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Title: Cardiovascular and pulmonary systems


1
Cardiovascular and pulmonary systems
2
Mid Session Quiz -25
  • Next week
  • Will be on WebCT? assessments
  • From 9 am 25/8/08 ? 5 pm 29/8/08
  • Multiple choice and matching
  • Practice test (question types) up now, practice
    (content) on companion website for text.
  • Covers all lecture, lab, text and reading
    materials from weeks 1-5
  • Time limit ½ hour
  • Grades will be released automatically
  • Contact me if tech problems

3
Today
  • Cardiovascular
  • System review
  • Acute adaptations to exercise
  • Chronic adaptations to exercise
  • Pulmonary
  • System review
  • Acute adaptations to exercise
  • Chronic adaptations to exercise

4
Major Cardiovascular Functions
  • Delivers oxygen to active tissues
  • Aerates blood returned to the lungs
  • Transports heat, a byproduct of cellular
    metabolism, from the bodys core to the skin
  • Delivers fuel nutrients to active tissues
  • Transports hormones, the bodys chemical
    messengers

5
CV system
  • Consists of
  • Blood 5L or 8 body mass
  • 55 plasma
  • 45 formed elements (99RBC, 1WBC)
  • Heart- pump
  • Arteries- High pressure transport
  • Capillaries- Exchange vessels
  • Veins- Low pressure transport

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Peripheral Vasculature
  • Arteries
  • Provides the high-pressure tubing that conducts
    oxygenated blood to the tissues
  • Capillaries
  • Site of gas, nutrient, and waste exchange
  • Veins
  • Provides a large systemic blood reservoir and
    conducts deoxygenated blood back to the heart

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Blood Pressure
  • Systolic blood pressure
  • Highest arterial pressure measured after left
    ventricular contraction (systole)
  • e.g., 120 mm Hg
  • Diastolic blood pressure
  • Lowest arterial pressure measured during left
    ventricular relaxation (diastole)
  • e.g., 80 mm Hg

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13
Heart Rate Regulation
  • Cardiac muscle possesses intrinsic rhythmicity
  • Without external stimuli, the adult heart would
    beat at about 100 bpm

14
Regulation of HR
  • Sympathetic influence
  • Catecholamine (NE/E)
  • Results in tachycardia
  • Parasympathetic influence
  • Acetylcholine
  • Results in bradycardia
  • Cortical influence
  • Anticipatory heart rate

15
CV system during exercise
  • Acute Adaptations
  • Chronic adaptations

16
Heart rate
  • At rest- 60-80 bpm
  • Trained athletes ? lower (28-40 bpm)
  • Pre exercise- anticipatory response
  • Sympathetic nervous system release N/E and
    ephedrine
  • Increases during exercise to steady state

17
Cardiovascular Dynamics
  • Q HR SV (Fick Equation)
  • Q cardiac output
  • HR heart rate
  • SV stroke volume

18
Cardiac Output
  • At Rest
  • Q 5 L p/Min
  • Trained RHR 50 bpm, SV 71
  • Untrained RHR 70 bpm, SV 100
  • During Exercise
  • Untrained- Q 22 000 mL p/min, MHR 195
  • SV av 113 ml blood p/beat
  • Trained- Q 35 000 ml p/min, MHR 195
  • SV av 179 ml blood p/beat

Q HR SV
19
Increases in Stroke Volume
  • Increases in response to exercise
  • Is ability to fill ventricles, particularly left
    ventricle
  • And more forceful contraction to pump blood out
  • Training adaptations
  • left ventricle hypertrophy
  • Increased blood volume
  • Reduced resistance to blood flow

20
Training Adaptations Heart
  • Eccentric hypertrophy
  • Slight thickening in left
  • ventricle walls
  • Increases left ventricular
  • cavity size
  • Therefore increases stroke
  • volume

21
Cardiac output distribution
22
Oxygen transport
  • When arterial blood is saturated with oxygen
  • 1 litre blood carries 200 ml oxygen
  • During exercise
  • Q 22L p /min
  • 4.4L oxygen per minute
  • At rest
  • Q 5L p/ min
  • 1 L oxygen per minute
  • 250 ml required at rest
  • Remainder- oxygen reserves

