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HUMAN ANATOMY & PHYSIOLOGY
CARDIOVASCULAR SYSTEM
Chapter 15 Notes
HOLE’S HA&P | CHAPTER FIFTEEN
OBJECTIVES
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Discuss the functions of the organs of the cardiovascular system.
Distinguish between the various coverings of the heart and the layers that compose the wall of the heart.
Identify and locate the major parts of the heart and discuss the function of each part.
Trace the pathway of the blood through the heart and the vessels of coronary circulation.
Describe the cardiac cycle and explain how heart sounds are produced.
Identify the parts of a normal ECG pattern and discuss the significance of this pattern.
Explain control of the cardiac cycle.
Compare the structures and functions of the major types of blood vessels.
Describe how substances are exchanged between blood in capillaries and the tissue fluid surrounding body
cells.
Explain how blood pressure is produced and controlled.
Describe the mechanisms that aid in returning venous blood to the heart.
Compare the pulmonary and systemic circuits of the cardiovascular system.
Identify and locate the major arteries.
PART ONE
15.1-15.2 General Characteristics of the Cardiovascular System
Cardio
Vascular
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 1
LOCATION OF THE HEART IN THE THORACIC CAVITY
The heart is a cone-shaped organ approximately the size of a fist and is located
within the mediastinum, or medial cavity, of the thorax. It is flanked laterally by the
lungs, posteriorly by the vertebral column, and anteriorly by the sternum. Its more
pointed apex extends slightly to the left and rests on the diaphragm, approximately
at the level of the fifth intercostal space. Its broader base, from which the great
vessels emerge, lies beneath the second rib and points toward the right shoulder.
In situ, the right ventricle of the heart forms most of the anterior surface.
1. The drawing at the right
shows the heart within the
chest cavity. Color the
following parts on the
diagram.
Pericardium-covered
heart (A)
Superior vena cava (B)
Pulmonary trunk (C)
Pulmonary artery (D)
Pulmonary vein (E)
Aortic arch (F)
Thoracic aorta (G)
Trachea (H)
Esophagus (I)
THE WALL OF THE HEART
The heart is enclosed within a double – walled fibrous sac called the pericardium. The thin
visceral pericardium, or epicardium, which is closely applied to the heart muscle,
reflects downward at the base of the heart to form its companion serous membrane, the
outer, loosely applied parietal pericardium, which is attached at the heart apex to the
diaphragm. Serous fluid produced by these membranes allows the heart to beat in a
relatively frictionless environment. The serous parietal pericardium lines the loosely fitting
superficial fibrous pericardium composed of dense connective tissue. Inflammation of the
pericardium, pericarditis, causes painful adhesions between the serous pericardial layers.
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 2
These adhesions interfere with heart movements. The wall of the heart is composed
primarily of cardiac muscle – the myocardium – which is reinforced internally by a dense
fibrous connective tissue network. The endocardium is the thin, inner lining of the heart. It
is composed of simple squamous epithelium and some connective tissue. The endocardium
is continuous with the inner lining of the blood vessels.
2. The drawing at the right
shows the wall of the heart
and the pericardium. Color
the following parts on the
diagram.
Endocardium (A)
Myocardium (B)
Visceral Pericardium (C)
Pericardial cavity (D)
Parietal pericardium (E)
Fibrous pericardium (F)
3. What is the covering around the heart called? ___________________________
4. What is the function of the fluid – filled sac surrounding the heart?
_____________________________________________________________
5. Identify the layer of the heart wall (EPIcardium, MYOcardium, or
ENDOcardium) described below.
______ Outer layer
______ Thick muscular layer
______ Continuous with the inner lining of blood vessels
______ Innermost layer
______ Also called visceral pericardium
______ Middle layer
______ Composed of simple squamous epithelium & some connective tissue
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 3
HEART CHAMBERS & VALVES
The heart is divided into four chambers; two superior atria and two inferior ventricles,
each lined with a thin serous lining called the endocardium. The septum that divides the
heart longitudinally is referred to as the interatrial or interventricular septum,
depending on which chambers it separates. Functionally, the atria are receiving chambers
and are relatively ineffective as pumps. Blood flows into the atria under low pressure from
the veins of the body. The right atrium receives relatively oxygen-poor blood from the body
via the superior and inferior vena cava. Four pulmonary veins deliver oxygen-rich
blood from the lungs to the left atrium.
