Ch 3. Circulatory Pathways Flashcards
1
Q
OVERVIEW OF SYSTEMIC ARTERIES
A
ENJOY
2
Q
Define Arteries & Details
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Blood vessels that carry blood away from the heart to the varies organs of the body
The Aorta is the longest artery in the body!
The Aorta has 4 sequential regions:
- Ascending Aorta (ascends from the left ventricle)
- Arch of the Aorta (aka aortic arch)
- Thoracic Aorta (ascends through the thoracic cavity)
- Abdominal Aorta (descends through the abd. cavity)
3
Q
Ascending Aorta & its Branches Details
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The only 2 branches of the Ascending Aorta:
- Right Coronary Artery
- Left Coronary Artery
The Coronary Arteries supply blood to the heart wall
4
Q
Arch of the Aorta & its Branches Details
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The 3 branches of the Aortic Arch:
- Brachiocephalic Trunk
- Left Common Carotid
- Left Subclavian
The Brachiocephalic Trunk divides into the:
- Right Common Carotid
- Right Subclavian
5
Q
Common Carotid Arteries Details
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Each Common Carotid Artery branches off into an:
- Internal Carotid
- External Carotid
—Generally, the Carotid Arteries supply blood to the head and neck.—
Internal Carotid: supplies blood to brain, pituitary gland, and the eye
External Carotid: supplies blood to all of the other parts of the head and neck ie, face, nose, oral cavity/teeth/tongue, scalp, neck, pharynx, larynx, and thyroid gland.
*The right internal/external carotid will supply blood to the right side of these things mentioned. The left carotids will supply the left side.
6
Q
Subclavian Arteries Details
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Location: Just beneath the collarbone
Right Subclavian Artery supplies blood to:
- Right Upper Limb
Left Subclavian Artery supplies blood to:
- Left Upper Limb
Each subclavian has a branch called the Vertebral which supplies blood to the brain & spinal cord
Pathway of Subclavian Arteries: The right subclavian artery extends from the brachiocephalic trunk, while the left subclavian artery extends from the arch of the aorta.
Travel: The subclavian artery travels into the axillary region and is now called the axillary artery.
7
Q
Axillary Artery Details
A
Supplies blood to the Axilla, Shoulders, and Chest Walls
- aka the skin and pectoral muscles of the chest
Travel: The Axillary Artery then enters the arm and becomes the brachial artery.
8
Q
The Brachial Artery Details
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Supplies blood to:
- Arm
Travel: Near the elbow, the brachial artery branches to form:
- The Radial Artery (which follows the radius)
- The Ulnar Artery (which follows the ulna)
These two arteries supply blood to the forearm
9
Q
Overview of Systemic Arteries!!
A
- Arteries are blood vessels that carry blood away from the heart to the various organs of the body.
- They aorta is the longest artery in the body. It branches to give rise to all of the smaller arteries that form the systemic circulation.
- The aorta is a continuous blood vessel that consists of four sequential regions.
1) Ascending aorta. Arch of the aorta. Thoracic aorta. Abdominal aorta. - The ascending aorta is the part of the aorta that ascends from the left ventricle. The arch of the aorta, also called the aortic arch, is the curved part of the aorta. The thoracic aorta is the part of the aorta that descends through the thoracic cavity. The abdominal aorta is the part of the aorta that descends through the abdominal cavity. In the next series of videos, you will learn more about each region of the aorta and the smaller arteries that that branch off of these regions.
10
Q
Ascending Aorta and its Branches!
A
- The ascending aorta is the part of the aorta that ascends from the left ventricle of the heart.
- The only branches of the ascending aorta are the right and left coronary arteries.
- The coronary arteries supply blood to the heart wall.
11
Q
Arch of the Aorta and its Branches!
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- The arch of the aorta, AKA the aortic arch, is the curved portion of the aorta. It connects the ascending aorta with the thoracic aorta.
- Three arteries branch off of the arch of the aorta.
1) The brachiocephalic trunk. Left common carotid artery. Left subclavian artery. - The brachiocephalic trunk further divides into a right common carotid artery and a right subclavian artery. In the body, usually there are right and left counterparts of each artery. For example, there is a right common carotid artery and a left common carotid artery. However, in some cases there is only one copy of a particular artery that exists. For example, there is only one brachiocephalic trunk, which is an artery, and it is located on the right side of the body. There isn’t a left brachiocephalic artery.
