Ch.9 The Vascular System Flashcards
Tiny arteries and veins that supply the walls of the blood vessels
Vasa Vasorum
Middle layer of the vascular system: veins have thinner tunica media than arteries
Tunica media
Outer layer of the vascular system, contains the vasa vasorum
Tunica adventitia
Inner layer of the vascular system
Tunica intima
Communication between two blood vessels without any intervening capillary network
Anastomosis
Minute vessels that connect the arterial and venouis systems
Capillaries
Arises inferior to the celiac axis to supply the proximal half of the colon and the small intestine
Superior mesenteric artery
Vascular structures that carry blood away from the heart
Arteries
Small branch supplying the caudate and left lobes of the liver
Left hepatic artery
The abdominal aorta bifurcates at the level of the umbilicus into these, which supply blood to the lower extremities
Common iliac arteries
Arises from the posterolateral wall of the aorta, travels posterior to the inferior vena cava to supply the kidney
Right renal artery
Branch of the common hepatic artery that supplies the stomach and duodenum
Gastroduodenal artery
Largest arterial structure in the body; arises from the left ventricle to supply blood to the head, upper and lower extremities, and abdominopelvic cavity
Aorta
Arises from the anterior aortic wall at the level of the third or fourth lumbar vertebra to supply the left transverse colon, descending colon, sigmoid colon, and rectum
Inferior mesenteric artery
Arises from the celiac axis to supply the stomach and lower third of the esophagus
Left gastric artery
Arises from the celiac axis to supply the spleen, pancreas, stomach, and greater omentum
Splenic artery
Arises from the celiac trunk to supply the liver
Common hepatic artery
Supplies the gallbladder via the cystic artery
Right hepatic artery
Arises from the posterolateral wall of the aorta directly into the hilus of the kidney
Left renal artery
Supplies the stomach
Right gastric artery
Drains the spleen; travels horizontally across abdomen (posterior to the pancreas) to join the superior mesenteric vein to form the portal vein
Splenic vein
Three lage veins that drain the liver and empty into the inferior vena cava at the level of the diaphragm
Hepatic veins
Formed by the union of the superior mesenteric vein and splenic vein near the porta hepatis of the liver
Portal vein
Leaves the renal hilum to enter the lateral wall of the inferior vena cava
Right renal vein
Collapsible vascular structures that carry blood toward the heart
Veins
Drains the left third of the colon and upper colon and joins the splenic vein
Inferior mesenteric vein
Leaves the renal hilum, travels anterior to the aorta and posterior to the superior mesenteric artery to enter the lateral wall of the inferior vena cava
Left renal vein
Drains the proximal half of the colon and small intestine, travels vertically (anterior to the inferior vena cava) to join the splenic vein
Superior mesenteric vein
Largest venous abdominal vessel that conveys blood from the body below the diaphragm to the right atrium of the heart
Inferior vena cava
Weakening of the arterial wall
Cystic medial necrosis
Permanent localized dilation of an artery, with an increase of 1.5 times the normal diameter
Aneurysm
Thrombosis of the hepatic veins
Budd- Chiari syndrome
Disease of the arterial vessels marked by the thickening, hardening, and loss of elasticity in the arterial walls
Arteriosclerosis
Circumferential enlargement of a vessel with tapering at both ends
Fusiform aneurysm
Transjugular intrahepatic portosystemic shunt
TIPS
Localized dilation of the vessel
Saccular aneurysm
Condition in which the aortic wall becomes irregular from plaque formation
Atherosclerosis
Periportal collateral channels in patients with chronic portal vein obstruction
Cavernous transformation of the portal vein
Tear in the intima or media of the abdominal aorta
Dissecting aneurysm
Communication between an artery and a vein
Arteriovenous fistula
Most commonly results from intrinsic liver disease; however, also results from obstruction of the portal vein, hepatic veins, inferior vena cava, or prolonged congestive heart failure; may cause flow reversal to the liver, thrombosis of the portal system, or cavernous transformation of the portal vein
Portal venous hypertension
