HSCI 100 Study Guide - Midterm Guide: Voltage-Gated Ion Channel, Endoplasmic Reticulum, Vasodilation
9 Apr 2014
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Document Summary
In the cardiovascular system, the heart pumps the blood, and the blood vessels transport blood around the body. Molecule exchanges at capillaries refresh the blood and the tissue fluid (interstitial fluid) as it moves nutrients, wastes, gases, blood cells and more. Blood vessels generally have 3 layers of tissue: an inner endothelium, a smooth muscle layer, and an outer connective tissue layer. Arteries, which branch into smaller arterioles, take blood away from the heart to capillaries. Arteries have thick vessel walls and have high blood pressure. Capillaries are single cell layer thick and carry out exchange with tissue. Flow to capillary beds can be regulated by sphincter muscles and shunt pathways. At tissue capillaries, nutrients and oxygen are exchanged for carbon dioxide and other wastes. In this way, tissue fluid and the body"s cells remain replenished. Leading away from the capillaries, venules join to form veins that take blood back to the heart.
