After Entering the Right Atrium, the Furthest a Red Blood Cell Can Travel Is the _________.
The Aorta and Its Branches
The aorta is the largest artery in the body and is divided into 3 parts: the ascending aorta, arch of the aorta, and descending aorta.
Learning Objectives
Outline the divisions of the aorta
Cardinal Takeaways
Key Points
- The claret is pumped from the left ventricle into the aorta and from in that location branches to all parts of the torso.
- The aorta is divided into three parts: the ascending aorta (where the aorta initially leaves the heart and points toward the head), the arch of the aorta (where the aorta changes direction), and the descending aorta (where the aorta points toward the anxiety).
- The ascending aorta has two small-scale branches, the left and right coronary arteries, that provide claret to the middle musculus.
- The arch of the aorta has three branches: the brachiocephalic avenue (which divides into right common carotid artery and the correct subclavian artery), the left common carotid artery, and the left subclavian artery. These arteries provide claret to both arms and the head.
- Within the abdomen, the descending aorta branches into the ii common iliac arteries; these provide blood to the pelvis and, eventually, the legs.
Key Terms
- descending aorta: The region of the aorta that passes inferiorly towards the feet.
- ascending aorta: The region of the aorta directly attached to the heart that passes superiorly towards the head.
- arch of the aorta: The region of the aorta that changes direction betwixt the ascending and descending aorta.
The aorta is the largest artery in the systemic circulatory organisation. Blood is pumped from the left ventricle into the aorta and from there branches to all parts of the torso. The aorta is an rubberband artery, meaning it is able to distend. When the left ventricle contracts to force blood into the aorta, the aorta expands. This stretching generates the potential energy that helps maintain blood pressure during diastole, since during this fourth dimension the aorta contracts passively.
The aorta is divided into 3 parts: the ascending aorta, where the aorta initially leaves the centre and points superiorly toward the head; the arch of the aorta where the aorta changes direction; and the descending aorta where the aorta points inferiorly toward the anxiety.
The ascending aorta has two minor branches, the left and right coronary arteries. These arteries provide blood to the heart muscle, and their blockage is the crusade myocardial infarctions or heart attacks.
The arch of the aorta has three branches: the brachiocephalic artery, which itself divides into right common carotid artery and the right subclavian avenue, the left common carotid artery, and the left subclavian artery. These arteries provide claret to both arms and the head.
The descending aorta is the largest artery in the body; it runs from the heart down the length of the breast and belly. It is divided into two portions, the thoracic and abdominal, in correspondence with the two keen cavities of the trunk in which it sits. Inside the abdomen, the descending aorta branches into the two mutual iliac arteries that provide blood to the pelvis and, eventually, the legs.
Ascending Aorta
The ascending aorta is the first portion of the aorta; it includes the aortic sinuses, the bulb of the aorta, and the sinotubular junction.
Learning Objectives
Describe the role of the ascending aorta in apportionment
Key Takeaways
Key Points
- The ascending aorta passes diagonally upward, forrard, and to the right, in the direction of the centre 'south axis.
- The aortic sinuses end at the sinotubular junction, the point in the ascending aorta where the aorta becomes a tubular structure.
- The ascending aorta has ii branching vessels, the left and right coronary arteries, which supply blood to the eye musculus.
Key Terms
- aortic sinuses: An aortic sinus is one of the anatomic dilations of the ascending aorta, which occurs just above the aortic valve.
- sinotubular junction: The sinotubular junction is the signal in the ascending aorta where the aortic sinuses end and the aorta becomes a tubular structure.
- seedling of the aorta: At the union of the ascending aorta with the aortic arch, the quotient of the vessel increases with a jutting of its right wall. This dilation is termed the bulb of the aorta, and on transverse department presents a somewhat oval figure.
The ascending aorta is a portion of the aorta start at the upper part of the base of the left ventricle, on a level with the lower border of the third costal cartilage behind the left half of the sternum; it passes diagonally upward, forward, and to the right, in the direction of the heart'southward axis, as high as the upper border of the second right costal cartilage. Its total length is almost 5 centimeters.
