1. Chapter 6: Vascular Supply

2. Blood Distribution
60% of blood volume at rest is in systemic veins and venules
function as blood reservoir
blood is diverted from it in times of need
increased muscular activity produces venoconstriction
hemorrhage causes
venoconstriction to help maintain
blood pressure
15% of blood volume in arteries & arterioles

3. Cardiovascular System
Blood vessels: Types
A. Arteries
-carry blood away from heart
-thicker than veins
-three layers: inner endothelium
middle smooth muscle
outer connective tissue
-arteriole = small artery
B. Veins
-carry blood toward heart
-same three layers as arteries
(less SM and connective tissue)
-thinner and more expansive than
arteries
-contain valves - to help the flow
of blood back to heart
-small vein = venule
C. Capillaries
-site of gas exchange with tissues
-connect arterioles and venules
-network of microscopic vessels
(one cell thick) = capillary bed
-site of exchange: gases, nutrients,
wastes
-can be closed off when not needed

4. Arteries Tunica interna (intima) Tunica media Tunica externa
simple squamous epithelium known as endothelium
basement membrane
internal elastic lamina
Tunica media
circular smooth muscle & elastic fibers
smooth muscle is innervated by sympathetic nervous system
decrease in stimulation or presence of certain chemicals causes vasodilation
increases diameter of vessel
nitric oxide, K+, H+ and lactic acid cause vasodilation
increase in stimulation causes muscle contraction or vasoconstriction
decreases diameter of vessel
Tunica externa
elastic & collagen fibers
Arteries

5. Elastic Arteries Muscular Arteries
Largest-diameter arteries have lot of elastic fibers in tunica media
Help propel blood onward despite ventricular relaxation (stretch and recoil -- pressure reservoir)
Muscular Arteries
Medium-sized arteries with more muscle than elastic fibers in tunica media
Capable of greater vasoconstriction and vasodilation to adjust rate of flow
walls are relatively thick
called distributing arteries because they direct blood flow

6. Veins Proportionally thinner walls than same diameter artery
tunica media less muscle
lack external & internal elastic lamina
Still adaptable to variations in volume & pressure
Valves are thin folds of tunica interna designed to prevent
backflow
Venous sinus has no muscle at all
coronary sinus or dural venous sinuses
are large blood-filled spaces between
two layers of tissue
e.g. dural sinus – between the two layers
of the dura mater meninges

7. Capillaries Microscopic vessels that connect arterioles to venules
Found near every cell in the body but more extensive in highly active tissue (muscles, liver, kidneys & brain)
entire capillary bed fills with blood when tissue is active
lacking in epithelia, cornea and lens of eye & cartilage
Function is exchange of nutrients & wastes between blood and tissue fluid
Structure is single layer of simple squamous epithelium and its basement membrane

8. Common Carotid -no branches as it travels up the neck
lateral to the trachea and larynx
beneath the sternocleidomastoid
wrapped in a sheath with the internal jugular and vagus nerve
ends in two divisions:
1. internal carotid
2. external carotid
just before the bifurcation – swelling = carotid sinus

9. Internal carotid
Internal carotid arteries (contribute to Circle of Willis)
lateral to the external carotid
branchless as it travels up the neck
at the base of the skull – forms the Circle
of Willis
supplies the brain
also gives off an opthalmic branch
supplies the eyes, orbits, and lacrimal gland

10. Common Carotid Branches
External carotid arteries
supplies structures external to skull as branches of maxillary and superficial temporal branches
8 branches divided into four portions:
anterior portion
ascending portion
posterior portion
terminal portion

11. External carotid 1. anterior portion: Superior thyroid Lingual
Facial (external maxillary)
2. ascending portion
Ascending pharyngeal
3. posterior portion
Occipital
Posterior auricular
4. terminal portion
superficial temporal
maxillary (internal maxillary
“Seven Little Fairies Ascended
Over Polly’s Super Mums”

