Arterial supply of the head and neck Flashcards
Anastomosis
Connection between blood vessels that allows collateral circulation
3 types of anatomosis
- Between 2 arteries
- Between 2 veins
- Between an artery and a vein
Terminal/ end artery
Artery with insufficient anastomoses to maintain viability of tissues supplied if occlusion of the artery occurs
(true/anatomic) terminal/ end artery
Does not anastomose
E.g. to retina
(Functional) terminal/ end artery
Ineffectual anastomoses
E.g. in brain
Arteriovenous anastomosis
type of anastomosis btw A and V
- Blood is shunted from arterioles to venules without passing through a capillary
Where do you find arteriovenous anastomosis
- superficial arteriovenous anastomosis opens when the body reaches a high temperature and enables the body to cool itself
(for thermoregulatory purposes)
Types of blood vessels
- Arteries
- veins
- Capillaries
Arteries carry blood
away from the heart
Most arteries carry ______ blood
- Except the _________
oxygenated
- pulmonary artery
Arteries carry oxygenated blood from ______ to ______
heart
tissues
At the tissues, the oxygen and nutrient exchange is carried out by the _________
capillaries
The capillaries return the ______ blood to the veins which bring it ________
- except the _______
deoxygenated
back to the heart
- pulmonary veins
The aorta pushes _______ blood into the ______
oxygenated
arteries
4 main artery types in the body
- Large elastic arteries
- medium muscular arteries
- Arterioles and then into the
- capillaries
The capillaries consist of
one layer of endothelium and a concordant basement membrane
Capillaries are specially adapted to provide
short diffusion distances for nutrients and gaseous exchange with the tissue they supply
Capillaries are specially adapted to provide
short diffusion distances for nutrients and gaseous exchange with the tissue they supply
Arteries -> capillaries -> veins
The venous system takes ________ from capillaries and deliver it to the ______
(except _________)
In the heart, blood can be pumped _________
deoxygenated blood
heart
pulmonary vein
in the lungs to be reoxygenated
Arteries carry blood _____ from the heart
= ____________
away
distributors of blood to arterioles
Arteries server as pressure reservoirs.
What does this mean?
Elastic fibres act as secondary pumps after heart
What helps to stabilize blood pressure?
Pressure receptors in the walls of arteries
All arteries except ______ carry oxygenated blood in an adult
pulmonary arteries
arterioles are
Small arteries that carry blood to capillaries (distributors)
How do arterioles maintain normal blood pressure and circulation
they serve as resistant vessels
Form pre-capillary sphincters near where capillary originates
Smooth muscle in walls of arterioles
What is the function of the pre-capillary sphincters?
reduce blood flow through a network of capillaries by constricting arterioles
may also increase flow by relaxing pre-capillary sphincters
____ pairs of arteries supply the head and the neck
4
4 pairs of arteries supply the head and the neck
- Common carotid artery
- 3 branches from the subclavian artery
2.1 Vertebral artery
2.2 Thyrocervical trunk
2.3 Costocervical trunk
Most parts of the head and neck receive their blood from the
right and left common carotid artery
Common carotid artery ascends in the
anterior of the neck, just lateral to the trachea
Common carotid artery is divided into two triangles by a muscle:
Sternocleidomastoid
common carotid artery located in the
anterior triangle, just deep to the sternocleidomastoid and relatively thin infra-hyoid muscle
At the superior border of the larynx (level of adams apple)
each common carotid ends by
dividing into an external and internal carotid artery
The right and the left external carotid artery supplies most of
the tissue of the head, external to the brain orbit
As each external carotid ascends, it sends a branch to
the thyroid and larynx
- Sup. thyroid artery
To the tongue
- Lingual artery
to the skin and muscle of the anterior face
- anterior facial artery
To the posterior part of the scalp
- occipital artery
And to the region around the ear
- posterior oracular artery
Near the tempo-mandibular joint, each external carotid artery ends by splitting into the
superficial temporal and maxillary arteries
Internal carotid artery supplies the
orbit and most of the cerebrum
Right subclavian artery originates from the
brachiocephalic trunk, following the branch of the right common carotid
Left subclavian artery arises from the
third vessel branching from the aortic arch
the branches from the subclavian arteries supply the
brain
= vertebral artery
Also supply neck and thoracic wall
- Thyrocervical trunk
- Costocervical trunk
- internal thoracic artery
the main arteriole vessels in the carotid triangle
the common carotid artery and one of its terminal branches (internal carotid)
branches of the external carotid also originate in the
carotid triangle
Each common carotid artery ascends in the __________ with the ______________ to the level of the superior border of the ______ (at C4)
carotid sheath
internal jugular vein and vagus nerve
thyroid cartilage
C4: This is where each common carotid artery terminates by
dividing into the internal and external carotid artery
the internal carotid artery has _________ in the neck
no branches
the internal carotid artery supplies
most of the structures of the brain and orbit
External carotid artery has several branches in the
neck
the carotid sinus is a
dilated area at the base of the internal carotid artery
the carotid sinus location
it is the site of
- Baroreceptors
- carotid body/ chemoreceptor
- Vagus and glossopharyngeal nerves
just superior to the bifurcation of the internal and external carotid artery at the level of the superior border of the thyroid cartilage
the carotid sinus is the site of
- Baroreceptors
- carotid body/ chemoreceptor
- Vagus and glossopharyngeal nerves
Blood supply to the brain is derived from internal carotid and vertebral artery
These are terminal branches that line the arachnoid space
Internal carotid artery arises in the neck from the common carotid artery
the vertebral artery begins in the root of the neck, as the first branches of the first part of the subclavian artery
the vertebral arteries are usually unequal in size and the cervical part of the vertebral arteries ascend through the transverse foramena
Blood supply to the brain is derived from
internal carotid and vertebral artery
Internal carotid artery arises in the _____ from the _________
neck
common carotid artery
the vertebral artery begins in the ____________, as the first branches of the first part of the _______________
root of the neck
subclavian artery
the vertebral artery begins in the ____________, as the first branches of the first part of the _______________
root of the neck
subclavian artery
the vertebral arteries are usually __________ and the cervical part of the vertebral arteries ascend through the _______________
unequal in size
transverse foramena in the first six cervical vertebrae
external carotid artery supplies
most structures external to the cranium
each external carotid artery runs
posterior-superiorly to the region between the neck of the mandible and the lobe of the oracle
Where it is embedded in the parotid gland
each external carotid artery terminates by dividing into 2 branches:
- the maxillary
- And the superficial temporal artery
