Chapter 11

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Chapter 11
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Applied Learning Outcomes

• Use the terminology associated with the
  cardiovascular system
• Learn about the following
• Blood vessel function and structure
• Circulatory system pathways
• Heart function and structure
• Electrocardiography principles
• Understand the aging and pathology of the
  cardiovascular system

Chapter 11 The Cardiovascular System
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Overview
Cardiovascular System Refers to the heart and
blood vessels Heart The hollow muscular organ
that pumps blood throughout the body Blood
Vessels A part of the cardiovascular system that
carries blood throughout the body
Chapter 11 The Cardiovascular System
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Overview

• Cardiovascular system refers to the heart and
  blood vessels.
• Circulatory system pertains to the blood
  circulation, blood vessels,
• and the heart.
• Blood presssure is the force of the blood pushing
  against blood
• vessel walls.
• Pulse is a throbbing of the blodd vessels
  produced by the heart beat.
• Cardiovascular system formation is present at the
  beginning of
• the third week of embryological development.
• Derived from same type of mesoderm that forms
• bone and muscle.

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Circulatory System Vessels

• Three major types of blood vessels
• Arteries
• Veins
• Capillaries

Arteries muscular, carry blood away from the
heart not visible through the skin Veins flexib
le vessels, carry blood from the body back to
the heart. often visible under the
skin Capillaries smallest vessels, connect
arteries to veins form networks that exchange
materials between the blood and cells
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Circulatory System Vessels

• Arteries and Veins
• major conduits for moving blood around the body
• Both composed of three layers
• Tunica adventitia the outer layer
• it contains collage fibers for strength
• it contains elastin fibers for flexibility
• fibroblasts assists with healing and main-
• tenance of this layer.
• Tunica media middle layer
• primarily composed of smooth muscle
• interspersed with collagen and elastin fibers.
• Tunica intima composed of simple squamous cells
• attached to a layer of loose connective tissue.

Lumen space within the interior of the blood
vessel.
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Circulatory System Vessels
Comparison of Arteries and Veins

• Arteries
• Stronger and thicker
• Under pressure
• More elastin in the tunica adventitia
• Tunica media is thicker because it has smooth
  muscle that
• provides strength and permits the arteries to
  control blood
• pressure.

Constriction or Vasoconstriction Narrowing of
the diameter of a blood vessel. Dilation or
Vasodilation Widening of the diamter of a blood
vessel.
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Circulatory System Vessels
Veins Respiratory activity and contraction of
skeletal muscles contribute to blood flow in
the veins. Many veins contain special one-way
valves that prevent the backflow of blood.
Arterioles and venules branch off arteries and
veins.
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Circulatory System Vessels
Capillaries are very small, just large enough to
allow the passage of blood
cells. Two types of capillaries 1. Continuous
most common, tightly connected to each other,
limits the type of material that can pass into
and out of the blood most often found in CNS,
lungs, muscles, and skin 2. Fenestrated have
openings, materials are readily exchanged through
them commonly found in digestive, endocrine, and
urinary system
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Two types of Capillaries
Continuous most found in the CNS, lungs,
muscles, and skin Fenestrated commonly found in
the digestive, endocrine, and urinary
systems. Capillaries and Venules are the major
vessels which materials are exchanged between the
blood and tissues.
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Circulatory System Vessels
The circulatory system is composed of three major
types of blood vessels arteries, veins, and
capillaries.
Hydrostatic pressurethe pressure of the water
that is circulated in the blood and
tissuespermits the exchange of materials.
Chapter 11 The Cardiovascular System
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Structure of the Human Heart
Chapter 11 The Cardiovascular System
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Structure of the Heart
The heart is composed of four chambers that are
separated by a septum into two halves. The left
half of the heart controls systemic circulation
circulation that supplies blood to all parts of
the body except the lungs The right half
controls pulmonary circulation circulation that
supplies blood to the lungs. It is separated
from the lungs by the cavity membrane called the
pericardium (membranous sac that encloses the
heart).
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Structure of the Heart
Layers of the heart Epicardium- the outer layer
of the heart. Formed by the visceral layer of
the pericardium. Myocardium- the muscle of the
heart wall that contracts to pump
blood. Endocardium- the inner lining of the heart.

