Heart Rate Response to Baroreceptor Feedback
Recommended for grades 9–12.
Introduction
One of the homeostatic mechanisms of the human body serves to maintain a fairly constant blood pressure. Major determinants of blood pressure are heart rate, amount of blood pumped with each beat (stroke volume), and the resistance of the arterial system which is receiving the blood. The heart rate is influenced by baroreceptors, special sensors in tissues in the aortic arch and carotid arteries which contain nerve endings that respond to stretching. An increase or decrease in stretch sends signals to the medulla in the brain which in turn acts on the heart through the vagus nerve, completing what is called a feedback loop. Sudden increase in pressure in the heart or carotid arteries causes an increase in stretch of the baroreceptor sensors and results in a decrease in heart rate. Sudden lowering of pressure causes the opposite effect. This feedback loop enables us to function in a gravity environment.
Objectives
In this experiment, you will
- Observe pulse response to sudden squatting.
- Observe pulse response to sudden standing from a squatting position.
- Correlate pulse response to sympathetic nervous system function.
Sensors and Equipment
This experiment requires each of the following Vernier sensors and equipment (unless otherwise noted):
Additional Requirements
You may also need an interface and software for data collection. What do I need for data collection?
Download Experiment Preview
The student-version preview includes:
- Step-by-step instructions for computer-based data collection
- List of materials and equipment
Note: The experiment preview of the computer edition does not include essential teacher information, safety tips, or sample data. Instructions for Logger Pro and other software (such as LabQuest App or TI handheld software, where available) are on the CD that accompanies the book. We strongly recommend that you purchase the book before performing experiments.
Standards Correlations
See all standards correlations for Human Physiology with Vernier »
Included in the Lab Book
Vernier lab books include a CD with word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.