Cardiorespiratory System

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Assessing Human Physiology Through Monitoring Dr
Gareth Davison Senior Lecturer in Exercise
Physiology Director of Human Performance
Laboratory University of Ulster
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• LEARNING OUTCOMES
• By the end of the session you should be able to
• Explain basic physiology of respiratory and
  cardiac function (and response to exercise)
• Explain how respiratory and cardiac function are
  measured

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Components of O2 Transport System
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Respiratory System
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Transportation

• Pulmonary ventilation the movement of gases into
  and out of the lungs
• Diffusion is the exchange of gases- lungs and the
  blood
• These two are external respiration- movement of
  gases outside the body to inside the body.
• Transport of O2 and CO2 via the blood
• Capillary gas exchange-capillary blood and the
  active tissues.
• Internal respiration-movement of gases between
  the blood and the tissues.

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Pulmonary Diffusion

• 2 functions
• Replenishes the O2 blood supply after being
  depleted at the tissue level
• Removes CO2 from returning venous blood
• 2 requirements
• air brings O2 into the lungs
• blood to receive the O2 and give up CO2

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Pulmonary Diffusion (contd)

• Blood returns through the venae cava to the
  pulmonary side of the heart (right).
• Right ventricle to pulmonary artery to the lungs
  to the pulmonary capillaries.
• Caps form a network around the alveolar sacs.
  Caps are small enough that red blood cells have
  to pass through in a single file line. They are
  exposed to the lung tissue.
• This is where diffusion takes place.

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Respiratory Membrane

• Very thin
• Gas exchange between air in the alveoli and the
  blood in the pulmonary caps occur across the
  respiratory membrane. It is composed of...
• Alveolar wall
• capillary wall
• basement membranes
• gases in the alveoli are in close proximity to
  the blood circulating through the caps. This
  presents a potential for diffusion for gas
  exchange.

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Respiratory Membrane
Gas exchange in the alveoli
Differences in the partial pressures of the gases
in the alveoli and the blood create a pressure
gradient across the membrane. If pressure is
equal, nothing would take place.
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Lungs
O2
O2
CO2
CO2
Muscle Cell
O2
CO2
O2
CO2
Red Blood Cell
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Blood (O2 Delivery)

• Made up of RBC (hematocrit), WBC, platelets,
  plasma.
• Blood

Transport of O2 is normally the limiting factor
in Exercise Capacity !!
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Transport of O2

• Carried by Hemoglobin
• Fe containing protein in RBC
• Fe atoms loosely capture O2 molecules
• Low iron intake Anemia
• Hemoglobin is almost always saturated with O2
  when it leaves the pulmonary system (97 ).
• O2 supplementation is useless!!! (placebo)
• Only at VERY HIGH altitudes!

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Gas Exchange and Transport

• Carbon Dioxide Transport
• dissolved in plasma (7)
• bound to hemoglobin (20)
• as a bicarbonate ion (75)
• CO2 H2O ? H2CO3 ? H HCO3-

- Blood gases are measured using a blood gas
analyser
- Oxygen saturation (SaO2) can be measured using
a pulse oximeter
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Gas Exchange and Transport
Resting conditions
Maximal exercise
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Ventilation during Exercise

• Moderate Exercise Ventilation increases linearly
  with increases in VO2.
• Intense Exercise Ventilation increases above and
  beyond O2 demand
• ? in CO2 stimulates brain to ? Ventilation
• Ventilation is never limiting factor for
  exercise, unless person is abnormal!

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Assessing respiratory function
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Monitoring respiration in patients with COPD

• Patient should be relaxed and resting.
• Observe movement of chest wall and count
  respirations for 60 secs
• If difficult to observe, place hand gently on
  chest wall
• Observe rhythm and depth
• Observe patients colour for signs of cyanosis
  blueness especially around lips
• Observe for symmetry of chest movement
• Also observe for
• Pain, difficulty, noisy respiration, cough,
  sputum
• Document

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Peak Flow

• A peak flow meter is a simple device that can
  measure air flow from your lungs. This can
  indicate improvements or deteriorations in
  condition.

