cardiac notch

(noun)

A concave impression molded into the left lung to accommodate the shape of the heart.

Related Terms

  • hilium
  • two chambers
  • Right Lung
  • Left Lung

Examples of cardiac notch in the following topics:

  • Lobes, Fissures, and Lobules

    • The left lung has a depression on the medial side of its surface called the cardiac notch, a concave impression molded to accommodate the shape of the heart.
    • Above and behind the cardiac impression is a triangular depression named the hilum.
    • The hilium is thinner in the left lung compared to the right lung because it lies between the cardiac notch and the groove for the aorta.
    • This has a concave depression that accommodates the shape of the heart, called the cardiac notch.
  • Lungs

    • The right lung is larger than the left lung, and the left lung contains the cardiac notch, a concave impression that the heart lies against.
  • Ulna and Radius (The Forearm)

    • The cornoid process, together with the olecranon, forms the trochlear notch where it articulates with the trochlea of the humerus.
    • Laterally to the trochlear notch lies the radial notch, which articulates with the head of the radius to form the proximal radioulnar joint.
    • Proximally, the radius terminates with a disk-shaped head that articulates with the capitulum of the humerus and the radial notch of the ulna.
    • Distally the radius expands, medially the ulnar notch articulates with the head of the ulnar.
    • Immediately adjacent to the ulnar notch, the radius articulates with the scaphoid and lunate carpal bones to form part of the wrist.
  • Cardiac Cycle

    • The cardiac cycle describes the heart's phases of contraction and relaxation that drive blood flow throughout the body.
    • Heart rate is a term used to describe the frequency of the cardiac cycle.
    • Every single heartbeat includes three major stages: atrial systole, ventricular systole, and complete cardiac diastole.
    • Complete cardiac diastole occurs after systole.
    • Blood pressure is a regulated variable that is directly related to blood volume, based on cardiac output during the cardiac cycle.
  • Types of Muscle Tissue

    • The function of muscles is movement, but the types of movement elicited differ between skeletal, cardiac, and smooth muscle.
    • There are three kinds of muscle tissue: skeletal, smooth, and cardiac.
    • Cardiac muscle is found in the walls of the heart.
    • Although cardiac muscle is involuntary in nature, it is structurally different from smooth muscle.
    • Cardiac muscle is striated, similar to skeletal muscle, but beats involuntarily.
  • Ischium

    • Two indentations run parallel to the spine—superiorly ,the greater sciatic notch and, inferiorly, the lesser sciatic notch, through which key nervous and vascular vessels pass.
  • Characteristics of Muscle Tissue

    • The three types of muscle tissue are skeletal, smooth, and cardiac.
    • Cardiac muscle tissue is found only in the heart where cardiac contractions pump blood throughout the body and maintain blood pressure.
    • Cardiac muscle can be further differentiated from skeletal muscle by the presence of intercalated discs which control the synchronized contraction of cardiac tissues.
    • Both cardiac and smooth muscle are involuntary while skeletal muscle is voluntary.
    • Differentiate among the structure and location of skeletal, smooth, and cardiac muscles
  • Microscopic Anatomy

    • Cardiac muscle appears striated due to the presence of sarcomeres, the highly-organized basic functional unit of muscle tissue.
    • Cardiac muscle, like skeletal muscle, appears striated due to the organization of muscle tissue into sarcomeres.
    • While similar to skeletal muscle, cardiac muscle is different in a few ways.
    • Cardiac muscles are composed of tubular cardiomyocytes, or cardiac muscle cells.
    • A sarcomere is the basic unit of muscle tissue in both cardiac and skeletal muscle.
  • Mechanism and Contraction Events of Cardiac Muscle Fibers

    • Cardiac muscle fibers undergo coordinated contraction via calcium-induced calcium release conducted through the intercalated discs.
    • In cardiac, skeletal, and some smooth muscle tissue, contraction occurs through a phenomenon known as excitation contraction coupling (ECC).
    • Similarly to skeletal muscle, the influx of sodium ions causes an initial depolarization; however, in cardiac muscle, the influx of calcium ions sustains the depolarization so that it lasts longer.
    • The actual mechanical contraction response in cardiac muscle occurs via the sliding filament model of contraction.
    • Calcium in the cytoplasm then binds to cardiac troponin-C, which moves the troponin complex away from the actin binding site.
  • Anatomy of the Heart

    • The heart is an organ responsible for pumping blood through the blood vessels using rhythmic contractions of cardiac muscle.
    • The heart has its own self-sustaining conduction system that sends nervous  impulses to cardiac tissue.
    • The middle layer of the heart, the myocardium, and contains specialized cardiac muscle tissue responsible for contraction.
    • Cardiac tissue is permanent tissue that does not heal or regenerate when damaged.
    • The position of valves ensures proper directional flow of blood through the cardiac interior.
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