Download The Cardiorespiratory System

Chapter 3
The Cardiorespiratory
System
Purpose
• To provide the fitness professional with a fundamental
knowledge and explanation of the cardiorespiratory
system.
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).
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.
Cardiovascular System
• The cardiovascular system is
composed of the heart, blood,
and blood vessels.
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.
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
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.
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.
• Ventricle pumps the blood out to
the rest of the body.
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).
Monitoring Heart Rate
• Place index and middle fingers around the backside of the
wrist (about one 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 zero to that number.
Example: Beats in 6 seconds = 17. Add a zero = 170.
Pulse rate = 170 bpm
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 as 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 using clotting
mechanism to seal off damaged tissue
– Provides specialized immune cells to fight foreign toxins
within the body, decreasing disease and sickness
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.
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.
Respiratory System
• The collection and transportation
of oxygen is made possible by the
respiratory pump and the
respiratory airways.
Respiratory Pump
• Located in the thoracic cavity
• Provides framework and flexibility to allow for the
expansion and compression needed for ventilation
– Divided into two phases
• Inspiratory (inhalation)
• Expiratory (exhalation)
Respiratory Pump
• Bones
– Sternum, ribs, vertebrae
• Muscles
– Inspiration: diaphragm, external intercostals, scalenes,
sternocleidomastoid, pectoralis minor
– Expiration: internal intercostals, abdominals
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
Respiratory Passageways
• Conduction passageways
–
–
–
–
–
–
Nasal cavity
Oral cavity
Pharynx
Larynx
Trachea
Right and left pulmonary bronchi
• Respiratory passageway
– Alveoli
– Alveolar sacs
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.
Oxygen Consumption
• The use of oxygen by the body is known as oxygen
consumption; at rest = 3.5 mL per kg per 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.
Dysfunctional Breathing
• The importance of all systems in the body working
synergistically can be further demonstrated by 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.
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.
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.