Download The Cardiorespiratory System

Chapter 3
The Cardiorespiratory
System
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Purpose
• To provide the fitness professional with a
fundamental knowledge and explanation of the
cardiorespiratory system.
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Objectives
Following this presentation the participant will be able to:
• Describe the structure and function of:
•
The cardiorespiratory system
•
The cardiovascular system
•
The respiratory system
• Explain how each of those systems relates to human
movement.
• Go through oxygen-testing procedures.
• Relate how oxygen is related to energy expenditure as
well as the influence that dysfunctional breathing can
have on the human movement system (HMS).
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The Cardiorespiratory System
• To maintain a constant state of efficient operation,
the HMS needs to have support systems.
• The cardiorespiratory system comprises the
cardiovascular and respiratory systems.
• Together they provide the tissues of the HMS with
oxygen, nutrients, protective agents, and a means to
remove waste products.
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Cardiovascular System
• The cardiovascular
system is composed of
the heart, blood, and
blood vessels.
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Heart
• A muscular pump that
rhythmically contracts to
push blood throughout the
body.
• Heart muscle is termed
cardiac muscle and has
characteristics similar to
skeletal muscle.
•
Cardiac muscle
•
contraction is involuntary.
The heart is in the
mediastinum.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
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Cardiac Muscle Contraction
• Cardiac muscle fibers are shorter and more tightly
connected.
• Enables the contraction of one fiber to stimulate
the others to contract synchronously.
• All cardiac muscle fibers have a built-in contraction
rhythm, and the fibers with the highest rhythm
determine the heartbeat or heart rate.
• Typical discharge rate (heart rate) is 70–80 beats
per minute.
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Cardiac Muscle Contraction
Specialized conduction system of cardiac
muscle that provides the rhythm for the
heart rate includes:
• Sinoatrial (SA) node:
•
•
•
Located in the right atrium.
Called the “pacemaker” because it initiates
the heartbeat
Internodal pathways:
•
Transfers the impulse from the SA to the
atrioventricular (AV) nodes
• Atrioventricular (AV) node:
•
Delays the impulse before moving on to the
ventricles
• Atrioventricular (AV) bundle (bundle of His):
•
Passes the impulse to the ventricles for
contraction via the left and right bundle
branches of the Purkinje fibers.
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Structure of the Heart
• The heart is composed of
four chambers that form two
interdependent but separate
pumps.
• Each side of the heart has
two chambers:
•
Atrium
•
Ventricle
• Atrium gathers blood coming
to the heart.
• Ventricles pump the blood
out to the rest of the body.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
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Function of the Heart
• Each contraction of a ventricle pushes blood from the
heart into the body.
• The amount of blood that is pumped out with each
contraction of a ventricle is the stroke volume (SV).
• The rate at which the heart pumps is the heart rate
(HR).
• Together, the heart rate and the stroke volume make
up the overall performance of the heart (cardiac
output).
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Monitoring Heart Rate
• Place index and middle fingers around the backside of
the wrist (about 1 inch from the top of wrist, on the
thumb side).
• Locate the artery by feeling for a pulse with the index
and middle fingers; apply light pressure to feel the
pulse.
• When measuring the pulse during rest, count the
number of beats in 60 seconds; when measuring the
pulse during exercise, count the number of beats in 6
seconds and add a 0 to that number
• Example: Beats in 6 seconds = 17. Add a zero =
170. Pulse rate = 170 bpm
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Blood
• Blood acts as a medium to deliver and collect
essential products to and from the body’s tissues.
• The average human body holds about 5 L (roughly
1.5 gallons) of blood at any given time.
• Blood is a vital support mechanism; it:
•
•
•
•
Transports oxygen, hormones, and nutrients to specific
tissues and collects waste products.
Regulates body temperature and pH levels.
Protects from injury and blood loss through its clotting
mechanism to seal off damaged tissue.
Provides specialized immune cells to fight against foreign
toxins within the body, decreasing disease and sickness.
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Blood Vessels
Blood vessels form a closed circuit of
hollow tubes that allow blood to be
transported to and from the heart:
•
Arteries transport blood away from
•
the heart.
Veins transport blood back to the
heart.
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Respiratory System
• The second functional component
of the cardiorespiratory system is
the respiratory system.
• Its primary role is to ensure proper
cellular functioning.
• Works intimately with the
cardiovascular system by
providing a means to collect
oxygen from the environment and
transport it to the bloodstream.
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Respiratory System
• The collection and
transportation of oxygen is
made possible by the
respiratory pump and the
respiratory airways.
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Respiratory Pump
• Located in the thoracic cavity.
• Provides framework and flexibility to allow for the
expansion and compression needed for ventilation.
• Ventilation is divided into two phases:
• Inspiratory (inhalation)
• Expiratory (exhalation)
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Respiratory Pump
• Bones:
• Sternum, ribs, vertebrae
• Muscles:
• Inspiration: Diaphragm, external intercostals,
scalenes, sternocleidomastoid, pectoralis minor
• Expiration: Internal intercostals, abdominals
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Respiratory Passageways
• Air must have
passageways to funnel
it in and out of the lungs
for proper utilization.
• Respiratory
passageways are
divided into:
• Conduction
•
passageway
Respiratory
passageway
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Respiratory Passageways
• Conduction passageways:
•
Nasal cavity
•
Oral cavity
•
Pharynx
•
Larynx
•
Trachea
•
Right and left pulmonary bronchi
• Respiratory passageway:
•
Alveoli
•
Alveolar sacs
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Cardiorespiratory Function
Cardiovascular and respiratory systems make up the
cardiorespiratory system:
• Respiratory system provides the means to gather
oxygen from the environment and transfer it to the
body.
• Cardiovascular system provides the means to
transport oxygen to the tissues of the body.
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Oxygen Consumption
• The usage of oxygen by the body is known as
oxygen consumption
• At rest = 3.5ml∙kg·min
• Maximal oxygen consumption is generally accepted
as the best means of gauging cardiorespiratory
fitness.
• Submaximal testing procedures have been
established to estimate maximal oxygen
consumption.
• Used in a fitness assessment, it can provide
important structural and mechanical information that
may help a fitness professional limit the risk of injury.
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Dysfunctional Breathing
• The importance of all systems in the body working
synergistically can be further demonstrated in the
intimacy between the cardiorespiratory system and
the HMS.
• If there is a dysfunction in the cardiorespiratory
system, this can directly impact the components of
the HMS and perpetuate into further dysfunction.
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Dysfunctional Breathing
Alterations in breathing patterns are a prime example of this
relationship:
• During shallow breathing patterns, the secondary respiratory
muscles are used more predominantly.
• If this shallow, upper-chest breathing pattern becomes habitual,
it can cause overuse of muscles, including the scalenes,
sternocleidomastoid, levator scapulae, and upper trapezius.
• These muscles also play a major postural role in the kinetic
chain, as they all connect directly to the head and neck.
• Their increased activity and excessive tension often result in
headaches, lightheadedness, and dizziness.
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Summary
• The respiratory system gathers oxygen from the
environment, inhales it through the nose and mouth, and
processes it to be delivered to the tissues of the body.
• As cells use oxygen, they produce carbon dioxide, which
is transported back to the heart and lungs in the
deoxygenated blood to be released through exhalation.
• The collection and transportation of oxygen is made
possible by the respiratory pump and the respiratory
airways.
• If there is a dysfunction in the cardiorespiratory system,
this can directly impact the components of the HMS and
perpetuate into further dysfunction.
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