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Arteries
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Dr Badri Paudel www.badripaudel.com
Characteristics of blood vessels
Arteries and arterioles carry blood away from heart Capillaries- site of exchange Venules, veins- return blood to heart
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Endothelium- prevents platelet aggregation secretes substances that control diameter
of blood vessel Tunica media- smooth muscle and connective tissue. Innervated by sympathetic nerves (vasoconstriction) Missing in smallest arteries
Tunica externa- connective tissue; is vascularized
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Capillaries most permeable (and more permeable in some parts than others) Especially so in liver, spleen and red marrow (so cells can enter and leave circulation) Blood flow can vary to different parts of the body, too
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What does this mean?
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Blood is forced through arteries and arterioles vessel walls are too thick for blood components to pass through In capillaries, oxygen and nutrients move out by diffusion; CO2 in (via lipid membrane, channels, etc.) Blood pressure moves molecules out by filtration Plasma proteins maintain osmotic pressure of blood 5/1/12 8
Returning blood to the heart Venules are continuous with capillaries; take in some returned fluid (rest is retained by tissues or returned to blood via lymphatic System) Veins have thinner walls; less muscle; but can hold much more blood
Many veins in limbs have valves to prevent Backflow (Varicose veins arise when pressure on valves is prolonged) 5/1/12 9 5/1/12 10
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Major arteries and veins of the systemic circuit
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The branches of the arch of aorta can be remembered as ABCS:
n A = Arch of Aorta n B = Brachiocephalic artery n C = Left common carotid artery n S = Left subclavian artery
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Aor$c Arch
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Aor$c Arch 5/1/12 17
External caro$d Artery
ECA a8er origin from the common caro$d artery takes a slightly curved course upwards and anteriorly before inclining backwards to the space behind the neck of the mandible.
Within the paro$d gland, it branches terminally into the superficial temporal and maxillary arteries. Along its course, it rapidly diminishes in size and as it does so, gives of various branches.
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Some Angry Lady Figured Out PMS
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Ext. caro$d a 5/1/12 21 5/1/12 22
Clinical aspects of External Caro1d Artery (ECA)
1. The 2 main vessels supplying the meninges are the meningeal branches of the occipital and maxillary arteries. Vasodila1on of these vessels creates excessive pressure on the sensory receptors within the meninges, resul1ng in a headache.
2. Superficial temporal artery is palpable on the zygoma1c process.
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3. Middle meningeal artery which is the branch of Maxillary artery ascends through the foramen spinosum and helps to supply the meninges. Its prac1cal importance is that it may be torn in a skull fracture and result in the forma1on of an extradural haematoma.
4. External caro1d artery stenosis may follow caro1d endarterectomy
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Aorta
• The thoracic aorta is contained in the posterior medias/nal cavity.
• It begins at the lower border of the fourth thoracic vertebra where it is con/nuous with the aor/c arch, and ends in front of the lower border of the twel;h thoracic vertebra, at the aor/c hiatus in the diaphragm where it becomes the abdominal aorta.
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Branches of Abd Aorta
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Abdominal Aorta
Celiac Artery • Le; Gastric Artery -‐ Supplies blood to the esophagus and por/ons of the stomach.
• Hepa/c Artery -‐ Supplies blood to the liver. • Splenic Artery -‐ Supplies blood to the stomach, spleen, and pancreas.
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• Superior Mesenteric Artery -‐ Supplies blood to the intes/nes.
• Inferior Mesenteric Artery -‐ Supplies blood to the colon.
• Renal Arteries -‐ Supplies blood to the kidneys. • Ovarian Arteries -‐ Supplies blood to the female reproduc/ve organs.
• Tes/cular Arteries -‐ Supplies blood to the male reproduc/ve organs. 5/1/12 28
Internal Iliac Artery • The internal iliac artery (formerly known as the hypogastric artery) is the main artery of the pelvis.
• It is a short, thick vessel, smaller than the external iliac artery, and about 3 to 4 cm in length.
• The internal iliac artery supplies the walls and viscera of the pelvis, the buWock, the reproduc$ve organs, and the medial compartment of the thigh.
• The vesicular branches of the internal iliac arteries supply the bladder.
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Branches
iliolumbar artery, lateral sacral artery, superior gluteal artery, inferior gluteal artery, middle rectal artery, uterine artery, obturator artery, inferior vesical artery, superior vesical artery, obliterated umbilical artery, internal pudendal artery
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Femoral Artery
• The artery which supplies the greater part of the lower extremity is the direct con$nua$on of the external iliac.
• It runs as a single trunk from the inguinal ligament to the lower border of the Popliteus, where it divides into two branches
• the anterior and posterior /bial. The upper part of the main trunk is named the femoral, the lower part the popliteal.
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Branches.—The branches of the femoral artery are:
Superficial Epigastric; Deep External Pudendal, Superficial Iliac Circumflex, Muscular Superficial External Pudendal, Profunda Femoris.
