Chapter 8
Have a Heart
© 2009 Delmar, Cengage Learning
The Cardiovascular System
• Delivers oxygen, nutrients, and hormones to
various tissues of the body.
• Transports waste products to the appropriate
waste removal system.
• Is also referred to as the circulatory system.
© 2009 Delmar, Cengage Learning
The Cardiovascular System
• Cardiovascular means pertaining to the
heart and blood vessels.
• The heart is a hollow muscular organ that
provides the power to move blood through
the body.
• The heart is located in the mediastinum, a
space in the thoracic cavity between the
lungs.
© 2009 Delmar, Cengage Learning
The Structures Surrounding
the Heart
• The pericardium is a double-walled
membrane that surrounds the heart.
– Peri- means around.
© 2009 Delmar, Cengage Learning
The Structures Surrounding
the Heart
• The pericardium has two layers:
– fibrous layer
– serous layer
• parietal layer
• visceral layer
© 2009 Delmar, Cengage Learning
The Structures Surrounding
the Heart
• The pericardial space is the space
between the two serous layers of the
pericardium.
– This space contains pericardial fluid.
• Pericardial fluid prevents friction between the heart and
the pericardium when the heart beats.
© 2009 Delmar, Cengage Learning
The Heart Walls
• The heart is made up of three walls:
– epicardium = external layer
• Epi- means upper.
– myocardium = middle layer
• My/o means muscle.
– endocardium = inner layer
• Endo- means within.
© 2009 Delmar, Cengage Learning
Blood Supply to the Heart
• The blood vessels that
deliver blood to and
take blood away from
the heart are known as
coronary vessels.
– Coronary occlusion
means blockage of
coronary vessels.
– Coronary occlusion may
lead to ischemia.
• Ischemia is a
deficiency in blood
supply to an area.
© 2009 Delmar, Cengage Learning
Blood Supply to the Heart
– Ischemia may lead to necrosis.
– An area of necrosis caused by an interrupted blood supply is an
infarct.
© 2009 Delmar, Cengage Learning
The Heart Chambers
• The superior chambers of
the heart are known
as atria (singular is atrium).
– atri/o = atria
• The inferior chambers of
the heart are known as
ventricles.
– ventricul/o = ventricles
© 2009 Delmar, Cengage Learning
The Heart Chambers
• A septum is a separating wall.
• The apex is the tip of the heart.
© 2009 Delmar, Cengage Learning
The Heart Valves
• A valve is a membranous
fold.
• The heart valves control
the flow of blood through
the heart.
– valv/o and valvul/o = valve
• Right atrioventricular
valve
– also known as tricuspid valve
© 2009 Delmar, Cengage Learning
The Heart Valves
• Pulmonary
semilunar valve
• Left atrioventricular
valve
– also known as mitral
valve
– also known as bicuspid
valve
• Aortic semilunar
valve
© 2009 Delmar, Cengage Learning
Tuesday Jan 13, 2015
• The pericardium is made of two layers:
Briefly describe each layer
• Which side of the heart will you find
de-oxygenated blood?
• The oxygenated blood leaves the heart
through which artery?
© 2009 Delmar, Cengage Learning
© 2009 Delmar, Cengage Learning
Pathological Conditions
• Abnormal Heart Rhythms
– Arrhythmia (also called Dysrhythmia)
• Irregular heart rate
– Bradycardia
• Slower than normal heart rate
• < 60 b/m in humans
– Tachycardia
• > 100 b/m in humans
What affects heart rate?
© 2009 Delmar, Cengage Learning
Heart Rate
• Rate and regularity of the heart rhythm is the
heartbeat.
• Heartbeat is influenced by the electrical impulses
from nerves that stimulate the myocardium.
• Sinoatrial node (SA node) is located in the right
atrial wall and initiates the heart rhythm.
– is termed the pacemaker of the heart
– Electrical impulses to rest of myocardium follows a network of
fibers through the myocardium
© 2009 Delmar, Cengage Learning
Heart Murmur
•
•
•
•
•
•
Interruption in blood flow in the heart
Opening and closing of valves
Lub-Dub
Lub = Tricuspid and Mitral
Dub = aortic and pulmonic
Right or Left sided
© 2009 Delmar, Cengage Learning
Auscultation
• Listening with a stethoscope
• Auscultating the heart
– Where?
• Dogs/cats the heart is between 3rd and 7th ribs
• Cattle/horses the heart is between 2nd and 6th ribs
– How?
