Cardiovascular Physiology Overview

Overview of Cardiovascular Physiology

• Definition: Study of the heart, blood vessels, and blood flow, focusing on how these components function to support bodily needs.

Components of the Cardiovascular System

1. Heart: Central organ that pumps blood.

   • Chambers:
     • Right Atrium
     • Right Ventricle
     • Left Atrium
     • Left Ventricle
   • Valves: Prevent backflow (tricuspid, pulmonary, mitral, aortic).

2. Blood Vessels:

   • Arteries: Carry oxygenated blood away from the heart (exception: pulmonary arteries).
   • Veins: Return deoxygenated blood to the heart (exception: pulmonary veins).
   • Capillaries: Microscopic vessels where gas, nutrient, and waste exchange occurs.

3. Blood: Composed of plasma, red blood cells, white blood cells, and platelets.

Blood Flow Pathway

• Systemic Circulation:
  • Left ventricle → Aorta → Arteries → Arterioles → Capillaries (tissue exchange) → Venules → Veins → Superior/Inferior Vena Cava → Right atrium.
• Pulmonary Circulation:
  • Right ventricle → Pulmonary arteries → Lungs → Pulmonary veins → Left atrium.

Cardiac Cycle

• Composed of:
  • Systole: Contraction phase; blood ejected from heart.
  • Diastole: Relaxation phase; heart fills with blood.

Electrical Conduction System

• Sinoatrial (SA) Node: Primary pacemaker, initiates heartbeat.
• Atrioventricular (AV) Node: Delays impulse before it reaches ventricles.
• Bundle of His & Purkinje Fibers: Distribute electrical impulses throughout ventricles.

Regulation of Heart Rate

• Influenced by:
  • Autonomic Nervous System: Sympathetic (increases heart rate) and parasympathetic (decreases heart rate).
  • Hormones: Adrenaline (increases heart rate), thyroid hormones.
  • Physical Activity: Increases demand for oxygen, raises heart rate accordingly.

Cardiac Output (CO)

• Definition: Volume of blood pumped by the heart per minute.
• Calculation: CO = Stroke Volume (SV) × Heart Rate (HR).

Blood Pressure

• Measurement of force exerted by circulating blood on the walls of blood vessels.
• Components:
  • Systolic Pressure: Pressure during heart contraction.
  • Diastolic Pressure: Pressure during heart relaxation.
• Regulation: Baroreceptors monitor and adjust blood pressure via nervous and hormonal mechanisms.

Important Concepts

• Stroke Volume: Amount of blood ejected by the heart in one beat.
• Cardiac Output: Critical for ensuring adequate tissue perfusion.
• Homeostasis: Cardiovascular system plays a key role in maintaining stable internal conditions.
• Pathophysiology: Understanding normal cardiovascular function helps identify disease states (hypertension, heart failure, arrhythmias).

Pathologies

• Common disorders related to cardiovascular physiology:
  • Hypertension: Elevated blood pressure.
  • Atherosclerosis: Thickening of arterial walls due to plaque buildup.
  • Heart Failure: Inability of the heart to maintain adequate blood flow.
  • Arrhythmias: Irregular heartbeats due to conduction system malfunctions.

Cardiovascular Physiology

• The study of the heart, blood vessels, and blood flow, focusing on how these components function to support bodily needs.

Components of the Cardiovascular System

• Heart: Central organ that pumps blood.
  • Chambers: Right Atrium, Right Ventricle, Left Atrium, Left Ventricle.
  • Valves: Prevent backflow (tricuspid, pulmonary, mitral, aortic).
• Blood Vessels:
  • Arteries: Carry oxygenated blood away from the heart (exception: pulmonary arteries).
  • Veins: Return deoxygenated blood to the heart (exception: pulmonary veins).
  • Capillaries: Microscopic vessels where gas, nutrient, and waste exchange occurs.
• Blood: Composed of plasma, red blood cells, white blood cells, and platelets.

Blood Flow Pathway

• Systemic Circulation:
  • Begins in the left ventricle, blood flows through the aorta and then through a network of arteries, arterioles, and capillaries for tissue exchange. It then returns through venules, veins, and the superior/inferior vena cava to the right atrium.
• Pulmonary Circulation:
  • Begins in the right ventricle, blood flows through the pulmonary arteries to the lungs, where it picks up oxygen. Oxygenated blood returns through the pulmonary veins to the left atrium.

Cardiac Cycle

• Composed of two phases:
  • Systole: Contraction phase where blood is ejected from the heart.
  • Diastole: Relaxation phase where the heart fills with blood.

Electrical Conduction System

• Sinoatrial (SA) Node: Primary pacemaker that initiates the heartbeat.
• Atrioventricular (AV) Node: Delays the electrical impulse before it reaches the ventricles, allowing the atria to contract completely before the ventricles.
• Bundle of His & Purkinje Fibers: Distribute electrical impulses throughout the ventricles, ensuring coordinated contraction.

Regulation of Heart Rate

• Influenced by:
  • Autonomic Nervous System: Sympathetic (increases heart rate) and parasympathetic (decreases heart rate).
  • Hormones: Adrenaline (increases heart rate) and thyroid hormones.
  • Physical Activity: Increases demand for oxygen, leading to a rise in heart rate.

Cardiac Output (CO)

• Definition: Volume of blood pumped by the heart per minute.
• Calculation: CO = Stroke Volume (SV) × Heart Rate (HR).

Blood Pressure

• Measurement of the force exerted by circulating blood on the walls of blood vessels.
• Components:
  • Systolic Pressure: Pressure during heart contraction.
  • Diastolic Pressure: Pressure during heart relaxation.
• Regulation: Baroreceptors monitor and adjust blood pressure via nervous and hormonal mechanisms.

Important Concepts

• Stroke Volume: Amount of blood ejected by the heart in one beat.
• Cardiac Output: Critical for ensuring adequate tissue perfusion.
• Homeostasis: Cardiovascular system plays a key role in maintaining stable internal conditions.
• Pathophysiology: Understanding normal cardiovascular function helps identify disease states like hypertension, heart failure, and arrhythmias.

Pathologies

• Common disorders related to cardiovascular physiology:
  • Hypertension: Elevated blood pressure.
  • Atherosclerosis: Thickening of arterial walls due to plaque buildup.
  • Heart Failure: Inability of the heart to maintain adequate blood flow.
  • Arrhythmias: Irregular heartbeats due to conduction system malfunctions.

This quiz explores the fundamentals of cardiovascular physiology, including the structure and function of the heart, blood vessels, and blood components. It will test your understanding of the blood flow pathway and the roles of arteries, veins, and capillaries in the circulatory system.