Written Questions Flashcards
What is the atria?
- upper two cavities of the heart – passes blood to the ventricles
- left atrium = receives oxygenated blood from veins
- right atrium receives deoxygenated blood from pulmonary vein
Which vessels enter or exit the atria?
- right atrium – receives deoxygenated blood from superior vena cava, inferior vena cava
- left atrium = receives oxygenated blood from the pulmonary vein
What are the ventricles?
- large lower chambers that collect + expel blood received from one of the atria
- right ventricle = receives blood from the right atrium
- left ventricle = receives blood from the left atrium
What vessels enter or exit the ventricles?
- right ventricle = pulmonary artery – sends blood to the lungs
- left ventricle = aorta/aortic arch – pumps blood to rest of the body
Describe the pathway of blood through the heart
- Blood enters the right atrium from the superior and inferior vena cava,
and the coronary sinus – carries deoxygenated blood - From right atrium, it goes through the tricuspid valve to the right ventricle.
- From the right ventricle, it goes through the pulmonary semilunar valves to
the pulmonary trunk - From the pulmonary trunk it moves into the right and left pulmonary
arteries to the lungs. - From the lungs, oxygenated blood is returned to the heart through the
pulmonary veins. - From the pulmonary veins, blood flows into the left atrium.
- From the left atrium, blood flows through the bicuspid (mitral) valve into
the left ventricle. - From the left ventricle, it goes through the aortic semilunar valves into the
ascending aorta. - Blood is distributed to the rest of the body (systemic circulation) from the
aorta.
Discuss the importance of the elasticity and contractility of the arteries
- elasticity = allows vessels to respond to + accommodate changes in blood pressure that comes from the pumping of the heart
- contractility = allows vasoconstriction + vasodilation – comes from signals in the nervous system
Explain how blood returns to the right atrium.
- assisted by skeletal-muscle pump + thoracic pump – breathing
- squeeze veins that run through them
- veins have one-way valves – pushes blood through valve + close to prevent backflow
Why should one “cool down” after
vigorous exercise rather than stop abruptly?
- strenuous activity causes blood vessels in legs to expand – brings more blood to legs + feet
- heartbeat slows abruptly if no cool down portion
- sudden drop in HR causes blood to pool in lower body – can cause dizziness + fainting
Describe the location of the heart in the thoracic cavity
medially between the lungs in the mediastinum
- separated from other structures by membrane – pericardium
- sits in own space – pericardial cavity
- dorsal surface of heart lies near bodies of vertebrae
- anterior surface = sits in sternum + costal cartilages
- base of heart = located at level of third costal cartilage
- inferior tip of the heart = left of the sternum between junction of 4th + 5th ribs
- right side = faces slightly anteriorly
- left side = faces slightly posteriorly
Why is the wall of the left ventricle thicker than the wall of the right ventricle?
higher forces needed to pump blood through the systemic circuit as compared to the pulmonary circuit – must pump blood throughout the body
Why are the heart valves important?
- opens so that blood can empty into the proper chamber
- closes when blood flows through so that blood doesn’t flow back to where it just was
Can the heart function with leaky valves?
can function if not too major but can cause many problems:
- lightheadedness
- rapid heartbeat
- heart fluttering
- fatigue
- congestive heart failure
- edema = swelling of the legs, abdomen, veins in neck
- chest pain/tightness
Describe the step by step procedure for measuring blood pressure
- patient should be seated with arms flexed + elbow placed around heart level – do not measure over clothes
- choose the sphygmomanometer proper blood pressure cuff + ensure that it isn’t wrapped too tightly – should be able to fit two fingers in between cuff + subject’s arm
- wrap cuff around upper arm approx. 1 inch above antecubital fossa
- lightly press the stethoscope over the brachial artery just below the cuff’s edge
- rapidly inflate the cuff to approx. 180mm Hg then release the air slowly by turning the knob slightly
- listen w/ the stethoscope while also looking at the sphymomanometer – first Korotkoff (knocking) sound = systolic pressure
- when knocking sound disappears = diastolic pressure
- release air all the way and remove cuff
When measuring blood pressure you must listen for Korotkoff sounds at the brachial
artery using a stethoscope. Why can’t you hear these sounds before the cuff is
inflated?
