Blood Vessel Lab

We will gain experience in measuring blood pressure, calculating mean arterial pressure and pulse pressure, and exploring the major arteries and veins of the human body. This practical session aims to enhance your understanding of cardiovascular physiology and anatomy.

In the first part of the lab, you will learn how to accurately measure blood pressure. Blood pressure is a vital indicator of cardiovascular health and provides insights into the functioning of the heart and blood vessels. You will practice taking blood pressure readings using a sphygmomanometer and a stethoscope. The measurements will be obtained in various positions, including sitting, standing, and supine. This will allow you to observe how blood pressure changes with body position.

Next, you will explore the effect of exercise on blood pressure. You will perform a simple exercise, such as jogging in place, and measure your blood pressure immediately after exercising. This will help you understand how physical activity influences cardiovascular parameters.

In addition to exercise, you will also examine the impact of temperature on blood pressure. You will immerse one arm in an ice bath and measure the blood pressure in that arm. This will provide insight into how temperature affects blood vessel constriction and dilation.

After studying blood pressure dynamics, we will shift our focus to the major arteries and veins of the body. You will be provided with anatomical diagrams and models to identify and locate the key blood vessels in the human body. This exercise will enhance your understanding of the circulatory system and its role in transporting oxygen, nutrients, and waste products throughout the body.

Throughout this laboratory session, safety precautions will be emphasized, including proper sterilization of equipment, correct measurement techniques, and maintaining a respectful and supportive environment for all participants.

Objectives

·         To understand the principles and techniques involved in accurately measuring blood pressure using a sphygmomanometer and stethoscope.

·         To learn how to calculate mean arterial pressure and pulse pressure, which are important indicators of cardiovascular health.

·         To investigate the effect of body position (sitting, standing, supine) on blood pressure and observe the changes in systolic and diastolic pressures.

·         To examine the impact of exercise on blood pressure and observe the immediate post-exercise changes in systolic and diastolic pressures.

·         To explore the influence of temperature on blood pressure by immersing the arm in an ice bath and observing the resulting changes in blood pressure.

·         To identify and locate the major arteries and veins of the human body using anatomical diagrams and models.

·         To develop proficiency in using laboratory equipment, such as sphygmomanometers, stethoscopes, and anatomical models, in a safe and accurate manner.

·         To cultivate an appreciation for the relevance of blood pressure measurement and arterial anatomy in various healthcare fields, including cardiology, physiology, nursing, and biomedical research.

Materials

·         Sphygmomanometers

·         Stethoscopes

·         Ice Bath

·         Alcohol Swabs

Blood Pressure

Activity 1:

During this activity, you will engage in the process of measuring arterial blood pressure by employing a sphygmomanometer with the assistance of a lab partner. Additionally, you will conduct calculations to assess pulse pressure and mean arterial pressure.

1.       Collaborate with your lab partner and gather the necessary equipment, including a stethoscope, a sphygmomanometer, and alcohol swabs. Sanitize the earpieces of the stethoscope using the swabs. Next, examine the cuff of the sphygmomanometer to ensure that no air is trapped inside, as this could lead to inaccurate measurements.

2.       Instruct your lab partner to sit in a comfortable position, with one arm resting on the lab bench as close to the heart's level as possible. Proceed by wrapping the sphygmomanometer cuff around either upper arm of your partner, ensuring that the inflatable part is positioned on the inner surface of the arm. If the cuff has an arrow marking, align it with the brachial artery. Pull the cuff until it fits snugly around the arm, and secure it by fastening the Velcro ends together.

3.       Using your forefinger and middle finger, locate the brachial pulse in the antecubital area, and mark the pulse point with a marking pencil. The brachial artery can be found on the anterior side of the arm, just above the antecubital fossa and medial to the biceps brachii muscle. Once the stethoscope is in position, place the bell on the pulse point and ensure that you can hear the sounds of the brachial pulse.

4.       To begin the measurement, inflate the cuff to a pressure level ranging from 160 to 180 mm Hg. Then, open the valve and allow the cuff to deflate slowly. While keeping your eyes on the pressure gauge, listen attentively for the initial tapping sound using the stethoscope. Record the pressure reading at the onset of the tapping sound as the systolic pressure in the provided Data Table. Continue to deflate the cuff slowly.

