Blood Flow: Heart and Vasculature

You are out for a run around campus on a cold winter day. With every step, you feel your heart pounding and see your cold breath in the air. As you end your run and enter the warmth of your home, your heart rate slows, and blood rushes to your face. You ask yourself: “why is that? How is that?” In this chapter, we will tackle these questions. This will help you understand how the body regulates heart rate and cardiac output depending on its needs. This regulation will help you understand why when entering the warm house, the veins and arteries in your face dilate and blood rushes to your cheeks, but when outside in the cold, this vasculature constricts to reduce blood flow to the skin and minimize heat loss. We will learn how resistance in the vasculature is controlled and how it affects blood flow. Readers will also learn the structure of the heart and how it uses electrical impulses and its compartments to pump blood to the far extremities of the human body. Finally, we will learn how blood returns to the heart to be pumped again and its journey along the way.

Here is a list of subchapters that will direct you to the corresponding page:

1. Heart Anatomy and Blood Flow 
2. Cardiac Action Potentials 
3.  The Pressure/Volume Loop & Cardiac Output
4. Cardiac Regulation 
5. Vasculature 
6. Fluid Flux and the Lymphatic System
7. Sensors 
8. Chapter Review

Blood Flow: Heart and Vasculature Podcast

The podcast and paired transcript for this chapter is another resource you can use when studying for exams. The podcast will not go as in-depth as the next several sections, but it will summarize the key concepts and provide some useful insight. The harder concepts, such as the Frank-Starling Mechanism, will be discussed and will promote greater understanding. The podcast is set up to resemble a discussion as it is often helpful to go over the concepts with your peers. You may even find it beneficial to your learning to discuss the podcast with a friend. Try listening to the podcast on your way to school or as you make yourself dinner!

The following list of hyperlinks will take you to each of the topics discussed in the podcast:

1. Cardiac Compartments and Relationships
2. Breakdown of how Compartmentalize Vasculature
3. Pathway of Blood Flow and Tips to Remember
4. Cardiac Action Potentials
5. Connections Between Contractile and Electrical System of Heart
6. Pressure-Volume Loop
7. Important Terms that Relate to the Heart
8. Key Equations
9. Introduction to Cardiac Regulation
10. Factors that Change Heart Rate
11. Brief Explanation of Atrial Reflex
12. Stroke Volume Regulating Factors
13. Example of Increased Stroke Volume
14. Example of Increased Contractility and Increasing Stroke Volume
15. Neuronal versus Hormonal Control
16. Frank-Starling Mechanism and Staircase Phenomenon
17. Vasculature Radius
18. Compliance and Resistance of Blood Vessels
19. Flow Equation and Example
20. Vasodilation and Vasoconstriction in the Flow Equation
21. Introduction to Fluid Flux and Sensors
22. Filtration and Absorption
23. Starling’s Law
24. Sensors (Chemoreceptors and Baroreceptors)
25. Clinical Example of AED (Automated External Defibrillator)
26. Molecular Mechanisms to Increase Heart Rate During Stress
27. How a Drop in Mean Arterial Pressure Influences Pressures