Circulatory system

Circulatory System

• Organ system that transports oxygen, nutrients, and heat throughout the body and carries away carbon dioxide and wastes

• 3 main components:

  • Blood

  • Blood vessels

  • Heart

Blood

• 4 components:

  • Red blood cell

  • White blood cell

  • Platelet

  • Plasma

Red blood cell

• 45% of blood volume

• Biconcave disk with no nucleus

• Contains a protein, hemoglobin, that helps to transport oxygen 

• Makes the blood appear red

White blood cell

• <1% of blood volume

• Fights against infections

• Contains nucleus

Platelet

• <1% of the blood volume

• Helps with clotting if a blood vessel is damaged

• Much smaller than red blood cells and white blood cells

• No nucleus

Plasma

• 55% of blood volume

• Contains proteins, gases, hormones, and other substances dissolved in water

• Appears yellow

Blood vessels

• 3 main components:

  • Arteries

  • Veins

  • Capillaries

arteries

• Carries blood away from the heart

• High pressure

• Thick muscles lining vessel walls

• Carries oxygenated blood (except for pulmonary artery)

Veins

• Carries blood to the heart

• Low pressure

• Thin muscles lining vessel walls

• Contains valves 

• Carries deoxygenated blood (except for pulmonary vein)

Capillaries

• Tiny blood vessels connecting the veins and the arteries

• Wall and lumen (opening) only one cell thick to allow for gas exchange

• Reaches every part of your body (your cells are never far away from one)

Heart (made of)

• 4 chambers:

  • Left/right ventricles

  • Left/right atria (sing. = atrium)

• Lined with cardiac muscles

• Pumps by electrical signals sent through specialized cells

Blood flow in heart

1. Deoxygenated blood from your body flows into the right atrium from the superior and inferior venae cavae (plural)

2. Deoxygenated blood gets pumped from the right atrium through the tricuspid valve

3. Deoxygenated blood gets pumped from the right ventricle into the pulmonary arteries through the pulmonary valve

4. Deoxygenated blood travels to the lungs from pulmonary arteries, where it becomes oxygenated

5. Oxygenated blood travels back to the heart from the lungs through the pulmonary veins

6. Oxygenated blood from the pulmonary veins flows into the left atrium

7. Oxygenated blood gets pumped from the left atrium to the left ventricle through the mitral valve

8. Oxygenated blood gets pumped from the left ventricle through the aortic valve into the aorta, where it flows into the rest of the body

Problems with the heart

• Heart attack

• Coronary artery disease

  • buildup of plaque in blood vessels