• Blood supply to the heart muscle
• Coronary arteries-vessels that supply oxygenated
  blood to the heart muscle (myocardium).
• Coronary veins- collect blood from the heart
  muscle.
• Blockage of the coronary vessels can lead to
• cardiac infarction (death of heart muscle due to
  lack of oxygen from the blood)
• cardiac ischemia (a lack of sufficient oxygen for
  normal heart function of heart muscle).

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The Adult Heart
Four heart chambers Top chambers atria Bottom
chambersventricles Septum- separates the left
side of the heart from the right side Heart
valves Left side- mitral (bicuspid) separates
left atria from left ventricle
aortic semilunar closes off the aorta from the
left ventricle Right side- tricuspid
separates right atria from right
ventricle pulmonary semilunar closes off
the pulmonary artery from the right
ventricle.
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The Adult Heart
Five major blood vessels direct blood flowing
into and out of the heart. Superior and
inferior Vena cava Brings deoxygenated blood from
the body to right atrium. Pulmonary
artery Carries deoxygenated blood from right
ventricle to the lungs. Pulmonary vein Brings
oxygenated blood from the lungs back to the left
atrium Aorta Carries oxygenated blood from left
ventricle to the body
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Blood Flow through the heart
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The Adult Heart
The electrical conduction system Composed of
special cardiac muscle cells that act like a
miniature nervous system. They produce
electrical signals that stimulate the heart to
contract. Composed of Sinoatrial (SA) node
called the pacemaker Atrioventricular (AV) node
Bundle of His Purkinje system The SA node
initiates the heart beat with contraction of
atria. The SA node then stimulates the AV node to
make the ventricles contract. The AV node
stimulates the bundle of His and Purkinje system
to carry out the contraction of ventricles.
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The Fetal Heart
By the 8th week of fetal development, the heart
is fully functional. The fetal heart differs from
the adult heart by two structures Ductus
arteriosus Foramen ovale Ductus arteriosis
Usually diverts blood from the pulmonary artery
to the aorta. This keeps large amounts of blood
from entering the fetus lungs. Lungs not needed
until after birth Ductus arteriosis usually
closes a day after birth Foramen ovale A flap
like opening within the septum between atria. It
directs blood flow from right atrium to left
atrium. Reduces blood flow to the lungs.
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Ductus arteriosus
Foramen Ovale
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Heart Function
One pumping action of the heart is called the
cardiac cycle. Diastole is the filling of the
atria and ventricles systole is the emptying of
the ventricles.
Chapter 11 The Cardiovascular System
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Heart Function
Cardiac Cycle means a single cycle of cardiac
activity. Two basic stages Diastole the
ventricles fill with blood delivered by
contractions of the atria. Systole the
contraction and discharge of blood from the
ventricles. Heart rate refers to the number of
ventricular contractions per
minute.
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Omit Electrocardiography Basics Pages 427-429
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Wellness and Illness over the Life Span

• Diseases of the cardiovascular system affect
  either blood vessels or the heart. Common
  vascular diseases disrupt blood flow common
  heart diseases prevent the chambers and/or valves
  from working properly.
• The heart becomes more susceptible to damage as a
  person ages. Arterial stiffening is a common
  event associated with cardiovascular system
  aging.

Chapter 11 The Cardiovascular System
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Pathology of the Cardiovascular System

• Cardiovascular diseases divided into two
  categories
• Vascular disorders -diseases of arteries,
  capillaries, veins
• Cardiac disorders- affect heart function, muscle,
  
• pericardium, valves.

