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 Clot

Blood Vessels

“Double Loop System”

Human Heart

Human Heart Anatomy

Vocabulary Words

• Circulation

• Hormone

• Plasma

• Erythrocyte

• Leukocyte

• Hemoglobin

• Platelets

• Arteries

• Veins

• Capillaries

• Atrium

• Ventricle

• Vena Cava

• Aorta

• Bicuspid valve

• Tricuspid valve

• Pacemaker

• Pulmonary artery

Vocabulary Words cont.

• Pulmonary veins

• Systemic circulation

• Pulmonary circulation

• Jugular vein

• Carotid artery

• Renal vein and artery

• Hepatic vein and artery

• Subclavian artery and vein

• Plaque

• Diastolic pressure

• Systolic pressure

• CBC

• HDL cholesterol

• LDL cholesterol

• Cardiovascular disease

• Atherosclerosis

• Hypertension

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).• With age, arteries become less elastic (less

flexible) and pressure builds up.

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.

Heart Attack

Causes of Cardiovascular Disease

• Genetics• Lack of exercise.• Diet high in saturated

fats.• Cigarette smoking.

Angioplasty