1
CARDIOVASCULAR 570 WEEK 3 STUDY
GUIDE 2027
Chapter 4 Cardiovascular Function
Anatomy & Physiology
A. Know the components, layers of the heart itself, movement through the different vessels, SA
node/AV node
Components: fibrous skeleton, cardiac muscle, and impulse conduction system constitute the basic framework
of the heart
Pericardium: fibroserous sac that surrounds the heart and the roots of vessels that enter/leave heart
● fibrous pericardium, composed of tough, white fibrous tissue, fits loosely around the heart, protecting it
● serous pericardium: parietal layer (lines inside of fibrous pericardium), visceral layer (adheres to
the surface of the heart)
● pericardial space: contains pericardial fluid that lubricates the surfaces of the space and allows the
heart to move easily during contraction
Layers of the heart wall:
● epicardium (outermost layer, is the visceral layers of the serous pericardium, covers the heart and
great vessels, made up of epithelial cells overlying connective tissue)
● myocardium (middle layer, muscular layer that contracts, controlled by autonomic nervous system)
● endocardium (very thin, 3 layered membrane, lines interior of heart, covers valves)
○ inner layer consists of endothelial cells supported by thin layer of fibrous tissue with elastin
○ middle layer is dense fibrous tissue with elastin
○ outer layer more dense connective tissue that contains blood vessels and nerves continuous
with myocardium
Chambers of the heart: right atrium, left atrium, right ventricle, left ventricle
Circulatory System
● Pulmonary circulation: moves blood from pulmonary artery into lungs and allows oxygenation and gas
exchange at capillary bed; low pressure system and allows blood to move through lungs slowly which is
important for gas exchange
● Systemic circulation: begins at the aorta, blood obtained from left ventricle and moved into tissue
for oxygenation. Cells get oxygenated and deoxygenated blood flows through veins back to the heart
○ veins in lower section of body drain into the inferior vena cava and veins from upper section
, of body drain into the superior vena cava. BOTH IVC and SVC drain into right atrium.
● SEE DIAGRAMS OF HEART BELOW
Conduction System
● SA node- located in high right atrium; normal origination of of conduction pathway; generates
impulses at 60-100bpm; pacemaker of the heart
● AV node- located in right atrium adjacent to septum; only initiates impulses if not receiving from SA
node, intrinsic rate of 40-60bpm; impulses delayed through AV node so that atria contracts right
before ventricle
● Bundle of His
● L and R bundle branches
, ● Purkinje fibers
● *note: ventricular intrinsic contraction rate if impulse not received is 20-40bpm
It is the spread of electrical activity beginning at the sinoatrial node ---> atrioventricular node---------> down to
bundle of His---------> then along the Purkinje fibres.
This process initiates myocardial contraction in the surrounding myocardial tissue.
B. Normal O2/CO2 exchange
Pulmonary circulation: movement of blood from the heart to the lungs for
oxygenation, then back to the heart again. Leaving systemic circulation
oxygen-depleted blood from the body enters --> right atrium through the
superior and inferior venae cavae--------------------------------------------------------->The
blood
is then pumped through the tricuspid valve into the right ventricle→ pulmonary
valve and into the pulmonary artery→ The pulmonary artery splits into the
right and left pulmonary arteries and travel to each lung.
In the lungs, the blood travels through capillary beds on the alveoli where gas exchange occurs, removing carbon
dioxide and adding oxygen to the blood. Gas exchange occurs due to gas partial pressure gradients across the
the alveoli of the lungs and the capillaries interwoven in the alveoli. The oxygenated blood then leaves the
lungs through pulmonary veins, which returns it to the left atrium, completing the pulmonary circuit. As the
pulmonary circuit ends, the systemic circuit begins.