- The common carotid arteries. Each common carotid artery branches into an internal carotid artery and an external carotid artery. In general, the carotid arteries supply blood to the head and neck. The internal carotid arteries supply blood to the brain, pituitary gland, and the eye. The external carotid arteries supply blood to all other parts of the head and neck. This means that the external carotid arteries supply blood to the face, nose, oral cavity (including the teeth and tongue), ear, scalp, neck, pharynx, larynx, and thyroid gland. So, the right internal carotid artery supplies the right side of the brain, right side of the pituitary gland, and the right eye. The right external carotid artery supplies all other parts of the right side of the head and neck. For example, the right side of the face, right side of the oral cavity, right side of the pharynx, right side of the larynx, and so on. The left internal carotid artery supplies the left side of the brain, left side of the pituitary gland, and the left eye. The left external carotid artery supplies all other parts of the left side of the head and neck. For example, the left side of the face, left side of the oral cavity, left side of the pharynx, left side of the larynx, and so on.
- Now let’s discuss the subclavian arteries. The right and left subclavian arteries are named as such because each subclavian artery passes just beneath the clavicle or collarbone. The subclavian arteries supply blood mainly to the upper limbs. The right subclavian artery supplies the right upper limb. The left subclavian artery supplies the left upper limb. As the subclavian artery passes through the different parts of the upper limb, its name constantly changes, and the new name depends on which part of the upper limb the artery is located. Although the subclavian arteries supply mainly the upper limbs, each subclavian artery has a branch, called the vertebral artery, that also supplies blood to the brain and spinal cord.
- Now, let’s put all of this information together and look at the pathway of the subclavian arteries. The rights subclavian artery extends from the brachiocephalic trunk. Whereas. The left subclavian artery extends from the arch of the aorta. Before each subclavian artery reaches the clavicle, it branches to form the vertebral. The vertebral artery supplies blood to the brain and spinal cord. The subclavian artery continues on into the axillary region and is now called the axillary artery. The axillary artery supplies blood to the axilla, shoulder, and chest wall (in other words, the skin and pectoral muscles of the chest). The axillary artery then enters the arm and becomes the brachial artery. The brachial artery supplies blood to the arm. Near the elbow, the brachial artery branches to form the radial artery, which follows the radius and the ulnar artery, which follows the ulna. These two arteries supply blood to the forearm. Near the wrist, the ulnar and radial arteries unite to form the superficial palm arch and deep palmar arch. The palmar arches supply blood to the palm of the hand. Digital arteries branch off of the palmar arches to supply blood to the fingers and thumb. Now let’s talk about the arteries of the brain. In this figure, you are looking at the ventral or undersurface of the brain. As mentioned earlier, the internal carotid arteries and the vertebral arteries are the major arteries that supply blood to the brain. Here are the internal carotid arteries. Here are the vertebral arteries. Each internal carotid artery branches to form an anterior cerebral artery. Although the anterior cerebral artery is labeled here, this entire structure is the anterior cerebral artery. So, again from here, up, and on is the anterior cerebral artery. Again, over here the same thing, the anterior cerebral artery. The left and right anterior cerebral arteries are interconnected by the anterior communicating artery. Along they ventral surface of the brainstem, the right and left vertebral arteries merge to form the basilar artery. The basilar artery in turn branches to form the posterior cerebral arteries. The posterior cerebral arteries branch, in turn, to form the posterior communicating arteries. Then the posterior communicating arteries connect to the internal carotids. Note that the internal carotid arteries and the basilar artery are interconnected by a circular anastomosis called the circle of Willis. Another name for the circle of Willis is the cerebral arterial circle. An anastomosis is a circular connection between blood vessels. So, again, this is an anastomosis because it is essentially a circle. Not all of the blood vessels in the brain form the circle of Willis. Only those that are part of the actual circle. The blood vessels that comprise the circle of Willis include the anterior cerebral arteries. Even though this portion technically isn’t part of the circle, this portion is. So, the anterior cerebral arteries are part of the circle. Another part of the circle is the anterior communicating artery. In addition, the internal carotid arteries, posterior communicating arteries, and posterior cerebral arteries. So, all of these arteries are part of the circle of Willis. Note that the basilar artery and the vertebral arteries are not part of the circle of Willis. Because the circle Willis is arranged as an anastomosis or circle, this arrangement provides an alternate pathway through which blood can flow if an internal carotid artery or vertebral artery becomes blocked or damaged. That’s because if there is a blockage, for example here, blood can go in the other direction along the circle allowing the blood to still get to its destination.
12
Q
Thoracic Aorta and its Branches!
A
- The thoracic aorta is the part of the aorta that is located in the the thoracic cavity. The thoracic aorta supplies blood to the chest wall and to many organs of the thoracic cavity.
- There are several branches of the thoracic aorta.
