cardiovascular

Course Overview

  • Overview of Week 12 (April 6-10)
    • Focus on Part Two of the Cardiovascular System following last week's Part One on blood.
    • Topics for this week include:
    • Anatomy and Physiology of the Heart
    • Anatomy and Physiology of Blood Vessels

Upcoming Exams and Lectures

  • Next Week's Schedule:
    • Tuesday: Review session for Exam 3
    • Thursday: Exam 3
    • Following week will cover the Respiratory System through a video lecture, separate from class time.
  • Structure of Remaining Weeks:
    • Week 13: Urinary and Reproductive Systems lectures
    • Practical 3 during the week of Urinary and Reproductive Systems
    • Following week, Exam 4
    • Final Exam following the units on the digestive systems and the conclusion of regular lectures.

Cardiovascular System Characteristics

  • Purpose of Blood: Transport
  • Key Components of the Cardiovascular System:
    • Heart
    • Blood Vessels
    • Blood
  • Blood Flow Dynamics:
    • Blood is constantly moving due to:
    • The pumping action of the heart
    • Blood vessels include arteries, veins, and capillaries

Heart Anatomy

General Characteristics

  • Shape:
    • Hollow, cone-shaped muscular pump
    • Average size: approximately that of a human fist (14 cm long, 9 cm wide)
  • Location:
    • Center of the chest, tilted towards the left
    • Between 2nd and 5th ribs

Structure of the Heart

  • Layers of the Heart Wall:
    • Epicardium: outermost layer
    • Myocardium: contractile muscle tissue
    • Endocardium: inner lining that contacts blood
  • Cardiac Muscle:
    • Striated muscle with intercalated discs that allow synchronized contractions
Heart Chambers
  • Four Chambers:
    • Two Atria (Right and Left)
    • Two Ventricles (Right and Left)
  • Interventricular Septum:
    • Wall separating right and left ventricles
  • Atrial Septum:
    • Wall separating right and left atria

Blood Flow Through the Heart

  • Blood Flow Dynamics:
    1. Deoxygenated blood returns to right atrium via:
    • Superior vena cava (upper body)
    • Inferior vena cava (lower body)
    1. Blood flows from right atrium to right ventricle via tricuspid valve
    2. Blood pumped from right ventricle through pulmonary valve into pulmonary artery to lungs (for oxygenation)
    3. Oxygenated blood returns to left atrium through pulmonary veins
    4. Passes from left atrium through bicuspid valve into left ventricle
    5. Blood pumped from left ventricle through aortic valve into aorta, distributing oxygenated blood to the body

Major Arteries

  • Pulmonary Artery:
    • Carries deoxygenated blood to lungs for gas exchange
  • Aorta:
    • Distributes oxygenated blood to the body

Heart Valves

  • Importance of Valves:
    • Prevent backflow of blood, ensuring unidirectional flow
  • Types of Valves:
    • Atrioventricular Valves:
    • Tricuspid Valve (Right Side)
    • Mitral (Bicuspid) Valve (Left Side)
    • Semilunar Valves:
    • Pulmonary Valve (between right ventricle and pulmonary artery)
    • Aortic Valve (between left ventricle and aorta)
  • Function of Chordae Tendineae and Papillary Muscles in maintaining valve function and preventing prolapse

Heart Physiology

Cardiac Cycle

  • Systole vs. Diastole:
    • Systole: contraction phase of heart
    • Diastole: relaxation phase
  • Heart performs a cyclical contraction and relaxation to maintain blood flow
  • Sounds of the Heart:
    • "Lub-Dub":
    • "Lub" during closure of atrioventricular valves
    • "Dub" during closure of semilunar valves

Cardiac Conduction System

  • Autorhythmic nature of the heart:
    • Self-regulated heartbeats initiated by the sinoatrial (SA) node
  • Sequence of Electrical Activation:
    • SA Node → Atrioventricular (AV) Node → Bundle of His → Purkinje Fibers
  • This pathway ensures coordinated contraction of the atria followed by the ventricles

EKG (Electrocardiogram)

  • An EKG measures the electrical activity of the heart.
  • Key Waves:
    • P Wave: Atrial depolarization
    • QRS Complex: Ventricular depolarization and atrial repolarization
    • T Wave: Ventricular repolarization

Control of Heart Rate

Autonomic Nervous System

  • Components:
    • Sympathetic Nervous System: Increases heart rate (fight or flight)
    • Parasympathetic Nervous System: Decreases heart rate (rest and digest)
  • Influence of the Vagus Nerve on heart rate regulation.

Factors Affecting Heart Rate

  • Influences from the hypothalamus on:
    • Body temperature
    • Ion concentrations (Potassium, Calcium)
  • Baroreceptors in arteries respond to blood pressure changes, modulating heart rate accordingly

Conclusion

  • Review of Cardiovascular Structure and Function
  • Preparations for the upcoming topics and final exam.