Blood and blood vessels

Arteries

  • Arteries go away from the heart, from the heart to the body

  • High pressure

  • It has a lot of oxygen, The blood in the arteries is filled with red blood cells that have hameoglobin attached to oxygenate the blood

  • Oxyhemoglobin forms when hemoglobin in red blood cells binds with oxygen molecules in the lungs causing a bright red colour

  • Our protected as they are deep inside the body as the blood the carry is of high importance

Veins:

  • go from the body to the heart

  • Low blood pressure so valves are neccesary

  • Less oxygen causing a dark red colour

  • Veins closer to the surface

Capillaries:

  • they are between the arteries and veins. The blood flows the from the Arteries → Arterioles → Capillaries → Venules → Veins. Capillaries connect the smallest arteries (arterioles) to the smallest veins (venules).Take the blood to and cells from the body

  • Capillaries are the site of exchange between blood and cells. They bring oxygen, nutrients, and other substances close to the cells.

  • Cells are surrounded by interstitial fluid, where capillaries release oxygen and nutrients, and cells deposit carbon dioxide and waste.The substances diffuse across the thin capillary walls into the interstitial fluid, which the cells then absorb.

Capillaries structure:

Allow exchange of oxygen, nutrients, and waste products between blood and tissues.

  • Walls are one cell thick (endothelium).

  • No muscle or elastic layers.

  • Extremely narrow (only wide enough for one red blood cell to pass through).

Arteries Structure:

  • It has Thick walls to withstand high blood pressure.

  • It has the 3 layers. The outer layer has Tough connective tissue. The Middle layer has a thick layer of smooth muscle and elastic fibers. The Inner layer Endothelium lining.

  • It has Narrow lumen to maintain high pressure.

• Carry oxygenated blood away from the heart (except the pulmonary arteries).

Veins Structure:

  • it has Thinner walls than arteries (less muscle and elastic tissue) because veins carry blood under low pressure.

  • it has Larger lumen to accommodate blood at lower pressure.

  • it Contain valves to prevent backflow of blood and works with endothelium tissue which lines the the inner most layer of the veins to ensure smooth blood flow in one direction and not back flow