The Circulatory System

The Circulatory System By: Bianca Calderone Jenna Kosmo Allie Hedlund and Hollis Toussaint

Overall Function • Body’s delivery system. • Blood flowing from the heart delivers oxygen and nutrients to every part of the body. • Blood going back to the heart picks up waste products so that the body can dispose of them

Main Features • Blood • Transports nutrients, waste, O2, CO2, hormones • 2 pumps (in heart) • One to pump deoxygenated blood to lungs • Other to pump oxygenated blood to other organs and tissues • Blood vessel system • Distributes blood • Organs for exchange of materials between blood & external environment

Functions: Transporting Materials • Gases • O2 goes from lungs to cell • CO2 goes from cells to lungs • Other nutrients • Glucose transported through body (goes to liver) • Other cell waste • Hormones • To help maintain internal conditions

Functions continued • Has cells to fight infection • Helps stabilize pH and ionic concentration of body fluids • Helps maintain body temp. by transporting heat

The Systems Path • From body, through veins, blood is full of CO2 • Into right atrium • Into right ventricle • Through pulmonary arteries • Into lungs, CO2 is replaced with O2 • From lungs, blood is now full of O2 • Through pulmonary veins • Into left atrium • Into left ventricle • Through Aorta • Into body, through arteries

Blood Animation • http://www.argosymedical.com/flash/the_blood/landing.html

Heart • One to pump deoxygenated blood to lungs • Other to pump oxygenated blood to other organs & tissues • http://www bostonscientific.com/templatedata/imports/HTML/lifebeatonline/winter2007/learning.shtml

Veins • Diameter of veins > diameter of arteries • Blood pressure in veins =so low so valves in veins help prevent backflow • Contraction of skeletal muscle during normal body movements, squeezes veins/assists with moving blood back to heart • Vena cava returns blood to right atrium of heart from body • Varicose veins develop when valves weaken • Veins act as blood reservoirs, contain 50% to 60% of blood volume • Smooth muscle in walls of veins expand/contract to adjust flow volume returning to heart and make more blood available when needed.

Vein Animation • http://www.simquest.com/animations/veins.html

Venules • Capillaries merge to form venules • Venules merge into veins • Can constrict due to contraction of smooth muscle • When constricted, more fluid loss in capillaries (increased pressure)

Arteries • Carry blood away from heart • Thick, elastic layer to stretch & absorb pressure (stretches & recoils in response to pumping) • Elastic layer surrounded by circular muscle to control diameter & rate of blood flow • Act as pressure reservoirs by maintaining (storing) pressure • Outer layer of connective tissue provides strength

Arterioles • Smooth muscle surrounding arteries • Control distribution of blood (blood vessels dilate when O2 levels decrease or wastes accumulate) – allows more blood into area to bring oxygen and nutrients or removes wastes

Capillaries • Smallest blood vessels (>1 mm long) • red blood cells travel single file • Vasodilation/vasoconstriction= dilation/constriction of blood vessels • Sphincter muscles control flow of blood to capillaries • Rate of blood flow (velocity) is low (blood pressure is highest in arteries, reduced in capillaries, lowest in the veins)

Interstitial Fluid • Exchange of substances between blood and body cells occurs in capillaries • Specialized for exchange of substances with interstitial fluid • No cell in body is more than 100 micrometers from capillary • Surrounds and bathes the cells • Continually being replaced with fresh fluid from blood in circulatory system • Body cells take up nutrients from fluid and empty wastes into it • Blood pressure forces fluid out and intro surrounding tissues • Blood flows through, fluid moves out, blood that remains behind becomes more concentrated (osmotic pressure = greater near venule end, results in increase in amount of fluid moving into capillary)

Portal Veins • Connect one capillary bed with another • Hepatic portal vein connects capillary beds in digestive tract with capillary beds in the liver

Endothelial Cells • Cells lining the blood vessels are called endothelial cells • Their structure is flat, which forms pavement like patterns on the inside of vessels • Good for function: keep the vessels from leaking • Acts as a selective barrier • Surface molecules act as receptors and interaction sites

Picture Bibliography • http://www.nhlbi.nih.gov/health/dci/images/ather_lowres.gif • http://www.uic.edu/classes/bios/bios100/lecturesf04am/bloodvessels_1.gif • http://www.scifly.co.uk/client_files/AQA%20Additional%20Science/diffusion_into_capillary_3.jpg • http://www.southdartmoor.devon.sch.uk/pe/300px-Diagram_of_the_human_heart_cropped.svg.png

Bibliography • Gregory, Michael. "Circulatory System". Clinton CC. Nov 9, 2009 <http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/Bio 102/Bio 102 lectures/Circulatory system/circulat.htm>. • Abdallah, Hasan. "How the Heart Works: Blood Flow Diagram". Children's Heart Institute. Nov 9, 2009 <http://www.childrensheartinstitute.org/educate/heartwrk/bloodflw.htm>. • Bailey, Regina. "Capillary". About.com. Nov 9, 2009 <http://biology.about.com/od/anatomy/ss/capillary.htm>. • McGeachie, John. "Blue Histology - Vascular System: Blue Histology - Vascular System." School of Anatomy and Human Biology - The University of Western Australia. 02/09/98. The University of Western Australia, Web. 6 Nov 2009. <http://www.lab.anhb.uwa.edu.au/mb140/MoreAbout/Endothel.htm>. • U.S. National Institutes of Health, . "Classification & Structure of Blood Vessels." SEER Training Modules. 2008. National Cancer Institute, Web. 6 Nov 2009. <http://training.seer.cancer.gov/anatomy/cardiovascular/blood/classification.html>. • "Capillaries." Web. 6 Nov 2009. <http://www.bbc.co.uk/schools/gcsebitesize/pe/images/capillaries.gif>.

The Circulatory System