Cardiovascular System

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Function of the Cardiovascular System

  • Main Role: Transportation.

    • Blood carries oxygen, nutrients, and hormones.

    • Essential for maintaining homeostasis by supplying nutrients and removing waste (like CO2).

    • Heart acts as the pump that circulates blood.

Heart Location

  • Size of a fist, weighing about a pound.

  • Located in the medial part of the thorax, flanked by lungs.

    • Apex: Pointy end resting on diaphragm.

    • Base: Top part where vessels emerge.

Heart Chambers

  • All mammals have four chambers:

    • Atria: Receive blood; do NOT pump.

    • Ventricles: Pump blood out of the heart.

Pathway of Blood through the Heart

  1. Deoxygenated blood flows into the right atrium.

  2. Moves to the right ventricle; pumped to the lungs.

  3. Oxygenated blood returns to the left atrium.

  4. Pumped by the left ventricle to the body.

  • Definitions:

    • Oxygenated: Blood containing oxygen from lungs.

    • Deoxygenated: Blood lacking oxygen from the body.

Vessels of the Heart

  • Arteries: Carry blood away from the heart.

  • Veins: Bring blood towards the heart.

  • Key vessels:

    • Superior and inferior vena cavae (veins).

    • Pulmonary arteries (to lungs).

    • Pulmonary veins (from lungs to heart).

    • Aorta (artery to body).

Heart Valves

  • Prevent backflow of blood:

    • AV Valves: Between atria and ventricles.

      • Left: Bicuspid/mitral valve.

      • Right: Tricuspid valve.

    • Semilunar Valves: Located between ventricles and arteries; half-moon shaped.

      • Pulmonary semilunar valve

      • Aortic semilunar valve.

    • Chordae Tendineae: Anchor AV valves.

Coronary Arteries

  • Supply blood to the heart tissue.

  • Risk of Coronary Artery Disease (CAD) from plaque build-up leads to heart attacks or strokes.

Heart Rhythm Control

  • Heart coordinated by the nervous system and nodal system.

    • SA Node: Heart's pacemaker, initiates heartbeat located in the right atrium.

Cardiac Cycle

  • Events of one heartbeat:

    • Systole: Contraction phase.

    • Diastole: Relaxation phase.

    • Heart sounds: "Lub-dup" produced by valve closures (S1, S2).

Blood Pressure

  • Pressure exerted by blood on vessel walls; written as systolic over diastolic.

Blood Composition

  • Only liquid tissue in the body:

    • Contains formed elements (red/white cells and platelets) and plasma (water, electrolytes, proteins).

Important Arteries and Veins

  • Arteries: Popliteal, Carotid, Femoral, Axillary.

  • Veins: Jugular, Hepatic portal, Subclavian.