Anatomy and Physiology of Veins and Arteries PDF

# Section IV: Clinical Application ## A. Anatomy and Physiology ### Table 1. Characteristics of Veins and Arteries | Direction of Blood Flow | VEIN | ARTERY | |---|---|---| | Direction of Blood Flow | Back to the heart | From the heart to the body | | Oxygen Concentration | Carry deoxygenated b...

# Section IV: Clinical Application ## A. Anatomy and Physiology ### Table 1. Characteristics of Veins and Arteries | Direction of Blood Flow | VEIN | ARTERY | |---|---|---| | Direction of Blood Flow | Back to the heart | From the heart to the body | | Oxygen Concentration | Carry deoxygenated blood (except pulmonary veins) | Carry oxygenated blood (except pulmonary artery) | | Pressure | Low | High | **VEIN** | Anatomy | Description | |---|---| | Thin outer walls, elastic and muscle layers | | | Location | Closer to the skin | | Valves | Yes | **ARTERY** | Anatomy | Description | |---|---| | Thick outer walls, elastic and muscle layers | | | Location | Deeper in the body | | Valves | No | #### Systemic Circulation * Transports deoxygenated blood from the tissues to the right side of heart * Thinner wall, 10% of vessel diameter * Collapsible and easily distended * Located superficial and deep * Contains valves to prevent backflow of blood * Dark, non-pulsatile blood * Flow rates relatively slow, compared with arterial flow #### Pulmonary Circulation * Pulmonary veins transport oxygenated blood to the left side of the heart * Outermost layer * Connective tissue, supportive layer * Middle layer * Composed of smooth muscle and elastic tissues * Collapsible/Easily distended * Contains nerve fibers for vasoconstriction and vasodilation; change in Temperature, mechanical or chemical imitation may produce spasms #### ARTERY * Transports oxygenated blood rapidly from left heart to organs and tissues * Thicker wall, 25% of vessel diameter * Elastic tissue in walls; maintains pressure during diastole to maintain forward movement of blood * Not likely to collapse * Likely to be deep seated * No valves * Bright red, pulsatile blood flow * Rapid rates of flow compared with venous flow #### Pulmonary Arteries * Pulmonary arteries transport deoxygenated blood to pulmonary capillary bed for oxygen and carbon dioxide exchange * Outermost layer * Thicker layer of connective tissue, compared with veins that supports increased force of blood flow * Middle layer * Composed of more layers of smooth muscle and elastic tissues and more rigid when compared to veins * Likely not to collapse * Regulates blood flow * Vasoconstricts with pain and anxiety (sympathetic nervous system); change in temperature, mechanical, or chemical imitation may produce spasms #### Tunica Intima (Endothelium) **VEIN** * Innermost layer * Single layer of smooth, flat endothelial cells, lining all blood vessels, including veins, arteries, heart and valves, and capillaries * Damage to this layer exposes underlying collagen layer and initiates activation of platelets to create a platelet plug, which activates clotting cascade to deposit fibrin in the platelet plug * Thrombus formation of larger deeper veins can lead to venous thrombosis™ **ARTERY** * Innermost layer * Single layer of smooth, flat endothelial cells, lining all blood vessels * Damage to this layer can cause thrombus formation; loosening of a thrombus may cause significant embolic events such as stroke (brain), pulmonary embolus (lung) end organ compromise, or deep vein thrombosis in the lower extremity #### Valves **VEIN** * Found in the larger veins of the extremities * Composed of endothelial leaflets * Function is to keep blood flowing toward the heart * Occur at points of branching and often cause noticeable bulge in veins **ARTERY** * N/A ## Table 2. Venous Anatomy | VEIN | ANATOMIC ROUTE | CLINICAL CONSIDERATIONS | |---|---|---| | Metacarpal | Along lateral-distal portion of fingers | Fingers may require splinting/ immobilization Increased risk for Infiltration DO NOT USE | | Digital | Dorsum of hand Formed by the union of the digital veins between the knuckle | Easily accessible; lies flat on the back of hand Painful Not recommended for most populations |