MBLEx Circulatory System

Anatomy and Physiology of the Heart

• Heart Chambers:

  • Atrium (Atria): Chamber that receives blood coming into the heart. Blood is prevented from moving backwards by a valve.

    • Right Atrium: Receives incoming deoxygenated blood.

    • Left Atrium: Receives incoming oxygenated blood.

  • Ventricle (Ventricles):

    • Right Ventricle: Pumps blood to the lungs.

    • Left Ventricle: Pumps blood to the rest of the body.

• Heart Valves:

  • Functional Role: Valves open and shut to regulate the flow of blood through the heart and keep it on its unidirectional course.

  • Right Side Valves:

    • Tricuspid valve

    • Pulmonary valve

  • Left Side Valves:

    • Mitral valve

    • Aortic valve

  • Unidirectional Flow Path:         $\text{Tricuspid} \rightarrow \text{Pulmonary} \rightarrow \text{Mitral} \rightarrow \text{Aortic}$

Vascular System and Vessel Classification

• Types of Blood Vessels:

  • Arteries: Carry oxygenated blood away from the heart to body tissues.

  • Veins: Carry deoxygenated blood towards the heart, where carbon dioxide is replaced with oxygen.

  • Capillaries: Microscopic arteries/vessels where gas exchange takes place between blood vessels and tissues.

• Major Vessels:

  • Largest Artery: The largest artery in the body carries blood away from the heart.

  • Superior Vena Cava and Inferior Vena Cava: The largest veins in the body.

• Major Arteries and Pulse Points:

  • Temporal Artery / Pulse Point: Located at the temple.

  • Carotid Artery / Pulse Point: Located on both sides of the neck; supplies oxygenated blood to the brain, face, and neck.

  • Brachial Artery / Pulse Point: Located in the upper arm and inside the elbow; commonly used when taking blood pressure.

  • Radial Artery / Pulse Point: Located on the thumb side of the wrist; most commonly used location to get a pulse.

  • Femoral Artery / Pulse Point: Located in the groin and upper thigh; supplies blood to the lower extremity.

  • Popliteal Artery / Pulse Point: Located behind the knee.

  • Posterior Tibial (Posterior Tibal) Artery / Pulse Point: Located on the inside of the ankle.

  • Dorsalis Pedis (Dorsal Pedis) Artery / Pulse Point: Located on the top of the foot.

Composition and Transport Roles of Blood

• Transport Functions: Blood transports blood cells, hormones, nutrients, and waste products throughout the body.

• Cellular Components:

  • Erythrocytes (Red Blood Cells): Take oxygen from the lungs and carry it to all parts of the body, then carry carbon dioxide back to the lungs to be exhaled.

  • Leukocytes (White Blood Cells): Fight off germs and infections, including bacteria and viruses.

  • Thrombocytes (Platelets): Stick together to form blood clots to stop bleeding when a cut or injury occurs.

  • Lymphocytes: Part of the immune system that helps the body fight disease and infection.

Mechanisms of Gas Exchange

• Sites of Exchange: Exchange of oxygen and carbon dioxide occurs in the capillaries of the lungs and body tissues.

• Pulmonary Gas Exchange Process:

  1. Deoxygenated blood travels from the heart to the right lung.

  2. Carbon dioxide diffuses into the alveoli to be exhaled.

  3. Oxygen is inhaled and diffuses from the alveoli into the pulmonary capillaries.

Hemodynamics and Blood Pressure Dynamics

• Definition: Blood pressure is the force of blood pushing against the wall of arteries as the heart pumps blood around the body.

• Factors That Increase Blood Pressure:

  • Stress

  • Vasoconstriction

  • Exercise

  • Increased blood volume

  • Increased cardiac output

• Factors That Decrease Blood Pressure:

  • Relaxation

  • Vasodilation

  • Blood loss and dehydration

  • Decreased cardiac output

Effects of Massage and Bodywork on Circulation

• Circulatory Impacts:

  • Promote vasodilation and circulation

  • Enhance venous return

  • Increase local capillary blood flow

  • Activate the parasympathetic nervous system