1) Bronchial arteries. 2) Esophageal arteries. 3) Posterior intercostal arteries, which are also just known as the intercostals. 4) Pericardial arteries. 5) Superior phrenic arteries. - The bronchial arteries supply blood to the bronchi and bronchioles of the lungs. Note that the bronchial arteries do not supply blood to the alveoli of the lungs. Instead, the pulmonary arteries, which are part of the pulmonary circulation, actually supply blood to the alveoli. The esophageal arteries supply blood to the esophagus. The intercostal arteries supply blood to the intercostal muscles, which are located in between the ribs. The pericardial arteries supply blood to the pericardium, which is the sac that surrounds the heart. The superior phrenic arteries supply blood to the upper portion of the diaphragm.
13
Q
Abdominal Aorta and its Branches!
A
- The abdominal aorta is the portion of the aorta that is located in the abdominal cavity. It supplies blood to abdominal organs. There are unpaired arteries and paired arteries that branch off of the abdominal aorta. Let’s first examine the unpaired arteries.
- 3 unpaired arteries branch off of the abdominal aorta. 1) The celiac trunk. 2) Superior mesenteric artery. 3) Inferior mesenteric artery.
- The celiac trunk is an artery that further divides into three branches. Left gastric artery. Splenic artery. Common hepatic artery. This figure shows you the celiac trunk in more detail. As you just learned, the celiac trunk has three branches. Left gastric artery. Splenic artery. Common hepatic artery. The left gastric artery supplies blood to the stomach. The splenic artery supplies blood to the spleen and pancreas. The common hepatic artery supplies blood to the liver and gallbladder. This figure shows you the superior mesenteric artery in more detail.
The superior mesenteric artery supplies blood to the entire small intestine and to the first half of the large intestine. This figure shows you the inferior mesenteric artery in more detail. The inferior mesenteric artery supplies blood to the second half of the large intestine. Now let’s discuss the paired arteries that branch off of the abdominal aorta. There are five paired arteries that branch off of the abdominal aorta. Inferior phrenic arteries. Suprarenal arteries. Renal arteries. Gonadal arteries. Lumbar arteries. The inferior phrenic arteries supply blood to the lower portion of the diaphragm. The suprarenal arteries, also known as the adrenal arteries, supply blood to the adrenal glands. The renal arteries supply blood to the kidneys. The gonadal arteries supply blood to the gonads and other structures. In men, the gonadal arteries are called the testicular arteries, which supply blood to the testes.
In women, the gonadal arteries are called the ovarian arteries, which supply blood to the ovaries, fallopian tubes, and uterus. The lumbar arteries supply blood to the spinal cord and to the lower back. Near the fourth lumbar vertebra, the abdominal aorta splits into two major arteries, the right and left common iliac arteries. Each common iliac artery branches to form an internal iliac artery and an external iliac artery. The internal iliac arteries supply blood to the pelvis, urinary bladder, buttocks, penis and scrotum (in men), and vagina (in women). The external iliac arteries supply blood to the lower limbs. The right external iliac artery supplies blood to the right lower limb. The left external iliac artery supplies blood to the left lower limb. In this figure you can see how the external iliac artery supplies blood to the lower limb. As the external iliac artery passes through the different parts of the lower limb, its name constantly changes, and the new name depends on which part of the lower limb the artery is located.
- Now, let’s look at the pathway of the external iliac arteries. As each external iliac artery descends into the thigh, it becomes the femoral artery. The femoral artery supplies blood to the thigh. Behind the knee, the femoral artery becomes the popliteal artery. The popliteal artery branches into the anterior tibial artery and the posterior tibial artery. The anterior tibial artery supplies blood to the anterior part of the leg. The posterior tibial artery supplies blood to the posterior part of the leg. Near the ankle, the anterior tibial artery becomes the dorsalis pedis artery, which supplies blood to the ankle. As it descends, the dorsalis pedis branches to form the dorsal arch or arcuate arch, which supplies blood to the dorsal surface of the foot. In addition, the posterior tibial artery eventually gives rise to the plantar arch, which supplies blood to the plantar surface of the foot. The digital arteries branch off of the plantar arch to supply blood to the toes.
14
Q
Overview of Systemic Veins!
A
- Veins are blood vessels that carry blood back to the heart. Veins are typically more superficial than arteries and, therefore, can often be seen through the skin.
- In some case, there are two copies of the same vein in the same part of the body. When this occurs, one copy of the vein is superficial and can be seeing through the skin, whereas the other copy is deeper in the tissue and cannot be seen through the skin.
- For example, there are two copies of the brachial vein that drain the arm. The upper brachial vein is superficial. The lower brachial vein is deeper within the tissue of the arm. As you probably noticed in the videos about arteries, arteries are named in a distal direction. This means that you start from the heart and work your way toward the peripheral or outer parts of the body.
