 This video will cover the following objective, identify the major blood vessels of the body. The pulmonary circuit consists of the blood vessels that carry blood to and from the lungs, starting with the pulmonary trunk, which receives blood coming from the right ventricle. The pulmonary trunk branches into the left pulmonary artery and the right pulmonary artery. The left pulmonary artery carries blood into the left lung, and the right pulmonary artery carries blood into the right lung. The pulmonary arteries branch into many smaller arteries within the lungs and eventually deliver blood into the pulmonary capillaries. Within the pulmonary capillaries, oxygen diffuses from the air inside of the lungs, inside of the air sacs of the lungs known as the alveoli. Oxygen diffuses from the air within the alveoli into the blood within the pulmonary capillaries. And then the oxygen-rich blood from the pulmonary capillaries flows through venules into pulmonary veins. The left pulmonary veins carry blood from the left lung into the left atrium, and the right pulmonary veins carry blood from the right lung into the left atrium. The systemic circulation includes the arteries that carry blood with a high oxygen concentration away from the left ventricle of the heart. The aorta begins as the ascending aorta that carries blood superiorly out from the left ventricle as blood moves through the aortic semilunar valve. Into the ascending aorta, the first branches coming off of the ascending aorta are coronary arteries. There's a left coronary artery and a right coronary artery that will branch further into smaller coronary arteries that eventually distribute blood into the capillaries of the myocardium in order to provide nutrients and carry away waste from the muscle of the heart. When the ascending aorta curves, its name changes to the aortic arch. There's three major branches coming off of the aortic arch. The brachiocephalic artery, also known as the brachiocephalic trunk. If we think about that word brachiocephalic, the first part of the word means arm, comes from the brachium for arm, and cephalic means head. So the brachiocephalic artery carries blood towards the right arm and the right half of the head. You can see that the brachiocephalic artery will branch to the right subclavian artery and the right common carotid artery. Then the next two major branches that come directly off of the aortic arch are the left common carotid artery and the left subclavian artery. The left common carotid artery carries blood to the left half of the head and the left subclavian artery carries blood towards the left arm. After the aortic arch, the aorta carries blood inferiorly as the descending aorta through the thoracic cavity and then the aorta travels through the diaphragm into the abdominal cavity to become the abdominal aorta. The coronary circuit are the blood vessels that are supplying the muscle of the heart. Coronary arteries carry blood to capillaries within the myocardium. Then the cardiac veins drain blood from those capillaries back into the right atrium. The left coronary artery is traveling in the coronary sulcus and then branches to form two major arteries, the circumflex artery that continues to travel in the coronary sulcus and curve around towards the posterior of the heart and the anterior interventricular artery that branches off from the left coronary artery and travels inferiorly through the anterior interventricular sulcus. There's a synonym for the anterior interventricular artery. It's also known as the left anterior descending artery, which is commonly abbreviated LAD. So LAD, left anterior descending artery, is a synonym for the anterior interventricular artery. The other major artery coming from the ascending aorta is the right coronary artery. The right coronary artery travels in the coronary sulcus and curves around on the right side towards the posterior of the heart and gives off several branches on the anterior of the right ventricle including a major branch known as the marginal artery and more specifically this is the right marginal artery or the marginal branch of the right coronary artery. The right marginal artery is found along the margin of the diaphragm and the right ventricle. Now we can also see in the blue color in this illustration the major cardiac veins. So the great cardiac vein is found in the anterior interventricular sulcus running adjacent to the LAD and then runs superiorly up to join the circumflex artery as it travels along the coronary sulcus wrapping around the left side of the heart. Over onto the right ventricle here we can see there are several anterior cardiac veins and also major cardiac vein known as the small cardiac vein runs adjacent to the marginal artery and then wraps around on the right side in the coronary sulcus running adjacent to the right coronary artery. From a posterior view here we can see the continuation of the small cardiac vein traveling in the coronary sulcus adjacent to the right coronary artery. The right coronary artery gives off the marginal artery branch along the margin of the diaphragm and the right ventricle and then the right coronary artery continues to travel in the coronary sulcus on the posterior of the heart and then gives off a major branch in the posterior interventricular sulcus known as the posterior interventricular artery. There is a synonym for the posterior interventricular artery. It's also known as the posterior descending artery which is commonly just abbreviated PDA. So PDA stands for posterior descending artery and is a synonym for the posterior interventricular artery referring to this large branch coming off of the right coronary artery and traveling