- as cuff inflates, brachial artery is constricted – blood flow through lower arm = turbulent
- turbulent blood flow causes walls of artery under stethoscope will vibrate
- no pressure = blood flow more smooth = no sounds heard
If blood pressure was measured at the level of a subject’s calf rather than at the level
of the upper arm, would you expect the blood pressure readings to be different?
Explain
- yes blood pressure readings would be different
- pull of gravity causes more blood to stay in lower extremities = greater pressure in legs
- vessels in legs narrower = higher reading
- blood pressure in legs shouldn’t be lower = can be indication of blocked arteries
Describe four sources of error when recording blood pressure from an exercising
subject.
- using the wrong size cuff – too large cuff will give falsely low readings, too small cuff will give falsely high readings
- incorrect limb position – limb must be at heart level = if too high, low reading, if too low, high reading
- cuff placed incorrectly – match up with antecubital fossa w/ stethoscope placed at the brachial artery
- subject not calm/rested/exercised before reading – eaten/smoked before test
Give a physiological explanation for the changes in systolic and diastolic blood pressure which you theoretically would expect to observe for your subject on the bicycle ergometer as exercise intensity increased from a low level to a higher level
- blood pressure should increase then plateau
- subject works harder w/ increasing work rate – heart would need to pump faster = raises systolic + diastolic blood pressure
- increase in SV, VO2, HR = increase in blood pressure
Describe three of the assumptions that test protocols to predict VO2
max using submaximum exercise heart rates are based on
- linear relation between HR + oxygen uptake = heavy work rates may cause VO2 to increase more than HR
- similar max HR for all subjects = standard deviation of approx. 10 beats/min on avg for subjects of same age group – use age correction factor as max HR decreases w/ age
- fixed mechanical efficiency assumed if VO2 is predicted from work rate = mechanical efficiency can vary by 6% on a bicycle ergometer
Why is an age correction factor needed during the Astrand-Rhyming Test for predicting VO2max?
max HR declines with age so age correction factor helps to make up for this to provide a more accurate reading for older people
How would the predicted VO2 max. of a 40 year old subject be affected if the age
correction factor was not used? Explain
increased error by 15%
- VO2 max peaks at 25 and goes down from there – VO2 max will seem lower than actual results
Do you think that the Astrand bicycle ergometer test for predicting VO2
max is a “well designed” physical fitness test? Explain.
well designed but not the best test
- good = less expensive, portable, doesn’t require electricity, patient more stable, body weight is supported, easier to quantify work rate
- bad = most people not used to cycling so muscles being used aren’t ones that are normally being used, can’t reach as high a VO2 max in comparison to the treadmill test
A well-conditioned individual has a heart rate of 122 bpm at a power output of 900
kpm/min., while a poorly conditioned subject has a heart rate of 164 bpm at the
same power output. Does this mean that the cardiac output is approximately one-third higher in the untrained subject (assuming that the two men are the same
height and weight)? Explain.
no b/c cardiac output is also dependent on stroke volume – trained individuals have lower heart rate but can have higher stroke volume so not always correlated
If you modified the Astrand Test such that you measured heart rate 20-30 seconds after cessation of exercise rather than during exercise, then used the same tables to predict the subject’s VO2 max., what effect would this have on the estimation of the
subject’s aerobic fitness level? Explain
HR would be lower – gives illusion that they have a higher VO2max than in reality
- VO2 max dependent on HR at a given work rate – lower HR = higher VO2 max
Which cycle ergometer test do you consider to be the best submaximal test for predicting VO2 max - the Astrand Test or the YMCA Test? Explain.
Astrand test is better because:
- more concise – results are obtained without tiring the subject more than need be
- involves correction factor to maintain accuracy in older people
