Cardiovascular Physiology Flashcards
VO2 (volume of oxygen)
product of oxygenated blood pumped from the heart per min called cardiac output (CO) and the amount of that oxygen used by bodily cells at a given time measured as (a-v) O2 difference
Easier info
Max amount of oxygen that someone can utilize during intense or maximal exercise
Cardiac output
heart rate x stroke volume
(a-v) O2 difference
difference in oxygen saturation when comparing the arteries and veins (blood leaving and returning to the heart); it indicates the level of oxygen uptake efficiency of working muscles and other tissues
Stroke volume
volume of blood expelled per contraction from the left ventricle during each heartbeat
Diastole
the relaxation state of the heart in between heart beats in which the atrial chambers fill with blood
Systole
the contraction state of the heart during heart beats when the ventricles pump blood out to the body
The heart repeatedly fills with blood which it pushes out to the
lungs via the pulmonary artery – there CO2 is exchanged for oxygen
Hemoglobin
Protein found in red blood cells that helps to transport oxygen to all tissues
Myocardium (heart/cardiac muscle)
specialized to allow for continuous contractions via an enhanced sarcoplasmic reticulum and calcium delivery system to allow it to manage rapid and non-stop neural impulses
Arteries
: large, muscular-walled vessels suited for transporting oxygenated blood away from the heart to bodily tissues
Arterioles
: smaller, thinner-walled arteries that serve as the connecting units to capillaries
Capillaries
: smallest vessels with the thinnest walls which allow for oxygen and nutrient exchange as well as waste product removal from muscles, organs, and other tissues
Venous pooling and a proper cool down:
An adequate cool down period after intense exercise is needed so that rapid blood flow back to the heart is not impeded.
Venous blood pooling can cause acute ischemia, leg heaviness, fainting or even a life-threatening cardiac episode among older adults
Veins
: serve to pump deoxygenated blood back to the heart and lungs via special valves
Role of blood
Blood is shunted throughout the body based on need:
It flows quickly through large arteries to transport oxygenated blood
It flows slowly through capillaries to allow for oxygen and waste product diffusion across their thin walls
It flows quickly through larger veins to get deoxygenated blood back to the heart and maintain cardiac output
Aerobic Training and Cardiac Output facts
As detailed earlier, cardiac output is the total volume of blood available for use by all bodily tissues as dictated by heart rate and stroke volume
Males tend to have higher CO and VO2max due to larger heart sizes and more muscle mass
Endurance training can improve cardiac output by improving the heart’s capacity to pump blood to working tissues via:
Increased ventricular mass and strength
An increased volume of blood expelled per heart beat
Higher cardiac output =
reduced resting and submaximal exercise heart rates - this explains why resting heart rate is a measure of cardiovascular fitness – as CRF goes up heart rate goes down reciprocally
Understanding blood pressure
Blood pressure: measure of force exerted by circulating blood against arterial walls; it is modulated in response to activity, nutrition, body size, and health status
Diastolic blood pressure and systolic blood pressure are measured during diastole and systole of the heart
Blood pressure = cardiac output x total peripheral resistance
Blood pressure is managed via baroreceptors located in major arteries which can promote dilation or constriction
Baroreceptors
: specialized receptors in the large arteries that detect changes in pressure and inform the central nervous system to decrease/increase blood pressure or heart rate
During exercise or high-stress situations:
Heart rate increases → which increases cardiac output → which increases blood pressure
Aerobic exercise increases mean arterial pressure much less than weightlifting; especially when using the Valsalva maneuver
Valsalva maneuver
: attempting to move a heavy load while holding one’s breath; it is contraindicated for those with hypertension
Hypertension
: clinical diagnosis of high blood pressure that has a negative impact on cardiovascular function and causes vascular damage over time
Radial and carotid pulse assessment
Radial- arm
Carotid- head/neck
Circulation and Oxygen Delivery During Exercise
Mechanisms that regulate blood flow to working muscles:
Central nervous system via adjustments in mean blood pressure and shunting of flow from one area to another
Hormonal communication between tissues that impacts blood flow characteristics (dilation, constriction)
Increased capillary activity in muscles that need the most oxygen (muscles will increase in size during resistance training due to blood flow
Cirulation for the heart:
The heart’s oxygen demand increases during exercise, requiring coronary blood flow to increase as the workload increases
To estimate the oxygen demands placed upon the heart during a given activity, systolic blood pressure is multiplied by heart rate to give a rate pressure product value
Rate pressure product RPP
estimate of myocardial oxygen demand and efficiency as well as cardiovascular disease risk; low fitness or cardiovascular compromise increase the value
Values over 11,000 are considered high risk
Ventilation During Exercise
Increased workload placed on the heart during exercise expedites an increase in ventilation (breathing) rate to meet oxygen demands
Once an individual’s lactate threshold has been crossed, breathing rate spikes quickly
Lactate threshold
: maximal intensity of work that a steady state condition can be maintained; lactate accumulation begins to exceed removal which indicates acidity in the tissue and blood
