The Cardiovascular System: Blood Vessels – Major Arteries of the Systemic Circulation

The Cardiovascular System: Blood Vessels

Introduction to Blood Vessels

The cardiovascular system is responsible for the transport of blood throughout the body, delivering oxygen and nutrients to tissues and removing waste products. Blood vessels are classified into arteries, veins, and capillaries, each with distinct structural and functional characteristics. This section focuses on the major arteries of the systemic circulation, which carry oxygenated blood from the heart to the body.

• Arteries: Blood vessels that carry blood away from the heart under high pressure.

• Systemic Circulation: The part of the circulatory system that carries oxygenated blood from the left side of the heart to the body and returns deoxygenated blood to the right side of the heart.

Major Arteries of the Systemic Circulation

Overview of Systemic Arterial Flow

The systemic arterial system begins with the aorta, the largest artery in the body, which branches extensively to supply all body tissues. The branching pattern ensures that each region receives an adequate blood supply.

• Aorta: The main artery leaving the left ventricle of the heart, divided into the ascending aorta, aortic arch, and descending aorta (thoracic and abdominal parts).

• Branching: The aorta gives rise to major arteries that supply the head, neck, upper limbs, thorax, abdomen, pelvis, and lower limbs.

Key Arterial Branches and Their Regions

The following table summarizes the major branches of the aorta and the regions they supply:

Arterial Branch	Region Supplied
Brachiocephalic trunk	Right head, neck, and upper limb
Left common carotid artery	Left head and neck
Left subclavian artery	Left upper limb
Coronary arteries	Heart
Thoracic aorta branches	Thoracic wall and organs
Abdominal aorta branches	Abdominal organs, pelvis, and lower limbs

Arteries of the Head, Neck, and Brain

Several major arteries supply the head, neck, and brain, ensuring adequate oxygenation of these vital areas.

• Common Carotid Arteries: Each divides into internal and external carotid arteries.

• Internal Carotid Artery: Supplies the brain.

• External Carotid Artery: Supplies the face and scalp.

• Vertebral Arteries: Branch from the subclavian arteries and supply the posterior part of the brain.

• Circle of Willis: An arterial circle at the base of the brain formed by branches of the internal carotid and vertebral arteries, providing collateral circulation.

Arteries of the Upper Limbs

The upper limbs receive blood from the subclavian arteries, which continue as the axillary, brachial, radial, and ulnar arteries.

• Subclavian Artery: Becomes the axillary artery as it passes the first rib.

• Axillary Artery: Supplies the shoulder and upper arm.

• Brachial Artery: Main artery of the upper arm; divides into radial and ulnar arteries at the elbow.

• Radial and Ulnar Arteries: Supply the forearm and hand.

Arteries of the Thorax

The thoracic aorta gives off branches to the chest wall and organs.

• Intercostal Arteries: Supply the muscles and skin of the chest wall.

• Bronchial Arteries: Supply the lungs (systemic circulation).

• Esophageal Arteries: Supply the esophagus.

Arteries of the Abdomen

The abdominal aorta supplies the abdominal organs through several major branches.

• Celiac Trunk: Supplies the stomach, liver, spleen, and upper duodenum.

• Superior Mesenteric Artery: Supplies the small intestine and part of the large intestine.

• Inferior Mesenteric Artery: Supplies the distal large intestine.

• Renal Arteries: Supply the kidneys.

• Gonadal Arteries: Supply the ovaries or testes.

Arteries of the Pelvis and Lower Limbs

The abdominal aorta bifurcates into the right and left common iliac arteries, which further branch to supply the pelvis and lower limbs.

• Common Iliac Arteries: Divide into internal and external iliac arteries.

• Internal Iliac Artery: Supplies pelvic organs.

• External Iliac Artery: Continues as the femoral artery in the thigh.

• Femoral Artery: Main artery of the thigh.

• Popliteal Artery: Located behind the knee; branches into anterior and posterior tibial arteries.

• Anterior and Posterior Tibial Arteries: Supply the lower leg and foot.

Summary Table: Major Arteries and Their Regions

Artery	Region Supplied
Common carotid	Head and neck
Subclavian	Upper limb
Coronary	Heart
Renal	Kidneys
Femoral	Thigh
Popliteal	Knee
Tibial	Lower leg and foot

Key Terms and Concepts

• Artery: A blood vessel that carries blood away from the heart.

• Aorta: The largest artery in the body, originating from the left ventricle.

• Bifurcation: The division of a vessel into two branches.

• Collateral Circulation: Alternative pathways for blood flow, such as the Circle of Willis in the brain.

Example: Clinical Relevance

• Pulse Points: The radial, carotid, and femoral arteries are commonly used to assess pulse in clinical settings.

• Arterial Blockage: Blockage in major arteries (e.g., coronary or carotid) can lead to serious conditions such as heart attack or stroke.