through the posterior interventricular sulcus. The middle cardiac vein is found in the posterior interventricular sulcus running right along side the posterior interventricular artery and drains the same regions of the heart. The middle cardiac vein joins with the small cardiac vein and the great cardiac vein to form the coronary sinus. Then the coronary sinus drains blood coming from the coronary circuit into the right atrium. The common carotid artery branches at the carotid sinus to form two major arteries the external carotid artery and the internal carotid artery. The external carotid artery travels more superficially and will give off branches to the face including the facial artery. Facial artery travels along the mandible and then up along the face supplying the major muscles of facial expression with blood supply. Another major branch of the external carotid artery is the superficial temporal artery that travels to the superficial regions on the lateral aspect of the head including the temporalis muscle and the internal carotid artery travels deep through the carotid foramen into the cranial cavity supplying major blood supply to the brain. There's another artery that is carrying blood towards the brain and this is the vertebral artery. So the vertebral artery and the internal carotid artery are both supplying blood into the brain. There are both left and right internal carotid arteries and left and right vertebral arteries and these four arteries will join together to form a structure of interconnected arteries known as the circle of willis. The circle of willis is a network of blood vessels supplying a redundant blood supply to the brain in case one blood vessel is blocked there will be an alternative path to supply some blood to keep the brain functioning. Whenever we have two or more blood vessels joining together to supply the same region of the body it's what we call an anastomosis. Anastomosis is a junction of blood vessels as we have arteries joining together carrying blood into the same organ. We have here the vertebral arteries. There's a right vertebral artery as well as here's a left vertebral artery and these right and left vertebral arteries join together to form the basilar artery. You can see the basilar artery is traveling right on the anterior surface of the pons. Then the basilar artery gives branches major branches known as the posterior cerebral arteries are traveling towards the posterior regions of the cerebrum towards the posterior temporal lobes and into the occipital lobe. But there are branches coming off from the posterior cerebral artery right away and connecting anteriorly to form an anastomosis with the internal carotid arteries. So the internal carotid arteries are the other major arteries carrying blood into the brain aside from the vertebral arteries. Here we see the right internal carotid artery but there's also over here the left internal carotid artery. The right and the left internal carotid arteries form anastomosis with the posterior cerebral arteries. They're connected via what's known as the posterior communicating artery. After connecting to the posterior communicating artery the major branch coming from the internal carotid artery laterally into the majority of the cerebral cortex is known as the middle cerebral artery. There is a branch that comes off anteriorly just as the internal carotid artery transitions to the middle cerebral artery. The internal carotid artery gives a small branch known as the anterior cerebral artery which travels towards the frontal lobe of the cerebrum and towards the olfactory bulbs. There's a left anterior cerebral artery that we can see is the one labeled here. There's also on this side the right anterior cerebral artery and the anterior cerebral arteries are connected to each other by another anastomosis. The anastomosis joining the right and left cerebral arteries is known as the anterior communicating artery. Notice the communicating arteries are these arteries that are forming anastomoses in the circle of Willis. The posterior communicating artery forms the anastomoses between the posterior cerebral artery and the internal carotid artery. Whereas the anterior communicating artery forms the anastomosis between the right and left anterior cerebral arteries. When the subclavian arteries travel under the clavicle towards the limb the name changes to the axillary artery that travels through the axillary region. Then as the artery reaches the diaphysis of the humerus traveling along the humerus is the brachial artery. The brachial artery then gives off two major branches. On the lateral side is the radial artery and along the medial side is the ulnar artery. The radial and ulnar arteries are interconnected by anastomoses known as the palmar arches. There's a deep palmar arch as well as a superficial palmar arch. Then the digital arches are branching off from the palmar arches supplying blood into the digital regions, into the fingers. Here we can see another branch coming off of the subclavian artery known as the internal thoracic artery. A synonym for the internal thoracic artery is the mammary artery. It does supply the anterior chest wall in the mammary region. The mammary or internal thoracic artery forms several anastomoses with other arteries that are traveling through the chest wall. The arteries that branch off from the thoracic artery and travel on the inferior surface of the ribs in the costal grooves are known as the intercostal arteries. The intercostal arteries form anastomoses with the internal thoracic artery. As the aorta travels down through the diaphragm, its name changes to become the abdominal aorta. The opening in the diaphragm is the aortic