The aortic root is the portion of the ascending aorta beginning at the aortic annulus, the fibrous attachment between the heart and the aorta, and extending to the sinotubular junction. Only higher up the aortic valve are 3 pocket-size dilations called the aortic sinuses. The ii anterior sinuses requite rise to the coronary arteries, while the third posterior sinus does non usually give rise to any vessels and then is known as the not-coronary sinus.
The sinotubular junction is the bespeak in the ascending aorta where the aortic sinuses stop and the aorta becomes a tubular structure.
At the junction of the ascending aorta with the aortic arch, the caliber of the vessel increases with a bulging of its correct wall. This dilatation is termed the "bulb of the aorta." The ascending aorta is contained inside the pericardium. It is enclosed in a tube of the serous pericardium, which also encloses the pulmonary artery.
The ascending aorta is covered at its beginning by the body of the pulmonary avenue and, higher up, is separated from the sternum past the pericardium, the right pleura, the anterior margin of the right lung, some loose areolar tissue, and the remains of the thymus. Posteriorly, it rests upon the left atrium and right pulmonary avenue.
Arch of the Aorta
The arch of the aorta follows the ascending aorta and begins at the level of the second sternocostal articulation of the right side.
Learning Objectives
Draw the function of arch of the aorta
Central Takeaways
Key Points
- Iii vessels come out of the aortic arch: the brachiocephalic artery, the left common carotid avenue, and the left subclavian artery.
- These vessels supply blood to the head, neck, thorax and upper limbs.
- In some individuals, the left common carotid artery and left subclavian artery may ascend from the brachiocephalic artery rather than the aortic arch.
Key Terms
- arch of the aorta: Also called the transverse aortic curvation, is continuous with the upper border of the ascending aorta and begins at the level of the upper edge of the second sternocostal articulation of the right side.
The arch of the aorta, or the transverse aortic arch, is continuous with the upper border of the ascending aorta and begins at the level of the upper border of the 2d sternocostal articulation of the right side. The arch of the aorta runs at get-go upward, astern, and to the left in front end of the trachea; it is and then directed astern on the left side of the trachea and finally passes downward on the left side of the body of the quaternary thoracic vertebra. At the lower border, this vertebra becomes continuous with the descending aorta.
Three vessels come out of the aortic arch: the brachiocephalic artery, the left common carotid avenue, and the left subclavian artery. These vessels supply blood to the caput, cervix, thorax and upper limbs. In approximately 20% of individuals, the left common carotid artery arises from the brachiocephalic artery rather than the aortic curvation, and in approximately seven% of individuals the left subclavian artery too arises here.
Thoracic Aorta
The thoracic aorta is the section of the aorta that travels through the thoracic cavity to carry claret to the head, cervix, thorax and artillery.
Learning Objectives
Explain the office of the thoracic aorta
Central Takeaways
Key Points
- The thoracic aorta is contained in the posterior mediastinal cavity, begins at the quaternary thoracic vertebra where it is continuous with the aortic arch, and ends in front of the lower border of the 12th thoracic vertebra.
- Branches from the thoracic aorta include the bronchial arteries, the mediastinal arteries, the esophageal arteries, the pericardial arteries, and the superior phrenic avenue.
- The thoracic aorta and the esophagus run parallel for most of its length, with the esophagus lying on the right side of the aorta. At the lower part of the thorax, the esophagus is placed in forepart of the aorta, situated on its left side shut to the diaphragm..
Fundamental Terms
- mediastinal cavity: The central compartment of the thoracic cavity. It contains the eye, the great vessels of the middle, the esophagus, the trachea, the phrenic nerve, the cardiac nerve, the thoracic duct, the thymus, and the lymph nodes of the central chest.
- Thoracic Aorta: Contained in the posterior mediastinal crenel, information technology begins at the lower border of the fourth thoracic vertebra where it is continuous with the aortic arch, and ends in front of the lower edge of the 12th thoracic vertebra, at the aortic hiatus in the diaphragm where it becomes the abdominal aorta.
The thoracic aorta forms role of the descending aorta and is continuous with the aortic arch at its origin before becoming the abdominal aorta. Contained within the posterior mediastinal crenel, it begins at the lower border of the fourth thoracic vertebra where information technology is continuous with the aortic arch, and ends in front of the lower edge of the twelfth thoracic vertebra at the aortic hiatus in the diaphragm. At its commencement, the thoracic aorta is situated on the left of the vertebral column; it approaches the median line as it descends, and at its termination lies directly in front of the column.