- Veins, however, are named in a proximal direction. This means that you start with the peripheral parts of the body and work your way back toward the heart. So, as we discuss the veins of the body, we have to start off with the small veins in the peripheral parts of the body. From there, the small veins drain into one of the three great veins that empty into the right atrium of the heart. The three great veins are as follows. Superior vena cava. Inferior vena cava. Coronary sinus. The superior vena cava drains blood from small veins coming from the head, neck, upper limbs, and chest. The inferior vena cava drains blood from small veins coming from the abdomen, pelvic organs, and lower limbs. The coronary sinus drains blood from small veins in the heart wall.
- As you already know, the veins in the heart wall are called cardiac veins. The cardiac veins, in turn, drain into the coronary sinus which carries the blood to the right atrium.
- So, there really isn’t anything else to say about the cardiac veins or coronary sinus, and our discussion about drainage of the heart wall is complete. However, at this point you don’t know about the various veins that drain into the superior vena cava or those veins that drain into the inferior vein cava. Therefore, in the remaining videos about veins, you will learn about those veins that drain into the superior vena cava. And those veins that drain into the inferior vena cava.
15
Q
Veins That Drain into the SUPERIOR Vena Cava
A
- The superior vena cava drains blood from small veins coming from: Head. Neck. Upper limbs. Chest.
- Let’s now discuss how blood from these regions of the body ultimately enters the superior vena cava. We shall begin with the upper limbs. The digital veins drain the fingers and thumb of the hand. The digital veins empty into the superficial palmar venous arch, the deep palmar venous arch, and the palmar venous plexus. These veins drain the palm of the hand. The palmar venous arches and the palmar venous plexus empty into the following veins. Basilic vein. Median antebrachial vein. Ulnar veins. Radial veins. Cephalic vein. These veins drain the forearm. Both the basilic vein and the cephalic vein course through the forearm and then ascend into the arm. In front of the antecubital region, the cephalic vein and the basilic vein form a side connection through the median cubital vein. The median cubital vein is the vein from which blood samples are typically obtained. Before leaving the forearm, the ulnar veins and the radial veins combine to form the brachial veins, which, in turn, ascend into the arm. Hence, the basilic vein, cephalic vein, and brachial veins are the major veins of the arm.
- Consequently, the arm is drained by these veins. As it approaches the axilla, the basilic vein and brachial veins join to form the axillary vein. The axillary vein drains the axilla, shoulder, and chest wall (in other words, the skin and pectoral muscles of the chest). The axillary vein and the cephalic vein ultimately join to form the subclavian vein. After traveling for a short distance, the subclavian vein merges with the. External jugular vein. Internal jugular vein. Vertebral vein. To form the brachiocephalic vein. Note that there are two brachiocephalic veins. However, there is only one brachiocephalic artery, which is known as the brachiocephalic trunk. We discussed that in earlier videos.
- Near the heart, the brachiocephalic veins merge to form the superior vena cava. The superior vena cava, as we already know, drains into the right atrium. As I just mentioned, the external jugular vein, internal jugular vein, and vertebral vein merge with the subclavian vein to form the brachiocephalic vein. The brachiocephalic veins, in turn, give rise to the superior vena cava. The jugular veins are responsible for draining blood from the head and neck. The vertebral vein drains part of the spinal cord.
- Let’s talk about these veins in more detail. The external jugular vein drains the scalp and ear. The internal jugular vein drains all other parts of the head and neck. This means that the internal jugular vein drains the brain, pituitary gland, eye, face, oral cavity (including the teeth and tongue), nose, neck, pharynx, larynx, and thyroid gland. The vertebral vein drains a portion of the spinal cord. Note that the vertebral vein does not drain the brain, even though the vertebral artery supplies blood to the brain.
- Now let’s discuss drainage of blood from the thorax. Blood is drained from various regions of the thorax or chest via the azygous system. The azygous system consists of the azygous vein and the accessory hemiazygous vein. By the way, the accessory hemiazygous vein is sometimes just called the hemiazygous vein. The azygous vein empties into the superior vena cava. The accessory hemiazygous vein empties into the left brachiocephalic vein. The brachiocephalic vein, in turn, empties into the superior vena cava.
- So, for both the azygous vein and the accessory hemiazygous vein blood ultimately goes into the superior vena cava. The azygous vein and the accessory hemiazygous vein receive blood from several veins that drain components of the thoracic cavity. These veins include the following. Posterior intercostal veins, which are just simply called the intercostal veins. Bronchial veins. Pericardial veins. Esophageal veins. The intercostal veins drain blood from the intercostal muscles and upper back. The bronchial veins drain the bronchi and bronchioles of the lungs. The pericardial veins drain the pericardium around the heart. The esophageal veins drain the esophagus. Again, blood from the intercostal veins, bronchial veins, pericardial veins, and esophageal veins goes into the azygous system, and from the azygous system, that blood ultimately goes into the superior vena cava.
