PTAS+102+Cardiovascular+Anatomy+and+Physiology+Practice+%28corrected%29+spring+2016

CARDIOVASCULAR SYSTEM NOTES

Introduction

  • Overview of the cardiovascular system and its functions.

  • Emphasis on key vessels, heart anatomy, and physiological responses.

Blood Vessels

Vessels Responsible for Oxygenated Blood

  • Aorta: Brings oxygenated blood away from the heart.

  • Other vessels mentioned:

    • Pulmonary artery

    • Pulmonary vein

    • Superior vena cava

Vessels for Nutrient and Waste Exchange

  • Capillaries: Direct exchange of nutrients and wastes with tissues.

  • Other options include:

    • Arterioles

    • Lymphatics

    • Veins

Control of Blood Flow

  • Arterioles: Regulate blood flow to specific areas based on body needs.

  • Other options include:

    • Capillaries

    • Lymphatics

    • Veins

Blood Pressure Regulation

  • Increase in blood pressure can occur due to:

    • Increased water retention

  • Other factors that might decrease blood pressure:

    • Decreased antidiuretic hormone

    • Decreased vasoconstriction of arterioles

    • Increased vasodilation of veins

Heart Anatomy

Layers of the Heart

  • Atrioventricular Valves: Derived from the endocardium.

  • Layers of the heart:

    • Epicardium

    • Myocardium

    • Pericardium

Pericardial Sac Fluid Purpose

  • Provides a frictionless environment for heart movement.

  • Other possible functions considered:

    • Immunity to infectious agents

    • Nutrients to the heart

Cardiac Cycle

Sequence of Blood Flow

  • After entering the right atrium, a red blood cell would next pass through the tricuspid valve into the right ventricle.

Systole Event

  • During systole, the bilateral ventricles are contracting.

Blood Pressure Norms

  • Normal blood pressure for an adult is 120/80 mmHg.

ECG Waves and Heart Rhythm

Atrial Depolarization on ECG

  • Represented by the P wave.

Pacemaker of the Heart

  • The Sinoatrial (SA) node acts as the pacemaker.

Pathways of Electrical Signal

  • The internodal pathway helps initiate simultaneous atrial contraction.

  • The Bundle of His delays signals to ensure atrial blood is emptied into the ventricles.

Heart's Electrical System

Slowest Innate Rate

  • Bundle of His has the slowest innate rate of conduction.

Branches from the Aorta

  • Coronary arteries are the first branches from the aorta.

Feeding the Sinoatrial Node

  • The right coronary artery is most likely responsible.

Parasympathetic Nervous System Control

  • Does not control:

    • Atrioventricular node

    • Sinoatrial node

  • Includes aspects affecting other cardiac structures.

Normal Sinus Rhythm on ECG

  • Characterized by the presence of the P wave indicating SA node activity.

Atrial Fibrillation Representation

  • Demonstrated by erratic and inconsistent P waves.

Ventricular Fibrillation Indicators

  • Also shows erratic and inconsistent P waves.

Heart Rates

  • Tachycardia defined as above 100 bpm; number example: 102 bpm.

Cardiac Output Influences

Decrease in Cardiac Output

  • Conditions such as kidney failure reduce output.

Increase in Cardiac Output (Frank-Starling Law)

  • Increased myocardial contraction force positively affects cardiac output.

Resistance to Blood Flow

  • Vessel length and lumen size are crucial factors affecting blood flow resistance.

Venous Return Methods

  • Skeletal muscle pumping is the most effective method for venous return.