• Major Cardiovascular conditions in North America
  and
• Western Europe
• Aneurysm-bulging of wall of a blood vessel
• usually form in large arteries
• treated with surgery
• 2. Angina pectoris-pain in the chest area
• usually felt when heart needs more blood
• no treatment-it is an indicator of disease
• 3. Arrhythmia-any deviation in normal heartbeat
  rhythm
• some require no treatment, severe conditions
• treated with medicines

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• Atherosclerosis-when plaque builds up on inner
  lining
• of an artery (usually used when fat or
  cholesterol
• build up)
• treatment-change in life style, surgery
• Arteriosclerosis- used when calcium deposits form
  in
• the vessels, gradual stiffening of arterial
  walls due
• to age
• Endocarditis-caused by bacterial infection,
  inflames the
• lining of the heart, can cause damage to heart
• valves and produce irregular blood flow
• Congenital heart disease- defect in heart or
  blood vessels
• near the heart before birth
• caused by many genetic conditions

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• 8. Congestive heart failure-describes the
  hearts loss of
• pumping ability. Blood enters the heart faster
  than it can
• be pumped out
• Caused by diabetes, high blood pressure, and
  lung disease.
• Treatment- change in lifestyle (stop smoking,
  diet changes)
• Enlarged heart-caused by thickening or
  hypertrophy of heart
• muscle
• Causes- vascular disorders that overwork the
  heart, obesity,
• excessive exercise also overwork heart
• No treatment available

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• 10. Fibrillation-rapid contraction of either
  atria or ventricles
• Atrial fibrillation- most likely occurs with
  age
• Rapid beating causes improper emptying of
  atria
• Leads to pooling of blood and formation
  of blood clots
• Ventricular fibrillation-more serious
  condition
• can lead to rapid heart failure
• Reduces blood flow to body, ventricles dont
  fill
• with adequate amount of blood
• Treatment-defibrillator devices
• 11. Heart Murmurs-usually result of defective
  heart valves
• can be caused by fevers, pregnancy
• Hypertension-high blood pressure
• can be caused by congenital cardiovascular
  condition
• and diseases of the kidneys and lungs
• linked to improper diets, obesity, smoking

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• Pericarditis-inflammation of the pericardium
• cause-sometimes unknown, could be bacterial,
  heart attack, heart surgery
• Can last for weeks or months
• Produces chest pain and fever
• Rheumatic heart disease-result of a bacterial
  infection
• usually starts out as infection in the throat
  (strep)
• if left untreated it can enter blood stream and
  damage organs
• mainly heart valves

14. Sudden cardiac death- caused by abrupt loss
of heart function. Sometimes referred to as
cardiac arrest or heart attack Symptoms appear
only minutes before death, making it difficult
to prevent. Atherosclerosis is believed to be
most common factor.
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15. Thrombosis - blood clot that forms in blood
vessels or the heart clots are plugs of proteins
and blood cells that form at a wound site Deep
vein thrombosis occurs in people over 40 years
old usually form in leg, cause pain 16.
Prolapse- mostly results in reduced blood-pumping
capacity by the heart, can cause thickening of
affected ventricle This occurs because of
incomplete closure of the valve. Mitral valve
prolapse affects almost 20 of American
population. Occurs more in females, may be
linked to hormonal differences. Surgery may be
used to repair the heart valve.
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Aging of the Cardiovascular System

• Aging of cardiovascular system is caused more by
  interactions
• between age, disease, and lifestyle.
• Some conditions of an aging cardiovascular
  system
• Arterial stiffness-arteries lose elastin with age
• Varicose veins-veins become stretched out
• Maximal heart rate decreases with age
• Ventricles thicken with time
• Enlarged atria with time-makes them more subject
  to atrial
• fibrillation

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Summary
The cardiovascular system is responsible for
distributing such resources as nutrients and
oxygen to the other organ systems. Its ability to
do this depends on the proper functioning of
blood vessels and the heart. The heart relies on
nervous system impulses and coordinated signals
from the hearts conduction system. Some
cardiovascular degeneration is due to changes
that occur with age however, lifestyle is the
major contributing factor to cardiovascular
system aging.
Chapter 11 The Cardiovascular System