The inferior thick – walled ventricles, which form the bulk of the heart, are the discharging
chambers. They force blood out of the heart into the large arteries that emerge form its
base. The right ventricle pumps blood into the pulmonary trunk, which routes flood to the
lungs to be oxygenated. The left ventricle discharges blood into the aorta, from which all
systemic arteries of the body diverge to supply the body tissues.
Four valves enforce a one – way blood flow through the heart chambers. The
atrioventricular (AV) valves, located between the atrial and ventricular chambers on
each side, prevent backflow into the atria when the ventricles are contracting. The left
atrioventricular valve, also called the mitral or bicuspid valve, consists of two cusps, or
flaps, of endocardium. The right atrioventricular valve, the tricuspid valve, has three
cusps. Tiny white collagenous cords called the chordae tendineae (literally, heart strings)
anchor the cusps to the ventricular walls. The chordae tendineae originate from small
bundles of cardiac muscle, called papillary muscles, project from the myocardial wall.
When blood is flowing passively into the atria and then into the ventricles during diastole
(the period of ventricular relaxation), the atrioventricular valve flaps hang limply in the
ventricular chambers and then are carried passively toward the atria by the accumulating
blood. When the ventricles contract (systole) and compress the blood in their chambers,
the intraventricular blood pressure rises causing the valve flaps to be reflected superiorly,
which closes the AV valves. The chordate tendineae, pulled taut by the contracting papillary
muscles, anchor the flaps in a closed position preventing backflow into the atria during
ventricular contraction. If unanchored, the flaps would blow upward into the atria rather like
an umbrella being turned inside out by a strong wind.
The second set of valves, the pulmonary and aortic semilunar valves, each composed of
three pocket-like cusps, guards the bases of the two large arteries leaving the ventricular
chambers. The valve cusps are forced open and flatten against the walls of the artery as the
ventricles discharge their blood into the large arteries during systole. However, when the
ventricles relax, blood flows backward toward the heart and the cusps fill with blood, closing
the semilunar valves and preventing arterial blood form reentering the heart.
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 4
6. The drawing below shows the internal structures of the heart and the great
vessels attached to the heart. Color the following parts on the diagram.
7. What is the function of the valves inside the heart?
_____________________________________________________________
_____________________________________________________________
8. Complete the following by filling in the blanks with the correct heart valve.
The _________________________ prevents backflow of blood from the right
ventricle into the right atrium. The _________________________ prevents back
flow of blood from the left ventricle into the left atrium. The
_________________________ prevents back flow of blood from the aorta into the
left ventricle. The _________________________ prevents back flow of blood from
the pulmonary trunk into the right ventricle.
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 5
9. Describe what happens during:
a. Diastole.________________________________________________
_______________________________________________________
b. Systole._________________________________________________
________________________________________________________
10. Identify the parts on the following diagrams.
1. __________________________
2. __________________________
3. __________________________
4. __________________________
5. __________________________
6. __________________________
7. __________________________
8. __________________________
9. __________________________
10.__________________________
11.__________________________
12.__________________________
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 6
11. Identify the parts on the following diagrams.
1. __________________________
2. __________________________
3. __________________________
4. __________________________
5. __________________________
6. __________________________
7. __________________________
8. __________________________
9. __________________________
10.__________________________
11.__________________________
12.__________________________
13.__________________________
14.__________________________
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 7
12. Color the following parts on the diagram below.
Deoxygenated blood (A)
Capillary blood (B)
Oxygenated blood (C)
Systemic circulation (D)
Pulmonary circulation (E)
The heart functions as a
double pump. The right side
serves as the pulmonary
circulation pump, shunting
the carbon dioxide – rich
blood entering its chambers to
the lungs to unload carbon
dioxide and pick up oxygen,
and then back to the left side
of the heart. The function of
this circuit is strictly to
provide for gas exchange.
