LO 6

• an arterial blood supply • a capillary network • a venous drainage

vascular plexus

anastomosis (pl. anastomoses)

• Part of the arterial blood supply • Begins at the heart and carries blood from it • Arteriole: smaller diameter artery • The smaller diameter arteries + arterioles control the filling of capillaries and the arterial pressure

• Smaller diameter than an arteriole • Can supply blood to a larger area • Capillary network: present through out the body for: Exchange of O2, Metabolic waste products, CO2

• Part of the venous drainage (drains blood from an area) • Travels to the heart and carries blood to it • Larger diameter and more numerous than arteries • Have valves to prevent to prevent backflow • Venule drains the capillaries of the tissue area • Venous sinuses: blood-filled spaces between two layers of tissue • All these venous networks are connected by anastomoses. • Blood vessels may not only spread cancer but can also spread dental (or odontogenic) infection.

• Tunica externa - connective tissue layer • Tunica media- smooth muscle layer+ elastic fibers • Tunica interna : inner endothelium; lines the blood vessels

• common carotid • subclavian arteries. The origins from the heart to the head and neck of these two major arteries are different depending on the side of the body; in contrast, the other branching arteries of the head and neck are usually symmetric in their coverage.

aorta

brachiocephalic artery

• Branchless • Travels superiorly along the neck, lateral to the trachea and larynx to the superior border of the thyroid cartilage

internal and external

Before the bifurcation of the common carotid artery

• Most reliable arterial pulse • Felt when the common artery is palpated against the larynx

• The subclavian artery arises lateral to the common carotid artery. • Supplies intracranial and extracranial structures • Upper extremity ( at the arm) is its major destination

• The internal carotid artery is a division that travels superiorly in a slightly lateral position to the external carotid artery after leaving the common carotid artery • Supplies blood to the internal structures of the head • Source of the ophthalmic artery- supplies the eye, orbit, lacrimal gland and much of the forehead • Covered by the large SCM on each side

• Begins at the superior border of the thyroid cartilage • Arises from the common carotid artery • Travels superiorly in a medial position to the internal carotid artery • Supplies the extracranial tissue of the head and neck, including the oral cavity. • Has four sets of branches - Anterior (3), Medial (1), Posterior (2), Terminal Branches (2)

• Superior thyroid • Lingual/sublingual • Facial

4 Branches: 1. infrahyoid 2. SCM 3. superior laryngeal 4. cricothyroid These branches supply the tissue inferior to the hyoid bone including: 1. the infrahyoid muscles 2. sternocleidomastoid muscle 3. muscles of the larynx 4. thyroid gland.

• branches off the external carotid artery below the facial artery • supplies the tissue superior to the hyoid bone including the • suprahyoid muscles and floor of the mouth (FOM) • well-developed blood supply to the tongue • Ends in 3 branches: dorsal lingual artery, deep lingual artery, sublingual artery

• dorsal lingual artery- deep posterior part of the tongue • deep lingual artery-deep anterior part of the tongue • sublingual artery-mylohyoid muscle / ventral surface of the tongue / FOM • Some sources suggest there are 2 more branches: the suprahyoid and the tonsillary branches

• serves components of the face; final anterior branch • ascends the side of the neck • runs deep to the submandibular gland to supply the gland • crosses the lower border of the mandible just in front of the angle of the mandible • From the inferior border of the mandible, the facial artery runs anteriorly and superiorly near the angle of the mouth and along the side of the nose. • terminates at the medial canthus.

• angular • superior labial • inferior labial • ascending palatine • submental • glandular branches

• first branch off the facial artery • supplies the soft palate, palatine muscles, and • palatine tonsils • can be the source of serious blood loss or hemorrhage if it is injured during a tonsillectomy