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The branches of the femoral artery
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As the Common femoral artery (CFA) can o8en be palpated through the skin, it is o8en used as a catheter access artery
The CFA is suscep$ble to peripheral arterial disease. When a CFA is blocked through atherosclerosis, percutaneous interven$on with access from the opposite CFA may be needed.
The common femoral artery can be used to draw arterial blood. Presence of a femoral pulse has been es2mated to indicate a systolic blood pressure of more than 50 mmHg, as given by the 50% percen2le. 5/1/12 34
Popliteal Artery
• In human anatomy, the popliteal artery is defined as the extension of the "superficial" femoral artery a;er passing through the adductor canal and adductor hiatus above the knee.
• The termina/on of the popliteal artery is its bifurca/on into the anterior /bial artery and posterior /bial artery.
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• The branches of the popliteal artery are: anterior $bial artery, posterior $bial artery, sural artery,medial superior genicular artery, lateral superior genicular artery, middle genicular arterylateral inferior genicular artery, medial inferior genicular artery
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Posterior $bial artery
• The posterior /bial artery of the lower limb carries blood to the posterior compartment of the leg and plantar surface of the foot, from the popliteal artery. It is accompanied by a deep vein, the posterior /bial vein, along its course.
• It typically gives rise to the fibular artery.It also gives rise to medial plantar artery and lateral plantar artery.In addi$on a calcaneal branch to the medial aspect of the calcaneus. 5/1/12 38
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• The posterior $bial artery pulse can be readily palpated posterior and inferior to the medial malleolus and is o8en examined by physicians when assessing a pa$ent for peripheral vascular disease.
• It is very rarely absent in young and healthy individuals; in a study of 547 healthy individuals only one person did not have a palpable posterior $bial artery.
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Anterior $bial Artery
• The anterior /bial artery of the lower limb carries blood to the anterior compartment of the leg and dorsal surface of the foot, from the popliteal artery.
• It is accompanied by a deep vein, the anterior /bial vein, along its course.
• It crosses the anterior aspect of the ankle joint, at which point it becomes the dorsalis pedis artery.
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dorsalis pedis artery
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Axillary artery
• In human anatomy, the axillary artery is a large blood vessel that conveys oxygenated blood to the lateral aspect of the thorax, the axilla (armpit) and the upper limb.
• Its origin is at the lateral margin of the first rib, before which it is called the subclavian artery.
• A;er passing the lower margin of teres major it becomes the brachial artery.
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"She Tastes Like Sweet Apple Pie."
First part (1 branch): Superior thoracic artery (Supreme thoracic artery)
Second part (2 branches): Thoraco-‐acromial artery, Lateral thoracic artery.
Third part (3 branches): Subscapular artery, Anterior humeral circumflex artery, Posterior humeral circumflex artery
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Brachial artery
• It con$nues down the ventral surface of the arm un$l it reaches the cubital fossa at the elbow. It then divides into the radial and ulnar arteries which run down the forearm.
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Radial and ulnar artery
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Radial Artery
• The artery's pulse is palpable in the anatomical snuff box and on the anterior aspect of the arm over the carpal bones
• Presence of radial pulse has been es2mated to indicate a systolic blood pressure of more than 70 mmHg
• The radial artery is used for coronary artery bypass gra@ing and is growing in popularity among cardiac surgeons.
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Dural venous sinuses
• The dural venous sinuses (also called dural sinuses, cerebral sinuses, or cranial sinuses) are venous channels found between layers of dura mater in the brain.
• They receive blood from internal and external veins of the brain, receive cerebrospinal fluid (CSF) from the subarachnoid space, and ul/mately empty into the internal jugular vein.
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dural venous sinuses • The walls of the dural venous sinuses are composed of dura mater lined with endothelium, a specialized layer of flaWened cells found in blood vessels.
• They differ from other blood vessels in that they lack a full set of vessel layers (e.g. tunica media) characteris$c of arteries and veins. It also lacks valves as seen in veins.
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Clinical relevance
• The sinuses can be injured by trauma. Damage to the dura mater, which may be caused by skull fracture, may result in blood clot forma$on (thrombosis) within the dural sinuses.
• While rare, dural sinus thrombosis may lead to hemorrhagic infarc$on with serious consequences including epilepsy, neurological deficits, or death.
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Superior venacava
The superior vena cava (also known as the precava or SVC) is truly superior, a large diameter, yet short, vein that carries deoxygenated blood from the upper half of the body to the heart's right atrium.
It is formed by the le; and right brachiocephalic veins, (also referred to as the innominate veins) which also receive blood from the upper limbs, head and neck, behind the lower border of the first right costal car/lage. 5/1/12 59
• The azygos vein (which receives blood from the rib cage) joins it just before it enters the right atrium, at the upper right front por/on of the heart. It is also known as the cranial vena cava in animals.