The second circuit, which
carries oxygen – rich blood
from the left heart through
the body tissues and back to
the right heart is called the
systemic circulation. It
supplies the functional blood
supply to all body tissues.
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 8
13. Trace the path of blood through the heart by coloring the arrows on the
diagram below. The shaded arrows show the path of deoxygenated blood. Use
blue to color the shaded arrows. The other arrows show the path of oxygenated
blood. Use red to color these arrows.
14. Identify the type of blood (Oxygenated or Deoxygenated) carried or pumped
by each of the following structures. Use the drawing in the previous question for
help.
______ Aorta
______ Inferior vena cava
______ Left atrium
______ Left ventricle
______ Pulmonary trunk/arteries
______ Pulmonary veins
______ Right atrium
______ Right ventricle
______ Superior vena cava
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 9
15. Identify the heart chambers represented by the numbers in the drawing from
the previous question.
1.________________________ 3.__________________________
2.________________________ 4.__________________________
16. Use the word list below to complete the following.
Aorta
Inferior vena cava (IVC)
Left atrium
Left ventricle
Pulmonary arteries
Pulmonary veins
Right atrium
Right ventricle
Superior vena cava (SVC)
The _______________ and ______________ carry blood into the right atrium.
The _________________________ pumps blood into the right ventricle.
The _________________________ pumps blood into the pulmonary trunk.
The _________________________ carry blood to the lungs.
The _________________________ carry blood to the left atrium.
The _________________________ pumps blood into the left ventricle.
The _________________________ pumps blood into the aorta.
The _________________________ carries blood to the body.
17. What is an ―Auricle?
18. Strong, fibrous strings that attach to the cusps of the tricuspid valve are
called:
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 10
PART TWO
15.4 BLOOD VESSELS
Closed circuit…
Misc.
Arteries
Arterioles
Capillaries
Venules
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 11
Veins
19. Trace a drop of blood through the body and heart!
a. Aortic Valve
b. Arteries
c. Arterioles
d. Bicuspid valve
e. Capillaries
f. Left Atrium
g. Left Ventricle
h. Lung
i. Pulmonary Trunk (arteries)
j. Pulmonary Valve
k. Pulmonary Veins
l. Right Atrium
m. Right Ventricle
n. Tricuspid Valve
o. Veins
p. Vena Cavas
q. Venules
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 12
BLOOD SUPPLY TO THE HEART ITSELF
It is a muscle… and all muscles need a blood supply!
Coronary Arteries
Thrombus or
Embolus
Myocardial
Infarction (MI)
RETURN OF VENOUS BLOOD TO THE HEART
A SMALL PRESSURE GRADIENT DRIVES BLOOD TOWARD THE HEART
Blood flows from regions where its mechanical energy is high to regions where it is low.
When we are in a recumbent position, most of this energy is in the form of pressure. As
blood passes through the narrow arterioles and capillaries, the pressure falls substantially.
In many venules, blood pressure is around 15 mm Hg. In the atria, the average pressure is
close to 0 mm Hg. It follows that there is a small but definite pressure gradient available to
force blood back to the heart. The fact that this small gradient (approximately 15 mm Hg) is
sufficient to drive large volumes of blood demonstrates the low resistance of the venous
pathway. Even veins that appear to be collapsed have a low resistance because the
apparent ―creases‖ in the vessel are never really flat; they always leave some space that
can be easily traversed by circulating blood.
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 13
1. The diagram below shows the pressure gradient discussed in the above
paragraph. Color the following diagram. Use Blue for A, Red for C, and
Purple for D.
2. What happens to the pressure as blood moves from the arteries into the
capillaries?
3. What happens to the pressure as blood moves form through the capillaries
and into the veins?
