In continuation of the circulatory system post, we started in my last post, today we will be discussing Arteries and Veins. After extensively explaining the anatomy of Anatomy of the Heart, Coronary Circulation, and Pulmonary Circulation, we will continue with blood vessels. So let's begin with the blood vessels of the head and neck from the left ventricle of the heart. If you do not understand circulation in the heart, then read through that post.
The left ventricle is the pump of the body, it is the systemic pump that allows for the circulation of blood and nutrients around the body. The contraction of the left ventricle pumps blood toward the Aorta (The ascending Aorta). The aorta is a large vessel as big in diameter as a hose. From the Ascending Aorta, the blood moves to the Aortic Arch. In the aortic arch, there are three vessels attached, and I explained this in my previous post but we are going to be picking two of them, and they are the Left Common Carotid Artery, and the Brachiocephalic artery. The Brachiocephalic artery branches into two arteries which are the Right common carotid artery and the Right subclavian artery. The third artery that comes out of the aortic arch is the Left Subclavian artery., ,
The left Carotid Artery splits into two-part, with one supplying the circle of Willis and the other supplying the face and the neck via the external carotid artery. The blood from the external carotid artery goes upward to the Superior Thyroid Artery which supplies the thyroid. The blood also moves to the Lingual artery which supplies the tongue. Another branch that the external carotid artery splits into is the Maxillary artery then the facial artery, Supplying the skull, it goes through the Occipital artery, and the Superficial Temporal Artery. The left Common Carotid Artery Second branch supplies blood to the internal carotid artery. From the internal carotid artery, it branches to the Middle Cerebral Artery. The Internal Carotid Artery also branches with the Anterior communicating artery, then to the posterior communicating artery, and the Ophthalmic artery which supplies the central retinal artery. The Right Subclavian Artery which is the second arterial branch will branch to give the vertebral arterial branches which move through the transverse foramina to give the Basilar Artery which branches to give the anterior inferior cerebellar artery, the superior cerebellar artery, the anterior spinal artery, the posterior inferior cerebellar artery. The blood from the right subclavian artery flows to the Posterior Communicating artery which communicates with the Circle of Willis. The right Common carotid artery has the supply as the left common carotid artery. , , ,
When it has to do with the return of blood from the head and neck to the right Atrium, then we start with the Dura Venous Sinus which is found within the Periosteal layer and the meningeal layer of the dura mater. Inside the skull, The inferior sagittal sinus sends blood to the Straight Sinus. The Occipital Sinus and the Superior sagittal sinus in the skull return blood to the Junction of Sinuses. The Straight sinus also sends blood to the Junction/confluence of sinuses. The junction of sinuses sends blood to the Transverse Sinuses, which then send blood to the Sigmoid sinus. From the Orbital cavity in the head are the Ophthalmic vein, SphenoidParietal Sinus, and the facial vein return blood to Cavernous Sinus. The Cavernous Sinus then splits into two branches which are the Superior Petrosal Sinus and the Inferior Petrosal Sinus. The Superior Petrosal Sinus returns blood to the Sigmoid Sinus, while the Inferior Petrosal Sinus sends blood to the Internal Jugular vein. The Sigmoid Sinus also empties blood to the internal Jugular vein. Before I continue, I said that the facial vein sends blood to the Cavernous Sinus, which also sends blood to the Superficial temporal vein and directly to the Internal Jugular vein. The Superficial temporal vein also sends blood to the internal jugular vein. The Superior Thyroid vein and the Middle thyroid vein connect to the Internal Jugular vein as it goes to return blood to the Brachiocephalic vein. The Occipital Vein which is located at the back of the skull different from the Occipital Sinus which is found inside the skull also returns blood. It Sends blood to the Posterior Auricular vein, which then returns blood to the External jugular vein, then to the subclavian vein. Let's pick from another area, so from the Upper arm is the Subclavian vein, and from the Vertebral column are the vertebral veins, which send blood to the brachiocephalic vein. The Internal Jugular vein, the External Jugular Vein, and the Vertebral vein send blood to the Brachiocephalic vein. The Brachiocephalic vein gives blood to the Superior Vena Cava which then gives the blood to the right atrium. For all the veins, the writing covers both the left and right veins., , , ,
Blood Movement in the circle of Willis starts with the blood from the vertebral artery which supplies from the subclavian artery. They move through the transverse foramen and then through the suboccipital triangle and then to the foramen magnum. As they move towards the foramen magnum, they give off the posterior inferior cerebellar branch/artery, which then gives off another branch towards the spine known as the posterior spinal artery. The anterior spinal artery also comes off from the vertebral artery. The vertebral artery after the foreman magnum fuses together to become the Basilar artery. The basilar artery gives off the anterior inferior cerebellar artery, then the Labyrinthine artery/ internal acoustic artery. The basilar artery then has pontine arteries at the pons. Supplying the Cerebellar is the Superior Cerebellar artery. The Basilar artery then fuses into the circle of Willis forming the posterior cerebral artery in P1 and P2 of the Posterior cerebral. In the circle of Willis, the Basilar artery branches to give the Posterior communicating artery. Also to the Circle of Willis is another artery that feeds it with blood, and that is the Internal Carotid artery (left and right). The Internal Coratid Artery branches to the Ophthalmic artery, then the Middle cerebral artery which branches to the anterior choroidal artery which then splits into smaller arteries known as the Lenticulo Striate arteries. The Internal Carotid artery gives off the anterior cerebral artery which is split into the A1 part and A2 part of the anterior cerebral artery. At the Optic Chiasma is another artery known as the Anterior Communicating Artery., ,
With this, I have been able to explain how blood flows from the Left Ventricle to the head and the neck region, as well as the Circle of Willis, then explains the circulation of blood back to the right atrium.