FIG. 7.47 Diagram of blood flow in the cardiovascular system. Blood leaves the heart through arteries, then travels through arterioles, capillaries, venules, and veins before returning to the opposite side of the heart. AV, Atrioventricular; SL, semilunar. (From Patton KT, Thibodeau GA: The human body in health & disease, ed 6, St Louis, 2014, Mosby.)
• Capillaries
• Venules
Anatomy
• Important blood vessels for review purposes:
• Abdominal aorta
• Carotid artery
• Jugular vessels
• Internal and external iliac arteries
• Femoral artery
• Popliteal artery
• Venae cavae
• Layers (both arteries and veins)
• Tunica adventitia: outer layer consisting of vaso vasorum, which supplies nutrient to the vessels
• Tunica media: middle layer consisting of smooth muscle that gives it the ability to dilate and contract
• Tunica intima: inner layer of smooth endothelium
• Veins contain valves that prevent backflow of blood
TABLE 7.1
Comparison of Arteries and Veins
| Arteries | Veins |
| Thick, elastic walls | Thinner, less elastic walls |
| No valves | Valves |
| Blood moves when the heart contracts | Blood moves when skeletal muscle contracts |
| Pressure is high | Pressure is low |
| Situated deeper from the surface of the skin | Situated closer to the skin |
| Injury results in rapid blood loss | Injuries bleed slowly |
Physiology
• Blood pressure: Force exerted on the arterial wall by the pumping of heart cycle
• Systole: occurs during the contracture of ventricles
• Diastole: occurs during ventricles are filling and relaxed
Procedures
• Angioplasty
• Embolectomy or thrombectomy
• Abdominal aortic aneurysm (AAA) repair
• Carotid endarterectomy (Fig. 7.49)
• Femoral-popliteal bypass
• Femoral-tibial bypass
• Aorto-femoral bypass
• Arteriovenous fistula and sinus
Additional Facts to Remember
Peripheral Vascular Diagnostic Procedures
• Arterial plethysmography
• This procedure is performed to check blood flow in the arteries of the legs. This is done in people with conditions like hardening of the arteries (atherosclerosis) that causes pain during exercise or poor healing of leg wounds.
• Three blood pressure cuffs are required: one on each arm and the third on one of the thighs.
• Each cuff’s reading produces a waveform that is then compared with the readings from the other two cuffs
• Arteriography
• This procedure involves the use of contrast medium.
• Viewing is done with the use of fluoroscopy or CT scan.
• It is performed before or during surgery or as an interventional procedure.
• Doppler scanning
• This procedure is performed to intensify the sounds of blood flowing in the vessels.
• The pitch, rhythm and quality of the sound reflect the pressure, volume, and flow rate of the blood.