Pulsatile hematoma that results from leakage of blood into the soft tissue abutting the puntured artery with fibrous encapsulation and failure of the vessel wall to heal
Pseudoaneurysm
Heredity disorder of connective tissue, bones, muscles, ligaments, and skeletal structure
Marfan syndrome
Permanent dilation of an artery that forms when tensile strength of the arterial wall decreases
True aneurysm
Vessels that have little or reversed flow in diastole and supply organs that do not need a constant blood supply (i.e., external carotid artery and brachial arteries)
Resistive
Flow toward the liver
Hepatopetal
Vessels that have high diastolic component and supply organs that need constant perfussion (i.e., internal carotid artery, hepatic artery, and renal artery)
Nonresistive
Peak systole minus peak diastole devided by the peak systole
Resistive index
Increase turbulence is seen within the spectral tracing that indicates flow disturbance
Spectral broadening
Flow away from the liver
Hepatofugal
Sonographer selects the exact site to record Doppler signals and sets the sample volume (gate) at this site
Doppler sample volume
The root of the aorta arises from the _______ outflow tract of the heart.
Left Ventricular
The _______ passes anterior to the third part of the duodenum and posterior to the neck of the pancreas, where it joins the splenic vein to form the main portal vein.
SMV
The __________supplies the gallbladder via the cystic artery and the liver.
Right hepatic artery
The aprta continues to flow in the __________ cavity anterior and slightly _______ of the vertebral column
Retroperitoneal, left
The _________ trunk is the first anterior branch of the aorta, arising 1 to 2 cm inferior to the diaphragm
Celiac
The __________ flows from the kidney posterior to the superior mesenteric artery and anterior to the aorta to enter the lateral wall of the inferior vena cava
Left renal vein
The diameter of the abdominal aorta measures approximately______cm, tapering to ______ cm after it proceeds inferiorly to the bifurication into the iliac arteries
2-3,1.0-1.5
The _______ is the second anterior branch, arising approximately 2 cm from the celiac trunk.
SMA
Portal veins become _______ as they progress into the liver from the porta hepatis.
Smaller
The _________ courses from the aorta posterior to the inferior vena cava and anterior to the vertebral column in a posterior and slightly caudal direction to enter the hilum of the kidney
Right renal artery
The _________ courses along the upper border of the head of the pancreas, behind the posterior layer of the peritoneal bursa , to the upper margin of the superior part of the duodenum, which forms the lower boundary of the epiploic foramen
Gastroduodenal artery
Three arterial branches arise from the superior border of the aortic arch to supply the head, neck, and upper extremities: the _________, ____________, and __________
Brachiocephalic, left common carotid, and left subclavian
The __________ is formed posterior to the pancreas by union of the superior mesenteric vein and splenic veins at the level of L2
Portal vein
The _______ artery takes a somewhat tortuous course horizontally to the left as it forms the superior border of the pancreas
Splenic
The portion of the femoral artery posterior to the knee is the ____________
Popliteal artery
The __________ originate in the liver and drain into the inferior vena cava at the level of the diaphragm
Hepatic veins
List the five sections into which the aorta is devided
- Root of the aorta
- Ascending aorta and arch
- Descending aorta
- Abdominal aorta and abdominal branches
- Bifurcation of the aorta into iliac arteries
Describe the specific differences between arteries and veins
Arteries are hollow elastic tubes that carry blood away from the heart. They are enclosed within a sheath that includes a vein and a nerve. The smaller arteries contain less elastic tissue and more smooth muscle than the larger arteries. The elasticity of the larger arteries is important for maintaining a steady blood flow. Veins are hollow collapsible tubes with diminished tunica media that carry blood toward the heart. The veins appear collapsed because they have little elastic tissue or muscle within their walls. Veins have a larger total diameter than the arteries, and they move blood more slowly.
