Anatomy of the Heart and Blood Vessels

Circulatory System Overview

Major Blood Vessels

  • Superior Vena Cava

    • Definition: Major vein returning deoxygenated blood from the upper body to the heart.

    • Important Note: The word "vena" is Latin for "vein."

  • Inferior Vena Cava

    • Definition: Major vein returning deoxygenated blood from the lower body to the heart.

    • Function: Drains everything below the heart (lower extremities).

Blood Flow Direction

  • Superior Vena Cava

    • Arrow direction: Point downwards.

    • Reason: Brings blood back to the heart.

  • Inferior Vena Cava

    • Arrow direction: Point upwards.

    • Reason: Brings blood back to the heart.

Heart Chambers and Their Structures

  • Atria

    • Definition: Chambers that receive blood.

    • Right Auricle: Structure associated with the right atrium, bumpy appearance on models.

    • Left Auricle: Structure associated with the left atrium, similar in appearance to the right.

  • Auricles

    • Function: They form the walls of the atria and can expand as needed.

    • Expansion Consequence: Increases the atrial size to alleviate pressure during high blood flow.

    • Comparison: Described as opening spare bedrooms to alleviate pressure in a crowded house.

Ventricles and Their Structures

  • Ventricles

    • Definition: Chambers that pump blood out of the heart.

    • Left Ventricle: Important for systemic circulation; has thicker walls.

    • Right Ventricle: Pumps blood to the lungs via pulmonary arteries.

  • Myocardium

    • Definition: The muscle tissue found within the ventricles.

    • Specificity: Must specify left or right ventricular myocardium when discussing tissue.

Important Blood Vessels

  • Pulmonary Trunk

    • Definition: Major vessel carrying deoxygenated blood from the right ventricle to the lungs, does not include the words "artery" or "vein" in its name.

  • Right and Left Pulmonary Arteries

    • Function: Carry deoxygenated blood towards the lungs.

    • Reference: Arteries always carry blood away from the heart.

  • Ascending Aorta

    • Definition: Main artery carrying oxygenated blood away from the heart. Located above the heart.

  • Aortic Arch

    • Definition: The curved part of the aorta, connecting the ascending aorta to the descending aorta.

  • Descending Aorta

    • Definition: Carries oxygenated blood down towards the lower body.

  • Branches from the Aortic Arch:

    • Brachiocephalic Trunk: First branch; supplies blood to the right arm and the head and neck.

    • Left Common Carotid Artery: Second branch; supplies blood to the left side of the head and neck.

    • Left Subclavian Artery: Third branch; supplies blood to the left arm.

  • Right Common Carotid and Right Subclavian Arteries

    • Derived from: Brachiocephalic trunk; supply right side of head and right arm respectively.

Pulmonary Veins

  • Definition: Vessels returning oxygenated blood from the lungs to the heart.

  • Color Note: Pulmonary veins are red due to carrying oxygenated blood, contrary to the general blue for veins.

Additional Anatomical Features

  • Ligamentum Arteriosum

    • Definition: A remnant of the ductus arteriosus connecting the pulmonary trunk to the aortic arch postnatally.

    • Before Birth: Ductus arteriosus; facilitates blood flow in fetal circulation.

Surface Blood Vessels of the Heart

  • Right Coronary Artery

    • Position: Located beneath the right auricle; major vessel supplying blood to the right heart.

  • Circumflex Artery

    • Definition: Artery that wraps around the left side of the heart.

  • Anterior Cardiac Vein

    • Position: Located near the right coronary artery; blue vessel.

  • Right Marginal Artery

    • Position: Follows near the right coronary artery.

  • Small Cardiac Vein

    • Position: Next to the right marginal artery.

  • Great Cardiac Vein

    • Definition: Major vein running down the center of the heart.

Anatomical Terms

  • Apex of the Heart

    • Definition: The pointed end of the heart.

  • Base of the Heart

    • Definition: The wider end opposite the apex.

Internal Anatomy of the Heart

  • Fossa Ovalis

    • Definition: An oval depression in the right atrium representing a remnant of the foramen ovale from fetal development.

    • Before Birth: Foramen ovale.

  • Coronary Sinus Opening

    • Location: Located near the fossa ovalis; entrance for deoxygenated blood from heart tissue into the right atrium.

  • Pectinate Muscles

    • Definition: Muscular ridges found in the atria.

  • Trabeculae Carneae

    • Definition: Muscular ridges found within the ventricles.