H5 The Transport System

Consists of the heart, blood, and vessels carrying oxygen throughout the body. 2 circuits: pulmonary and systemic. The Transport System

Carries deoxygenated blood from the right side of the heart to the lungs and back to the left side. Pulmonary Circuit

Left side of the heart pumps oxygenated blood throughout the body’s organs. Systemic Circuit

Receiving chambers of the heart. Right atrium receives deoxygenated blood from the body, left atrium receives oxygenated blood from the lungs. Atria

Responsible for pumping blood out of the heart. The tricuspid valve of the right ventricle stops backflow into the right atrium. The bicuspid valve prevents backflow into the left atrium. Ventricles

Vessels Lumen- Opening in blood vessel Tunica intima- Inner layer of vessel made of epithelium cells. Low friction Tunica media- Circular muscle fibers and elastin fibers. Can stretch and contract Tunica adventia-Longitudinal collagen and elastin. Strengthen and link to connective tissues.

Responsible for carrying large volumes of blood from the ventricles and pump into capillaries. Must be able to withstand high blood pressures. Have no valves, thick tunica media and adventia to help prevent hemorrhaging and aneurysms. Arteries

Responsible for transporting blood from capillaries to the atria without leaks and backflow. Depend on muscles to help pump back. Thin tunica media, but thick tunica adventia. Veins

Have to transport blood as close as possible to living cells. Allow substances to enter and leave. Very thin, very narrow. Only one layer of endothelium coated by filter like protein gel. Capillaries

Repeating sequence of events in the heart that results in blood circulation. Consists of systole, or contractions, and diastole, relaxations. The Cardiac Cycle

The atria contract and blood is forced from the atria to the ventricles. 1. Atrial Systoles

Ventricles contract and force blood into arteries. The bicuspid and tricuspid valves are both closed to prevent backflow of blood. 2. Ventricle Systole

Both atria and ventricles are relaxed and the heart fills with blood. Semilunar vales closed to prevent backflow from arteries. 3. Diastole

The contractions of the heart are myogenic. Contraction starts with the sinoatrial node firing an electrical signal throughout the walls of the atria causing systole. The signal then reaches the atrio-ventricular node. It spreads the signal via Purkinje fibers causing ventricular systole. This makes the bi and tricuspid valves shut causing a lub sound. After ventricles empty, the semilunar valves close, causing a dub sound. Controlling the Cycle

Arteriosclerosis Hardening and narrowing of the arteries due to plaque build up. Damage to arteries from high pressure can lead to fats building up in lumen. Clots may form and eventually myocardial infarction.

Several factors that affect risk of having. 1.Exercise 2.Genetics- Having history of high bp or heart attacks. 3.Gender- Males more likely than females 4.Smoking 5.Obesity 6.Diet 7.Age Coronary Heart Disease