The Cardiovascular System: Blood Vessels – Major Arteries of 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.

• Arteries: Vessels that carry blood away from the heart, typically oxygenated except for pulmonary arteries.

• Veins: Vessels that carry blood toward the heart, typically deoxygenated except for pulmonary veins.

• Capillaries: Microscopic vessels where exchange of gases, nutrients, and waste occurs between blood and tissues.

Key Point: The highest blood pressure is found in the aorta, while the lowest is in the veins. Veins contain valves to prevent backflow of blood.

Major Arteries of the Systemic Circulation

Overview of Systemic Arteries

Systemic arteries distribute oxygenated blood from the left ventricle of the heart to all body tissues. The aorta is the main artery, branching into smaller arteries that supply specific regions.

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

• Branches: Includes the brachiocephalic trunk, left common carotid artery, and left subclavian artery.

• Arterial Pressure: Highest in the aorta, decreases as blood moves through the arterial system.

Flowchart of Major Arteries

The systemic arterial system can be visualized as a branching network from the aorta to various regions:

Main Artery	Branches	Supplied Regions
Aorta	Brachiocephalic trunk, Left common carotid, Left subclavian	Head, neck, upper limbs
Thoracic aorta	Intercostal arteries, bronchial arteries	Chest wall, lungs
Abdominal aorta	Celiac trunk, superior mesenteric, renal, inferior mesenteric	Abdominal organs
Common iliac arteries	Internal iliac, external iliac	Pelvis, lower limbs

Major Arteries of the Systemic Circulation (Body Map)

The body map highlights the main arteries and their distribution:

• Head and Neck: Common carotid arteries, vertebral arteries

• Upper Limbs: Subclavian, axillary, brachial, radial, ulnar arteries

• Thorax: Intercostal arteries, internal thoracic arteries

• Abdomen: Celiac trunk, superior/inferior mesenteric arteries, renal arteries

• Lower Limbs: Femoral, popliteal, anterior/posterior tibial arteries

Example: The femoral artery supplies blood to the thigh and lower leg, while the brachial artery is the main vessel of the upper arm.

Arteries of the Head, Neck, and Brain

Key Arteries Supplying the Brain and Head

The head, neck, and brain receive blood from several major arteries branching from the aortic arch and subclavian arteries.

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

• Internal Carotid Artery: Supplies the brain, enters the skull through the carotid canal.

• External Carotid Artery: Supplies face, scalp, and neck structures.

• Vertebral Arteries: Ascend through the transverse foramina of cervical vertebrae, join to form the basilar artery, which supplies the posterior brain.

• Cerebral Arteries: Anterior, middle, and posterior cerebral arteries supply different regions 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.

Summary Table: Arteries of the Head, Neck, and Brain

Artery	Origin	Supplied Region
Common carotid	Aortic arch (left), brachiocephalic trunk (right)	Head and neck
Internal carotid	Common carotid	Brain
External carotid	Common carotid	Face, scalp, neck
Vertebral	Subclavian	Posterior brain
Basilar	Vertebral arteries	Brainstem, cerebellum

Additional info: The Circle of Willis is crucial for maintaining cerebral perfusion even if one major artery is blocked.