12. External Carotid artery
16 – infraorbital
17 – internal maxillary
10 – descending palatine
29 – superficial temporal
9 – deep lingual (lingual)
15 – inferior labial (facial)
24 – sublingual (lingual)
20 – middle meningeal (maxillary)
28 – superficial temporal
22 – posterior auricular
2 – ascending palatine (facial)
21 – occipital
18 – lingual
11 – facial
6 – carotid, external

13. Superior thyroid Lingual
-supplies the infrahyoid region - muscles of the larynx, and the thyroid gland
-branches: infrahyoid
sternocleidomastoid
superior laryngeal
superior and inferior thyroid
Lingual
-supplies the suprahyoid region, floor of mouth and tongue
-branches: deep lingual – apex of tongue
dorsal lingual – base and body of tongue
sublingual – mylohyoid, sublingual gland, mucous membranes of mouth floor
suprahyoid - suprahyoid muscles

14. 9 – deep lingual
24 – sublingual
26 – submental
18 – lingual artery
6 – external carotid

15. Facial = external maxillary -can have a common trunk with the lingual
-runs medial to the mandible
-over the submandibular gland
-over the lateral side of the mandible
(under the platysma)
-parallels the facial vein – separated by the
posterior belly of the diagastric
-divided into cervical and facial branches
Cervical branches = supplies soft palate, roof of mouth, submandibular gland
ascending palatine – soft palate and palatine muscles
submandibular/glandular – glandular tissues
submental – submandibular lymph nodes, submandibular salivary gland, mylohyoid and diagastric
tonsillar – palate and roof of mouth
Facial branches = supplies lips, nose, facial muscles
inferior labial – lower lip and its muscles
superior labial – upper lip and its muscles
angular – side of nose, ends a medial commisure
muscular

16. Facial artery (external maxillary)
16 – infraorbital
10 – descending palatine
27 – subnasal
29 – superior labial
15 – inferior labial
26 – submental
17 – internal maxillary
14 – inferior dental
25 – submandibular gland
(glandular)

17. Ascending pharyngeal Posterior auricular
-ascending portion of external carotid
-supplies throat, ear (tympanic region), cranial meninges
-several small branches
1. palatine – may replace the ascending pharyngeal of the facial artery
2. pharyngeal – pharynx
3. meningeal – meninges
4. inferior tympanic – with the glossopharyngeal nerve, it enters the temporal
bone to supply the tympanic region
Posterior auricular
-supplies internal ear, occipatalis muscle and scalp
auricular branch – internal ear
stylomastoid branch – mastoid air cells
occipitalis branch – occipitalis muscle and scalp at back of head
-may join with the occipital artery

18. Occipital -arises near the hypoglossal cranial nerve (XII)
-travels to and supplies the posterior
scalp, muscles of back of neck, nasal conchae
-branches:
1. muscular – diagastric, stylohyoid
splenius, and long. capitis
2. meningeal – through the jugular f.
supplies the dura mater in
the posterior fossa
3. SCM – may arise directly from the EC
supplies the SCM
4. descending – largest branch, descends
along the back of the neck,
supplies the trapezius and semispinalis capitis
5. auricular – supplies the conchae and dura mater,
enters via the stylomastoid foramen

19. Superficial temporal
-supplies front of scalp, frontalis, temperoparietalis, temporalis, outer ear
1. transverse facial – runs along zygomatic arch
-supplies the parotid gland, cheek bone and masseter
2. middle temporal – runs along the zygomatic arch,
-supplies the temporalis
3. anterior auricular – supplies the outer ear structures
4. frontal – supplies the frontalis, front scalp
5. parietal – supplies muscles of the parietal region

20. Internal Maxillary -largest of the terminal branches of
the external carotid
-begins at neck of mandibular condyle
-can be divided into three portions
it arises from the EC
1. Mandibular
2. Pterygoid
3. Pterygopalatine

