The Human Circulatory SystemSection 9-2

VeinsVeins have thinner, slightly elastic walls.

Veins have flap-like valves that allow blood to flow in only one direction toward the heart.

The smallest veins are called venules.Venules branch from capillary networks.

CapillariesCapillary networks connect arterioles (smallest arteries) and venules (smallest veins).

Red blood cells pass through capillaries in single file.

RBCs Pass Through Capillaries In Single File

EKG Simulator

Blue:Oxygen PoorBlood.Red: Oxygen Rich Blood.

Lungs replenish the blood with oxygen. How it works: RBCs pick up O2 through diffusion across the capillary membrane.

Can You Label The Parts?

The Circulatory System Interacts With Other Systems To Maintain Homeostasis.

The ECG/EKGECG (or EKG) stands for electrocardiogram. Electrical impulses coordinated by the nervous system control the beating of the heart. An EKG records these impulses.

See Animationhttp://www.medmovie.com/dqt77b/index.htm

Electrical Signals From The Nervous System Coordinate The Beating Of The Heart

The Developing Heart of a Zebrafish Embryohttp://bioimaging.caltech.edu/index_content.html

Note: In Crocodilians, heart is actually completely separated. They can prevent blood from flowing through the pulmonary circuit while underwater by using a muscular valve.

Disorders of the Circulatory SystemDisorders of the circulatory system are very common in this country.

They are the leading cause of death in America every year.

Arteriosclerosis and Atherosclerosis.Arteriosclerosis: a condition involving the hardening of the arteries. When this happens, the heart must work harder to push blood through the circulatory system. In severe cases, the body is unable to get oxygen to all of its cells.Most Common Type:Atherosclerosis: a buildup of fat deposits (plaque) in the innermost lining of medium and large arteries.Plaque: material containing lipids (i.e. cholesterol) and minerals such as calcium.Thrombus: a clot of blood formed within a blood vessel and remaining attached to its place of origin.

Atherosclerosis, contdWhen plaque and blood clots block part of or all of an artery, blood pressure goes up and blood flow can be reduced. See AnimationAtherosclerosis (High Speed)

Plaque

Disorders, ContdMost disorders are a result of arteriosclerosis/atherosclerosis.

They include high blood pressure, heart attack, and stroke.

High Blood PressureHypertension = High Blood Pressure.

Hypertension makes the heart work harder, which can damage the heart and other tissues.

Each pound of fat adds 1 mile of capillaries, forcing the heart to work harder.

Blood Pressure ClassificationClassification of blood pressure levels for adults 18 years and older. Systolic pressure, the higher number of a blood pressure reading, is the pressure as the heart pumps; diastolic pressure is the pressure when the heart relaxes between beats.Microsoft Encarta Encyclopedia 2003. 1993-2002 Microsoft Corporation. All rights reserved.

CategorySystolic BPDiastolic BP

Coronary Heart Disease is a chronic illness in which the coronary arteries, the vessels that supply oxygen-carrying blood to the heart, become narrowed and unable to carry a normal amount of blood. When its blood supply is reduced, the heart does not receive sufficient oxygen. This oxygen deficit leads to two main consequences: chest pain known as angina pectoris, and heart attack, in which part of the heart dies because of oxygen deprivation. Coronary heart disease is the leading cause of death in the United States, responsible for nearly 460,000 deaths each year.Microsoft Encarta Encyclopedia 2003. 1993-2002 Microsoft Corporation. All rights reserved.Coronary Heart Disease/Heart Attack

Treatments for Coronary Heart Disease (CHD)Angioplasty: During angioplasty, the doctor threads a thin tube called a catheter through your artery to insert a balloon. When the doctor inflates the balloon, it opens up the blocked part of the artery. Sometimes a small, flexible tube, called a stent, is placed in the artery and left there to help keep the blood vessel open. This procedure is called stenting. Doctors often recommend angioplasty, and possibly stenting, for people who have angina that isn't helped by medicines. Angina is another name for chest pain. Discovery Health Coronary Bypass Surgery: In bypass surgery, a length of blood vessel is removed from elsewhere in the patients bodyusually a vein from the leg or an artery from the wrist. The surgeon sews one end to the aorta and the other end to the coronary artery, creating a conduit for blood to flow that bypasses the narrowed segment. Surgeons today commonly use an artery from the inside of the chest wall because bypasses made from this artery are very durable.Microsoft Encarta Encyclopedia 2003. 1993-2002 Microsoft Corporation. All rights reserved.

