P2

Cardiovascular System

Anatomy of the Heart

  • Size, Shape, and Location of the Heart

    • The heart is approximately the size of a fist.

    • It is shaped like a cone, with the base pointing upward and the apex pointing downward.

    • The heart is located in the mediastinum, which is the central compartment of the thoracic cavity, between the lungs and behind the sternum.

Muscle Tissue Comparisons

  • Comparison of Cardiac Muscle to Skeletal and Smooth Muscle

    • Cardiac Muscle:

      • Found only in the heart.

      • Involuntary muscle control.

      • Striated appearance due to the organized structure of myofibrils.

      • Contains intercalated discs that allow for synchronized contraction.

    • Skeletal Muscle:

      • Attached to bones and facilitates movement.

      • Voluntary muscle control.

      • Also striated, but lacks intercalated discs.

    • Smooth Muscle:

      • Found in walls of hollow organs (e.g., intestines, blood vessels).

      • Involuntary muscle control.

      • Non-striated appearance.

Cardiac Conduction System

  • Explanation of the Cardiac Conduction System

    • The cardiac conduction system consists of specialized cardiac muscle cells that initiate and conduct impulses through the heart.

    • Components include:

      • Sinoatrial (SA) Node: The natural pacemaker, located in the right atrium.

      • Atrioventricular (AV) Node: Located at the junction of the atria and ventricles; delays the impulse to allow for ventricles to fill.

      • Bundle of His: Conducts impulses from the AV node into the ventricles.

      • Purkinje Fibers: Spread the electrical impulses throughout the ventricles to trigger contraction.

Electrocardiogram (ECG or EKG)

  • Process and Purpose of an Electrocardiogram

    • An electrocardiogram is a test that records the electrical activity of the heart over a period of time.

    • It involves placing electrodes on the skin that detect the electrical impulses.

    • Purpose:

      • Diagnose arrhythmias, heart attacks, and other heart conditions.

      • Assess heart function and monitor changes over time.

Cardiac Cycle

  • Explanation of the Cardiac Cycle

    • The cardiac cycle refers to the sequence of events that occur in one heartbeat, including:

      • Systole: The phase when the heart muscle contracts and pumps blood.

      • Diastole: The phase when the heart muscle relaxes and the chambers fill with blood.

    • Typically involves the atria and ventricles contracting in a coordinated manner.

Cardiac Output

  • Calculation of Cardiac Output

    • Cardiac Output (CO) is the volume of blood pumped by the heart per minute.

    • Formula:
      (CO = Stroke Volume imes Heart Rate)

    • Where:

      • Stroke Volume: The amount of blood pumped by the left ventricle per contraction.

      • Heart Rate: The number of heartbeats per minute.

Effects of Exercise on Cardiac Output and Heart Rate

  • Description of the Effects of Exercise on Cardiac Output and Heart Rate

    • During exercise, both cardiac output and heart rate increase to meet the body's demand for oxygen and nutrients.

    • Increased stroke volume and increased heart rate contribute to higher cardiac output.

Regulation of Heart Rate

  • Centers of the Brain that Control Heart Rate

    • The cardiac centers located in the medulla oblongata regulate heart rate.

    • Sympathetic Nervous System: Increases heart rate and force of contraction during stress or exercise.

    • Parasympathetic Nervous System: Decreases heart rate during restful states.

  • Other Factors Affecting Heart Rate

    • Hormones (e.g., adrenaline), body temperature, physical fitness level, and overall health can influence heart rate.

Fetal Heart Development

  • Description of Fetal Heart Development

    • Fetal development of the heart involves several stages, beginning as a simple tube that folds and regions become distinct chambers.

    • The septation of the heart chambers occurs to separate the left and right sides, contributing to a fully functional heart.

Blood Vessels

Anatomical Structure of Arteries and Veins

  • Comparison of the Anatomical Structure of Arteries and Veins

    • Arteries:

      • Thick, muscular walls to withstand high pressure.

      • Narrow lumen compared to veins.

      • Elastic tissue to help maintain blood pressure and facilitate blood flow.

    • Veins:

      • Thinner walls compared to arteries.

      • Wider lumen to accommodate larger volumes of blood.

      • Valves present to prevent backflow of blood.

Capillary Exchange Forces

  • Description of the Forces that Account for Capillary Exchange

    • Hydrostatic Pressure: The pressure exerted by blood against the capillary walls, promoting filtration of fluid out of the capillaries.

    • Osmotic Pressure: The force exerted by proteins in the blood that pulls fluid into the capillaries, counteracting filtration.

    • Together, these forces regulate the movement of fluids, gases, and nutrients between blood and tissues.

Factors Affecting Blood Flow and Pressure

  • Major Factors Affecting Blood Flow, Blood Pressure, and Resistance

    • Blood Flow: Influenced by cardiac output and vascular resistance.

    • Blood Pressure: Product of cardiac output and total peripheral resistance.

    • Resistance: Primarily determined by vessel diameter, blood viscosity, and total vessel length.

Regulation of Blood Vessels

  • Discussion of how Neural and Endocrine Mechanisms Maintain Blood Vessels

    • Neural Mechanisms: Sympathetic stimulation causes vasoconstriction, increasing blood pressure; parasympathetic stimulation causes vasodilation, decreasing blood pressure.

    • Endocrine Mechanisms: Hormones like adrenaline and angiotensin II regulate blood vessel tone.

Interaction of the Cardiovascular System

  • Description of Interaction of the Cardiovascular System with Other Body Systems

    • The cardiovascular system interacts with the respiratory system to deliver oxygen and remove carbon dioxide.

    • It also works with the renal system to maintain fluid balance and blood pressure through filtration and reabsorption.

Major Blood Vessels

  • Labeling of Major Blood Vessels of the Pulmonary and Systemic Circulation

    • Pulmonary Circulation:

      • Pulmonary arteries carry deoxygenated blood from the heart to the lungs.

      • Pulmonary veins return oxygenated blood from the lungs to the heart.

    • Systemic Circulation:

      • Aorta carries oxygenated blood from the heart to the rest of the body.

      • Superior and inferior vena cava return deoxygenated blood to the heart.

Hepatic Portal System

  • Identification and Description of the Hepatic Portal System

    • The hepatic portal system refers to a network of veins that drain blood from the gastrointestinal tract and spleen to the liver.

    • It enables nutrient-rich blood from the digestive organs to be processed by the liver before it enters systemic circulation.

Development of Blood Vessels

  • Description of the Development of Blood Vessels and Fetal Circulation

    • Blood vessels develop through a process called angiogenesis, which involves the growth of new blood vessels from pre-existing ones.

    • Fetal circulation includes shunts (e.g., foramen ovale and ductus arteriosus) that allow blood to bypass the lungs, which are non-functional before birth.

Comparison of Fetal and Postnatal Circulation

  • Comparison of Fetal Circulation to Postnatal Circulation

    • In fetal circulation, the right ventricle pumps blood primarily to the