Circulatory Structures Lab Report

Circulatory Structures

The body's circulation has two parts, with the heart acting as a double pump. Blood from the right side pump is dark red (bluish) and low in oxygen. It travels along pulmonary arteries to the lungs where it receives fresh supplies of oxygen and becomes bright red. It flows along pulmonary veins back to the heart's left side pump.Your heart is about the size of your clenched fist. It has thick muscular walls and is divided into two pumps. Each pump has two chambers. The upper, smaller, thin-walled atrium receives blood coming in from the veins. The blood flows through a one-way valve, which makes sure it always moves in the correct direction, into the larger, lower chamber called the ventricle. It has thick strong walls that contract to squeeze blood through another valve, out into the arteries. Blood leaves the left side of the heart and travels through arteries which gradually divide into capillaries. In the capillaries, food and oxygen are released to the body cells, and carbon dioxide and other waste products are returned to the bloodstream.The blood then travels in veins back to the right side of the heart, and the whole process begins again.

Disease or Disorder:

Varicose veins - distended, visible superficial veins on the legs - are almost always the result of problems with valves within the venous system of the leg. All leg veins contain one-way flap valves which are designed to help the flow of blood in the veins in an upward direction on its return to the heart.

When one or more of these valves fails to function correctly ("leaks"), some blood is able to flow back down into the leg - in the wrong direction - and tends to overfill and distend branches of superficial veins under the skin. Over a period of time, this additional pressure of blood causes the veins to stretch, bulge and become visible. At the same time, tiny capillary branches of the veins are also overfilled with blood, producing multiple spider veins and purple discoloration.

Function: Transports oxygen, carbon dioxide, nutrients and cells

Major Components: Heart,

blood vessels, lymphatic

vessels