BIOS 255 Week 2 Cardiovascular System: Heart

Student Name

Chamberlain University

BIOS-255: Anatomy & Physiology III with Lab

Prof. Name:

Date

Learning Outcomes of the Cardiovascular System: Heart

Identify the Chambers of the Heart
Gain an understanding of the structure of the heart, focusing on its four chambers: the right atrium, right ventricle, left atrium, and left ventricle.
Understand the Location and Function of Valves
Explore the heart’s valves, including the tricuspid, pulmonary, mitral, and aortic valves, to understand their roles in directing blood flow.
Describe Blood Flow Through the Heart
Analyze the sequential flow of blood through the superior vena cava, heart chambers, valves, lungs, and back to the systemic circulation.
Define Stroke Volume and Cardiac Output
Learn the concepts of stroke volume (SV) as the volume of blood ejected per contraction and cardiac output (CO) as the total blood volume pumped per minute.
Understand Cardiovascular Response to Exercise
Examine how exercise increases the workload on the cardiovascular system, enhancing the demand for oxygenated blood.
Learn Measurements of Cardiac Output and Blood Pressure
Study the methodologies for assessing cardiac output and blood pressure and their significance during rest and exercise.

Introduction

The heart is a robust, muscular organ responsible for sustaining life by circulating blood through two complementary systems: the systemic and pulmonary circulations. This circulation ensures the delivery of oxygen and nutrients to cells while removing waste products. The heart’s structure comprises specialized cardiac muscle cells capable of intrinsic rhythmic contraction, essential for continuous pumping.

During exercise or tissue repair, cells demand increased oxygen, leading to heightened cardiac workload. Conversely, during rest, reduced metabolic activity decreases the heart’s exertion. Cardiac output, defined as the blood flow rate from the left ventricle, adjusts dynamically to meet cellular demands. This lab focuses on understanding the variables influencing cardiac output, measuring them, and analyzing the heart’s responses under varying workloads.

Table: Key Components of the Cardiovascular System

Component	Description	Relevance to Lab
Chambers & Valves	Four chambers: right/left atria and ventricles; valves ensure unidirectional blood flow.	Explains blood flow dynamics and how structural issues may impair circulation.
Blood Flow Pathway	Superior vena cava → Right atrium → Tricuspid valve → Right ventricle → Pulmonary valve → Lungs → Left atrium → Mitral valve → Left ventricle → Aortic valve → Aorta.	Tracks systemic and pulmonary circulation pathways.
Cardiac Variables	Stroke Volume (SV): Blood ejected per contraction. Cardiac Output (CO): Blood ejected per minute (CO = HR × SV).	Explains the physiological adjustments during exercise and provides measures for evaluating cardiac health.

Lab Activities Overview

1. Purpose

The lab aimed to understand the interplay between the cardiovascular and respiratory systems during exercise, focusing on how cardiac output, heart rate, and blood pressure respond to increased physical activity.

2. Procedure

Participants analyzed cardiovascular parameters at rest and during exercise using tools like a sphygmomanometer for blood pressure and Doppler ultrasound for heart rate, stroke volume, and cardiac output. Data was recorded under conditions ranging from rest to 125 watts of exercise.

3. Data Summary

The following table highlights the data collected:

Variable	Rest	Max Exercise (125 watts)
Subject A (HR, bpm)	60	150
Subject E (HR, bpm)	80	200
Stroke Volume (ml)	Subject A: 70 (rest), 120 (exercise)	Subject E: 40 (rest), 35 (exercise)
Cardiac Output (L/min)	Subject A: 4.2 (rest), 18 (exercise)	Subject E: 3.2 (rest), 7.0 (exercise)

4. Key Questions and Answers

Blood Flow Pathway: Blood flows from the superior vena cava into the right atrium, through the tricuspid valve into the right ventricle, and exits via the pulmonary valve to the lungs. Oxygenated blood returns to the left atrium, passes through the mitral valve into the left ventricle, and exits through the aortic valve to the body.
Stroke Volume: Defined as the volume of blood pumped out by a ventricle per contraction.
Cardiac Output: Calculated as CO = HR × SV.

5. Discussion

The comparative analysis indicated that Subject A demonstrated healthier cardiovascular performance compared to Subject E, whose low stroke volume and cardiac output hinted at possible aortic valve regurgitation.

Reflection
- Gained insights into interpreting normal cardiac parameters (e.g., HR: 60–70 bpm, SV: ~70 ml/beat, CO: ~5 L/min).
- Developed an understanding of Doppler ultrasound principles and their applications in measuring cardiovascular dynamics.

References

American Heart Association. (2023). Understanding heart rate, stroke volume, and cardiac output. Retrieved from www.heart.org

Tortora, G. J., & Derrickson, B. (2021). Principles of Anatomy and Physiology (16th ed.). Wiley.