Circulatory routes

Blood Vessels and Circulatory Routes

Overview of Circulation

  • Pulmonary Circulation:

    • Definition: This process allows the blood to pick up oxygen and remove carbon dioxide in the lungs.

    • Components:

    • Superior Vena Cava: Returns deoxygenated blood from the upper parts of the body to the right atrium.

    • Inferior Vena Cava: Returns deoxygenated blood from the lower parts of the body to the right atrium.

    • Right Pulmonary Artery: Carries deoxygenated blood from the right ventricle to the right lung.

    • Pulmonary Trunk: Splits into right and left pulmonary arteries, transporting blood to the lungs.

    • Right Pulmonary Veins: Bring oxygenated blood from the right lung to the left atrium.

    • Left Pulmonary Artery: Carries deoxygenated blood from the right ventricle to the left lung.

    • Left Pulmonary Veins: Bring oxygenated blood from the left lung to the left atrium.

    • Alveoli of Right and Left Lungs: Tiny air sacs where the exchange of gases occurs.

    • Diaphragm: The muscle that facilitates breathing, influencing pulmonary circulation.

Systemic Circulation: Summary

  • Definition: The systemic circulation takes oxygenated blood from the left ventricle through the aorta to all parts of the body and returns deoxygenated blood to the right atrium.

  • Components:

    • Aorta: The major artery branching from the heart, which includes:

    • Ascending Aorta

    • Arch of Aorta

    • Thoracic Aorta

    • Abdominal Aorta

    • Arteries: Each section of the aorta provides branches that supply blood to the entire body.

    • Veins: Deoxygenated blood returns to the heart via systemic veins, and all such veins drain into either the superior vena cava or inferior vena cava or the coronary sinus, which empties into the right atrium.

Major Arteries of the Body

  • Diagram References: See Figure 17.27 for visual representation of major arteries.

  • List of Arteries:

    • Brachiocephalic Trunk

    • Common Carotid Arteries (Left and Right)

    • Subclavian Arteries (Left and Right)

    • Axillary Artery (Left and Right)

    • Brachial Artery (Right)

    • Radial Artery (Right)

    • Ulnar Artery (Right)

    • Deep and Superficial Palmar Arches (Right)

    • Common Iliac Arteries (Left and Right)

    • Femoral Artery (Left and Right)

    • Popliteal Artery (Left and Right)

    • Tibial Arteries (Anterior, Posterior, and Fibular)

    • Dorsalis Pedis (Right)

Upper Limb Arteries

  • Arteries in the Upper Limb: See Figure 17.31 for diagrams of the upper limb circulation.

  • Notable Components:

    • Subclavian Artery

    • Axillary Artery: Changes name after passing the first rib.

    • Palmar Arches: Deep and Superficial.

Circle of Willis

  • Description: An arterial circle at the base of the brain that provides blood supply.

    • Components:

    • Anterior Cerebral Arteries (2)

    • Anterior Communicating Artery (1)

    • Posterior Cerebral Arteries (2)

    • Posterior Communicating Arteries (2)

    • Function: Anastomoses — providing collateral circulation.

Thoracic and Abdominal Aorta

  • Thoracic Aorta: Extends from T5 to T12, supplying blood to the thorax.

    • Branches:

    • Internal Thoracic Artery

    • Bronchial Arteries

    • Esophageal Arteries

    • Pericardial Arteries

  • Abdominal Aorta: Major artery supplying blood to the abdomen and lower body.

    • Branches:

    • Celiac Trunk

    • Superior Mesenteric Artery

    • Inferior Mesenteric Artery

    • Renal Arteries

    • Common Iliac Arteries

    • Terminal Segments: Middle Sacral Artery.

Systemic Veins

  • Function: Return blood to the heart, working in opposition to arteries.

  • Overview of Veins:

    • Major Veins:

    • Superior Vena Cava

    • Inferior Vena Cava

    • Brachiocephalic Vein (Right and Left)

    • Jugular Veins (Internal and External)

    • Hepatic Portal System: Returns blood from the gastrointestinal tract to the liver.

Checking Circulation

  • Pulse:

    • Definition: The alternate expansion and elastic recoil of an artery with each heartbeat.

    • Normal Pulse Rate: Approximately 75 beats per minute.

    • Tachycardia: Fast heart rate, over 100 beats per minute.

    • Bradycardia: Slow heart rate, less than 50 beats per minute.

  • Blood Pressure:

    • Definition: The pressure exerted by blood on the walls of arteries during cardiac cycles.

    • Systolic Blood Pressure (SBP): Force of blood during ventricular contraction.

    • Diastolic Blood Pressure (DBP): Force of blood during ventricular relaxation.

    • Normal Blood Pressure: For a young adult male, it is less than 120/80 mmHg.