Study Question – unit 15
Is the mechanical advantage of a first-class lever greater than, less than, or equal to one?
- Recall that MA = FA/RA
- First class levers are can be either or force or speed levers
- Therefore: MA could be greater than or less than 1 or equal
- The FA and RA can vary in length
Study Question – UNIT 16
The experiment described in this lab fixes the centre of gravity along the transverse plane of the body. How would you
fix the exact location of the centre of gravity along the frontal and sagittal planes of the body?
- Use segmental method
- Determines COG for each of body segments, the position of each gravity point with respect to x&y axes and with
the ratio between individual segment mass and total body mass
- PG 129 study guide
Study Questions – Unit 18
Define “atria” and “ventricles.” Which vessels enter or exit the atria and ventricles?
Atria: body cavity/chamber in the heart that receives blood from veins and forces it into a ventricle
o Receptors of deoxygenated blood
Ventricles: chamber on left and right side of heart
o Right ventricle receives venous blood (deoxygenated) from right atrium and pumps into pulmonary
o Left ventricle receives arterial blood (oxygenated) from left atrium and pumps into aorta
Describe the flow of a red blood cell from the right atrium to the aortic arch, identifying the major structures along the
way, and the function associated with each structure.
o R atrium – R Ventricle – Pulmonary Artery (L/R) – ateriole – capillary – pulmonary vein (blood returns to
heart for systemic circuit)
o L atrium – L ventricle – Aorta – R Iliac Artery – Arteriole – Capillary @ toe of R foot – venule – R femoral
vein – vena cava – R atrium
Discuss the importance of the elasticity and contractility of the arteries.
Large changing pressures they need to be very elastic to do so w/o breaking
Have to spring back into shape – walls becoming bigger reduces blood pressure Explain how blood returns to the right atrium. Why should one “cool down” after vigorous exercise rather than stop
R ventricle > semi lunar valve to lungs (pulmonary artery) > lung sback to left atrium through pulm vein and AV
valve< left ventricle to semi lunar valve> through aorta back to body via vena cava > right atrium through
tricuspid valve > right ventricle
Prevent post exercise low bP & dizziness
o Lack of blood flowing back to heart and brain because blood pooling in legs
Describe the location of the heart in the thoracic cavity.
Mediastinal space of thoracic cavity between 2 pleura enclosing the lungs
Why is the wall of the left ventricle thicker than the wall of the right ventricle?
Left ventricle pumps blood @ higher pressure because it has to reach further distance (all areas of body)
Left v only pumps to lungs
Why are the heart valves important? Can the heart function with leaky valves?
Prevent backflow of blood
Oxygenated blood doesn’t mix with deoxygenated
Blood running from pulmonary wont mix with aortic side
Yes as long as impairment isn’t too bad (may need open heart surgery)
Why are artery walls so much thicker than those of corresponding veins?
Blood pumped directly into arteries (more pressure)
Study Questions – UNIT 19
1. 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?
- The blood is pumped through smoothly by the heart throughout the arteries (non-turbulent)
- Sounds can only be heard when pressure is in between systolic/diastolic
- Artery will be contricted/no blood flow to lower arm
- Sounds made when blood flow through causes wall of artery underneath stetho to vibrate
2. 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.
- Ankle should be higher than arm
- Additional pressure from elastic compression of vessel walls
3. Describe four sources of error when recording blood pressure from an exercising subject.
- Improper positioning of subject (should be @ level of heart)
- Improper deflation of cuff (should be 2mmHg / beat)
- Recording the first bP measurement (should wait a few minutes or it will be extremely high)
- Improper application of cuff (applied too loose, bulging, ballooning)
4. 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.
- Systolic increases up to 200 mmHg, diastolic remains relatveily the same and changes a little
5. Procedures which use submaximum exercise heart rates to predict VO2max are based on a number of