The thoracic aorta's relation, from above downward, is as follows: anteriorly with the root of the left lung, the pericardium, the esophagus and the diaphragm; posteriorly with the vertebral column; on the right side with the hemiazygos veins and thoracic duct; and on the left side with the left pleura and lung. The esophagus lies on the right side of the aorta for most of its length, just at the lower function of the thorax is placed in front end of the aorta and close to the diaphragm, situated on its left side.
Every bit it descends in the thorax, the aorta gives off several paired branches. In descending order these are the bronchial arteries, the mediastinal arteries, the esophageal arteries, the pericardial arteries, and the superior phrenic artery. The posterior intercostal arteries are branches that originate throughout the length of the posterior aspect of the thoracic aorta.
Abdominal Aorta
The intestinal aorta is the largest artery in the abdominal crenel and supplies blood to most of the intestinal organs.
Learning Objectives
Depict the abdominal aorta
Central Takeaways
Key Points
- The abdominal aorta lies slightly to the left of the midline of the body.
- The intestinal aorta has a venous counterpart called the junior vena cava that travels parallel to information technology on its right side.
- The abdominal aorta branches into many arteries that supply blood to the abdominal organs.
Fundamental Terms
- abdominal aorta: The largest artery in the abdominal crenel. As part of the aorta, it is a direct continuation of the descending aorta (of the thorax).
- omentum: Either of two folds of the peritoneum that support the viscera.
- inferior vena cava: The large vein which returns blood from the lower extremities and the pelvic and abdominal organs to the correct atrium of the middle.
The abdominal aorta is the largest artery in the abdominal crenel. As part of the descending aorta, it is a direct continuation of the thoracic aorta.
It begins at the level of the diaphragm, crossing information technology via the aortic hiatus. This pigsty in the diaphragm that allows the passage of the great vessels at the vertebral level of T12. The abdominal aorta travels down the posterior wall of the belly, inductive to the vertebral column, following the curvature of the lumbar vertebrae. The abdominal aorta runs parallel to the inferior vena cava, located just to the correct of the abdominal aorta.
The abdominal aorta lies slightly to the left of the midline of the torso. It is covered anteriorly past the lesser omentum and tummy. Posteriorly, it is separated from the lumbar vertebrae by the anterior longitudinal ligament and left lumbar veins.
The abdominal aorta supplies blood to much of the intestinal cavity through numerous branches that go smaller in diameter equally it descends. Terminally it branches into the paired common iliac arteries, which supply the pelvis and lower limbs.
Arteries of the Pelvis and Lower Limbs
The abdominal aorta divides into the major arteries of the leg: the femoral, popliteal, tibial, dorsal human foot, plantar, and fibular arteries.
Learning Objectives
Outline blood flow in the arteries of the pelvis and lower limbs
Key Takeaways
Central Points
- The pelvic crenel is supplied past the paired internal iliac arteries.
- The internal iliac artery divides into posterior and anterior trunks which supply the reproductive and other organs of the pelvis with blood.
Primal Terms
- internal iliac arteries: Formed when the mutual iliac artery divides the internal iliac artery at the vertebral level L5 descends inferiorly into the lesser pelvis.
The pelvic cavity is largely supplied by the paired internal iliac arteries, formed when the common iliac avenue divides the internal iliac artery at the vertebral level L5 descends inferiorly into the lesser pelvis. The external iliac artery passes into the thigh, condign the femoral avenue.
At the most superior edge of the greater sciatic foramen, the large opening to the rear of the pelvis, the internal iliac avenue divides into inductive and posterior trunks.
The anterior trunk gives rise to numerous arteries that supply the organs of the pelvis and the gluteal and adductor muscles of the leg. Key branches include the obturator artery, the inferior vesical artery in men and the equivalent vaginal artery in females, and the rectal and gluteal arteries.
The posterior torso gives rise to arteries that supply the posterior pelvic wall and the gluteal region, including the iliolumbar artery that supplies the psoas major musculus, the lateral sacral arteries, and the superior gluteal artery.
