Effect of Exercise on Heart Rate and Blood Pressure

OBJECTIVES:

In this experiment you will use the auscultatory method to determine the response of the

cardiovascular system to various body positions and exercise.

INTRODUCTION:

The function of the heart is to generate the hydrostatic pressure necessary to pump the

oxygen-depleted, carbon dioxide-rich venous blood to the lungs where the carbon dioxide is

released and oxygen is absorbed, both by diffusion. Subsequently, the heart pumps, via the

systemic arteries, the oxygenated blood to all other body tissues in quantities large enough to

insure their vitality. The blood flow is separated within the left and right halves of the heart.

The coordinated, rhythmic contraction of the two atria and two ventricles keeps the blood

pumping and is called the cardiac cycle. This cycle consists of two phases: systole, a period of

atrial filling and ventricular contraction, and diastole, a period of atrial emptying, and ventricular

relaxation and filling.

Heart Sounds

The directionality of blood flow is controlled by a system of valves which open and close

passively (due to blood pressure differences) throughout this excitation - contraction - relaxation

sequence of the cardiac cycle. The atrioventricular (AV) valves prevent backflow of blood from

the ventricle to the atria during systole and the semilunar valves prevent backflow from the aorta

and pulmonary arteries into the ventricles during diastole. Heart sounds are produced by the

closure of these valves. Auscultation (listening) with a stethoscope may reveal the normal heart

sounds, described as, "lub, dup....lub, dup." The first heart sound, usually associated with the

"lub," is caused by the closing of the AV valves at the beginning of systole. The second heart

sound, the "dup," is caused in turn by the closure of the semilunar valves at the beginning of

diastole. Abnormalities of the valves cause abnormal heart sounds known as murmurs.

The areas for listening to the different heart sounds with a stethoscope are not directly

over the valves themselves. The sounds caused by the AV valves are transmitted to the chest

wall as vibrations through each respective ventricle, and are best heard over the fifth intercostal

space (Figure 9-1). The sounds from the semilunar valves are transmitted along the large

arteries leaving the heart, and are best heard by placing the stethoscope in the second intercostal

space to the right or left of the sternum (Figure 9-1).

Page 9-1

Partial preview of the text

Download Effect of Exercise on Heart Rate, Blood Pressure and Cardiovascular System and more Lab Reports Physiology in PDF only on Docsity!

Effect of Exercise on Heart Rate and Blood Pressure

OBJECTIVES:

In this experiment you will use the auscultatory method to determine the response of the cardiovascular system to various body positions and exercise. INTRODUCTION: The function of the heart is to generate the hydrostatic pressure necessary to pump the oxygen-depleted, carbon dioxide-rich venous blood to the lungs where the carbon dioxide is released and oxygen is absorbed, both by diffusion. Subsequently, the heart pumps, via the systemic arteries, the oxygenated blood to all other body tissues in quantities large enough to insure their vitality. The blood flow is separated within the left and right halves of the heart. The coordinated, rhythmic contraction of the two atria and two ventricles keeps the blood pumping and is called the cardiac cycle. This cycle consists of two phases: systole, a period of atrial filling and ventricular contraction, and diastole, a period of atrial emptying, and ventricular relaxation and filling. Heart Sounds The directionality of blood flow is controlled by a system of valves which open and close passively (due to blood pressure differences) throughout this excitation-contraction-relaxation sequence of the cardiac cycle. The atrioventricular (AV) valves prevent backflow of blood from the ventricle to the atria during systole and the semilunar valves prevent backflow from the aorta and pulmonary arteries into the ventricles during diastole. Heart sounds are produced by the closure of these valves. Auscultation (listening) with a stethoscope may reveal the normal heart sounds, described as, "lub, dup....lub, dup." The first heart sound, usually associated with the "lub," is caused by the closing of the AV valves at the beginning of systole. The second heart sound, the "dup," is caused in turn by the closure of the semilunar valves at the beginning of diastole. Abnormalities of the valves cause abnormal heart sounds known as murmurs. The areas for listening to the different heart sounds with a stethoscope are not directly over the valves themselves. The sounds caused by the AV valves are transmitted to the chest wall as vibrations through each respective ventricle, and are best heard over the fifth intercostal space (Figure 9-1). The sounds from the semilunar valves are transmitted along the large arteries leaving the heart, and are best heard by placing the stethoscope in the second intercostal space to the right or left of the sternum (Figure 9-1).