hiatus where the aorta travels down through the diaphragm. There's a small branch coming off of the aorta on either side of the diaphragm known as superior and inferior phrenic arteries which the phrenic arteries carry blood into the diaphragm. Then the first major branch that comes off from the abdominal aorta is known as the celiac trunk. The celiac trunk is an unpaired artery. It will give rise to three major branches, the left gastric artery which supplies blood to the stomach. The splenic artery carries blood towards the spleen and the pancreas and the common hepatic artery supplies blood to the liver. The next major branch from the abdominal aorta is the superior mesenteric artery which supplies blood into the intestinal organs. Then the renal arteries carry blood into the kidneys. There are two renal arteries. Those are paired arteries. The right renal artery carries blood into the right kidney and the left renal artery carries blood into the left kidney. But the superior mesenteric artery is unpaired. There's only one superior mesenteric artery just like there's only one celiac trunk. There are two renal arteries. Then the next major artery branching off from the abdominal aorta just inferior to our renal arteries is the inferior mesenteric artery. And this is also an unpaired artery. Like the superior mesenteric artery, the inferior mesenteric artery also supplies blood into the intestines. Inferior to the inferior mesenteric artery, the abdominal aorta will branch forming the iliac arteries. And the common iliac arteries are the large branches that will then branch further into smaller internal iliac arteries and external iliac arteries. Internal iliac arteries carry blood into the pelvis, whereas the external iliac arteries supply blood to the lower limbs. There are also several lumbar arteries branching from the posterior of the abdominal aorta and supplying blood to the vertebrae and to the muscles of the posterior region of the abdominal wall. I find it helpful to try and draw major branches that are coming off of the aorta. So if I start by drawing the ascending aorta, there's three major branches coming off from the ascending aorta. Suppose we could put in our coronary arteries, which are a little smaller, but this would be the left coronary artery, the right coronary artery. This is the brachiosophallic trunk, then this is the left carotid, and this is the left subclavian. Then we'll have a major branch coming off from our abdominal aorta. So let's just label this part thoracic aorta, and we can draw a line here to represent the diaphragm. This will be the celiac trunk, left gastric, splenic, and then this one will kind of make curve off the other direction. Off towards the right, this would be the common hepatic artery. So it's curving towards the right because of course the liver is in the upper right abdominal quadrant. Draw another major branch that's unpaired, the superior mesenteric. Then here we'll have our right renal artery, renal artery, and this is the inferior mesenteric. So drawing them out like this just helps me remember the order at which they branch from the aorta. Remembering the order of branching is the way that I figure out the naming helps me to identify what artery I'm looking at. The blood supply to the lower limb starts with the external iliac artery. As it travels through the inguinal ligament, the external iliac artery changes to become the femoral artery. Then the femoral artery travels down deep into the posterior where it arrives at the back of the knee in the popliteal region. Its name changes to the popliteal artery. Then the popliteal artery branches as it travels into the leg. The two major branches that come off from the popliteal artery are the posterior tibial artery traveling through the serral region and the anterior tibial artery which travels along the anterior of the tibia. Then the anterior tibial artery as it moves into the tarsal region and along the dorsal aspect of the foot, its name changes to become the dorsalis pedis. The veins of the systemic circulation carry blood with a relatively low oxygen concentration back from the systemic capillaries and drain blood into the right atrium. Within the brain numerous small veins drain blood into sinuses that are folds in the dural matter. The superior sagittal sinus and inferior sagittal sinus are located within the longitudinal fissure. They drain blood into the transverse sinuses that then join into the sigmoid sinus and the right and left sigmoid sinuses connect into the internal jugular veins at the jugular canals. Then the internal jugular vein drains into the brachiocephalic vein which then drains into the superior vena cava. There are both deep and superficial veins draining blood from the upper limb. The deep veins have the same names as the arteries that supply blood into the upper limbs and so the brachial vein is traveling deep along the humerus. The radial vein is deep along the lateral side of the antibracial region and the ulnar vein is deep along the medial side of the antibracial region. The ulnar and radial veins join together to form the brachial vein and then the brachial vein will join with one of the superficial veins to become the axillary vein. The superficial vein found along the medial side of the brachial and antibracial region is called the basillic vein. Here we see the basillic vein in the brachial region and down here we see the basillic vein in the antibracial region. When the basillic vein joins with the brachial vein, they form the axillary vein. Then the axillary vein joins with another superficial vein. The cephalic vein is the superficial vein found in the lateral region. The lateral antibracial