Systemic circulation: movement of blood from the heart through the body to provide oxygen and nutrients to the
tissues of the body while bringing deoxygenated blood back to the heart. Oxygenated blood enters the left
atrium from the pulmonary veins ---> mitral valve into the left ventricle > pumped through the aortic valve
and into the aorta, the body’s largest artery. The aorta arches and branches into major arteries to the upper body
before passing through the diaphragm, where it branches further into the illiac, renal, and suprarenal arteries
which supply the lower parts of the body.
https://med.libretexts.org/Bookshelves/Anatomy_and_Physiology/Book
%3A_Anatomy_and_Physiology_(Boundless)/17%3A_Cardiovascular_System
%3A_The_Heart/17.2%3A_Circulation_and_Heart_Valves/17.2D%3A_Systemic_and_Pulmonary_Circulation
C. Difference in the male versus female anatomy of heart the male heart are usually slight;y
larger at0.45% of body weight while womens are 0.40% of body weight (p.119 book)
D. Heart cycle with its corresponding sounds on exam (diastole, systole)
The cardiac cycle represents the hemodynamic and electric changes that occur in systole and diastole.
Phases of the Cardiac Cycle
1. Isovolumetric ventricular contraction: This phase marks the beginning of systole and starts with
the appearance of the QRS complex on the EKG and the closure of the AV valves. With all
valves closed, the ventricle generates positive pressure without any change in its volume
(isovolumetric) to overcome the semilunar valves resistance that open. This phase usually lasts
for 6% of the cardiac cycle.
, 2. Rapid ejection: As the semilunar valves open, there is a rapid ejection of blood due to increased
ventricular contractility. The arterial pressure increases until reaching its maximum. This
phase usually lasts for 13% of the cardiac cycle.
3. Reduced ejection: This phase marks the beginning of ventricular repolarization as depicted by the
onset of the T wave on the EKG. Repolarization leads to a rapid decline in ventricular pressures
and hence the reduced rate of ejection. However, some forward flow of blood continues secondary
to remnant kinetic energy from the previous phase. This phase usually lasts for 15% of the
cardiac cycle.
4. Isovolumetric relaxation: When the ventricular pressures drop below the diastolic aortic and
pulmonary pressures (80 mmHg and 10 mmHg respectively), the aortic and pulmonary valves
close producing the second heart sound. This marks the beginning of diastole. The ventricles
generate negative pressure without changing their volume (isovolumetric) so that the
ventricular pressure becomes lower than the atrial pressure. This phase usually lasts for 8% of
the cardiac cycle.
5. Ventricular filling: As the AV valves open, ventricular filling starts. The initial rapid filling is
mainly augmented by ventricular suction which results from ventricular untwisting and the
return of each ventricular muscle fiber to its slack length. The ventricular pressure gradually
increases until it equals the atrial pressure and the AV valves close. This phase usually lasts for
44% of the cardiac cycle.
6. Atrial contraction: Finally, near the end of ventricular diastole, the atrial contraction
contributes about 10% of the ventricular filling volume. This is represented by the P wave on the
EKG of the following cycle. This phase usually lasts for 14% of the cardiac cycle.
The first heart sound (S1) represents closure of the atrioventricular (mitral and tricuspid) valves as
the ventricular pressures exceed atrial pressures at the beginning of systole (point a). S1 is
normally a single sound because mitral and tricuspid valve closure occurs almost simultaneously.
Clinically, S1 corresponds to the pulse.
The second heart sound (S2) represents closure of the semilunar (aortic and pulmonary) valves (point
d). S2 is normally split because the aortic valve (A2) closes before the pulmonary valve (P2). The
closing pressure (the diastolic arterial pressure) on the left is 80 mmHg as compared to only 10
mmHg on the right. This higher closing pressure leads to earlier closure of the aortic valve. In
addition, the more muscular and stiff "less compliant" left ventricle (LV) empties earlier than the
right ventricle. The venous return to the right ventricle (RV) increases during inspiration due to
negative intrathoracic pressure and P2 is even more delayed, so it is normal for the split of the
second heart sound to widen during inspiration and to narrow during expiration. Clinically, this
is more remarkable with slow heart rates.
The third heart sound (S3) represents a transition from rapid to slow ventricular filling in early
diastole. S3 may be heard in normal children.
The fourth heart sound (S4) is an abnormal late diastolic sound caused by forcible atrial contraction
in the presence of decreased ventricular compliance.
Systolic ejection murmurs (SEM, crescendo-decrescendo) result from turbulent blood flow due to
obstruction (actual or relative) across the semilunar valves, outflow tracts or arteries. The murmur is
heard shortly after S1 (pulse). Diastolic murmurs are usually abnormal, and may be early, mid or late
diastolic.