Figure 9-1. Locations for auscultation of heart sounds. Heart Rate Heart rate is the amount the heart beats per minute. Generally, a person’s heart rate is their pulse rate. There are several places that pulse rate can be measured and the carotid (neck) and radial (wrist) arteries are usually where the pulse is the strongest. Can you think of any other places pulse could be taken? To take the pulse rate use your index and middle fingers and gently depress the artery against the bone. Count the pulses per 30 seconds and multiply by 2 to get the pulses/ min. Blood Pressure Blood pressure is the product of cardiac output times the resistance of the closed circulatory system, represented by the equation:

Mean ABP = CO x TPR

where MAP = mean arterial blood pressure, CO = cardiac output, and TPR = total peripheral resistance. Mean Arterial Pressure can be calculated using systolic blood pressure (SP) and diastolic blood pressure (DP) for a normal healthy individual by:

MAP = DP + 1/3 (SP-DP)

Blood pressure is measured in the arteries. The specific artery is unimportant because all large arteries have about the same pulsatile pressure within them. Two pressures are usually measured: systolic pressure, the pressure in the arteries at the peak of ventricular ejection, and

b. Compare the heart sounds with the stethoscope in these two positions during quiet breathing, slow-deep inhalation, and slow exhalation. During inhalation, both heart sounds can usually be split into two sounds, the separate closure of the right and left AV and semilunar valves, respectively. Listen carefully to verify this.

2. Orthostatic Blood Pressure Changes. For steps 2 and 3 you will need your entire group working together to collect the data. One person should collect BP, another person should collect HR, and the last person should be recording the values in the appropriate table. a. Before you start collecting data, predict what will happen to BP and HR upon standing (question #2 in lab report). b. For one subject in your group, measure systolic and diastolic blood pressure using the arm cuff and measure heart rate by measuring the pulse with your finger on the opposite wrist or neck. c. Have your subject lye down and record resting blood pressure and pulse rate. d. Have your subject sit up, wait one minute and record resting blood pressure and pulse rate. e. Have your subject stand up, wait one minute and record their resting blood pressure and pulse rate. f. A drop of 20 mm Hg in systolic blood pressure, or 10 mm Hg in diastolic blood pressure is considered abnormal. 3. Effects of Exercise on Blood Pressure and Pulse Rate. a. For the one subject in your group, measure systolic and diastolic blood pressure using the sphygmomanometer and measure heart rate by measuring the pulse with your finger on the opposite wrist. b. Record resting blood pressure and pulse rate each minute for a total of 5 minutes. Record data in data table. c. Determine blood pressure and pulse rate each minute for 5 min of exercise and after that, for 5 min of recovery. Be sure to keep the BP cuff on at all times and take measurements quickly so your volunteer does not recover during the exercise period. At the end of 5 min, have the subject stop exercising and stand in place for 5 minutes (recovery period). Evaluate BP and PR for each minute during the 5 minute recovery period. Enter the data in data table.

Name:___________________ Lab Section:_____________ BIOL 261 HR and BP Lab Report (10 pts)

Discuss each of the steps below in the negative homeostatic feedback loop for blood pressure upon lying down. STIMULUS INCREASE IN BLOOD PRESSURE SENSOR INTEGRATOR EFFECTOR RESPONSE RESULT
How would BP and PR change for standing versus lying down if you had to make a prediction?

TIME SYSTOLIC BLOOD PRESSURE (mm Hg) DIASTOLIC BLOOD PRESSURE (mm Hg) HEART RATE (BPM) 1 min RESTING 2 min RESTING 3 min RESTING 4 min RESTING 5 min RESTING 1 min EXERCISE 2 min EXERCISE 3 min EXERCISE 4 min EXERCISE 5 min EXERCISE 1 min RECOVER 2 min RECOVER 3 min RECOVER 4 min RECOVER 5 min RECOVER

What is the equation used to determine cardiac output (CO)? Can heart rate decrease as stroke volume increases?
After you have collected your group’s HR and BP data for resting, exercise and recovery construct two graphs and attach them to your lab report and answer the following questions: a. What trends do you see as far as exercise effects on BP and PR? b. How do you think being out-of-shape would affect these trends?
What neurotransmitter(s) is responsible for increasing HR and decreasing HR; How do these neurotransmitters affect BP?
Identify the three layers of an artery and vein on a histology slide. What are these layers comprised of? What is the function of each layer?

Effect of Exercise on Heart Rate, Blood Pressure and Cardiovascular System, Lab Reports of Physiology

Related documents

Partial preview of the text

Download Effect of Exercise on Heart Rate, Blood Pressure and Cardiovascular System and more Lab Reports Physiology in PDF only on Docsity!

Effect of Exercise on Heart Rate and Blood Pressure

OBJECTIVES:

Mean ABP = CO x TPR

MAP = DP + 1/3 (SP-DP)