23
Stroke Volume and Cardiac Output
  • Exercise ? increases stroke volume during
    rest and exercise
  • Slight decrease heart rate
  • Increase in cardiac output comes from
    increased stroke volume

24
Heart Rate
  • Elite athletes have a lower heart rate relative
    to training intensity than sedentary people

25
Saltin, 1969
Endurance athletes Sedentary college BEFORE 55
day aerobic training program Sedentary college
AFTER
26
  • Total Blood Volume
  • Plasma volume
  • 4 training sessions can increase plasma volume by
    20
  • Increased RBC
  • - Number of RBC increases, but due to increase in
    Plasma volume, concentration stays the same

27
Blood Pressure
  • Aerobic exercise reduces systolic and diastolic
    BP at rest and during exercise
  • Particularly systolic
  • Caused by decrease in catecholamines
  • Another reason for exercise to be prescribed for
    those with hypertension
  • Resistance training not recommended due to acute
    high BP it causes

28
Oxygen Extraction
  • Training increases quantity of O2 that can be
    extracted during exercise

29
Chronic Adaptations to Exercise- Chapter 10
  • Cardiovascular adaptations to training are
    extremely important for improving endurance
    exercise performance, and preventing
    cardiovascular diseases.
  • The more important of these adaptations are,
  • ? Size of heart ? ventricular volumes
  • ? total blood volume
  • - ? plasma volume
  • - ? red cell mass
  • ? systolic and diastolic blood pressures
  • ? maximal stroke volume
  • ? maximal cardiac output
  • ? extraction of oxygen

30
Factors Affecting Chronic adaptations
  • Initial CV fitness
  • Training
  • Frequency- 3 x p/week
  • Only slightly higher gains for 4 or 5 times
    p/week
  • Intensity
  • Most critical
  • Minimum is 130/ 140 bpm (av) 50-55 Vo2 max/
    70 HR max
  • Higher better
  • Time
  • Or duration- 30 min is minimum
  • Type
  • Specificity

31
Pulmonary System
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Pulmonary Structure and Function
  • The ventilatory system
  • Supplies oxygen required in metabolism
  • Eliminates carbon dioxide produced in metabolism
  • Regulates hydrogen ion concentration H to
    maintain acid-base balance

34
Breathing
  • At rest
  • Air in ? Trachea- humidified and brought to body
    temperature
  • ? divides into 2 branches? lungs
  • Lungs hold 4-6 litres of ambient air- huge
    surface area
  • 300 million alveoli
  • 250 ml oxygen in and 200 ml Carbon dioxide out
    each minute

35
  • Inspiration
  • Ribs rise
  • Diaphragm contracts (flattens)
  • Moves downward (10cm)
  • Thoracic volume
  • Air in lungs expands
  • Pressure
  • to 5 mm Hg below atmospheric pressure
  • Difference between outside air and lungs air is
    sucked in until pressure inside and out is the
    same

36
Expiration
  • Ribs move back down
  • Diaphragm relaxes (rises)
  • Thoracic volume
  • Pressure
  • Difference between outside air and lungs air is
    pushed out until pressure inside and out is the
    same

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Pulmonary system during exercise
39
Lung Volumes
  • Static lung volume tests
  • Evaluate the dimensional component for air
    movement within the pulmonary tract, and impose
    no time limitation on the subject
  • Dynamic lung volume tests
  • Evaluate the power component of pulmonary
    performance during different phases of the
    ventilatory excursion

40
Spirometry
  • Static and Dynamic lung volumes are measured
    using a spirometer

41
Static Lung Volumes Page 146 of text
42
Dynamic lung volumes
  • Depend on Volume of air moved
  • and the
  • Speed of air movement
  • FEV/FVC ratio
  • MVV

43
FEV/FVC Ratio
  • Forced Expiratory Volume
  • Forced Vital Capacity
  • Ratio tells us the speed at which air can be
    forced out of lungs
  • Normal 85 FVC can be expired in 1 second.

