PBSL1114 Physiology for Human Movement Cardiovascular Dynamics Laboratory Report Student ID 2010004614 Due date and Value: This report must be submitted as a soft copy via email to abarnett@hku. hk no later than 5:00 pm 4 April 2012. Penalties apply for late submission, see course outline for details. You must attend the laboratory session to get a mark for the related report. References used when answering questions must appear in a reference list at the end of your report. Value: This report contributes 10% of your final grade. RESULTS Subject name: Cheng Yat Hin

Sex: 0MF (circle)Age: 21 Table 1. Heart Rate (HR), sitting, lying and standing Time (min)HR (b. min-1) Sitting HR (readings 3 minutes post-sitting BP determination)3:0075 3:0577 3:1080 3:1580 3:2080 3:2580 3:3076 Mean sitting HR78. 29 Lying HR (5 minutes after lying down)5:0070 5:0570 5:1068 5:1568 5:2070 5:2569 5:3069 Mean Lying HR69. 14 Standing HR- immediately after standing from lying0:00104 -10 sec after standing from lying0:1084 - 20 sec after standing from lying0:2086 - 30 sec after standing from lying0:3088 Standing HR- 2 min after standing from lying80 Table 2.

Blood Pressure (BP), sitting, lying and standing. BP readerSystolic BP (mmHg)Diastolic BP (mmHg)MAP (mmHg) Sitting BP11227490 21207489. 33 31237188. 33 41237289 51217489. 67 Mean sitting BP121. 87389. 27 Sitting BP (automated BP monitor)1087082. 67 Trial Lying BP 11035269 2985670 Mean Lying BP100. 55469. 5 Standing BP Standing BP - ASAP after standing from lying12989102. 33 Standing BP - 2 min after standing from lying1208395. 33 Rebreathing air from a paper bag. Resting sitting HR pre-breathing into bag:75 (b. min-1) HR after 30 seconds breathing into bag: 70 (b. in-1) HR after 120 seconds breathing into bag:75 (b. min-1) Human diving response. Water Temperature: 17 o C HR (b. min-1)Systolic BP (mmHg)Diastolic BP (mmHg)MAP (mm Hg) Pre-immersion (immersion position)711187388 At 30-sec immersion (1)431467699. 33 At 30-sec immersion (2)511298197 Average deviation of immersion values from pre-immersion value-2419. 56. 510. 165 QUESTIONS (marks shown in brackets: total = 30, percent of final grade = 10%): Answers must not be longer than the number of lines stated at the end of each question (10 pt font minimum).

Answers exceeding the stated limits will receive a mark of zero. Use your own words. This is an individual report. Plagiarism (e. g. , copying or lending answers, not referencing sources) will be penalized. Marks will be deducted if you break any of these rules. Include the references you used in a list at the end of your report. 1. Marks for data recording (correctly/neatly) and calculations (DO NOT ANSWER) _____ (5) 2. Are the relationships between resting values for HR while lying, sitting and standing (2-minute post-lying value) what would be expected?

Justify your response. (maximum 4 line response) (5 marks) From lying to sitting to standing, the resting HR is expected to increase, which the effect is shown in the subject (lying mean value = 69. 14 bpm, sitting mean value = 78. 29 bpm and standing after 2 min = 80 bpm). From lying to sitting to standing, more blood is pulled downward by gravity to the lower part of the body, making less venous return thus lowering the stroke volume. To compensate the decrease of SV thus to maintain the cardiac output, HR increases. 3.

Are the relationships between resting values for BP while lying, sitting and standing (2-minute post-lying value) what would be expected? Justify your response. (maximum 4 line response) (5 marks) The blood pressure should gradually rise from lying to sitting to standing, which is observed in the subject (MAP of lying: 69. 5mmHg, sitting: 82. 67 mmHg and standing: 95. 33 mmHg). From lying to sitting to standing, more blood is pulled downward by gravity to the lower part of the body. To push the blood upward so as to maintain enough blood flow to the brain, blood pressure needs to increase for working against the effect of gravity. . Explain the changes observed in HR and BP during the period following the subject moving from lying to standing. (maximum 4 line response) (5 marks) When the subject moving from lying to standing, BP should drop momentarily and HR should rise. The drop in BP is due to the pooling of blood in the lower part of the body. After sensing the drop in BP, the baroreceptor increases HR by the control of SNS and PNS. Then BP should rise again as the result of increased HR. The change is not seen in the subject. It might be due to other factors like the psychological factors masking the effect, or errors in measurement. . Were the observed changes in HR when your subject was rebreathing air from a paper bag as expected? Explain your answer with reference to what was expected and why. (maximum 4 line response)(5 marks) The rise in HR is expected when the subject is rebreathing air. The expectation is due to the increased CO2 concentration in the expired air will increase the blood PCO2, which be noticed by the chemoreceptors in carotid and aortic bodies. The receptors will then relay the information to CNS and indirectly leads to the increase in HR by autonomic nervous system.

But the effect is not observed in the subject. 6. What is the human diving response? Did your subject show the diving response? (maximum 4 line response)(5 marks) Human diving response is the increase in MAP and decrease in HR as a result of breath holding and the reflex after the face touched water. This is done by the increased parasympathetic activities to the heart pacemaker cells (lower HR), increased sympathetic activities to limbs leading to vasoconstriction in the limbs (increase MAP). The subject showed the diving response, as there is a egative change in HR and a positive change in MAP 30s after immersion List of references used 1. http://ep. physoc. org/content/23/1/1. full. pdf+html 2. http://www. livestrong. com/article/307646-posture-heart-rate/ 3. http://www. livestrong. com/article/268891-heart-rate-body-positions/ 4. http://www. livestrong. com/article/299614-blood-pressure-supine-vs-standing/ 5. http://en. wikipedia. org/wiki/Aortic_body 6. http://en. wikipedia. org/wiki/Cartoid_body 7. http://www. mendeley. com/research/mechanism-human-diving-response/