Cardiovascular Physiology Flashcards
the heart
inferior and superior vena cava > right atrium > tricuspid valve > right ventricle > pulomonary semilunar valve > pulmonary arteries > lungs > pulmonary veins > left atrium > bicuspid valve > left ventricle > aortic valve > aorta > body
Conduction Pathways
SA Node > Internodal pathways > AV Node > Bundle of His > Left and Right bundle branches > Purkinje fibers
The right side of the heart
Receives blood returning from the body
The left side of the heart
Receives oxygenated blood from lungs
The two sides of the heart are separated by
interventricular system septum
Which is the largest and most powerful chamber?
Left ventricle
Parasympathetic Nervous System (PNS)
through the vagus nerve and decrease HR and force of contraction
Sympathetic Nervous System (SNS)
stimulated by stress to increase HR and force of contraction
Epinephrine and Norepinephrine are released due to
sympathetic stimulation
Bradycardia
resting HR below 60 bpm
Tachycardia
resting HR above 100 bpm
P wave
Atrium depolarization
QRS complex
Ventricular depolarization
T wave
Ventricular repolarization (ventricular diastole)
Diastole
relaxation phase during which the chambers fill with blood (T wave to QRS complex)
Systole
contraction phase during which the chambers speed blood (QRS to T)
Stroke Volume
the volume of blood pumped per contraction
SV formula
SV = EDV- ESV
End-diastolic volume (EDV)
the volume of blood in ventricle before contraction
End-systolic volume (ESV)
the volume of blood in ventricle after contraction
Cardiac output (Q)
the total volume of blood pumped by the ventricle per minute
Cardiac output formula
Q = HR x SV
Ejection Fraction (EF)
the proportion of blood pumped out of the left ventricle each beat
Ejection Fraction formula
EF = SV / EDV
Vascular System
Arteries > arterioles > capillaries > venules > veins
Autoregulation
arterioles within organs or tissue dilate or constrict
Extrinsic neural control
when sympathetic nerves within the walls of vessels are stimulated
BP formula
BP = cardiac output x Total peripheral resistance (TPR)
Mean Arterial Pressure (MAP)
average pressure exerted by the blood as it travels through arteries
MAP formula
MAP = DBP + {0.333 (SBP -DBP)]
Total Pheripheral Resistance (TPR) formula
TPR =MAP / Q or Q = MAP/ TPR
Composition of Blood
55% plasma
45% elements
Compositon of plasma
90% H20
7% plasma proteins
3% other
Compositions of elements
99% RBCs
1% WBCs and platelets
White blood cells
protect body from disease organism
Blood Platelets
cell fragments that help blood coagulation
RBCs
carry oxygen to tissue with the help of hemoglobin
Hematocrit
the ratio of formed elements to the total blood volume
Higher hematocrits result in
higher blood viscosity
Acute response to exercise
increase HR, SV, and Q
Resting HR
28 -100 bpm
Factors that decrease resting HR
Age and increased cardiovascular fitness
Factors that affect resting HR
environmental conditions (altitude and temperature)
HRmax
highest heart rate value one can achieve in an all-out effort to the point of exhaustion
HRmax formula
HRmax= 220 - age in years
Steady-state HR
HR plateau reached during a constant rate of submaximal work
What represents a low steady-state HR?
a more efficient heart
What does SV determine?
a cardiorespiratory endurance capacity at maximal rates of work
Why a slight decline occurs at SVmax?
Due to a smaller venous return because the heart rate is so high that there isn’t enough time to fill the heart up with blood
Frank Startling mechanism
More blood in the ventricle causes it to stretch more and contract with more force
An increased in the SV during exercise is due to?
the Frank-Starling mechanism and because the heart just contracts harder
Cardiovascular Drift
A gradual decrease in SV and systematic and pulmonary arterial pressures and increase in HR
How does cardiovascular drift occur?
With steady-state prolonged exercise or exercise in a hot environment
Cardiovascular Endurance Training
SBP increases and DBP changes little
Resistance Exercise
Exaggerates BP responses 480/350 mmHg
Arterial- Venous Oxygen Difference
Amount of oxygen extracted from the blood as it travels through the body