44
Maximal Voluntary Ventilation
  • Breath as hard and fast as you can for 15 seconds
  • Multiply by 4
  • And you have Maximal Voluntary Ventilation
  • MVV-
  • Males140-180 Litres
  • Females 80-120 Litres
  • Elite athletes up to 240 Litres

45
Minute Ventilation
  • At Rest
  • 12 breaths per minute
  • Tidal volume 0.5L per breath
  • 6 Litres of air breathed p/min
  • During Exercise
  • 50 breaths p/ minute
  • Tidal Volume 2 L per breath
  • 100L p/min

46
Alveolar Ventilation
  • Minute ventilation is just total amount of air
  • Alveolar ventilation refers to the portion of
    minute ventilation that mixes with the air in the
    alveolar chambers
  • Minute ventilation minus anatomical dead space
    (150-200 ml)- the air that is in the trachea,
    bronchi etc

47
Alveolar Ventilation Minute ventilation (TV x
breathing rate) dead space
48
Gas exchange
49
Gas Exchange in the Body
  • The exchange of gases between the lungs and
    blood, and their movement at the tissue level,
    takes place passively by diffusion

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51
Oxygen Transport in the Blood
  • Combined with hemoglobin In loose combination
    with the iron-protein hemoglobin molecule in the
    red blood cell
  • Each Red Blood Cell contains 250 million
    hemoglobin molecules
  • Each one can bind 4 oxygen molecules

52
CO2 Transport in Blood
  • In physical solution
  • (7) dissolved in the fluid portion of the blood
  • As carbamino compounds
  • (20) in loose combination with amino acid
    molecules of blood proteins
  • As bicarbonate
  • (73) combines with water to form carbonic acid

53
Regulation of Pulmonary Ventilation
54
Regulation at rest Plasma Pco2 and H
Concentration
  • The partial pressure of CO2 provides the most
    potent respiratory stimulus at rest
  • H in the cerebrospinal fluid bathing the
    central chemoreceptors provides a secondary
    stimulus driving inspiration

55
Ventilatory Regulation During Exercise
  • Chemical control
  • Po2
  • Pco2
  • H
  • Nonchemical control
  • Neurogenic factors
  • Cortical influence
  • Peripheral influence

56
Ventilation in steady rate exercise
  • Of oxygen ( V E/ V O2)
  • Quantity of air breathed per amount of oxygen
    consumed
  • Remains relatively constant during steady-rate
    exercise- 25 L air breathed per 1L o2 consumed at
    55 Vo2 max
  • Of carbon dioxide ( V E/ V CO2)
  • Remains relatively constant during steady-rate
    exercise

57
Ventilatory Threshold
  • The point at which pulmonary ventilation
    increases disproportionately with oxygen uptake
    during graded exercise
  • The excess ventilation relates to the increased
    CO2 production associated with buffering of
    lactic acid

58
Pulmonary adaptations to Exercise
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Adaptations to
  • Maximal exercise
  • Minute ventilation increases
  • Increased oxygen uptake

61
Submaximal Exercise
  • Ventilatory muscles stronger
  • Ventilatory equivalent for oxygen
  • ( V E/ V O2) reduces? indicates breathing
    efficiency
  • This leads to
  • Reduced fatigue in ventilatory muscles
  • O2 that would have been used by those muscles can
    be used by skeletal muscle.

62
Pulmonary Adaptations
  • Increased tidal volume
  • Decreased breathing frequency
  • Increased time between breaths (Increased time
    for oxygen to get into bloodstream)
  • Therefore less oxygen in exhaled air

63
Summary
  • Need to know
  • Cardiac and pulmonary Structure and Function
  • Veins/arteries/cappilaries
  • Flow of blood through the heart
  • Alveoli bronchii etc
  • Flow of inspired air and pulmonary exchange
  • Acute adaptations to exercise
  • Chronic adaptations to exercise
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