• No valve separates the superior vena cava from the right atrium. As a result, the (right) atrial and (right) ventricular contrac/ons are conducted up into the internal jugular vein and, through the sternocleidomastoid muscle, can be seen as the jugular venous pressure. In tricuspid valve regurgita/on, these pulsa/ons are very strong. 5/1/12 60
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Superior vena cava syndrome (SVCS)
• is usually the result of the direct obstruc/on of the superior vena cava by malignancies such as compression of the vessel wall by right upper lobe tumors or thymoma and/or medias/nal lymphadenopathy.
• The most common malignancies that cause SVCS is bronchogenic carcinoma. Cerebral edema is rare, but if it occurs it may be fatal
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Bronchogenic carcinoma-‐SVC Obstruc$on
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Inferior Vena Cava
• is the large vein that carries de-‐oxygenated blood from the lower half of the body into the right atrium of the heart.
• It is posterior to the abdominal cavity and runs alongside of the vertebral column on its right side (i.e. it is a retroperitoneal structure).
• It enters the right atrium at the lower right, back side of the heart.
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• Health problems aWributed to the IVC are most o8en associated with it being compressed (ruptures are rare because it has a low intraluminal pressure).
• Typical sources of external pressure are an abdominal aor$c aneurysm, the gravid uterus and abdominal maligancies, such as colorectal cancer, renal cell carcinoma and ovarian cancer.
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• Since the inferior vena cava is primarily a right-‐sided structure, unconscious pregnant females should be turned on to their le8 side (the recovery posi$on), to relieve pressure on it and facilitate venous return.
• In rare cases, straining associated with defeca$on can lead to restricted blood flow through the IVC and result in syncope (fain$ng).
• Occlusion of the IVC is rare, but considered life-‐threatening and is an emergency. It is associated with deep vein thrombosis, IVC filters, liver transplanta$on and instrumenta$on (e.g. catheter in the femoral vein) 5/1/12 67
Lympha$c duct • largest vessel of the lympha$c system. • The thoracic duct collects LYMPH from the CISTERNA CHYLI and the le8 upper body, and drains into the le8 subclavian VEIN to deliver lymph to the bloodstream.
• a distance of about 16 inches long. • Rhythmically contract and contains valves to prevent its contents from back flowing.
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• Muscular movement, such as occurs with physical ac$vity or exercise, massages lymph through the thoracic duct toward the subclavian vein.
• Several branches of lymph vessels feed into the thoracic duct as it courses through the chest, rejoining to form a single segment that intersects with the subclavian vein beneath the clavicle.
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It collects most of the lymph in the body (except that from the right arm and the right side of the chest, neck and head, and lower le8 lobe of the lung, which is collected by the right lympha$c duct) and drains into the systemic (blood) circula$on at the le8 brachiocephalic vein between the le8 subclavian and le8 internal jugular veins.
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• In adults, the thoracic duct transports up to 4 L of lymph per day.
• The lymph transport in the thoracic duct is mainly caused by the ac$on of breathing, aided by the duct's smooth muscle and by internal valves which prevent the lymph from flowing back down again.
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When the thoracic duct is blocked or damaged a large amount of lymph can quickly accumulate in the pleural cavity, this situa$on is called chylothorax.
The first sign of a malignancy (especially an intraabdominal one) may be an enlarged Virchow's node, a lymph node in the le8 supraclavicular area, in the vicinity where the thoracic duct emp$es into the le8 subclavian vein. 5/1/12 73
Axillary lymph nodes
The Axillary lymph nodes are of large size, vary from twenty to thirty in number, and may be arranged in the following groups:
brachial lymph nodes (or "lateral") pectoral axillary lymph nodes (or "anterior") subscapular axillary lymph nodes ("posterior") central lymph nodes apical lymph nodes (or "medial” or "subclavicular")
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• About 75% of lymph from the breasts drains into the axillary lymph nodes, making them important in the diagnosis of breast cancer.
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Inguinal Lymph nodes
• Inguinal lymph node is a type of lymph node in the inguinal region.
• It can refer to: Superficial inguinal lymph nodes and Deep inguinal lymph nodes
• The superficial inguinal lymph nodes form a chain immediately below the inguinal ligament.
• The superficial nodes drain to the deep inguinal lymph nodes.
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Deep inguinal lymph • The deep inguinal lymph nodes are located medial to the femoral vein and under the cribriform fascia.
• There are approximately 3 to 5 deep nodes. The superior-‐most node is located under the inguinal ligament and is called Cloquet's node.
• The presence of swollen inguinal lymph nodes are an important clinical sign because swelling may indicate an infec$on spread from cancers, such as anal cancer and vulvar cancer. 5/1/12 79
Paraaor$c LN
• The paraaor/c lymph nodes (also known as para-‐aor/c, periaor/c, peri-‐aor/c, and lumbar) are a group of lymph nodes that lie in front of the lumbar vertebral bodies near the aorta.
• These lymph nodes receive drainage from the lower gastrointes/nal tract and the pelvic organs.
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