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Maximal Oxygen Consumption (VO2max)

• maximal rate at which aerobic system utilizes O2
• What limits VO2?
• ventilation
• O2 delivery

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Analysis of Respiratory Function

• Expired gas collected during test allows for
  non-invasive means of obtaining values

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Normalized Data for VO2max (mlkg-1min-1)
Females
Males
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Cardiovascular system

• DELIVERY OF O2 RICH BLOOD TO ORGANS AND MUSCLES

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Circulation

• Cardiovascular System
• Heart and over 60,000 miles of blood vessels!!!
• Delivers O2 rich blood to organs and exercising
  muscles
• Returns blood - lungs for restoration of O2
• Transports heat to skin
• Delivers nutrients and removes waste

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Circulation

• Heart
• Arteries
• Veins

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The Heart
w The heart has four chambers left and right
ventricle left and right atrium
w The heart functions as two separate pumps

• The left side pumps oxygenated blood to the body
  (systematic circulation)

wThe right side pumps deoxygenated blood to the
lungs for aeration (pulmonary circulation)
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After passing through the capillaries of the
lungs, the blood which is now oxygenated returns
to the heart in the pulmonary veins.
From lungs
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The left atrium receives blood from the pulmonary
vein.
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Blood passes through the mitral valve into the
left ventricle.
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Contraction of the left ventricle pushes blood
through the aortic semilunar valve into the aorta.
To rest of body
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Deoxygenated blood returns from the rest of the
body through the superior and inferior vena cava.
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The right atrium receives the deoxygenated blood.
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Blood then enters the right ventricle through the
tricuspid valve.
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Contraction of the right ventricle pushes blood
through the pulmonary semilunar valve into the
pulmonary arteries in which it travels to the
lungs.
To lungs
To lungs
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THE CARDIO-VASCULAR SYSTEM
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MyocardiumThe Cardiac Muscle
w Thickness varies directly with stress placed on
chamber walls.
w Left ventricle is the most powerful of chambers
and thus, the largest.
w With vigorous exercise, the left ventricle size
increases.
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Direction of Blood Flow
lungs
heart
peripheral circulation
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Stroke Volume and Cardiac Output
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Pulse

• Pulse is an impulse transmitted to arteries by
  contraction of the left ventricle. It can be
  palpated where an artery near the body surface
  can be pressed against a firm structure
• Average rate for an adult is 60-100.
• Tachycardia Abnormally fast heart rate ie. gt100
  beats/min
• Bradycardia Heart rate slower than 60
  beats/min
• Most commonly assessed using the radial artery
  although there are other sites.

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Pulse Sites
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What is an electrocardiogram (ECG)?

• A graphic recording of the electrical activity
  generated in the heart and mapped against time..

ECG is a composite recording of action potential
produced by all heart muscle fibres during each
heart beat
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During the cardiac cycle, a series of action
potentials are produced which are recorded as
waves on an ECG.
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PQRST

• One complete cycle of the conduction
• system produces what is known as the
• PQRST complex on an ECG.

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Common Cardiac Rhythms

• Sinus Rhythm normal rhythm of the heart

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Sinus Bradycardia

• 3-5
  2-2.5

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Sinus Tachycardia

• 3-5
  2-2.5

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Atrial Fibrillation
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Ventricular Fibrillation
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Asystole
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Heart Adaptations to Exercise Training
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HEART RATE AND TRAINING
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LEFT VENTRICULAR HYPERTROPHY
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Cardiovascular Testing

• Field Tests for Predicting Cardiovascular Aerobic
  Capacity
• Field Tests
• Maximal effort (run tests) or submaximal (step
  tests walk tests)
• Predict aerobic capacity
• Benefits
• Mass testing
• Cost effective
• Limitations
• accuracy

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What is Blood Pressure?

• Blood pressure refers to the hydrostatic pressure
  exerted by the blood on the blood vessel walls.
  It is generated by the contraction of the
  ventricles.
• It is a function of blood flow and vascular
  resistance.
• Systolic maximum pressure of the blood against
  the wall of the vessel following ventricular
  contraction
• Diastolic Minimum pressure of the blood against
  the vessel wall following closure of the aortic
  valve - relaxation

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Peripheral Blood Pressure
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Blood pressure (BP) values Normal BP can range
from 100/60 to 150/90

• There is no agreed values for normal upper
  limits of blood pressure (BP).
• BP varies from person to person and also from
  moment to moment.

• Factors such as age, sex, and race can influence
  BP values. Pressure also varies with exercise,
  emotional reactions, sleep, digestion and time of
  the day.

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• Hypotension Low blood pressure. Generally
  defined in adults as a systolic BP lt100mm/Hg
• Hypertension Defined as an elevation of
  systolic blood pressure. Never diagnosed on a
  single BP measurement.

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Korotkoff Sounds

• A series of five phases that can be heard as BP
  falls from the systolic to diastolic
• Phase 1 clear tapping recorded as the systolic
  pressure
• Phase 2 a softening of the sound may become
  swishing
• Phase 3 return of sharper sounds not as intense
  as 1
• Phase 4 muffling sound becomes soft and blowing
  (diastolic 4)
• Phase 5 disappearance of sound (diastolic 5)

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Taking blood pressure

• Explanation to patient
• Preparation of patient equipment - Stethoscope
  sphygmomanometer

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Questions?