Anatomy of the Heart
(Be able to identify the following)
General Structures:
1. Apex
2. Base
3. Right Auricle
4. Left Auricle
5. Papillary Muscle
6. Chordae tendineae
7. Myocardium
8. Interventricular Septum
Vessels:
1. Coronary Artery
2. Cardiac Vein
3. Superior Vena Cava
4. Inferior Vena Cava
5. Pulmonary Trunk
6. Pulmonary Arteries
7. Pulmonary Veins
8. Aorta
Chambers:
1. Right Atrium
2. Right Ventricle
3. Left Atrium
4. Left Ventricle
Valves:
1. Tricuspid Valve
2. Bicuspid (Mitral) Valve
3. Pulmonary Semilunar
Valve
4. Aortic Semilunar Valve
Do you have the heart for this?
Chapter 20: Heart
Anatomy & Physiology
Gross anatomy of the heart
Characteristics
• 4-chambers - size of a
fist
• located behind 2nd- 6th
ribs within mediastinum;
base or upper border lies
below 2nd rib; apex or
lower border lies on
diaphragm
Characteristics
• beats 100,000 times a
day; pumps 2,500
gallons of blood a day
or 5 quarts a blood per
minute
• atria contract together
and the ventricles
contract together to
pump blood to lungs
and body, respectively
Anatomy
1. Pericardium- surrounding sac of dense fibrous tissue and
serous membrane; parietal
2. Epicardium- on the heart; visceral layer of serous pericardium;
fat
3. Pericardial fluid- lubricating fluid secreted by serous
membrane
Anatomy (continued)
4. Myocardium- cardiac muscle with intercalated disks;
autorhythmic
5. Endocardium- simple squamous epithelial
6. Atria- two superior chambers; walls not thick; auricleear-like protruding flap
7. Ventricles- two inferior chambers; walls thick
Heart Valves
Atrioventricular (AV) valves- between atria and
ventricles
LUB
a.Tricuspid- three flaps connected by chordae
tendinae, (tendonous chords– use papillary
muscles to contract)
b.Bicuspid- two flaps connected by chordae
tendinae; AKA mitral valve
Semilunar (SV) valves- half-moon shaped flaps
leaving ventricles; prevent backflow DUB
a.Pulmonary semilunar valve- at entrance to
pulmonary artery
b.Aortic semilunar valve- at entrance to aorta
Atrioventricular (AV) valvesbetween atria and ventricles
LUB
a.Tricuspid- three flaps connected
by chordae tendinae, (tendonous
chords– use papillary muscles to
contract)
b.Bicuspid- two flaps connected
by chordae tendinae; AKA mitral
valve
Semilunar (SV) valves- halfmoon shaped flaps leaving
ventricles; prevent backflow
DUB
a.Pulmonary semilunar valve- at
entrance to pulmonary artery
b.Aortic semilunar valve- at
entrance to aorta
Heart Valves
AV Valve Function
• A-V valves open and
allow blood to flow
from atria into
ventricles when
ventricular pressure is
lower than atrial
pressure
• A-V valves close
preventing backflow of
blood into atria
Blood flow through the heart
(blood no oxygen; red oxygenated blood)
1. superior & inferior vena cava empty deoxygenated blood into
right atrium 
2. through tricuspid (AV) valve into right ventricle 
3. through pulmonary semilunar valve into pulmonary artery 
4. to lungs 
5. oxygenated blood returns to heart thru pulmonary veins 
6. left atrium 
7. through bicuspid (AV) valve into left ventricle 
8. through aortic semilunar valve into aorta 
9. distribute to body from arteries to capillaries to veins
AV valve function during contraction
Semilunar valve function
D. Coronary Circulation:
• Right and left coronary
arteries from aorta bring
blood to heart.
• Cardiac veins dump
blood into coronary sinus,
which leads to right
atrium.
• Blood clots may deprive
heart cells from O2 in
coronary diseases such
as myocardial infarction.
