hi let's talk about the great vessels aorta and aortic branches in this video
we'll discuss the great vessels of the heart we'll also discuss the major distribution
networks of the aorta by region we'll outline the regions served by various aortic
major branches such as the common internal and external carotid arteries
we'll also discuss the major arterial branches of the thoracic part of the aorta
the great vessels are vessels that deliver blood to and conduct blood away from the heart
so you can start at any point of the story here but let's just begin with the uh the vessels
serving the right atrium so we have the vena kv which are the superior and inferior vena cava
which return blood from systemic loop to the right atrium that blood is then pushed through
to the right ventricle where it is pushed out through the pulmonary valve
through the pulmonary trunk conducted via pulmonary arteries
to the lungs it's there in the alveolar capillary beds that carbon dioxide is offloaded and oxygen
is unloaded in that richly oxygenated blood is returned from the lungs
to the left atrium via pulmonary veins from the left atrium blood is conducted through to the left
ventricle and the left ventricle pushes blood out through the aortic valve into the ascending aorta
which becomes the arch of the aorta which then becomes the descending aorta
that blood is drained from the tissues via the cable system so
there are two loops going on here there is a pulmonary loop which is
this and then there is a systemic loop
which is that so let's look at the elements of the systemic loop here
the systemic loop begins in the left ventricle blood is pushed out through the aortic valve
into the ascending aorta the ascending aorta is here we can differentiate that from the
pulmonary trunk because we can see the coronary arteries which are the only branches
of the ascending aorta there's a left and a right coronary artery and these arteries serve the heart
from the ascending aorta blood is then conducted through the arch of the aorta
that arch of the aorta has three main branches there is the brachiocephalic trunk
the left common carotid artery and the left subclavian artery that brachiocephalic trunk
has a right subclavian artery and a right common carotid artery
let's take a look at the subclavian artery which we'll see in much greater detail
in videos to follow the subclavian artery on the right side originates from the brachiocephalic
trunk on the left side originates from the arch of the aorta it moves along the root of the neck
and in the root of the neck the subclavian artery has three parts the first part is everything
medial to the anterior scalene muscle the second part is posterior to the anterior scalene muscle
and the third part is lateral to the anterior scalene muscle and this subclavian artery ends at
the lateral margin of the first rib where it then becomes the axillary artery which is conducting
blood through the axilla in terms of major targets of the subclavian artery via its branches it will
serve the thoracic and abdominal walls it will serve elements of the neck it will serve the
brain within the cranial cavity but the majority of its blood is flowing out to the upper limb
the common carotid artery on the right side will originate from the brachiocephalic trunk
and on the left side will be a direct branch of the arch of the aorta the common carotid artery
is going to be transmitted within the carotid sheath that carotid sheath has major contents
of the common carotid artery which we can see here the internal jugular vein and deep here
the vagus nerve and all of their branches towards the superior portion of the carotid sheath that
common carotid artery is going to bifurcate into the internal carotid artery and the
external carotid artery that internal carotid artery has no branches within the neck it ascends
to the basic cranium where it enters the skull through the carotid canal of the temporal bone
once within the cranial cavity it's going to serve the brain with blood it's going to be a
major contributor to the cerebral arterial circle of willis it will have a branch
proximal to where it participates in that cerebral arterial circle of willis called the ophthalmic
artery which will be conducted out into the orbit and will be the major blood supply to the orbit
and it will have branches then that will leave the orbit to supply the superior face or forehead
with blood the external carotid artery however will have many branches that supply
the neck and superficial face as well as the deep face and the scalp
its terminal branches include the maxillary artery which supplies
deep face and the superficial temporal artery which supplies the scalp with blood
after the arch of the aorta blood is then within the descending aorta
that descending aorta begins at about the level of
t3 t4 and it has two distinct parts a thoracic part which is everything superior to the diaphragm
and an abdominal part which is everything inferior to the diaphragm that abdominal part
is going to bifurcate into the common iliac arteries at about l4
the division between the two that aortic hiatus is at about the 12th thoracic
vertebra level it's about as low as the diaphragm will go
in the posterior that thoracic part of the aorta will have both visceral and parietal branches
the parietal branches are quite straightforward there are posterior intercostal arteries
these are supplying the intercostal spaces with blood specifically their posterior intercostal
arteries 3 through 11. below that we have the subcostal arteries and we also have the
superior phrenic arteries which supply the superior surface of the diaphragm with blood
these parietal branches typically are going to exit the aorta posterior laterally
the visceral branches are more anterolateral the visceral branches are going to include
bronchial arteries pericardial arteries mediastinal arteries and esophageal arteries
the bronchial arteries supply the bronchi with blood they'll also supply the superior
portion of the esophagus with blood the pericardial arteries supply the pericardium
with blood the mediastinal arteries supply elements of the mediastinum especially
lymph nodes with blood and the esophageal arteries supply the lower esophagus with blood
that leads us to the assessment question for this video and that is the brachiocephalic trunk
predominantly serves which areas of the body with blood a the head and neck and upper limbs
b the left head and neck c the left head and neck upper limb and portions of the thoracic wall
d the right head and neck or e the right head and neck upper limb and portions of the thoracic wall
the correct answer here is e the brachiocephalic trunk is going to bifurcate into the right common
carotid artery and the right subclavian artery the right common carotid artery will supply the right
head and neck with blood and the right subclavian artery will supply the right
upper limb and right portions of the thoracic wall with blood thank you very much for your time