CARDIOVASCULAR 2

• Arteries and veins are composed of three essential layers

  1. tunica intima
  2. tunica media
  3. tunica adventitia
• Tunica intima: an inner layer of simple squamous epithelium, called the endothelium, that lines all arteries, veins, and

  capillaries
• Tunica media: a middle layer of concentrically oriented layers

  of smooth muscle; in large arteries (aorta), elastic lamellae are

  interspersed between the smooth muscle layers
• Tunica adventitia: an outer layer of connective tissue,

  composed primarily of collagen and a few elastic fibers
• 4 types of arteries

  1. large (elastic) arteries
  2. Medium (muscular) arteries
  3. Small arteries and arterioles
  4. Capillaries
• aorta and proximal portions of the

  subclavian and common carotid arteries

  Large (elastic) arteries
• most of the commonly “named”

  arteries in the body

  Medium (muscular) arteries
• responsible for most of the

  vascular resistance; arterioles regulate the blood flow into the

  capillary beds

  Small arteries and arterioles
• consist of only an endothelium and are function-

  ally responsible for the exchange of gases and metabolites

  between the tissues and the blood

  capillaries
• 
  

  Venules include postcapillary venules (endothelium and pericytes only) and muscular venules

  (1-2 layers of smooth muscle in the tunica media); small veins

  have two to three smooth muscle layers
• most of the commonly “named” veins in the

  body; these veins in the extremities contain valves that assist

  in the venous return against gravity

  Medium veins
• a much thicker tunica adventitia compared with

  the tunica media, and include the subclavian veins and venae

  cavae

  large veins
• Arteries supplying the head and neck region arise principally

  from the subclavian and common carotid arteries.
• Ascends through C6-C1 foramen transversarium

  and enters foramen magnum

  vertebral
• Descends parasternally to anastomose with

  superior epigastric artery

  internal thoracic
• Gives rise to inferior thyroid, transverse cervical,

  and suprascapular arteries


  thyrocervical trunk
• Gives rise to deep cervical and superior

  intercostal arteries

  costocervical trunk
• Is inconstant; may also arise from transverse

  cervical artery

  dorsal scapular
• Vertebral: provides blood to the posterior portion

  of the brain
• Costocervical trunk: its deep cervical branch supplies

  the deep lateral neck
• Thyrocervical trunk: its transverse cervical and

  inferior thyroid branches supply portions of the neck

  and the thyroid and parathyroid glands
• The common carotid artery ascends in the carotid sheath, which

  also contains the internal jugular vein and vagus nerve, and di-

  vides into the internal and external carotid branches.
• The internal carotid artery essentially does not give off any branches in the neck (it does, but they are very small and seldom mentioned), but

  does pass into the carotid canal to supply the middle and anterior of the brain
• The external carotid artery gives

  rise to eight branches that supply the neck, face, scalp, dura,

  nasal and paranasal regions, and the oral cavity.
• Supplies thyroid gland, larynx, and infrahyoid

  muscles

  Superior thyroid
• Supplies pharyngeal region, middle ear, meninges,

  and prevertebral muscles

  Ascending pharyngeal
• Passes deep to hyoglossus muscle to supply

  the tongue

  Lingual
• Courses over the mandible and supplies the face

  facial
• Supplies sternocleidomastoid muscle and

  anastomoses with costocervical trunk

  occipital
• Supplies region posterior to ear

  Posterior auricular
• Passes into infratemporal fossa

  Maxillary
• Supplies face, temporalis muscle, and lateral scalp

  Superficial temporal
• branches of the subclavian artery

  1. vertebral
  2. costocervical trunk
  3. thyrocervical trunk
• branches of the external carotid

  artery

  1. maxillary
  2. facial
  3. lingual
  4. superior thyroid
  5. superficial temporal
• The maxillary artery supplies the infratemporal region, dura mater, nasal region, and a portion of the oral cavity.
• It is the largest

  and has the most extensive distribution of the branches of the

  external carotid artery.


  maxillary artery
• arteries enter foramina of the skull or jaw and

  supply the dura, mandibular teeth and gums, ear, and chin

  Retromandibular
• branches supply the muscles of mastication and

  buccinator muscle

  Pterygoid
• branches enter foramina of the skull and

  supply maxillary teeth and gums, orbital floor, nose, paranasal

  sinuses, palate, auditory tube, and superior pharynx

  Pterygopalatine
• Inferior alveolar (to mandibular teeth and gums)