Year 1 Dental Hygiene: Heart and Circulation

Year 1 Dental Hygiene & Therapy DE7102: Biomedical Sciences - Anatomy & Physiology - The Heart and Circulation Learning Outcomes

• Students will be able to define the heart's position in the thorax.
• Students will be able to label a diagram of the heart.
• Students will be able to describe the structure of the heart wall.
• Students will be able to describe the heart's chambers.
• Students will be able to define the location and function of the heart valves.
• Students will be able to define normal blood pressure.
• Students will be able to describe blood flow through the heart.
• Students will be able to define the three main types of blood vessels and discuss their differences.
• Students will be able to describe the heart's conducting system.
• Students will be able to describe the path of oxygenated blood from the heart to the head and neck.
• Students will be able to identify and describe the major branches of the common carotid arteries.
• Students will be able to describe the pathways of veins draining into the internal jugular veins and to the heart.

Heart Structure

• Cone-shaped, hollow, muscular organ.
• Approximately 10 cm long, similar in size to a fist.
• Located obliquely in the thoracic cavity, slightly more to the left than right.

Pericardium

• Double-layered sac surrounding the heart.
• Outer sac (fibrous pericardium): composed of fibrous tissue, continuous with the great vessels, and anchored to the diaphragm. Prevents over-distension.
• Inner sac (serous pericardium): consists of a parietal layer (outer) lining the fibrous pericardium and a visceral layer (inner) adhering to the myocardium. Secretes serous fluid for smooth movement during heartbeats.

Myocardium

• Specialized cardiac muscle, unique to the heart.
• Microscopic appearance resembles a "trellis."
• Organized as a sheet of muscle rather than individual cells, allowing for coordinated contraction waves throughout the entire heart muscle.

Endocardium

• Thin, smooth, glistening membrane lining the myocardium.
• Composed of flattened epithelial cells.
• Continuous with the tunica intima (inner layer) of blood vessels.

Interior Heart Structure

• Septum: Dividing wall between the heart's chambers.
• Atrioventricular valves: Tricuspid and mitral valves controlling blood flow between atria and ventricles.
• Chordae tendineae: Strong tendinous cords connecting valve leaflets to papillary muscles, preventing valve inversion.
• Papillary muscles: Projections from the ventricular walls that anchor the chordae tendineae.
• Atrium: Receives blood from veins.
• Ventricles: Pump blood out to arteries.

Cardiac Cycle

• Atrial systole: Atria contract to pump blood into the ventricles.
• Ventricular systole: Ventricles contract, pushing blood into arteries.
• Complete cardiac diastole: All heart chambers relax to fill with blood.

Conducting System

• Sinoatrial (SA) Node: Pacemaker of the heart.
• Atrioventricular (AV) Node: Receives electrical impulses from SA node, delays the signal to permit atrial emptying.
• Atrioventricular bundle (bundle of His): Conducting fibers carrying electrical impulses from the AV node to the ventricles.
• Bundle branches: Branches of the bundle of His conveying impulses through the interventricular septum.
• Purkinje fibers: Specialized fibers distributing the impulses throughout the ventricular myocardium.

Blood Vessels

• Capillaries: Single layer of endothelial cells, forming a tube, for gas exchange.
• Arteries: Rigid, cylindrical shape, thick walls, carry oxygenated blood (except pulmonary artery).
• Veins: Not rigid, slightly flattened, thin walls, contain valves to prevent backflow, carry deoxygenated blood (except pulmonary vein).
• Arterioles: Smallest arteries, controlling blood flow into capillaries.
• Venules: Smallest veins, collecting blood from capillaries.
• Types of Arteries: Arterioles, muscular arteries, elastic arteries
• Types of Veins: Venules, veins.

Layers of Arteries and Veins

• Tunica intima: Inner layer composed of endothelial cells.
• Tunica media: Middle layer with smooth muscle cells and elastic fibers.
• Tunica adventitia: Outer layer made of connective tissue and elastic fibers.

This quiz focuses on the anatomy and physiology of the heart and circulation. It covers the heart's position, structure, chambers, valves, and the blood flow through the cardiovascular system. Students will also learn about blood pressure and the types of blood vessels involved.