region down here contains the cephalic vein and in the superficial portions of the lateral brachial region up here is the cephalic vein. The cephalic vein joins with the axillary vein to form the subclavian vein. There is an anastomosis between the cephalic vein and the basillic vein. This is known as the median cubital vein. It's found in the anticubital region. The median cubital vein is the most common location for venopuncture to take a sample of blood from a patient. The median cubital vein is typically the vein that the sample is taken from. I also wanted to point out here that the word cephalic is the term, the anatomical term for the region of the head. However, the term cephalic referring to the cephalic vein is unrelated to the head. There's no connection to the word for head. This word just is coincidentally used to refer to the superficial vein found laterally in the brachial and antibracial regions, which forms an anastomosis through the median cubital vein connecting to the basillic vein, which is the other superficial vein, but the basillic vein is found medially in the brachial and antibracial regions. While there's only one brachiosephalic artery and it's carrying blood to the right side of the head and right arm, there are two brachiosephalic veins. And so here we see the left brachiosephalic vein, whereas over here we have the right brachiosephalic vein. The right and left brachiosephalic veins join together to form the superior vena cava. And so the brachiosephalic veins are draining blood from the head as well as blood from the arms. The subclavian veins join together with the internal jugular veins to form the brachiosephalic veins. We can see just before the subclavian vein becomes the brachiosephalic vein by joining with the internal jugular vein, it receives blood coming from the external jugular vein and from the vertebral vein. There's also an unpaired system of veins that's draining the thoracic cavity. The azygous vein, azygous means unpaired, and the azygous vein is receiving blood coming from intercostal veins. And the azygous vein will drain that blood into the superior vena cava. The azygous vein forms an anastomosis with the hemi-azygous vein that also receives blood from the intercostal veins. The hemi-azygous vein is located along the left side just on the left of the aorta, whereas the azygous vein is located just along the right side of the aorta, just anterior to the bodies of the thoracic vertebrae. Moving down into the pelvic region, we can see there are internal iliac veins draining blood coming out of the pelvis. And there's external iliac veins that receive the blood that's draining out of the lower limbs. These internal and external iliac veins join together to form the common iliac veins. Then the common iliac veins join together to form the inferior vena cava in the abdominal cavity. Several small lumbar veins are draining blood from the vertebrae and the posterior abdominal wall. The renal veins are carrying blood from the kidneys into the inferior vena cava. The gonadal veins carry blood from the testes and ovaries, while the right gonadal vein drains blood directly into the inferior vena cava. The left gonadal vein drains into the left renal vein and then the left renal vein drains into the inferior vena cava. The hepatic veins carry blood from the liver into the inferior vena cava. However, the liver also receives blood coming from the digestive system organs and the spleen, which travel in a vein known as the hepatic portal vein. So the hepatic portal vein receives blood that's coming from the superior mesenteric vein. The superior mesenteric vein is draining blood from the intestines. There's also blood coming from the inferior mesenteric vein, which is also draining blood out of the intestines. The inferior mesenteric vein will join together with the spleenic vein. The spleenic vein is draining blood from the spleen as well as from the pancreas and from regions of the stomach. So the spleenic vein and the inferior mesenteric vein join together and then the inferior mesenteric vein and the superior mesenteric vein join together. And this all forms the hepatic portal vein. And the hepatic portal vein here is carrying this blood into the liver. So the hepatic artery proper carries blood into the liver and the hepatic portal vein carries blood into the liver. Then the hepatic veins drain blood out of the liver into the inferior vena cava and then the inferior vena cava will return the blood to the right atrium. Blood flows from the lower limbs in a system of deep veins as well as a system of superficial veins. The deep veins have the same names as the arteries that are traveling parallel to them. There's a posterior tibial vein that joins with the anterior tibial vein to form the popliteal vein. Then the popliteal vein travels into the thigh to become the femoral vein. And the femoral vein will then join with a large superficial vein found in the medial region running all the way through the leg and thigh, through the coral region and femoral region. This is the longest vein in the body, the great saphenous vein. So the great saphenous vein is the longest vein in the body found in the superficial medial thigh and leg. And it joins with the femoral vein. It drains into the femoral vein just before the femoral vein crosses into the external iliac vein. There's another major superficial vein found in the leg. It's not as long as the great saphenous vein. The small saphenous vein is found laterally and the small saphenous vein will drain into the popliteal vein. So running through the lateral, sural region, small saphenous vein is another superficial vein draining blood from the lower limb.