5.       As the tapping sound persists, it will increase initially, then decrease to a faint tapping, and finally stop. Record the pressure reading when the last faint sound is heard as the diastolic pressure in the Data Table.

6.       Repeat steps #1 through #5 twice more to obtain a total of three measurements. After each measurement, ensure that you completely deflate the cuff before commencing the next one. Calculate the average of the three measurements and record it in the Data Table.

7.       Now, switch roles with your lab partner and repeat steps #1 through #6 to obtain blood pressure readings for a second subject. Record the values in the Data Table.

8.       Calculate the pulse pressure and mean arterial pressure. In this exercise, you will focus on determining pulse pressure, which is the difference between systolic and diastolic blood pressure. Pulse pressure provides valuable information as it represents the volume of blood ejected from the left ventricle, often referred to as the "working blood pressure." Additionally, compute the mean arterial pressure (MAP), which denotes the average blood pressure throughout a single cardiac cycle. Record the calculated values in the provided Data Table.

Pulse pressure = systolic pressure - diastolic pressure
Mean arterial pressure = (systolic + (2*diastolic))/3

Compare and explain all of the results.
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Activity 2:

Blood pressure is a dynamic phenomenon that varies in response to the body's needs in order to ensure the continuous circulation of blood to tissues and organs. Several factors can increase blood pressure, including sudden changes in body position, physical exercise, and emotional stress. The body regulates blood pressure by adjusting cardiac output (CO), which refers to the volume of blood pumped by the left ventricle per minute. Additionally, the constriction and dilation of arterioles affect peripheral resistance. In this activity, you will explore the factors influencing blood pressure by employing a sphygmomanometer and stethoscope once again.  Record all collected data in the table provided.

Change in Body Position:

1.       To examine the impact of body position on blood pressure, follow steps #1 through #5 from activity 1 to obtain a new blood pressure measurement while your lab partner is seated at rest.

2.       Then instruct your subject to stand up from the seated position, maintaining the cuff around their arm, placing the stethoscope bell on the brachial pressure point, and monitoring the pressure gauge. Immediately measure the blood pressure after your subject has stood up.

3.       Next, measure the blood pressure again after your subject has been standing for 5 minutes.

4.       Finally, ask your subject to lie down supine (on back) while keeping the cuff on their arm. After your subject has been lying supine for 5 minutes, measure the blood pressure once again. Record the results in the provided Data Table.

5.       Repeat this procedure for a second subject. Repeat the entire process for both subjects.

Exercise:

1.       In this experiment, you will measure the blood pressure of two subjects.  Choose a volunteer as your subject and ensure that they do not have any health risks associated with exercise. Follow steps #1 through #5 from activity 1 to obtain a blood pressure measurement at rest.

2.       Then instruct your subject to engage in physical exercise for approximately 5 minutes, such as jogging in place, stepping up and down on a bench, or briskly walking up and down a stairway. After 5 minutes of exercise, ask your subject to sit down, and immediately measure and record their blood pressure in the provided Data Table.

3.       Repeat the entire procedure with your second subject. Repeat the process for both subjects.

Sympathetic Response:

1.       Once your subject has fully recovered from the previous experiments, measure their blood pressure while they are seated, following the instructions from steps #1 through #5 in activity 1. Record this measurement.

2.       Now, have your subject immerse their arm or foot in an ice bath and promptly measure their blood pressure. Record the data immediately after immersion.

3.       Repeat the entire procedure with your second subject. Repeat the process for both subjects.

Compare and explain all of the results.
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Blood Vessels

Write the name next to the line pointing to the artery.

Write the name next to the line pointing to the vein.

Review Questions

1.       What are the three types of blood vessels found in the human body?
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2.       What is the function of arteries in the circulatory system?
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3.       How do the walls of arteries differ from the walls of veins?
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4.       What is the significance of the differences in the structure of arteries and veins in terms of their function?
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5.       How does the structure of capillaries enable them to exchange nutrients and waste products with the surrounding tissues?
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6.       Design an experiment to investigate the effect of exercise on blood vessel function in humans.
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7.       What is the name of the condition where the walls of the arteries become thickened and hardened?
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8.       How does high blood pressure contribute to the development of cardiovascular disease?
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9.       What are some lifestyle changes that can help to improve blood vessel health?
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10.    What are some of the risk factors for developing varicose veins, and how do they contribute to their development?
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