The Cardiovascular System

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26

• The Cardiovascular System

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Learning Outcomes (cont.)

• 26.1 Describe the structures of the heart and
  the function of each.
• 26.2 Explain the cardiac cycle, including the
  cardiac conduction system.
• 26.3 Compare pulmonary and systemic circulation.

3
Learning Outcomes (cont.)

• 26.4 Differentiate among the different types of
  blood vessels and their functions.
• 26.5 Explain blood pressure and tell how it is
  controlled.
• 26.6 Describe the causes, signs and symptoms,
  and treatments of various diseases and disorders
  of the cardiovascular system.

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Introduction

• The cardiovascular system
• Heart
• Blood vessels
• Sends blood to
• Lungs for oxygen
• Digestive system for nutrients
• Also circulates waste products for removal

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The Heart

• Cone-shaped organ
• Size of a loose fist
• Slightly left of the midline
• Bordered by
• Lungs
• Sternum and vertebral column
• Diaphragm

6
Cardiac Membranes

• Pericardium
• Covers the heart and large blood vessels
• Fibrous outer layer
• Visceral pericardium epicardium
• Parietal pericardium
• Pericardial sac
• Pericardial cavity pericardial fluid

Cardiac Membranes
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Cardiac Membranes (cont.)
Back
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The Heart Wall

• Epicardium
• Myocardium
• Endocardium
• Thin, smooth layer
• Contains part of electrical conduction system

Heart Wall
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Heart Chambers and Valves

• Four chambers
• Two atria
• Upper chambers
• Interatrial septum
• Atrioventricular septum separates the atria from
  the ventricles

• Two ventricles
• Lower chambers
• Interventricular septum

Click for View of Heart
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Heart Chambers and Valves (cont.)

• Valves between atria and ventricles
• Tricuspid three cusps
• Bicuspid two cusps
• Valves between ventricles and arteries
• Pulmonary semilunar
• Aortic semilunar

Click for View of Heart
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The Heart Labeled
Back
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Apply Your Knowledge
ANSWER
Match the following __ Tricuspid
valve A. Outermost layer of the heart wall __
Bicuspid valve B. Covering of the heart and
aorta __ Intraventricular C. Between the right
atrium and the right septum ventricle
Ventricles D. Pump blood into the arteries
Pericardium E. Primarily cardiac muscle
Epicardium F. Between the left atrium and the
left ventricle Myocardium G. Inner most
layer of the heart wall Endocardium H.
Separates the ventricles
C
F
H
D
B
A
E
G
Good Job!
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Cardiac Cycle

• One heart beat one cardiac cycle
• Right atrium contracts ? tricuspid valve opens
• ? blood flows into right ventricle
• Left atrium contracts ? bicuspid valve closes
• ? blood flows into left ventricle

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Cardiac Cycle (cont.)

• Right ventricle contracts ? tricuspid valve
• closes ? pulmonary semilunar valve opens ?
• blood is pushed into pulmonary artery
• Left ventricle contacts ? bicuspid valve closes
• ? aortic semilunar valve opens ? blood is
• pushed into aorta

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Cardiac Cycle (cont.)

• Influenced by
• Exercise
• Parasympathetic nerves
• Sympathetic nerves
• Cardiac control center
• Body temperature
• Potassium ions
• Calcium ions

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Heart Sounds

• Lubb
• First sound
• Occurs when ventricles contract and the tricuspid
  and bicuspid valves snap shut
• Dubb
• Second sound
• Occurs when atria contract and the pulmonary and
  aortic valves snap shut
• Murmur abnormal heart sound

Click for Heart Sounds
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Cardiac Conduction System

• Sinoatrial node
• Right atrium
• Natural pacemaker
• Sends impulse to AV node
• Atrioventricular node
• Between atria and just above ventricles
• Sends impulse to the bundle of His

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Cardiac Conduction System (cont.)