Balloon Angioplasty

Angioplasty often involves a stent.

See AnimationAngioplastyhttp://www.healthscout.com/animation/68/38/main.html

Coronary Bypass Surgery

See AnimationHeart Bypass Surgeryhttp://www.healthscout.com/animation/68/36/main.html

Comparison of Treatments for CHDDiscovery Health

AngioplastyBypass SurgerySurgeryMinorMajorCostLess ExpensiveMore ExpensiveLength of Procedure30 minutes - 2 hours3 hours 6 hoursAnesthesiaLocal (Less Risk)General (Greater Risk)Hospital Stay1-3 days4-7 daysRecovery TimeShortLong (Many Weeks)EffectivenessMay need to be repeated in 6 months.Results normally last longer.

Symptoms of a Heart AttackNauseaShortness of BreathSevere, Crushing Chest Pain

Dietary Approaches to Stop Hypertension (DASH).Prevention

StrokeA Stroke results when blood clots formed as a result of atherosclerosis break free and get stuck in the blood vessels leading to a part of the brain. This is called ischemic stroke. Ischemic strokes happen in about 80% of stroke cases.

A stroke can also happen when a weakened artery in the brain bursts, flooding the area with blood.This is called hemorrhagic stroke. Hemorrhagic stroke happens in about 20% of stroke cases.

Brain cells die from a lack of oxygen, and brain function in that region may be lost.

Strokes can result in death.

Symptoms/Consequences of StrokesParalysisLoss of the ability to speakImpaired speech

Ischemic StrokeEmbolic and thrombolic strokes are the two types of ischemic strokes. In embolic stroke, a blood clot from outside the brain or neck (i.e. heart) blocks a blood vessel of the brain. In thrombolic stroke, a blood clot from the brain or neck blocks a blood vessel of the brain.

Hemorrhagic StrokeIn hemorrhagic stroke, a blood vessel in the brain breaks and leaks blood into its surroundings, leaving a portion of the brain without oxygen. This is a more serious type of stroke than ischemic stroke, and often results from an aneurysm. An aneurysm is a localized enlargement of a blood vessel that forms a bulge or sac. Aneurysms are caused by disease, weakening of the vessels wall, injury, or an abnormality present at birth.

Aneurysms can be the precursors to hemorrhagic stroke.

Regions of the Brain Affected By Stroke

Interactivityhttp://www.klbschool.org.uk/interactive/science/heart.htm

Just For Fun: Watch Web AdvertisementSt. Joseph Aspirin Commercialhttp://www.stjosephaspirin.com/images/stjoseph/pumpblood/index.htmlPump, pump, pumps your Blood.The right atriums where the process begins, where the CO2 Blood enters the heart.Through the tricuspid valve, to the right ventricle, the pulmonary artery, and lungs.Once inside the lungs, it dumps its carbon dioxide and picks up its oxygen supply.Then its back to the heart through the pulmonary vein, through the atrium and left ventricle.Pump, pump, pumps your Blood.

Pump, pump, pumps your Blood.The aortic valves, where the Blood leaves the heart, then it's channeled to the rest of the bod.The arteries, arterioles, and capillaries too bring the oxygenated Blood to the cells. The tissues and the cells trade off waste and CO2, which is carried through the venules and the veins Through the larger vena cava to the atrium and lungs, and we're back to where we started in the heart. Pump, pump, pumps your Blood

Hear the Complete Song Here (Sung by Potsie on Happy Days)