Transcript Chapter 3 - Fitness Mentors

Chapter 3
The Cardiorespiratory
System
Objectives
• Following this presentation the participant will be
able to:
– Describe the structure and function of:
• The cardiovascular system
• The respiratory system
– Explain how each of the systems relates to human
movement.
– Learn about 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.
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
– Atrioventricular (AV) node
• Delays the impulse before
moving on to the ventricles
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.
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 gentle pressure to feel the radial pulse.*
• When measuring the pulse during rest, count the number of
beats in 60 seconds. The best time to measure the resting
heart rate is after waking up in the morning.
• 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 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
Blood Vessels
• Blood vessels form a closed
circuit of hollow tubes that allow
blood to be transported to and
from the heart.
• For systemic blood circulation
blood flows through in this
order.
– Arteries transport blood away from
the heart.
– Arterioles are smaller arteries
followed by *
– Capillaries is where nutrient
exchange occurs with the cells.
– Venules collect blood from
capillaries and are smaller veins.
– 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 by
working intimately with the
cardiovascular system 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 usage of oxygen by the body is known as
oxygen consumption. At rest= 3.5ml∙kg·min
• Maximal oxygen consumption (VO2 Max) is
generally accepted as the best means of gauging
cardiorespiratory fitness.
– Submaximal testing procedures have been established to
estimate maximal oxygen consumption such as the
Rockport Walk Test in Chapter 6.
• 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 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.
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.