• Bundle of His
• Between ventricles
• Right and left bundle branches
• Sends impulse to Purkinje fibers
• Purkinje fibers
• Lateral walls of ventricles
• Ventricles contract

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Cardiac Conduction System (cont.)
Back
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Apply Your Knowledge
ANSWER
Match the following __ Right ventricle A. Two
branches sends impulse to Purkinje fibers __
Left ventricle B. Located in the medulla
oblongata __ Cardiac control C. Contraction
pushes blood into the lungs center __ SA
node D. In the lateral walls of ventricles __
Bundle of His E. Natural pacemaker __ Purkinje
fibers F. Contraction sent blood to the aorta
C
F
B
E
A
D
Smashing!
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Circulation

• Pulmonary circulation
• Oxygenates blood
• Removes carbon dioxide
• Systemic Circulation
• Delivers oxygen and nutrients
• Removes carbon dioxide and waste products

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Circulation (cont.)
Pulmonary Circulation
Right Atrium
Right Ventricle
Pulmonary SemilunarValve
TricuspidValve
Left Atrium
BicuspidValve
Left Ventricle
AorticSemilunarValve
Systemic Circulation
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Apply Your Knowledge
What are the functions of the pulmonary and
systemic circulations?
ANSWER The pulmonary circulation functions to
oxygenate the blood and remove carbon dioxide.
The systemic circulation delivers oxygen and
nutrients to and removes carbon dioxide and waste
products from the bodys cells.
Correct!
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Blood Vessels

• Form a closed pathway that carries blood from the
  heart to cells and back to the heart

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Arteries and Arterioles

• Thick muscular wall
• Carry blood under high pressure
• Arterioles

• Coronary arteries
• Supply heart muscle
• Coronary sinus
• Pulmonary arteries
• Heart to lungs
• Deoxygenated blood
• Aorta

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Veins and Venules

• Veins
• Deoxygenated blood
• Skeletal muscle contractions move blood
• Valves prevent back flow
• Sympathetic nervous system effect

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Veins and Venules

• Venules
• Pulmonary veins oxygenated blood
• Superior and inferior vena cava
• Hepatic portal system

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Capillaries

• Branches of arterioles
• Connect arterioles to venules
• Exchange vessels
• Oxygen and nutrients
• Carbon dioxide and waste products
• Water

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Apply Your Knowledge
ARTERIES
Match the following coronary arteries
A. exchange vessels arterioles
B. supply blood to the heart tissues
veins C. largest veins in the body
arteries D. supplies the forearm and hand
capillaries E. carry blood toward
heart vena cavae F. drain the knees
radial artery G. strongest blood vessels
popliteal veins H. small branches of
arteries
B
H
E
G
A
C
D
F
YIPPEE!
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Blood Pressure

• The force blood exerts on the inner walls of
  blood vessels
• Highest in arteries
• Lowest in veins
• Rises and falls as ventricles contract and relax

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Blood Pressure

• Systolic pressure
• Systole
• Ventricles contract
• Blood pressure in arteries greatest

• Diastolic pressure
• Diastole
• Ventricles relax
• Blood pressure in arteries lowest
• Pulse

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Blood Pressure (cont.)

• Factors affecting blood pressure
• Cardiac output
• Blood volume
• Vasoconstriction and vasodilation
• Blood viscosity

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Blood Pressure (cont.)

• Controlled by the amount of blood pumped out of
  the heart
• Starling's law of the heart
• Blood entering the left ventricle stretches its
  wall
• The more the wall is stretched the harder it will
  contract

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Blood Pressure (cont.)

• Baroreceptors
• Help regulate blood pressure
• Located in the aorta and carotid arteries
• Send information to cardiac center in the medulla
  oblongata

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Apply Your Knowledge
What is the difference between the systolic
pressure and diastolic pressure?
ANSWER Systolic pressure is the result of the
contraction of the ventricles increasing the
pressure in the arteries. Diastolic pressure is
the result of the relaxation of the ventricles
lowering the pressure in the arteries.
Good Answer!
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Diseases and Disorders of the Cardiovascular
System

• Chest pain
• Cardiac causes
• Myocardial infarction
• Angina
• Pericarditis
• Coronary spasm

• Non-cardiac causes
• Heartburn
• Panic attacks
• Pleurisy
• Costochondritis
• Pulmonary embolism
• Sore muscles
• Broken ribs