List the four branches of the aorta that supply other visceral organs and the mesentery
The celiac trunk, superior and inferior mesenteric arteries, and the renal arteries
The function of the circulatory system is
To transport gases, nutrient materials, and other essential substances to the tissues and subsequently transport waste products from the cells to appropriate sites for excretion
The characteristics of veins are
Vein contain special valves that prevent backflow and permit blood to flow only in one direction- towards the heart. Numerous valves are found within the extremities, especially the lower extremities, because flow must work against gravity. Venous return is also aided by muscle contraction, overflow from the capillary beds, gravity, and suction from negative thoracic pressure.
Describe how blood is transported from the artery and returned by the veins
Blood is carried away from the heart by the arteries and is returned from the tissues to the heart by the veins. Arteries divide into progressively smaller branches, the smallest of which are the arterioles. These lead into the capillaries, which are minute vessels that branch and form a network where the exchange of materials between blood and tissue fluid take place. After the blood passes through the capillaries, it is collected in the small veins, or venules. These small vessels unite to form larger vessels that eventually return the blood to the heart for recirculation.
Describe a capillaries and their function
Capillaries are minute, hair-sized vessels connecting the arterial and venous systems. Their walls have only one layer. The cells and tissues of the body receive their nutrients from fluids passing through the capillary walls: at the same time, waste products from the cells pass into the capillaries. Arteries do not always end in capillary beds; some end in anastomoses, which are end-to-end grafts between different vessels that equalize pressure over vessel length and also provide alternative flow channels.
Describe how Doppler is used to distinguish the presence or absence of flow in a vessel from nonvascular structures
Doppler ultrasound frequently is used to differentiate vessels from nonvascular structures. For example, to distinguish the common bile duct from the hepatic artery, look for direction of flow: to differentiate aneurysm from pancreatic psuedocyst, look for slow flow in the aneurysm; to differentiate dilated intrahepatic bile ducts and prominent hepatic artery, again look for absence of flow in the bile duct
A flow disturbance (increased velocity or obstruction of flow) may result from the formation of an atheroma, AV fistula, ________, or aneurysmal dilation
Pseudoaneurysm
The technique that should be used to image the inferior vena cava
The patient should be instructed to hold his or her breath; this causes the patient to perform a slight Valsalva maneuver toward the end of inspiration which dilates the inferior vena cava. The inferior vena cava may expand to 3-4 cm in diameter with this maneuver.
Nonresistive vessels have a high _______ component and supply organs that need constant perfusion, such as the internal carotid artery, the hepatic artery, and the renal artery
Diastolic
Resistive vessels have very little or even reversed flow in diastole and supply organs that do not need a constant blood supply, such as the ___________ carotid and the iliac and brachial arteries
External
Differentiate the inferior vena cava from the aorta
The pulsatile aorta is easily differentiated from the inferior vena cava because the IVC travels is a horizontal course with its proximal portion curving slightly anterior as it pierces the diaphragm to empty into the right atrial cavity. The aorta, on the other hand, follows the curvature of the spine, with its distal portion lying more posterior, before bifurcating into the iliac vessels
________ is a pattern of blood flow, typically seen in large arteries, in which most cells are moving at the same velocity across the entire diameter of the vessel. In other vessels the different velocities are the result of friction between the cells and arterial walls
Plug flow
Doppler only records accurate velocity patterns when the beam is _______ to the flow
Parallel
The flow pattern of the proximal abdominal aorta above the renal arteries shows a high _________ peak and a relatively low ________ component
Systolic, diastolic
The main renal artery has a(n) _______ impedance (nonresistive) pattern with significant diastolic flow - usually 30% to 50% of peak systole
Low
During rejection, the vascular impedance _________ , resulting in a decrease or even reversal of the diastolic flow
Increases
