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Circulatory System
SBI 3U
Ms. Raper
Open circulatory system• Found in many
insects• Blood returns to the
heart via the movement of the animal’s body.
• inefficient
http://fajerpc.magnet.fsu.edu/Education/2010/2010_INDEX.HTM
Closed Circulatory System
• Found in some invertebrates such as worms and in fish, reptiles, birds and mammals
• Blood never leaves a system of tubes
• Heart pumps blood around the body
William Harvey 1568 -1657
• Was a physician trained in Italy.
• Was the first to accurately describe the action of the heart pumping blood around the body.
• He confirmed the presence of valves in the veins to prevent the backflow of blood.
• He confirmed his theories by carrying out dissections. http://www.bbc.co.uk/history/historic_figures/harvey_william.shtml
Blood Vessels• Arteries – carry blood AWAY from the heart.
• Veins – carry blood back to the heart – blood returns VIA the veins.
• Capillaries – CONNECT arteries and veins, it is here that substances are loaded and unloaded into the
blood by diffusion.
http://www.owensboro.kctcs.edu/gcaplan/anat2/notes/Notes5%20Circulatory%20Anatomy.htm
Arteries
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookcircSYS.html
•Thick elastic muscular walls
•Small lumen
•Carry oxygenated blood (except pulmonary artery)
•Carry blood away from the heart.
Veins
• Have thin walls
•Large lumen
•Carry deoxygenated blood (except pulmonary vein)
•Have valves to prevent backflow of blood
•Carry blood back to the heart
Circulatory System
Blood vessels
Arteries
• Have a smaller lumen than veins
• Have thick Muscular walls.• Carry oxygenated blood
(except the Pulmonary artery)• Have a pulse• Carry blood away from the
heart• Have blood under high
pressure• Blood is BRIGHT red• A cut artery spurts with the
heart beat.• Main artery is the AORTA
Cross section through an artery.
Capillaries
• Connect arteries and veins.
• Are found in organs.• Are where substances
are dropped off or picked up from the cells
• Are only one cell thick.• Red Blood Cells must
travel through in single file.
• Low pressure• Cut capillaries ooze Cross section of a capillary
• Veins have thinner muscular walls than arteries,
• Have a large lumen,• Have valves to prevent
backflow of blood• Carry blood back to the heart• Carry deoxygenated blood
(except the pulmonary vein)• Have blood that is DARK red.• Low pressure• A cut Vein will gushes.• Main vein is the VENA CAVA
Blood Vessels.
http://iws.ccccd.edu/mweis/Images/Histology/2402%20histology/Circulatory%20Histo/labeled%20circ%20histo/circ_vessels_av_compare_heading.png
Exchange in Capillaries
Coronary Arteries
http://www.patient.co.uk/showdoc/Pilsinl/112.gif
Peripheral Arteries
http://www.patient.co.uk/showdoc/Pilsinl/101.gif
3 parts to the Circulatory System
• Cardiac - blood supply to and through the heart.
• Pulmonary – blood flow through the lungs.• Systemic – blood flow through the body other
than the lungs and heart.• Because blood flows through the heart twice for
every complete circuit, it is referred to as a DOUBLE circulation.