Structures to know: Axial Blood Vessels (notes)

Blood Vessel Layers

  • Axial Blood Vessels Layers

    • Lumen: Central cavity through which blood flows.

    • Endothelium: Innermost layer of blood vessels.

    • Tunica Interna: Comprised of endothelium and subendothelial layers.

    • Tunica Media: Middle layer, containing smooth muscle and elastic tissue.

    • Tunica Externa (Adventitia): Outer layer, providing structural support and elasticity.

Differences between Arteries and Veins

  • Arteries

    • Have a thicker tunica media with more elastic tissue to withstand high pressure.

  • Veins

    • Thinner walls and larger lumen; have valves to prevent backflow.

Aortic Arteries and Their Functions

  • Ascending Aorta: Supplies blood to coronary arteries and branches out to the body.

    • Why is it thick-walled?: To withstand high pressure generated by the heart's pumping action.

  • Aortic Arch: Distributes blood to branches leading to the head, neck, and arms.

    • Branches:

      • Brachiocephalic Trunk: Supplies right arm and right side of the head.

        • Right Common Carotid: Supplies the right side of the head.

        • Right Subclavian Artery: Supplies the right upper limb.

      • Left Common Carotid Artery: Supplies the left side of the head.

      • Left Subclavian Artery: Supplies the left upper limb.

Arteries and Veins of the Head & Neck

  • Arteries

    • Common Carotid Arteries: Split into internal and external branches.

    • External Carotid Artery: Supplies the face.

    • Internal Carotid Artery: Supplies the brain.

    • Vertebral Arteries: Supply the brain (branches from subclavian arteries).

  • Veins

    • External Jugular Vein: Drains superficial structures, joins subclavian before brachiocephalic.

    • Internal Jugular Vein: Drains blood from the brain.

    • Subclavian Vein: Drains blood from the upper limb.

    • Vertebral Veins: Drain neck muscles and bones, join subclavian vein.

    • Brachiocephalic Vein: Formed by the union of internal jugular and subclavian veins.

Arteries and Veins of the Abdomen & Pelvis

  • Arteries

    • Abdominal Aorta: Major vessel supplying the abdomen.

    • Celiac Trunk: Supplies stomach, spleen, and pancreas.

      • Branches:

        • Splenic Artery: Supplies spleen.

        • Left Gastric Artery: Supplies the stomach.

        • Common Hepatic Artery: Supplies liver, stomach, duodenum, pancreas.

    • Superior Mesenteric Artery: Supplies small intestine and proximal large intestine.

    • Suprarenal Arteries: Supply adrenal glands.

    • Renal Arteries: Supply kidneys.

    • Gonadal Arteries: Supply gonads (testes/ovaries).

    • Inferior Mesenteric Artery: Supplies distal large intestine.

    • Common Iliac Arteries: Divides into internal and external iliac arteries to supply pelvis and lower limb.

  • Veins

    • Inferior Vena Cava: Major vein draining lower body, receiving:

      • Hepatic Veins: Drain liver.

      • Adrenal Veins: Drain adrenal glands.

      • Renal Veins: Drain kidneys.

      • Gonadal Veins: Drain gonads.

      • Common Iliac Veins: Include internal iliac (pelvis) and external iliac (lower limb).

Hepatic Portal System

  • Definition: A system of veins that carries blood from the digestive organs to the liver.

  • Components:

    • Hepatic Portal Vein: Main vessel of the portal system.

    • Splenic Vein: Drains spleen and joins with the inferior mesenteric vein.

    • Inferior Mesenteric Vein: Drains distal large intestine.

    • Superior Mesenteric Vein: Drains small intestine and parts of proximal large intestine.

  • Function: Allows the liver to process nutrients and detoxify substances from the first capillary bed (digestive system).