• Listen to right side
– Tricuspid valve
• Listen to left side
– Mitral valve
– Pulmonary and aortic valve
© 2009 Delmar, Cengage Learning
Congestive Heart Failure
• Heart muscle or valves
• Right or Left side
• If right sided
– Blood returning cannot move through the right side
as quickly
– Causes increased blood pressure in the system circulation
– Fluid accumulates in tissues (edema) and abdomen (ascites)
• If left sided
– Affects blood returning from the lungs
– Accumulation of fluid in lungs (pulmonary edema)
© 2009 Delmar, Cengage Learning
© 2009 Delmar, Cengage Learning
Cardiomyopathy
• Disease of heart muscle
• Ventricles (lower chambers)
• Dilated or hypertrophic
– Dilated
• Chambers of the heart are enlarges/walls are stretched thin
• Left side most commonly affected
– Hypertrophic
• Walls of the heart thicken
• Decrease in efficiency of pumping action
© 2009 Delmar, Cengage Learning
Cardiomyopathy
© 2009 Delmar, Cengage Learning
Heart Rate
• Rate and regularity of the heart rhythm is the heartbeat.
• Heartbeat is influenced by the electrical impulses from nerves
that stimulate the myocardium.
• Cardiac output is the volume of blood pumped by the heart per
unit time.
© 2009 Delmar, Cengage Learning
The Conduction System of the Heart
•
Sinoatrial node (SA node) is located in the right atrial wall and
initiates the heart rhythm.
–
•
is termed the pacemaker of the heart
Atrioventricular node (AV node) is located in the interatrial septum
and receives impulses from the
SA node.
–
sends impulses to the bundle of His
© 2009 Delmar, Cengage Learning
The Conduction System of the Heart
• The bundle of His is located in the interventricular
septum and continues through the ventricle as the
ventricular Purkinje fibers.
– Purkinje fibers carry impulses through the ventricular muscle,
causing the ventricles to contract.
© 2009 Delmar, Cengage Learning
Heart Rate Terms
•
•
•
•
Systole: contraction
Asystole: without contraction
Diastole: relaxation
Arrhythmia: abnormal heart rhythm (also
known as dysrhythmia)
© 2009 Delmar, Cengage Learning
Heart Rate Terms
• Bradycardia: abnormally slow heartbeat
• Tachycardia: abnormally fast heartbeat
© 2009 Delmar, Cengage Learning
Electrocardiography
• An electrocardiogram (ECG or EKG) is the record of
electrical activity of the myocardium.
– ECG or EKG is a tracing that shows changes in voltage and polarity of
the heart over time.
• Electrocardiography is the process of recording
electrical activity of the heart.
© 2009 Delmar, Cengage Learning
Electrocardiography
• Electrical activity of the heart can be visualized as
wave movements on the ECG or EKG.
– P wave = depolarization (excitation) of the
atria
– QRS complex = depolarization (excitation) of the ventricles
– T wave = repolarization (recovery) of the ventricles
© 2009 Delmar, Cengage Learning
Heart Sounds
• Auscultation is listening to body sounds
with a stethoscope.
• When the heart is auscultated, a lubb/dubb
sound is heard.
– lubb = closing of the atrioventricular valves
– dubb = closing of the semilunar valves
– murmur = abnormal sound associated with turbulent
blood flow
© 2009 Delmar, Cengage Learning
Blood Vessels
• Three major types of blood vessels in
animals:
– arteries
– capillaries
– veins
• The lumen is the opening in these
vessels through
which blood flows.
– Constriction is narrowing of the
lumen.
– Dilation is widening
of the lumen.
© 2009 Delmar, Cengage Learning
Blood Vessels
• Combining forms for a
vessel are angi/o and
vas/o.
• Arteries are blood
vessels that carry blood
away from the heart.
– Combining form is
arteri/o.
– Smaller arteries are
arterioles.
© 2009 Delmar, Cengage Learning
Blood Vessels
• Capillaries are
single-cell-thick
vessels that connect
the arterial and
venous systems.
• Veins are blood
vessels that carry
blood toward the
heart.
– Combining forms for vein
are ven/o and phleb/o.
© 2009 Delmar, Cengage Learning
Blood Pressure
• Blood pressure is the tension exerted by blood on
the arterial walls.
– The combining form for pressure or tension is tensi/o.
• A pulse is the rhythmic expansion and contraction
of an artery produced by pressure.
• Blood pressure is measured by a
sphygmomanometer.
© 2009 Delmar, Cengage Learning
Medical Terms for the
Cardiovascular System
• Additional terms for circulatory system
tests, pathology, and procedures can be
found in the text.
• Review StudyWARE to make sure you
understand these terms.
© 2009 Delmar, Cengage Learning