the human circulatory system

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 VesselsArteries=Oxygenated

(exception is pulmonary artery)Veins=Deoxygenated(exception is pulmonary vein)

Oxygen gas leaves the blood herein the capillaries

ARTERYCAPILLARYVEIN

“Double Loop System”

TO/FROM THE LUNGto pick up oxygen and drop off carbon dioxide

TO/FROM THE BODYto drop off oxygen and pick up carbon dioxide

Human Heart4 Chambers!!!

ON TOP: atria pick up blood from body 2 “COLLECTING” chambers

ON BOTTOM: pumps bloodto body.2 “PUMPING” chambers

Human Heart Anatomy4 Chambers! Largest

Artery!

Septum separatesright and left halves

Tricuspidvalve

Human Heart

Right half: accepts oxygenpoor blood from body and pumps this blood to the lungs to pick up oxygen.

Left half: pumps O2 rich bloodto 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 atrium3. Right ventricle4. 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