CARDIOVASCULAR 570 WEEK 3 STUDY
GUIDE 2027
Chapter 4 Cardiovascular Function
Anatomy & Physiology
A. Know the components, layers of the heart itself, movement through the different vessels, SA
node/AV node
Components: fibrous skeleton, cardiac muscle, and impulse conduction system constitute the basic framework
of the heart
Pericardium: fibroserous sac that surrounds the heart and the roots of vessels that enter/leave heart
● fibrous pericardium, composed of tough, white fibrous tissue, fits loosely around the heart, protecting it
● serous pericardium: parietal layer (lines inside of fibrous pericardium), visceral layer (adheres to
the surface of the heart)
● pericardial space: contains pericardial fluid that lubricates the surfaces of the space and allows the
heart to move easily during contraction
Layers of the heart wall:
● epicardium (outermost layer, is the visceral layers of the serous pericardium, covers the heart and
great vessels, made up of epithelial cells overlying connective tissue)
● myocardium (middle layer, muscular layer that contracts, controlled by autonomic nervous system)
● endocardium (very thin, 3 layered membrane, lines interior of heart, covers valves)
○ inner layer consists of endothelial cells supported by thin layer of fibrous tissue with elastin
○ middle layer is dense fibrous tissue with elastin
○ outer layer more dense connective tissue that contains blood vessels and nerves continuous
with myocardium
Chambers of the heart: right atrium, left atrium, right ventricle, left ventricle
Circulatory System
● Pulmonary circulation: moves blood from pulmonary artery into lungs and allows oxygenation and gas
exchange at capillary bed; low pressure system and allows blood to move through lungs slowly which is
important for gas exchange
● Systemic circulation: begins at the aorta, blood obtained from left ventricle and moved into tissue
for oxygenation. Cells get oxygenated and deoxygenated blood flows through veins back to the heart
○ veins in lower section of body drain into the inferior vena cava and veins from upper section
, of body drain into the superior vena cava. BOTH IVC and SVC drain into right atrium.
● SEE DIAGRAMS OF HEART BELOW
Conduction System
● SA node- located in high right atrium; normal origination of of conduction pathway; generates
impulses at 60-100bpm; pacemaker of the heart
● AV node- located in right atrium adjacent to septum; only initiates impulses if not receiving from SA
node, intrinsic rate of 40-60bpm; impulses delayed through AV node so that atria contracts right
before ventricle
● Bundle of His
● L and R bundle branches
, ● Purkinje fibers
● *note: ventricular intrinsic contraction rate if impulse not received is 20-40bpm
It is the spread of electrical activity beginning at the sinoatrial node ---> atrioventricular node---------> down to
bundle of His---------> then along the Purkinje fibres.
This process initiates myocardial contraction in the surrounding myocardial tissue.
B. Normal O2/CO2 exchange
Pulmonary circulation: movement of blood from the heart to the lungs for
oxygenation, then back to the heart again. Leaving systemic circulation
oxygen-depleted blood from the body enters --> right atrium through the
superior and inferior venae cavae--------------------------------------------------------->The
blood
is then pumped through the tricuspid valve into the right ventricle→ pulmonary
valve and into the pulmonary artery→ The pulmonary artery splits into the
right and left pulmonary arteries and travel to each lung.
In the lungs, the blood travels through capillary beds on the alveoli where gas exchange occurs, removing carbon
dioxide and adding oxygen to the blood. Gas exchange occurs due to gas partial pressure gradients across the
the alveoli of the lungs and the capillaries interwoven in the alveoli. The oxygenated blood then leaves the
lungs through pulmonary veins, which returns it to the left atrium, completing the pulmonary circuit. As the
pulmonary circuit ends, the systemic circuit begins.