21. 1. Mandibular portion a. anterior tympanic
b. middle meningeal – largest branch, supplies the
dura mater, thru the foramen spinosum
c. deep auricular – branch to the TMJ, supplies the
tympanic membrane
d. accessory meningeal – thru the foramen ovale,
supplies the dura mater
e. inferior alveolar – thru the mandibular f. with the
inferior alveolar nerve, travels thru the mandibular canal
-gives off four main branches
1. myloyoid branch – branches off before it
enters the mandibular canal, supplies the floor or mouth and mylohyoid
2. lingual branch – supplies the mucus
membranes of the mouth
3. mental branch – exits thru the mental f.,
supplies the chin
4. incisive branch – divides about the first
premolar into dental and alveolar branches
-dental = pulp tissue
-alveolar = peridonteum + gingiva

22. 2. Pterygoid portion -supplies muscles
-accompanies the trigeminal cranial
nerve (V)
-branches:
deep temporal – anterior and posterior
temporalis
2. masseteric
3. pterygoid – lateral & medial pterygoid m.
4. buccinator

23. 3. Pterygopalatine portion
-branches:
posterior superior alveolar = post-dental
artery
-gives off dental and alveolar branches
-supplies the premolars and molars
-also the lining of the maxillary sinuses
b. artery of the pterygoid canal = vidian artery
-upper pharynx and auditory canal
c. infraorbital – thru the infraorbital f., supplies facial structures
-gives off an orbital branch and a superior alveolar branch (dental and alveolar branches)
d. pharyngeal – upper pharynx and auditory tube
e. sphenopalatine – thru the sphenopalatine f., enter the nasal cavity
-supplies the nasal conchae, the anterior part of the hard palate, the ethmoid, maxillary
and frontal sinuses (lateral nasal branch)
-also supplies the nasal septum (posterior septal branch)

24. -so dental and alveolar branches come from
1. the incisive branch of the inferior alveolar (mandibular portion)
2. posterior superior alveolar – pterygopalatine portion
3. anterior superior alveolar branch of the infraorbital (pterygopalatine portion)
-supplies the upper incisors & canines
-plus the maxillary sinus
-dental branches supply the pulp of the teeth
-alveolar branches supply the associated gingiva and peridontium

25. Veins of the Head and Neck
External and Internal jugular veins drain the head and neck into the superior vena cava
Dural venous sinuses empty into internal jugular vein

26. Veins of the Head and Neck
Frontal
Supraorbital
Angular
Superficial temporal
Maxillary
Posterior Facial
Posterior Auricular
Occipital
Facial - retromandibular

27. Facial Vein drains lips, tongue, chin, orbit
drains into the internal jugular
begins at the medial corner of the eye
forms from the union of supratrochlear
and supraorbital veins (drains the orbit)
-also connects with the:
-superior labial vein
-inferior labial vein
-submental vein – chin and submandibular
region
-lingual (dorsal, deep/ventral, sublingual branches)
two major branches:
retromandibular
superior thyroid
-joins with the pterygoid plexus
-union of the meningeal, posterior superior alveolar branches +
branches from the nasal region and palate
-drains the deep portions of the face & meninges

28. Retromandibular Vein
-forms from the superficial temporal and maxillary veins
-emerges from the parotid gland and travels down the neck
-below the parotid – divides into two branches
1. anterior division – drains the facial region
2. posterior division – drains the facial region,
travels down the SCM
-the posterior division is joined by the
posterior auricular vein = External Jugular

29. Superficial Temporal
-drains the lateral scalp
-joins up with the retromandibular vein
Maxillary
-drains the pterygoid plexus
-merges with the superficial temporal – into the retromandibular vein
-forms from the:
posterior superior alveolar – dental and alveolar branches (maxillary arch)
inferior alveolar – dental and alveolar branches (mandibular arch)
middle meningeal - meninges