Main Veins
Veins are claret vessels that behave blood towards the heart, accept sparse, inelastic walls, and incorporate numerous valves.
Learning Objectives
Distinguish amid the main veins of the circulatory organisation
Key Takeaways
Key Points
- Veins, blood vessels which return blood to the heart, are unlike in structure and part from the arteries, which acquit blood to the circulation.
- Almost veins carry deoxygenated claret from the tissues back to the heart. The exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the eye, only the umbilical vein deteriorates shortly after nascence.
- The venae cavae are ii big veins which drain into the right atrium of the heart, returning the majority of claret from the systemic circulation.
Key Terms
- vein: A blood vessel that transports blood from the capillaries back to the heart.
In the circulatory system, veins are blood vessels that carry blood towards the heart. Veins have thin, inelastic walls, and contain numerous valves in lodge to prevent backflow of blood. Most veins acquit deoxygenated claret from the tissues dorsum to the heart with the exceptions of the pulmonary and umbilical veins, both of which carry oxygenated claret to the heart.
Veins can be broadly classified based on their depth within the body. Superficial veins are located close to the surface of the body and have no respective arteries, such every bit the great saphenous vein which runs the length of the leg. The deep veins prevarication deeper in the trunk and often run next to corresponding arteries, such as the femoral vein which sits adjacent to the femoral artery in the thigh. Deep veins are often of larger caliber than superficial veins and bear the bulk of the claret inside the circulatory system. Communicating veins, or perforator veins if they laissez passer through a large muscle mass, straight connect superficial and direct veins. The above veins form office of the systemic circulatory arrangement. The pulmonary veins and venules that run from the lungs to the heart form part of the pulmonary circulatory system and are singled-out from other veins in that they behave oxygenated blood.
Venae Cavae
The venae cavae are the veins with the largest diameter. Both enter the right atrium of the centre with the superior vena cava carrying blood from the artillery, head, and thoracic cavity and the inferior vena cava carrying blood from the legs and belly. The inferior vena cava runs parallel to the abdominal aorta.
The superior vena cava is formed from the brachiocephalic veins which are in turn formed from the subclavian and internal jugular veins that serve the arm and head respectively. The inferior vena cava is formed from the common iliac veins that serve the legs and abdomen. The renal and hepatic veins from the kidneys and liver respectively as well feed into the inferior vena cava.
Other Important Veins
Other important venous systems include the cardiac veins, which return blood from the heart tissue back to the general apportionment. The cardiac veins merge into the coronary sinus, which empties directly into the right atrium.
The pulmonary veins are big blood vessels which receive oxygenated claret from the lungs and render it to the left atrium of the heart. There are 4 pulmonary veins, two from each lung, each of which forms from three to four bronchial veins. In approximately 25% of individuals, the left pulmonary veins may merge into a single vein; the same effect on the right side is merely seen in approximately 3% of individuals.
The hepatic portal vein carries blood from the gastrointestinal tract to the liver. The portal vein is often described every bit a simulated vein because information technology conducts claret between capillary networks rather than between a capillary network and the middle. It functions to supply the liver with blood and required metabolites, but also ensures that ingested substances are first candy in the liver before reaching the wider systemic circulation.
Veins of the Head and Cervix
In the caput and neck, blood circulates from the upper systemic loop, which originates at the aortic curvation.
Learning Objectives
Outline the flow of blood in veins in the head and neck
Primal Takeaways
Key Points
- The dural sinuses inside the dura mater surrounding the brain receive blood from the brain. From these sinuses, claret eventually enters the internal jugular vein.
- The caput and neck are emptied of blood by the internal and external jugular veins.
Primal Terms
- jugular vein: Any of several veins on each side of the neck that drain the brain, face and neck of deoxygenated blood.
2 principal jugular veins are responsible for the venous draining of the head and neck.
The superficial external jugular vein is formed from the retromandibular vein and the posterior auricular vein at a bespeak side by side to the mandible. The external jugular vein passes down the neck and underneath the clavicle before draining into the subclavian vein.
