The Human Circulatory System

What is Circulation? All living things must capture materials from their environment that enables them to carry on life processes. Single celled organisms “capture” materials from their environment through diffusion. In larger organisms, these “materials” not only have to be captured, but also circulated to all cells in the organism.

Human Circulatory Functions Transport oxygen gas (hemoglobin). Transport carbon dioxide gas. Transport food molecules (lipids, carbos, amino acids). Transport hormones. Maintain body temperature. Works with immune system to help fight disease.

Blood In 1628, William Harvey demonstrated that blood travels in one direction and in a “closed circuit.” Blood is pumped out of the heart to all parts of the body to “drop off” materials and “pick up” waste products. Blood is a “liquid tissue” that consists of different parts.

Blood Composition

Blood Vessels Arteries=Oxygenated (exception is pulmonary artery) Veins=Deoxygenated (exception is pulmonary vein) Oxygen gas leaves the blood here in the capillaries ARTERY  CAPILLARY  VEIN

“Double Loop System” TO/FROM THE LUNG to pick up oxygen and drop off carbon dioxide TO/FROM THE BODY to drop off oxygen and pick up carbon dioxide

Human Heart 4 Chambers!!! ON TOP: atria pick up blood from body 2 “COLLECTING” chambers ON BOTTOM: pumps blood to body. 2 “PUMPING” chambers

Human Heart Anatomy 4 Chambers! Largest Artery! Septum separates right and left halves Tricuspid valve

Human Heart Right half: accepts oxygen poor blood from body and pumps this blood to the lungs to pick up oxygen. Left half: pumps O 2 rich blood to body

RED-BLOOD WITH OXYGEN BLUE-BLOOD W/O OXYGEN

Go with the Flow! 5. Pulmonary vein from lung (oxygenated!) 6. Left atrium 7. Left ventricle 8. Aorta out to body 1.Vena Cava from body (deoxygenated!) 2. Right atrium 3. Right ventricle 4. Pulmonary artery to lungs

Blood Pressure When ventricles contract, blood is forced into the arteries Pressure When ventricles relax, pressure decreases. How is blood pressure measured?

Blood Pressure 120/80 mmHg What does this mean? Numerator gives pressure in artery when heart is squeezed (systolic). Denominator gives pressure in artery when heart is relaxed (diastolic).

Blood Chemistry With a blood sample, many things can be studied about the blood. A “CBC” or complete blood count can count the red and white blood cells, platelets, and amount of plasma to look for irregularities.

Cholesterol Cholesterol is needed by the body for making cells and hormones. Two types: HDL and LDL LDL “bad cholesterol” cannot be removed from the body. Builds up on artery walls. HDL “good cholesterol” can be carried to the liver and removed from the body. A “cardiac risk profile” measures the amount of cholesterol in the blood.

Diseases of the Heart “Cardiovascular disease.” Diseases of the heart and blood vessels. Leading cause of death in the U.S. Plaque. Atherosclerosis (blocked arteries). Results in hypertension (high blood pressure), strokes, or heart attacks.

Causes of Cardiovascular Disease Genetics Lack of exercise. Diet high in saturated fats. Cigarette smoking.

Angioplasty