Arterial and Venous Supply

Artery  Arterioles  Capillaries  Venules  Veins Types of Blood Vessels Artery – carry blood away from heart to arterioles Arterioles – carry blood from arteries to capillaries. “Resistance Vessels” Vein – carry blood to the heart from the Venules-Acts as collector and reservoir vessels. “Capacitance Vessels” Capillaries – carry blood from Arterioles to Venules. Artery  Arterioles  Capillaries  Venules  Veins

Structure of Blood Vessel Three layers for both arteries and veins Tunica adventitia Tunica media Tunica intima

Tunica Adventitia Outermost layer Flexible Fibrous Connective Tissue Helps hold vessel open Prevents tearing of vessel In veins – thickest layer In arteries – middle layer is thicker

Tunica Media Middle layer Made of smooth muscle with a layer of elastic connective tissue Allows blood vessel to change diameter Thicker in Arteries than in veins

Tunica Intima Inner most layer Made of endothelium In arteries – smooth lining In veins forms semilunar valves

Capillaries Only one layer – Endothelium One layer allows for diffusion between plasma and interstitial fluid Function in delivery and collection of substances – “Exchange Vessels”

Control of Blood Flow Precapillary sphincters – circular, valve-like muscle at arteriole-capillary junction Vasoconstriction – narrowing blood vessel’s lumen (“passageway” Vasodilation – explanding blood  vessel’s lumen

Blood Flow Blood flow through veins – not very efficient. Slow, weak “pushing” by arterial blood pressure is not much of a factor at all. Important factors include: 1. Contraction of the diaphragm. 2. Pumping action of the skeletal muscles. 3. Valves in the veins.

Circulatory Routes Systemic Circulation – blood flows from the left ventricle of the heart through blood vessels to all parts of the body, excluding lungs, and back to the right atrium. Pulmonary Circulation – Venous blood moves form right atrium to right ventricle to pulmonary artery to lung capillaries where gas exchange occurs, then returns to left atrium and left ventricle.

Some Major Arteries Carotids (Common, Internal and External) Subclavian Brachiocephalic Brachial Radial Ulnar Coronary Celiac Splenic Renal Mesenteric (Inferior and Superior) Abdominal Aorta Iliac (Common, Internal and External) Femoral Popliteal Tibial (Anterior and Posterior)

Some Major Veins Facial Jugular (External and Internal) Brachiocephalic Subclavian Cephalic Auxiliary Vena cava (Superior and Inferior) Pulmonary Cardiac (Great and Small) Basilic Hepatic and Hepatic portal Spleenic Mesenteric (Inferior and Superior) Iliac (Common, External and Internal) Femoral Saphenous (Great and Small) Popliteal Tibial (Anterior and Posterior)

Sites To Take Pulse Temporal Artery Facial Artery Common Carotid Artery Brachial Artery Radial Artery Femoral Artery Popliteal Artery Posterior Tibial Artery Dorsalis Pedis Artery

Aneurysm An aneurysm is a balloon-like bulge in an artery. http://www.nhlbi.nih.gov/health/dci/Diseases/arm/arm_types.html

Stents A stent is a wire metal mesh tube used to prop open an artery during angioplasty. The stent is collapsed to a small diameter and put over a balloon catheter. It's then placed into the area of the blockage. Then the balloon is inflated, the stent expands, locks in place and forms a scaffold. The stent stays in the artery permanently, holds it open, improves blood flow to the heart muscle.  Within a few weeks the inside lining of the artery grows over the stent. http://www.americanheart.org/presenter.jhtml?identifier=4721

Stent Video Video Showing a Stent and Angioplasty (Mayo Clinic)