The deep-lying internal jugular vein receives blood from the dural venous sinuses in the brain besides as the cognitive and cerebellar veins. Dural sinuses are equanimous of dural mater lined with endothelium, making them singled-out from arteries, veins, and capillaries. The dural sinuses receive blood from the veins that drain the brain and skull.
Formed at the base of operations of the encephalon from the inferior petrosal sinus and the sigmoid sinus, the internal jugular vein runs down the side of the neck adjacent to the internal carotid avenue. Also as removing blood from the brain, the anterior retromandibular, facial, and lingual veins also drain into the internal jugular. Upon exiting the neck, the internal jugular vein merges with the subclavian vein to form the brachiocephalic vein.
Additional veins such as the occipital, deep cervical, and thyroid veins drain direct into the brachiocephalic vein.
Veins of the Upper Limbs
The veins of the upper extremity are divided into superficial and deep veins, indicating their relative depths from the skin.
Learning Objectives
Distinguish betwixt the superficial and deep veins of the upper limbs
Key Takeaways
Primal Points
- The brachial, radial, and ulnar veins are the major deep veins that drain blood from the arm.
- The major superficial veins of the arm include the cephalic and basilic veins, also as the median cubital vein which joins the two at the elbow.
- At the shoulder, the brachial and basilic veins merge to form the axillary vein, to which the cephaliac vein merges to form the subclavian vein.
Central Terms
- brachial vein: Runs from the elbow to the shoulder parallel to the brachial artery.
- cephalic vein: Arises from the dorsal venous network of the hand and passes the elbow anteriorly, standing upwardly the upper arm to the shoulder.
- median cubital vein: The vein that links the basilic and cephalic veins.
- basilic vein: Located medially to the cephalic vein, following a like path.
Veins of the arm are either deep or superficial and are responsible for draining the mitt and arm.
The major deep veins of the arm are the radial and ulnar veins, which run along the length of their respective bones and merge at the elbow to form the paired brachial vein. The brachial vein runs from the elbow up to the shoulder parallel to the brachial artery.
The major superficial veins of the upper limb are the cephalic, median cubital and basilic veins. The cephalic vein arises from the dorsal venous network of the paw and passes the elbow anteriorly, continuing up the upper arm to the shoulder. The basilic vein follows a similar path but is located medially to the cephalic vein. At the elbow, the basilic and cephalic veins are linked by the median cubital vein, from which claret is oftentimes drawn.
At the shoulder, the basilic vein passes deep into the arm and merges with the brachial veins to form the axillary vein, to which the cephaliac vein merges, forming the subclavian vein.
Veins of the Thorax
The veins of the thorax drain deoxygenated claret from the thorax region for return to the heart.
Learning Objectives
Differentiate among the veins of the thorax
Key Takeaways
Key Points
- Major veins of the thorax include the superior and inferior vena cava.
- The superior vena cava is formed past the left and right brachiocephalic veins, which receive blood from the upper limbs, head and neck.
- The inferior vena cava returns blood from the abdomen and lower limbs. The hepatic veins of the liver and renal veins of the kidney drain directly into the inferior vena cava.
Primal Terms
- supreme intercostal vein: A paired vein that drains the commencement intercostal space on its corresponding side.
- internal thoracic vein: Drains the breast wall and breasts.
- inferior vena cava: Returns blood from the abdomen and lower limbs to the right atrium of the heart.
- superior vena cava: Formed from the left and correct brachiocephalic veins, this vein returns deoxygenated claret from the upper half of the body and carries blood from the upper limbs, head, and neck via the thyroid and jugular veins.
Two venae cavae render deoxygenated claret from the systemic apportionment to the right atrium of the center.
The superior vena cava, formed from the left and right brachiocephalic veins, returns deoxygenated blood from the upper half of the trunk and carries blood from the upper limbs, head, and cervix via the thyroid and jugular veins. It is joined merely before entering the centre by the azygos vein, which runs up the right side of the thoracic vertebral column and transports blood from the external thoracic cavity.
The internal thoracic vein is a vessel that drains the chest wall and breasts. Bilaterally, information technology arises from the superior epigastric vein, accompanies the internal thoracic artery forth its class, and terminates in the brachiocephalic vein.
