BION 326 Discussion 9.1: Cardiovascular Physiology Essay

BION 326 Discussion 9.1: Cardiovascular Physiology Essay

BION 326 Discussion 9.1: Cardiovascular Physiology Essay

BION 326 Discussion 9.1: Cardiovascular Physiology Sample Essay

Atherosclerosis is an abnormal accumulation of lipid or fatty substances and fibrous tissue in the arterial blood vessel walls lining. These substances narrow and block the coronary vessels, reducing blood flow to the myocardium. Atherosclerosis produces symptoms and complications according to the location and degree of narrowing of the arterial lumen, thrombus formation, and obstruction of blood flow to the myocardium (Jebari-Benslaiman et al., 2022). The obstruction of blood flow through the arteries is usually progressive. This causes an inadequate supply that deprives the cardiac muscle cells of oxygen for survival. Consequently, myocardial ischemia occurs, which leads to Angina pectoris.

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If the decrease in blood supply is great enough, long enough, or both, irreversible damage and death of myocardial cells or myocardial infarction results. Furthermore, significant myocardial damage may result in persistently low cardiac output. The heart fails to support the body’s need for blood, leading to heart failure (Jebari-Benslaiman et al., 2022). A decreased supply from atherosclerosis can cause the heart to stop beating, resulting in sudden cardiac death.

Stiff, non-compliant arteries caused by atherosclerosis cause increased systemic vascular resistance, which increases afterload on the left ventricle. When the left-ventricular afterload increases, the end-systolic volume increases, and stroke volume decreases. The heart is then unable to contract forcefully enough during systole to eject adequate amounts of blood into circulation (Yoo et al., 2018). This causes diminished tissue perfusion, and blood accumulates in the pulmonary vessels. Diastolic heart failure occurs when the left ventricle cannot relax adequately during diastole. Inadequate relaxation prevents the ventricle from filling with sufficient blood to ensure an adequate cardiac output. Left-sided heart failure develops, presenting symptoms of decreased cardiac output like fatigue, weakness, weak peripheral pulses, nocturia, angina, confusion, tachycardia, palpitations, pallor, and cool extremities.
References

Jebari-Benslaiman, S., Galicia-García, U., Larrea-Sebal, A., Olaetxea, J. R., Alloza, I., Vandenbroeck, K., Benito-Vicente, A., & Martín, C. (2022). Pathophysiology of Atherosclerosis. International journal of molecular sciences, 23(6), 3346. https://doi.org/10.3390/ijms23063346

Yoo, J. K., Okada, Y., Best, S. A., Parker, R. S., Hieda, M., Levine, B. D., & Fu, Q. (2018). Left ventricular remodeling and arterial afterload in older women with uncontrolled and controlled hypertension. Menopause (New York, N.Y.), 25(5), 554–562. https://doi.org/10.1097/GME.0000000000001046

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Value: 10 points

Discussion Guidelines

Initial Post

People with chronic high blood pressure often have stiff and noncompliant arteries due to atherosclerosis. In your initial post explain how this will effect the following:

Blood flow through the arteries

Left ventricular afterload

Response Post(s)

Reply to at least two of your classmates’ initial posts by Sunday.

Submission

Post your initial and follow up responses and review full grading criteria on the Discussion 9.1: Cardiovascular Physiology page.

Week 9: Cardiovascular Physiology

Welcome to Week 9. This week, we turn our attention to the cardiovascular system, with coverage of normal cardiovascular physiology this week and pathophysiology associated with the system next week.

The extensive presentation of the cardiovascular material does not directly follow that in the textbook, although much of the material is covered in the textbook (Chapters 25–28). Rather, it follows a logical flow of content from heart morphology and structural information to blood flow throughout the body. The electrical activity of the heart is also presented. You should pay attention to the pathway of movement of the electrical signal, as well as the time course of movement of the signal.

In terms of heart performance, we will cover various aspects of cardiac mechanics, including examining the determinants of cardiac output. Since venous return is one determinant of cardiac performance, we will examine cardiac function curves and venous return curves. You should be aware of the blood pressures to the outflow areas and how the heart has to step up pressures above the outflow areas during the isovolumic contraction phase. Agents that affect heart performance are discussed, and you should be aware of the results of neuronal stimulation or other agents on heart function.

The coronary circulation is presented, primarily as a result of clinical problems resulting from alterations to coronary blood flow. Since EKGs or ECGs can be used to assess heart disorders, three lead EKGs are presented. In terms of the circulation, everything is about blood pressure differentials and factors, like blood vessel diameter or blood viscosity, that can alter blood flow. Arteries, capillaries, and vein morphology is briefly discussed, as are the blood flow patterns that exist in each area. Finally, the principles of control of blood flow are described.

Lesson 1: Structure and Function of the Cardiovascular System

We will cover all aspects of the cardiovascular system this week. The learning outcomes for this material directly reflect the organization scheme used in the presentations. Cardiovascular disease is the number one cause of death in the United States; therefore, to fully understand the potential ramifications of diseases, you must grasp the normal cardiovascular physiology.

Learning Outcomes

At the end of this lesson, you will be able to:
Cardiovascular Blood Flow, Output, and Blood Pressures

Describe the overall blood flow through the cardiovascular system

Understand a cardiac cycle (and a pressure-volume curve) and pulse pressures, and pressure differentials that affect blood flow in the cardiovascular system
Use a specific formula for determining cardiac output and ejection fraction

Describe a ventricular function curve, and relate the importance of venous return to the heart

Compare and contrast the pressures in the pulmonary and systemic circuits

Delineate the roles of the sympathetic and parasympathetic systems in affecting heart performance and compare these effects to those seen with ions and temperature

Coronary Circulation
Describe the coronary circulation, and the role of the coronary circulation to meet myocardial demand for oxygen

Heart Electrical Activity
Understand movement of the electrical signal through the heart, including the cells responsible for transmission of the electrical impulse and speed of conduction

Describe the basic electrical events in a EKG

Blood Flow Profiles
List the Poiseuille equation, and understand the role of resistance elements to affect blood flow

Understand transmission of the pressure pulse and how the pressure pulse pulsatility is eliminated as blood moves to the capillary beds

Arteries, Capillaries, and Veins
List the roles of arteries, capillaries, and veins, and compare and contrast their morphology

Regulation of Blood Flow
Compare and contrast local, nervous system, and humoral regulation of blood flow

Understand the role of the renal system in regulating or controlling blood flow

Before attempting to complete your learning activities for this week, review the following learning materials:

Learning Materials

Read the following in your Porth’s Pathophysiology: Concepts of Altered Health States textbook:

Chapter 25, “Structure and Function of the Cardiovascular System”

Note that the presentation materials do not follow directly from the chapter content.