4. Explain how the small pressure gradient between aids in the return of blood
to the heart.
MUSCLE CONTRACTION PUSHES VENOUS BLOOD
In addition to pressure gradients, there are other mechanisms that aid venous return of
blood to the heart. These include ―pumping actions‖ of noncardiac muscles as well as
movements of the heart itself, and they depend on the valves in the veins, which point in
the direction of the heart. This orientation ensures a forward flow toward the heart: blood
flowing forward forces the valves open; backflow snaps them shut. The picture below shows
this action in a vein lodged between two skeletal muscles. When the muscles are relaxed,
blood flows forward because of the pressure gradient described above, and the vein fills
with blood. The contracting muscles squeeze on the vein and force blood in all directions.
Blood flowing backward closes the bottom valve, but forward-flowing blood keeps the upper
valve open so that blood spurts in the forward direction. When the muscle relaxes, there is
no longer any external force pushing on the venous walls: the pressure gradient from below
(farthest from the heart) forces blood flow in the forward direction, opening the lower valve
and reestablishing the initial condition.
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 14
Thus, each time the muscle contracts and relaxes a spurt of venous blood is sent toward the
heart. This action is called the muscle pump. A good illustration of the importance of the
muscle pump in exercise is provided when a runner remains motionless just after finishing a
strenuous race. His cardiac output is still high and his capillaries and small blood vessels are
still dilated in response to the exercise. Without the muscle pump the veins are quickly
drained, venous return to the heart decreases, and the cardiac output may falter sufficiently
to compromise the blood supply to the brain. Fainting can be avoided if the runner
continues mild exercise for a few minutes.
5. What causes the valves in the veins to open?
6. What causes the valves in the veins to close?
7. Describe how the muscle pump works.
8. A runner who remains motionless after completing a strenuous race may faint.
Why?
9. Color the following parts on the diagram below.
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 15
10. Examine the cross section of an artery and vein at the right.
Which letter represents the
artery?_____
How do you know this is an artery?
____________________________
Which letter represents the
vein?_____
How do you know this is the vein?
____________________________
11. Use the key below to identify the blood vessel being described.
A. Arteries
B. Arterioles
C. Capillaries
D. Venules
E. Veins
______ Efferent blood vessels
______ Carry blood away from
______ Walls consist of 3 layers
______ Walls 1 cell layer thick
______ Have valves
______ Branch to form arterioles
______ Converge to form veins
______ Provide large surface area for
exchange of materials
______ Afferent blood vessels
______ Carry blood to the heart heart
______ Have the thickest walls
______ Walls consist of only
endothelium
______ Branch to form capillaries
______ Converge to form venules
______ Smallest, most numerous b.v.s
______ Site of diffusion
12.What factors are involved in the movement of blood to the heart?
13.What is the role of valves in the veins?
14.Explain what goes wrong when varicose veins appear on legs.
15.How can you tell by simple observation whether bleeding is arterial or
venous?