The portal vein shows a relatively _________ flow at low velocities, which may vary slightly with respirations
Continous
Cavernous transformation of the portal vein demonstrates ___________ collateral channels in patients with chronic portal vein obstruction
Periportal
With a recanalized ________ vein, the main portal vein and the left portal vein show normal flow but the flow in the right portal vein is reserved
Umbilical
Describe the effect of gain settings when performing an abdominal aortic ultrasound
Sagittal scans should be made beginning in the midline with slight angulation of the transducer to the left, from the xiphoid to well below the level of bifurcation of the aorta gradually tapers as it proceeds distally in to abdomen. a low to medium gain should be used to demonstrate the walls of the aorta without “noisy” artifactual internal echoes. These weak echoes may result from increased gain, reverberation from the anterior abdominal wall fat or musculature, or poor lateral resolution. These factors result in echoes being recorded at the same level as those from soft tissues that surround the vessel lumen, particularly if the vessels are smaller in diameter than the transducer. Try to use different techniques of breath holding to eliminate these artifactual echoes. Sometimes increased gentle pressure may help displace the bowel gas or may compress the fatty tissue, so the transducer will be closer to the abdominal aorta. If the abdomen is very concave, the patient may be instructed to “extend his abdomen” (“push the abdomen muscle out”), so as to provide a better scanning plane
The most common causes of aneurysms are _________ and ________________
Arteriosclerosis and atherosclerosis
The large aneurysm may rupture into the peritoneal cavity or retroperitoneum, causing ___________ and a drop in _______
Intense back pain, hematocrit
The normal measurement for an adult aorta is less than 3 cm, measuring from ______ to _______ walls
Outer to outer
Thrombus usually occurs along the _______ or ___________ wall
Anterior or anteriolateral
A(n) __________ is a pulsatile hematoma that results from the leakage of blood into the soft tissue abutting the punctured artery, with subsequent fibrous encapsulation and failure of the vessel wall defect to heal
Pseudoaneurysm
What are the clinical findings in a patient with a dissecting aneurysm?
The typical patient is 40 to 60 years old and hypertensive; male are predominant over females. The patient usually is known to have and aneurysm, and sudden excruciating chest pain radiating to the back may develop because of a dissection. Patients may go into shock very quickly, and CT is generally ordered to obtain the most information in the shortest amount of time. However, patients who present with some symptoms and are stable may have a slow leak aneurysm, and these patients are appropriately imaged with sonography. The sonographer should look for a dissection “flap” or a recent channel with or without frank aneurysmal dilatation. Dissection of blood is noted along the laminar planes of the aortic media with formation of a blood-filled channel within the aortic wall.
Describe the three locations where a dissection of the aorta may occur
Type 1- Dissection begins at the root of the aorta and may extend the entire length of the arch, descending to the aorta and into the abdominal aorta. This is the most dangerous, especially if the dissection spirals around the aorta, cutting off the blood supply to the coronary, carotid, brachiocephalic,and subclavian vessels.
Type 2- occurs secondary to cystic medial necrosis (weakening of the arterial wall), to the inherited disease Marfan’s syndrome or to hypertension. Color Doppler may be used to detect flow into the false channel.
Type 3- Begins at the lower end of the aorta. This may be critical if the dissection spirals around to impede the flow of blood into the renal vessels
Pseudopulsatile abdominal masses may stimulate an aortic aneurysm by
Masses that can stimulate a pulsatile abdominal mass are retroperitoneal tumors, fibroid uterus, and para-aortic nodes. Because the mass is adjacent to the aorta, pulsations are transmitted from the aorta to the mass. After an abdominal aneurysm, the most common cause for a pulsatile abdominal mass is enlarged retroperitoneal lymph nodes
In patients with right ventricular failure, the inferior vena cava does not collapse with _______
Expirations
Describe the complications of inferior vena caval thrombosis
Complete thrombosis of the IVC is life threatening. Patients present with leg edema, low back pain, pelvic pain, gastrointestinal complaints, and renal and liver abnormalities
The most common origin of pulmonary emboli is venous thrombosis from the ______ extremities
Lower