Take all complaints of chest pain seriously!
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Diseases and Disorders of the Cardiovascular
System (cont.)
Disease Description
Aneurysm A ballooned, weakened arterial wall
Arrhythmias Abnormal heart rhythms
Endocarditis Inflammation of the innermost lining of the heart, including valves
Myocarditis Inflammation of the muscular layer of the heart
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Diseases and Disorders of the Cardiovascular
System (cont.)
Disease Description
Pericarditis Inflammation of the membranes that surround the heart (pericardium)
Congestive heart failure Weakening of the heart over time heart is unable to pump enough blood to meet bodys needs
Coronary artery disease (CAD) Atherosclerosis narrowing of coronary arteries caused by hardening of the fatty plaque deposits within them
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Diseases and Disorders of the Cardiovascular
System (cont.)
Disease Description
Hypertension High blood pressure consistent resting blood pressure equal to or greater than 140/90 mm Hg
Mitral valve prolapse Valve falls into the left atrium during systole prevents proper closing
Murmurs Abnormal heart sounds
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Diseases and Disorders of the Cardiovascular
System (cont.)
Disease Description
Myocardial infarction Heart attack damage to cardiac muscle due to a lack of blood supply
Stenosis of the heart valves The valve does not fully open aortic stenosis, mitral stenosis
Thrombophlebitis Blood clots and inflammation develop in a vein
Varicose veins Twisted, dilated veins
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Apply Your Knowledge
ANSWER
True or false A myocardial infarction
results from a lack of oxygen
to the cardiac muscle Myocarditis is
inflammation of the innermost lining of
the heart. A potentially fatal arrhythmia
is ventricular fibrillation. Murmurs
are abnormal heart rhythms.
T
F
Endocarditis
T
sounds
F
Bravo!
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In Summary

• 26.1 The structures of the heart include the
  pericardium, epicardium, myocardium, and
  endocardium.
• The chambers of the heart consist of the upper
  atria and the lower ventricles.
• The septa are the interatrial, interventricular,
  and atrioventricular.
• The four valves within the heart are the
  tricuspid, the bicuspid, the pulmonary
  semilunar, and the aortic semilunar valves.

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In Summary (cont.)

• 26.2 One cardiac cycle consists of one complete
  heartbeat.
• The atria contract and relax together, and the
  ventricles contract and relax together.
• As each chamber contracts, associated valves
  open and close to control the flow of blood
  through the heart.
• Contractions are initiated by the cardiac
  conduction system.

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In Summary (cont.)

• 26.3 Pulmonary circulation Right atrium ?
  tricuspid valve ? right ventricle ? pulmonary
  semilunar valve ?pulmonary trunk ? pulmonary
  arteries ? lungs ?pulmonary veins ? left atrium.
  
• Systemic circulation Left atrium ? bicuspid
  valve ?left ventricle ? aortic semilunar valve
  ? aorta ? arteries ? arterioles ? capillaries ?
  venules ? veins ? venae cavae ? right atrium.

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In Summary (cont.)

• 26.4 Types of blood vessels include arteries and
  arterioles, which bring blood from the heart to
  the body capillaries, which act as the
  connectors between the arterioles and venules.
• The largest artery in the body is the aorta.
  Others arteries are listed in the chapter.
• The largest veins in the body are the superior
  and inferior venae cavae. Others veins are listed
  in the chapter.

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In Summary (cont.)

• 26.5 Blood pressure is the force exerted on the
  inner wall of blood vessels by blood as it
  flows through vessels.
• It is highest in arteries and lowest in veins.
  Clinically, blood pressure refers to the force
  of blood within the arteries.
• Blood pressure is largely controlled by the
  amount of blood pumped out of the heart, but
  various other events also may raise and lower
  blood pressure.

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In Summary (cont.)

• 26.6 Many different types of cardiac and blood
  diseases are described within this chapter.
• The signs, symptoms, and treatments are as
  varied as the diseases themselves.
• The last section of this chapter outlines the
  most common of these diseases, their signs and
  symptoms, as well as their treatments.

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End of Chapter 26
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