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 16
16. Match the artery with the correct letter from the diagram.
______ Abdominal aorta
______ Aorta
______ Brachiocephalic
______ Left axillary artery
______ Left common carotid artery
______ Left common iliac artery
______ Left external iliac artery
______ Left subclavian artery
______ Right axillary artery
______ Right common carotid artery
______ Right common iliac artery
______ Right external iliac artery
______ Right subclavian artery
______ Thoracic aorta
17. Match the vein with the correct letter from the diagram.
______ Brachiocephalic vein
______ Inferior vena cava
______ Left common iliac vein
______ Left external iliac vein
______ Left subclavian vein
______ Right common iliac vein
______ Right external iliac vein
______ Right external jugular vein
______ Right subclavian vein
______ Superior vena cava
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 17
18. Match the artery or vein with the correct letter from the diagram.
______ Abdominal aorta
______ Aorta
______ Common carotid artery
______ Common iliac artery
______ Common iliac vein
______ External iliac artery
______ External iliac vein
______ External jugular vein
______ Inferior vena cava
______ Subclavian artery
______ Subclavian vein
______ Superior vena cava
______ Thoracic aorta
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 18
PART THREE
15.3 HEART ACTIONS
Cardiac Cycle
Systole
Diastole
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 19
THE FIVE PERIODS OF THE CARDIAC CYCLE
ATRIAL CONTRACTION
Atrial contraction is signaled by the P wave of the ECG. As atrial pressure rises, blood is
thrust into the ventricles through the open AV valves. These valves are open (as they have
been throughout the diastole) because pressure in the atrium is higher than pressure in the
quiescent ventricle. Blood enters the ventricle but cannot leave because the aortic valves
are closed (pressure in the aorta is greater than the pressure in the ventricle). Note that the
resulting volume increase on the ventricular volume curve appears as a small ―bump.‖ The
atrium serves as a ―booster‖ pump, but its contribution to ventricular filling is small; most of
the ventricular filling occurred earlier, when both atrium and ventricle were at rest. When
the heart rate goes up, as in exercise, there is less time between beats for filling, and the
atrial contribution becomes more significant.
ISOVOLUMETRIC VENTRICULAR CONTRACTION
Now the impulse invades the ventricles (QRS in the ECG), and, after a short delay, they
begin to contract. This is the beginning of systole. Ventricular pressure builds up steeply and
quickly exceeds atrial pressure. The AV valves snap shut, producing the first heart sound –
―Lupp or Lub.‖ Following closure of the AV valves, ventricular pressure continues to rise
steeply until it exceeds aortic pressure. Pressure rises rapidly because both sets of heart
valves are closed. The heart continues to contract, but there is no place for the blood to go
to relieve the ascending pressure. (Contraction of the heart during this period is similar to
an isometric contraction in skeletal muscle.) During this period, the ventricular volume
cannot change – note the flat horizontal trace on the ventricular volume curve. The constant
ventricular volume is the reason for naming this period ―isovolumetric ventricular
contraction.‖
VENTRICULAR EJECTION
As soon as the ventricular pressure exceeds aortic pressure, the aortic valves are thrust
open, and blood is ejected into the aorta. Pressure in the aorta begins to rise because blood
is entering from the ventricles faster than it can leave through the smaller arteries. Prior to
this time, pressure in the aorta had been falling because the aortic valves were closed;
blood continued to leave the aorta through smaller arteries, but none could enter from the
ventricle. Blood entering the ventricles is reflected in the ventricular volume curve, which
drops precipitously as soon as ejection begins. Soon afterward, the contractile force of the
ventricle wanes; the ventricular pressure ascent slows and begins to reverse while the initial
rapid change in ventricular volume begins to level off. As the ventricles begin to repolarize
(T wave of the ECG) and relax, the ventricular pressure curve crosses the aortic curve and
goes below it. Shortly thereafter, the aortic valve snaps shut, producing a sharp ―Dup‖
sound (the second heart sound) and bringing the ventricular ejection period, as well as the
period of systole, to an end. It also produces a bump notch on the aortic pressure curve.
The aortic valve closure is not simultaneous with the crossover of the ventricular and aortic
pressure curves because the blood flowing through the valves has an appreciable
momentum (mass X velocity) in the direction of forward flow. Applying a force (pressure
difference) in the opposite direction requires a small amount of time to stop or reverse the
motion. (Imagine trying to stop a rolling automobile with a hand push in the opposite
direction.) Notice that not all of the blood contained within the ventricle is ejected with each
beat. The residual blood is almost equal to the amount ejected.
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 20
ISOVOLUMETRIC VENTRICULAR RELAXATION
Now, as in isovolumetric contraction, both valves are closed, and blood cannot enter or
leave the ventricles. This time, however, the ventricular muscles relax; it is the beginning of
diastole. Pressure falls precipitously, but ventricular volume does not change. Soon the
ventricular pressure falls below atrial pressure, the AV valves open, and isovolumetric
relaxation ends.
