of blood
Purkinje fibers stimulate papillary muscles to brace AV valves
3) Ventricular Ejection - moves blood from ventricles into arterial trunks
Ventricles contract and semilunar vlaves are forced open.
Amount of blood ejected during ventricular contraction called the stroke volume.
Not all blood is ejected from the ventricles. (ESV)
4) Isovolumetric relaxation - ventricles begin relaxing, semilunar valves close, no movement of blood
5) Atrial relaxation/ventricular filling - end of cycle; ventricles continue relaxing allowing av valves to open.
blood passively fills ventricles
256
The ____ is the max volume of blood within ventricles before ventricular contraction (systole)
EDV or end-diastolic volume
| STEP 2 of the cardiac cycle
257
As atria relax, ventricles contract causing no movement of blood
isovolumetric contraction
258
moves blood from ventricles into arterial trunks
ventricular ejection
259
amount of blood ejected during ventricular contraction
stroke volume (SV)
260
blood remaining in ventricle at end of contraction (=EDV - SV)
ESV (end systolic volume)
261
when ventricles begin relaxing, semilunar valves close, no movement of blood
isovolumetric relaxation
262
In the cardiac cycle the atrial contraction represents the ____.
p-r segment
263
In the cardiac cycle the isovolumetric contractions occurs at the end of the ____.
QRS complex (R-S )
264
In the cardiac cycle the ventricular ejection represents the _____.
S-T segment
265
In the cardiac cycle the isovolumetric relaxation represents the ___.
T wave
266
In the cardiac cycle the atrial relaxation/ventricular filling represents the ___.
T wave to following the P wave
267
____ is the amount of blood that is pumped by a single ventricle (right or left) in 1 minute (expressed in liters/minute)
Cardiac output
268
Ventricles pump and ___ amount of blood which is referred to as ventricular balance.
equal
269
Cardiac output is determined by heart rate and _____.
stroke volume
| CO = HR x SV
270
Increase in both HR and SV results in an ____ in Cardiac Output
increase
271
increase in cardiac output above resting level
cardiac reserve
272
CO exercise - CO resting =
Cardiac reserve
273
The ____ is the measure of level and duration of physical effort an individual engage in.
cardiac reserve
274
factors that change heart rate
chronotropic agents
275
_____ chronotropic agents decrease heart rate.
negative chronotropic agents
276
______ chronotropic agents increase heart rate.
positive chronotropic agents
277
_____ chronotripic agents hyperpolarizes nodal cells
negative chronotropic
278
Negative chronotropic agents cause the parasympathetic division to release Ach which binds muscarinic receptors which are _______.
K+ channels
279
Positive chronotropic agents cause the sympathetic division to release ____.
norepinephrine
280
Positive chronotropic agents releases _____ and ___ from adrenal medulla.
epinephrine
| norepinephrine
281
volume of blood ejected per heart beat
stroke volume
282
Stroke volume is dependent upon volume of blood that enters heart (fills ventricles, ____) and how much is ejected (or how much is left in heart, ____)
EDV
| ESV
283
Inotropic agents alters ______, which is the force of contraction at a given stretch of the cardiac cells.
contractillity
284
Stroke volume or volume ejected from the heart depends upon venous return, inotropic agents, and ____.
agterload
285
amount of blood return to heart
venous return
286
external factors that alter the force of contraction
inotropic agents
287
resistance in arteries to ejection of blood from heart
afterload
288
Venous return is influenced by venous pressure and ____ fill time.
ventricular
289
Venous return increases during ____ due to greater venous pressure (skeletal muscle pump)
exercise
290
Lower heart rate allows for longer ventricular filling, also it increases ______ (athletes have low resting HR's)
venous return
291
Venous return decreases due to low _____ as well as increased HR (less filling time).
blood volume
292
Inotropic agents alter contractility by altering Ca++ concentration within the sarcoplasm of the ____.
myocytes
293
Ca++ channel blocking drugs (used for high blood pressure) are __ inotropic agents.
negative
294
Small arterial lumen causes greater ____.
resistance
295
Slide 55
Review
