Arteries, veins, capillaries

• types of blood vessels that create a closed system of tubes that continually deliver blood to form cells and tissues

• the continual movement in called circulation

  • pulmonary (heart lungs heat)

  • systemic (heart body heart)

Arteries

• blood away from the heart

• thick walls with smooth muscles + elastic tissue

  • elastic tissue: stretch + recoil as blood is forced through

  • muscle: with stand high blood pressure and so they can narrow (vasoconstrict) or widen (vasodilate) to control blood flow

  • Vasodilation = more blood in the cell

  • Vasoconstriction = less blood in the cell

Veins (venules)

• blood toward heart

• little/none elastic or muscle tissue

  • very low blood tissue that’s relatively constant

  • have valves to prevent backflow

Capillaries

• link arterioles + venules

• microscopic network close to most cells in body

• walls are one call thick to allow materials to be exchanged

  • O² + nutrients leave blood at arterial end (due to BP + concentration gradient)

  • CO² + waste enter blood at venous end (due to osmotic pressure + concentration gradient)