VENTRICULAR FILLING
In this period, atrial pressure is higher than ventricular pressure because blood continues to
flow into the atrium from the pulmonary veins. Blood flows through the open AV valve from
atrium to ventricle. Ventricle filling continues throughout diastole, not just when the atrium
contracts. The ventricular volume curve during diastole shows that early ventricular filling is
not prominent and that contraction of the atrium contributes only a minor portion to the
ventricular contents. Toward the end of this period, atrial contraction ensues, and this
period, as well as diastole, ends with closure of the AV valves.
DIRECTIONS FOR COLORING THE DIAGRAM ON NEXT PAGE…
1. Pick colors for each item listed in the key below. Use red for Blood (F).
o Left atrium (A)
o AV valve (B)
o Left ventricle (C)
o Aortic valve (D)
o Aorta (E)
o Blood (F) use red
2. Using the key in #1:
a. Color the titles for 1 – 5 and all the labeled structures in each heart
diagram. Color the heart sounds and the sound bars surrounding the relevant
valve.
b. Color the pressure graph and refer to the relevant period in the cardiac
cycle shown at the top.
c. Color the volume graph and refer to the relevant period in the cardiac
cycle shown at the top.
3. Pick a color, one not used in the key, to color the ECG graph.
4. Pick a color, one not used in the key, to color the bottom numbers representing
the time intervals.
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 21
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 22
CARDIAC CONDUCTION SYSTEM
SA Node
Atrial Syncytium
Junctional Fibers
AV Node
AV Bundle
Bundle Branches
Purkinje Fibers
Ventricular Syncytium
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 23
HEART SOUNDS
Lub
Dup
ELECTROCARDIOGRAPHY (ECG/ EKG)
General
Description
P
Q
R
S
T
Heart Rate
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 24
15.5 BLOOD PRESSURE
Arteriole Blood Pressure
Factors affecting arterial blood pressure
Heart Action
Blood Volume
Peripheral Resistance
Viscosity
Control of Blood Pressure… p. 585-587
BP = CO x PR (recall: CO = SV x HR) & (SV = EDV-ESV)
Mechanical—Frank -Starling law of the heart: Increased stretch (preload) =
increased strength of contraction
Neural—Increased sympathetic innervation increases the force of contraction which
increases the percentage of EDV pumped out in a single beat.
Chemical—Epinephrine increases heart rate. Carbon Dioxide, Oxygen, H+ ions,
Nitric Oxide, Angiotensin, Bradykinin
Fear, anger, physical exercise, rise in external temperature
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 25
Questions
1. Match the description with the correct conduction system component. Use the
key provided to indicate your answers.
A. SA node
B. AV node
C. AV bundle & branches
D. Purkinje fibers
______ Sinoatrial node
______ Located in the right atrium inferior to the entrance of the sup. vena cava
______ Atrioventricular node
______ Located in the lower atrial septum at the junction of atria and ventricles
______ Located within the interventricular septum
______ Located within the walls of the ventricles
______ Pacemaker
______ Provides the stimulus for contraction
______ Sets the rate of depolarization for heart as whole
______ Delays conduction of the impulse
2. Listed below are the events that cause the heart to contract. Put the steps in the
correct order.
______ Depolarization of the SA node
______ Impulse passes along the Purkinje fibers
______ Impulse spreads throughout the atria
______ AV node receives impulse
______ Impulse passes through the AV bundle
______ AV node delays conduction of the impulse for approximately 0.1 sec.
______ Atria contract
______ Impulse passes through the bundle branches
______ Ventricles contract
3. Identify the ECG wave (P, QRS, or T) described in each of the following:
______ Atrial depolarization
______ Depolarization wave travels from the SA node to the AV node
______ Depolarization travels along AV bundle, bundle branches, Purkinje fibers
______ Ventricular depolarization
______ Ventricular repolarization
______ Causes atria to contract
______ Causes ventricles to contract
______ Atria empty
______ Ventricles empty
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 26
______ Atria fill
______ Ventricles fill
4. Match the ECG component and
event with the correct letter from the
diagram at the right.