Systemic circulation: movement of blood from the heart through the body to provide oxygen and nutrients to the
tissues of the body while bringing deoxygenated blood back to the heart. Oxygenated blood enters the left
atrium from the pulmonary veins ---> mitral valve into the left ventricle > pumped through the aortic valve
and into the aorta, the body’s largest artery. The aorta arches and branches into major arteries to the upper body
before passing through the diaphragm, where it branches further into the illiac, renal, and suprarenal arteries
which supply the lower parts of the body.
https://med.libretexts.org/Bookshelves/Anatomy_and_Physiology/Book
%3A_Anatomy_and_Physiology_(Boundless)/17%3A_Cardiovascular_System
%3A_The_Heart/17.2%3A_Circulation_and_Heart_Valves/17.2D%3A_Systemic_and_Pulmonary_Circulation
C. Difference in the male versus female anatomy of heart the male heart are usually slight;y
larger at0.45% of body weight while womens are 0.40% of body weight (p.119 book)
D. Heart cycle with its corresponding sounds on exam (diastole, systole)
The cardiac cycle represents the hemodynamic and electric changes that occur in systole and diastole.
Phases of the Cardiac Cycle
1. Isovolumetric ventricular contraction: This phase marks the beginning of systole and starts with
the appearance of the QRS complex on the EKG and the closure of the AV valves. With all
valves closed, the ventricle generates positive pressure without any change in its volume
(isovolumetric) to overcome the semilunar valves resistance that open. This phase usually lasts
for 6% of the cardiac cycle.
, 2. Rapid ejection: As the semilunar valves open, there is a rapid ejection of blood due to increased
ventricular contractility. The arterial pressure increases until reaching its maximum. This
phase usually lasts for 13% of the cardiac cycle.
3. Reduced ejection: This phase marks the beginning of ventricular repolarization as depicted by the
onset of the T wave on the EKG. Repolarization leads to a rapid decline in ventricular pressures
and hence the reduced rate of ejection. However, some forward flow of blood continues secondary
to remnant kinetic energy from the previous phase. This phase usually lasts for 15% of the
cardiac cycle.
4. Isovolumetric relaxation: When the ventricular pressures drop below the diastolic aortic and
pulmonary pressures (80 mmHg and 10 mmHg respectively), the aortic and pulmonary valves
close producing the second heart sound. This marks the beginning of diastole. The ventricles
generate negative pressure without changing their volume (isovolumetric) so that the
ventricular pressure becomes lower than the atrial pressure. This phase usually lasts for 8% of
the cardiac cycle.
5. Ventricular filling: As the AV valves open, ventricular filling starts. The initial rapid filling is
mainly augmented by ventricular suction which results from ventricular untwisting and the
return of each ventricular muscle fiber to its slack length. The ventricular pressure gradually
increases until it equals the atrial pressure and the AV valves close. This phase usually lasts for
44% of the cardiac cycle.
6. Atrial contraction: Finally, near the end of ventricular diastole, the atrial contraction
contributes about 10% of the ventricular filling volume. This is represented by the P wave on the
EKG of the following cycle. This phase usually lasts for 14% of the cardiac cycle.
The first heart sound (S1) represents closure of the atrioventricular (mitral and tricuspid) valves as
the ventricular pressures exceed atrial pressures at the beginning of systole (point a). S1 is
normally a single sound because mitral and tricuspid valve closure occurs almost simultaneously.
Clinically, S1 corresponds to the pulse.
The second heart sound (S2) represents closure of the semilunar (aortic and pulmonary) valves (point
d). S2 is normally split because the aortic valve (A2) closes before the pulmonary valve (P2). The
closing pressure (the diastolic arterial pressure) on the left is 80 mmHg as compared to only 10
mmHg on the right. This higher closing pressure leads to earlier closure of the aortic valve. In
addition, the more muscular and stiff "less compliant" left ventricle (LV) empties earlier than the
right ventricle. The venous return to the right ventricle (RV) increases during inspiration due to
negative intrathoracic pressure and P2 is even more delayed, so it is normal for the split of the
second heart sound to widen during inspiration and to narrow during expiration. Clinically, this
is more remarkable with slow heart rates.
The third heart sound (S3) represents a transition from rapid to slow ventricular filling in early
diastole. S3 may be heard in normal children.
The fourth heart sound (S4) is an abnormal late diastolic sound caused by forcible atrial contraction
in the presence of decreased ventricular compliance.
Systolic ejection murmurs (SEM, crescendo-decrescendo) result from turbulent blood flow due to
obstruction (actual or relative) across the semilunar valves, outflow tracts or arteries. The murmur is
heard shortly after S1 (pulse). Diastolic murmurs are usually abnormal, and may be early, mid or late
diastolic.
