New A & P 2 Lecture (Bio 2320)-20250305_110418-Meeting Recording

Overview of Cardiac Physiology

• Complexity of Material: Understanding heart physiology requires careful examination of images and concepts discussed in class.

• Resources and Office Hours: Encourage students to utilize office hours for clarification on complex topics, with specific persons mentioned (Dmitry and Katherine).

Recommended Study Materials

• Physiology Coloring Book: Emphasizes the complexity of physiology compared to anatomy. Students can opt to submit these coloring pages instead of standard pages from the anatomy coloring book.

Upcoming Lab Session

• Focus on Lower Body Vessels: The complexity of lower body vessels is significant; students are advised to prepare in advance for next week’s lab.

Questions and Clarifications

• Understanding Action Potential Transmission: Discusses how epinephrine and norepinephrine affect the SA node’s depolarization and the sympathetic nervous system's influence on heart rate.

• Calcium Role in Depolarization: Highlights that calcium is crucial for SA node activity, while potassium plays a role in repolarization.

Chapter Review Goals

• Finish Chapter 20: An objective to complete discussions around key cardiac cycles and EKG readings before moving on to Chapter 21.

• Cardiac Cycle Events: Understanding the significance of the P wave, QRS complex, and T wave.

Electrical Events of the Heart

• P Wave: Represents atrial depolarization, where the wave travels from the SA node to the AV node—contraction aligns with this segment.

• QRS Complex: Indicates ventricular depolarization and the simultaneous repolarization of the atria.

• ST Segment: No electrical activity occurs; the ventricles are in contraction but no voltage change present.

• T Wave: Indicates ventricular repolarization.

Cardiac Cycle Phases

• Isovolumetric Contraction: Initial contraction phase following the QRS complex where blood volume remains constant.

• Ejection Phase: Ventricles contract, generating pressure to eject blood into the aorta and pulmonary trunk.

• End Systolic Volume: Volume remaining in the ventricles post-contraction (about 50-60 milliliters).

• Isovolumetric Relaxation: Phase post-ejection where the heart muscle is relaxing, and all valves are closed.

• Passive Ventricular Filling: Blood passively flows from the atria to the ventricles.

• Atrial Kick: Active portion of filling where atria contract to empty the final blood volume into the ventricles.

Heart Sounds and EKG Correlation

• Heart Sounds: Understanding turbulence associated with heart sounds is important; 1st sound (lub) occurs at AV closure & 2nd sound (dub) at semilunar valve closure.

• EKG Timing: Events are outlined in relation to EKG phases, highlighting transitions from depolarization to contraction and relaxation states.

EKG Abnormalities and Clinical Relevance

• Ectopic Action Potential: Discuss consequences of neurons firing from atypical locations—can arise from injury or inflammation.

• Common EKG Signs: Larger P waves may indicate atrial enlargement; larger Q waves signify a potential myocardial infarction.

• Potassium Levels: Noting the significance of hyperkalemia and hypokalemia in relation to cardiac health.

Conclusion and Future Topics

• Next Class: Will advance into the next chapter whereas further exploration of cardiac regulatory mechanisms occurs. The importance of linking these physiological concepts within a clinical context is emphasized.