______ T wave
______ P wave
______ QRS complex
______ Depolarization of ventricles
______ Repolarization of ventricles
______ Depolarization of atria
______ Causes contraction of atria
______ Causes contraction of ventricles
______ Ventricles empty
______ Ventricles fill
______ Atria empty
______ Atria fill
5. How is the pressure on in the right side of the heart different from the pressure
in the left side of the heart?
_____________________________________________________________
Why does this difference exist? ____________________________________
_____________________________________________________________
6. The opening and closing of the valves results from the changes in pressure
within the heart. Match the event with the correct cause.
A. AV valves close
B. AV valves open
C. Semilunar valves open
D. Semilunar valves close
______ Pressure inside the ventricles is higher than the pressure inside the atria
______ Pressure inside the larger arteries is higher than the pressure inside the ventricles
______ Pressure inside the large arteries is lower than the pressure inside the ventricles
______ Pressure inside the ventricles is lower than the pressure inside the atria
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 27
7. Identify the period of the cardiac cycle during which each of the following events
occur. Use the key below to indicate your answers.
1.
2.
3.
4.
5.
Atrial contraction
Isovolumetric ventricular contraction
Ventricular ejection
Isovolumetric ventricular relaxation
Ventricular filling
______ Signaled by the P wave of the ECG
______ Atria contract forcing blood into the ventricles
______ Signaled by the QRS complex of the ECG
______ Ventricles begin to contract
______ Systole begins
______ Pressure inside the ventricles increases until the pressure in the ventricles exceeds
the pressure inside the atria
______ Pressure inside the ventricles is lower than the pressure inside the aorta
______ AV valves close
______ Lupp (Lub) heart sound produced
______ Ventricular volume cannot change
______ Pressure inside ventricles exceeds pressure inside the aorta
______ Semilunar valves (aortic) open
______ Contraction of the ventricles forces blood out of the ventricles into the aorta
______ Volume in the ventricles decreases
______ Semilunar valves snap shut
______ Dup heart sound produced
______ Ventricles relax
______ Diastole begins
______ Pressure in the ventricles decreases
______ AV valves open
______ Pressure in the atria is higher than the pressure in the ventricles
______ Blood flows from the atria into the ventricles
______ Ventricular volume increases
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 28
8. Indicate if each of the following events occurs during Systole or Diastole.
______ Ventricles contract and empty
______ Ventricles relax and fill
______ Atria contract and empty
______ Atria relax and fill
______ AV valves close
______ Semilunar valves close
9. What would happen if the length of the quiescent (ventricular relaxation) period
decreased?
_____________________________________________________________
_____________________________________________________________
10. Identify the heart sound (Lub or Dup) described in each of the following.
______ First heart sound
______ Second heart sound
______ Longer, louder sound
______ Shorter, sharper sound
______ Associated with closure of the AV valves
______ Associated with closure of the semilunar valves
11. Define cardiac output.
_____________________________________________________________
_____________________________________________________________
12. What two factors determine cardiac output?
_____________________________________________________________
_____________________________________________________________
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 29
13. Complete the following equation by filling in the missing parts.
14. What is the average heart rate for an adult at rest? ____________________
15. What does ―bpm‖ represent? ______________________________________
16. Define stroke volume.
_____________________________________________________________
17. What is the average stroke volume for an adult at rest? _________________
18. Explain the three primary factors regulating Stroke Volume. (p. 585-586)
Mechanical:
Neural:
Chemical:
19. An increase in venous blood returning to the heart will __________________
heart rate.
20. In general, more blood entering the ventricles causes an _______________
in ventricular contraction resulting in an ______________ in cardiac output.
21. Stimulation of parasympathetic neurons causes the release of
_________________________ which _________________ heart rate.
22. Stimulation of sympathetic neurons causes the release of
_________________________ and ______________________ which
_________________________ heart rate.
CARDIOVASCULAR SYSTEM | HA&P Notes Chapter 15 page 30