cardiac

Introductory Remarks

  • Initial Interactions

    • Discusses casual items like bags and calendars.

    • Welcomes students to the session, hints at upcoming quizzes and exams.

Quiz and Assessment Overview

  • Next Quiz Details

    • Scheduled before midterm grades are due.

    • Focused on material learned so far, specifically including autonomic divisions.

    • Emphasizes not waiting until the last minute to complete it.

  • Exam Structure

    • One large cumulative exam worth 100 points.

    • Three quizzes and one lab exam contribute to the final grade; no midterm exam due to the unique schedule.

    • The next major exam will be after spring break, including content on the autonomic nervous system, heart, and vasculature.

Heart Anatomy and Cardiac Cycle

  • Finishing Up Heart Anatomy

    • Today's focus will be on completing heart anatomy and understanding the conduction pathways.

    • Expect to review blood flow and heart functions comprehensively.

  • Cardiac Cycle Overview

    • Defined as one complete heartbeat involving multiple phases of circulation.

    • Steps involved in the cardiac cycle:

    • Diastole: Complete relaxation of the heart, where pressure dynamics lead to blood flow.

    • Systole: Contraction of the ventricles leading to the closing of valves.

    • Step breakdown isn’t rigid; students should approach the cycle dynamically rather than symptomatically.

  • Flow of Blood through the Heart

    • Blood flows based on pressure differences and valve status (open or closed).

    • Conduction patterns involving the SA node and AV node drive heartbeat.

    • Importance of understanding terms such as systole, diastole, atrial systole, and ventricular systole.

  • AV Valves and Pressure Dynamics

    • AV valves open when atrial pressure exceeds ventricular pressure, and close during ventricular contraction.

    • Semilunar valves function similarly, providing one-way flow from the ventricles into the arteries.

Review of Cardiac Structures

  • Heart as a Pump

    • The heart is described as a muscular pump that fulfills oxygen-demanding systems.

    • Ample review of heart chambers and valves consistent with anatomical structure is emphasized.

  • Coronary Circulation

    • Concept that the heart itself requires its own blood supply, known as coronary circulation.

    • Coronary arteries branch directly from the aorta to supply oxygenated blood to heart muscle; includes the left and right coronary systems.

Importance of Coronary Arteries

  • Branches of the Left Coronary Artery

    • Descriptions of major branches, including circumflex and anterior interventricular artery.

  • Flow mechanics and arterial health

    • Discussions around the health of coronary arteries relative to lifestyle factors, emphasizing prevention of blockages (atherosclerosis).

Clinical Terms and Conditions

  • Pathophysiology

    • Atherosclerosis: Hardening/narrowing of the arteries due to lipid deposits.

    • Angina Pectoris: Chest pain due to ischemia, indicative of coronary artery blockage.

    • Myocardial Infarction: Heart attack leading to myocardial cell death due to prolonged ischemia.

Cardiac Output and Measurement

  • Definitions

    • Cardiac Output (CO) = Stroke Volume (SV) x Heart Rate (HR).

    • Stroke Volume defined as the amount of blood pumped by a ventricle per beat.

    • CO is measured in liters per minute and normal values calculated in context (e.g., HR = 75 beats/min, SV = 70 mL/beat results in CO = 5 L/min).

  • Variations of Heart Rate and Stroke Volume

    • Factors affecting stroke volume include heart size, health, and fitness levels.

    • Discussion on differing SV across populations (e.g., children versus professional athletes).

Frank-Starling Law

  • Conceptual Overview

    • Frank-Starling Mechanism: Relationship between heart muscle stretch and contraction strength.

    • Too much filling pressure can reduce stroke volume due to improper actin-myosin overlap.

    • Importance in understanding cardiovascular efficiency and patient care.

Autonomic Nervous System Influence on Heart Rate

  • Chronotropic Effects

    • Positive inotropics increase heart rate (e.g., norepinephrine, caffeine).

    • Negative inotropic effects (e.g., parasympathetic stimulation through acetylcholine, beta blockers) slow heart rates.

ECG Patterns

  • Electrocardiogram (ECG) Basics

    • Sections of normal and abnormal beats discussed, including heart block types (first-degree, second-degree, and third-degree blocks).

    • Abnormal rhythms (e.g., atrial flutter, fibrillation) described with potential physiological challenges outlined.

Conclusion and Next Steps

  • Summary of Key Terms

    • Emphasis on ensuring understanding of vessels' flow direction (away from heart for arteries) and other foundational concepts from the cardiac cycle.

  • Final Notes

    • Preparations for the upcoming quiz, encouraging revisions of lecture materials and studying of associations with larger vascular principles.