Passage of Blood through the Heart
Body
SVC/IVC
Right Atrium
(tricuspid valve)
Right Ventricle
(pulmonary semilunar valve)
Pulmonary Arteries
Lungs
Pulmonary Veins
Left Atrium
bicuspid (mitral) valve
Body
Aorta
(aortic semilunar valve)
Left Ventricle
Control of the Heart Beat
Unison contractions;
conduction system;
cardiac muscle tissue
has own intrinsic beat
even if removed;
independent of
nervous system
1. Sinoatrial node (SA)pacemaker; heartbeat
is initiated
2. Atrioventricular (AV)
node- delayed relay
point; in right atrium,
near septum; causes
atrium to contract
Control of the Heart Beat
3. Atrioventricular
(AV) bundle- AKA
4. Bundles of His;
impulse travels
down septum
5. Purkinje fibersextend impulse to
ventricles and
papillary muscles
for contraction
Heart rate is affected by nervous system and endocrine glands.
Average adult heart rate at rest is 70-75 beats per minute.
Conduction System of Heart
• Autorhythmic Cells
– Cells fire spontaneously, act as
pacemaker and form conduction
system for the heart
• SA node = 1.
– cluster of cells in wall of Rt. Atria
– begins heart activity that spreads
to both atria
– excitation spreads to AV node
• AV node = 2.
– in atrial septum, transmits signal
to bundle of His
• AV bundle of His = 3 & 4.
– the connection between atria and
ventricles
– divides into bundle branches &
purkinje fibers, large diameter
fibers that conduct signals quickly
Rhythm of Conduction System
• SA node fires spontaneously 90-100 times
per minute
• AV node fires at 40-50 times per minute
• If both nodes are suppressed fibers in
ventricles by themselves fire only 20-40 times
per minute
• Artificial pacemaker needed if pace is too
slow
• Extra beats forming at other sites are called
ectopic pacemakers
Electrocardiogram---ECG or EKG
• EKG
– Action potentials of all
active cells can be detected
and recorded
• P wave
– atrial depolarization
• P to Q interval
– conduction time from atrial
to ventricular excitation
• QRS complex
– ventricular depolarization
• T wave
– ventricular repolarization
Innervation of the Heart
• Speed up the heart with sympathetic stimulation
• Slow it down with parasympathetic stimulation
(X)
• Sensory information from baroreceptors (IX)
The
Heartbeat
-contraction of
atria
-AV valves open
-filling of
ventricles =
“Ventricular
Filling stage”
each heartbeat = cardiac cycle
-SL valves close
“dup”
-AV valves open
-filling of atria &
ventricles begins
-contraction of ventricles
-AV valves close “lub”
-SL valves open
-blood to lungs and body
**Heart Murmur**
Heart Sounds
Auscultation
• Stethoscope
• Sounds of heartbeat
are from turbulence in
blood flow caused by
valve closure
– first heart sound (lubb)
is created with the
closing of the
atrioventricular valves
– second heart sound
(dupp) is created with
the closing of semilunar
valves
Cardiac Output
• Amount of blood pushed into aorta or
pulmonary trunk by ventricle
• Determined by stroke volume and heart rate
• CO = SV x HR
– at 70ml stroke volume & 75 beat/min----5 and 1/4
liters/min
– entire blood supply passes through circulatory
system every minute
• Cardiac reserve is maximum output/output at
rest
– average is 4-5 while athlete is 7-8
Regulation of Heart Rate
• Nervous control from the cardiovascular center in the medulla
– Sympathetic impulses increase heart rate and force of contraction
– parasympathetic impulses decrease heart rate.
– Baroreceptors (pressure receptors) detect change in BP and send info to the
cardiovascular center
• located in the arch of the aorta and carotid arteries
•
Heart rate is also affected by hormones
– epinephrine, norepinephrine, thyroid hormones
– ions (Na+, K+, Ca2+)
– age, gender, physical fitness, and temperature
Coronary Arteries
• Branches off aorta
above aortic semilunar
valve
• Left coronary artery
– circumflex branch
• in coronary sulcus,
supplies left atrium and
left ventricle
– anterior
interventricular art.
• supplies both ventricles
• Right coronary artery
– marginal branch
• in coronary sulcus,
supplies right ventricle
– posterior
interventricular art.
• supplies both ventricles
Coronary Veins
• Collects wastes from cardiac muscle
• Drains into a large sinus on posterior surface of heart
called the coronary sinus
• Coronary sinus empties into right atrium