Cardiac & Respiratory Dynamics. Vascular System Carry blood away from heart Arteries Arterioles ...
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Transcript of Cardiac & Respiratory Dynamics. Vascular System Carry blood away from heart Arteries Arterioles ...
Carry blood away from heartArteries Arterioles Capillaries
Carry blood to heartCapillaries Venules Veins Large Veins
Venous Return• One-way valves
– Ensure blood goes back to the heart and not backwards
• Skeletal muscle pump– Low pressure in veins
skeletal contracts to increase pressure
• Thoracic pump– Difference in pressure between
2 cavities– Each breath taken, pressure in
chest cavity low, abdominal pressure increases
– Blood from abdominal to thoracic cavity
• Venoconstiction– Nervous system sends signal to
veins to slightly constrict
Cardiac Cycle• Diastole – phase of relaxation • Systole – phase of
contraction
Systolic blood pressure – measure in arteries during contraction (120 mm Hg)
Diastolic blood pressure – measure in arteries during contraction (80mm Hg)
Blood
• Erythrocytes (red blood cells)– Transport O2 and CO2
– Contain hemoglobin bind O2 and CO2
• Leukocytes (white blood cells)– Protect body from diseases– Contain platelets blood clotting
Cardiac Output
• Volume of blood pumped out of the left ventricle in 1 minute (L/min)
• Factors: stroke volume & heart rate
Q = SV x HRCardiac Output (L/min) Stroke
Volume (mL)
Heart Rate (beats/min)
• Stroke Volume (SV)– Amount of blood ejected from left ventricle in
single beat
SV = LVEDV – LVESV
• Heart Rate (HR)– Number of times hear beats in one minute
Maximum Heart Rate = 220 – age (years)
Stroke Volume
(mL)
Left Ventricular End-Systolic Volume (mL)
Left Ventricular Diastolic Volume (mL)
Increase SV or HR?
• Preferred way: ↑ stroke volume• Heart pushes more blood volume with each
pump in left ventricle• Heart can beat fewer times• Less stress on heart
• Athlete has lower heart rate and beats less than a sedentary person
Cardiovascular Training
• Cardiac output increase linearly with exercise intensity
• Body needs more oxygen = more blood is needed to be pumped to body
• Aerobic training• Increase in ventricular volume & thickness of
ventricular wall• ↑ ventricular volume = ↑stroke volume
Respiratory Dynamics
Pulmonary Ventilation• Rate and/or intensity of work being done = air in
and out of the body
Ventilation (VE)
• Inspiration + expiration• Volume of air moved by lungs in 1 minute
VE = VT x ƒ Ventilation (L/min)
Tidal Volume (L) – volume of air in each breath
Respiratory Frequency (breaths/min) – # of
breaths taken per minute
Oxygen Uptake
• Amount of oxygen consumed by body during cellular respiration
• Measure as volume of oxygen consumed in given time (VO2)
• Increases with activity
• VO2max – maximal volume of oxygen that can be supplied to and consumed by body