The supreme intercostal vein is a paired vein that drains the first intercostal space on its corresponding side. It usually drains into the brachiocephalic vein.
The inferior vena cava returns blood from the abdomen and lower limbs to the right atrium of the heart. The renal veins from the kidney and hepatic veins of the liver drain directly into the inferior vena cava. Additionally, the superior and inferior phrenic veins drain the diaphragm and unremarkably open into the internal mammary vein and inferior vena cava, respectively.
Veins of the Abdomen and Pelvis
The major veins of the abdomen and pelvis render deoxygenated blood from the abdomen and pelvis to the heart.
Learning Objectives
Place the veins of the belly and pelvis
Primal Takeaways
Key Points
- The external iliac vein, the upward continuation of the femoral vein, passes upwardly along the pelvis and ends to class the common iliac vein.
- The tributaries that feed into the external iliac vein include the inferior epigastric, deep iliac circumflex, and pubic veins.
- The inferior epigastric vein refers to the vein that drains into the external iliac vein and arises from the superior epigastric vein.
Key Terms
- External iliac vein: Large veins that connect the femoral veins to the common iliac veins
- Common iliac vein: Formed by the external iliac veins and internal iliac veins.
A number of veins remove deoxygenated blood from the abdomen and pelvis. The external iliac vein, the upward continuation of the femoral vein, passes upward along the pelvis and ends to form the common iliac vein.The tributaries of the external iliac vein are the inferior epigastric, deep iliac circumflex, and pubic veins.
The internal iliac vein begins most the upper part of the greater sciatic foramen, the large opening at the rear of the pelvis, passes upward behind and slightly medial to the internal iliac artery and, at the brim of the pelvis, joins with the external iliac vein to grade the common iliac vein.
The left and right common iliac veins come together in the belly at the level of the fifth lumbar vertebra, forming the intestinal vena cava. They drain blood from the pelvis and lower limbs.
The superior epigastric vein refers to a blood vessel that carries deoxygenated blood and drains into the internal thoracic vein. It anastomoses with the junior epigastric vein at the level of the omphalos and drains the anterior part of the abdominal wall and some of the diaphragm.
The inferior epigastric vein refers to the vein that drains into the external iliac vein and arises from the superior epigastric vein.
The deep circumflex iliac vein is formed by the union of the venae comitantes of the deep iliac circumflex artery, and joins the external iliac vein about two cm higher up the inguinal ligament.
Veins of the Lower Limbs
The deep veins of the lower extremity have valves for unidirectional menses and accompany the arteries and their branches.
Learning Objectives
Outline the flow of blood in the veins of the lower limbs
Key Takeaways
Key Points
- The tibial veins unite to form the popliteal vein.
- The femoral vein is the ascending office of the popliteal vein.
- The femoral vein accompanies the femoral avenue into the thigh. It is later on joined by the great saphenous vein forming the external iliac vein.
Key Terms
- popliteal vein: Derived from the merging of the tibial veins information technology forms the femoral vein mid thigh.
- great saphenous ve: A long vein which runs the length of the leg before joining the femoral vein to form the external iliac vein.
- Femoral Vein: A blood vessel that accompanies the femoral avenue in the thigh. It merges with the great saphenous vein to form the external iliac vein.
- Tibial Vein: Blood vessel of the calves which render blood from the foot, talocrural joint and dogie and merges into the popliteal vein behind the knee.
The deep veins of the leg accompany the arteries and their branches and possess numerous valves that aid in unidirectional blood flow. The musculature of the leg is cardinal in generating force per unit area in the veins to prevent pooling.
The posterior and inductive tibial veins return blood from the dogie, talocrural joint, and pes and merge into the popliteal vein behind the articulatio genus. The popliteal vein so carries blood from the articulatio genus articulation upwardly through the thigh. Mid-thigh, it becomes the femoral vein, which is closely associated with the femoral artery. The femoral vein merges with the smashing saphenous vein in the groin to form the external iliac vein.
Running the full length of the leg, making it the longest vein in the torso, the great saphenous vein is a superficial vein that returns blood from the human foot and superficial muscles of the leg before merging with the femoral vein to course the external iliac vein.
Source: https://courses.lumenlearning.com/boundless-ap/chapter/circulatory-routes/
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