Circulatory SystemBy Alex, Sarah, Carter, and Emily

Main structures in the circulatory system

Blood- fluid that transports oxygen, nutrients, and other solutes to cells. It carries away the cells’ metabolic waste and hormones and serves as a highway for phagocytic cells, which fight infection and scavenge debris in different tissues. Equalizes body temp. by carrying excess heat from skeletal muscles and other areas of high metabolic activity to the skin, where the heat can be dissipated. Blood vessels- the tubes that blood flows through to reach certain parts of the body Heart- muscular pump that keeps blood moving through the vessels by generating pressureVideo on heart function: https://www.youtube.com/watch?v=H04d3rJCLCE up to 1:07Capillaries- small blood vessels that branch out and slow down the velocity to facilitate diffusionInterstitial fluid- solution of water dissolved with nutrients, hormones, gases, and waste that surrounds all cells

What is the structure of the circulatory system?

The circulatory system is like a highway of garbage trucks, carrying supplies for activity to cells and removing their waste. In humans, the heart is fully partitioned into two halves. Blood circulates in two circuits, the pulmonary and systemic. The heart acts like two side by side pumps. The right half pumps oxygen-poor blood to the lungs, where it gets more oxygen and gets rid of CO2. Then, the oxygenated blood is pumped back to the left side of the heart. This is called the pulmonary circuit. In the systemic circuit, the left half pumps the fresh blood to every cell in the body where O2 is used. Then it takes the cells CO2 waste back to the right half, where it can be sent to the lungs and reoxygenated. The double circuit is a rapid, efficient method of blood delivery. It supports the high metabolic activity of human cells.

Diagrams

Three Main Blood Vessels● Arteries (thick walls)● Veins (thin walls)● Capillaries (very thin walls)● transport blood - contains plasma, white and red blood cells, and platelets● entire circulatory system is lined with endothelial cells, thin layer of cells

that line blood vessels, form an interface between circulating blood in the lumen and the rest of the vessel wall

Arteries● carry blood away from the heart to the tissues● most carry oxygenated blood with the exceptions of the

- pulmonary artery (carries deoxygenated blood from the heart to the lungs) - umbilical artery (supply deoxygenated blood from the fetus to the placenta)

● blood is under high pressure, due to elasticity does not use muscles to “pump” blood

Arteries Continued● largest artery is the aorta, the main high-pressure

pipeline connected to the heart's left ventricle● impermeable, plasma cannot seep out● thick middle layer - smooth muscle and elastic fibers● small internal diameter/lumen● no valves● strength and elasticity withstand the pulsing of blood,

prevent bursting, and maintain pressure wave

Arteries vs. Veins

Veins● carries blood back to the heart● carries deoxygenated blood except the pulmonary vein

-during exercise when blood must circulate faster the smooth muscle contracts, the wall then stiffens causing the vein to bulge, therefore the venous pressure increases and sends more blood back to the heart● venous pressure can be increased by heavy breathing

and muscle movement

Veins Continued● impermeable● no pulse, cannot feel the pumping from the heart● thin walls ● less muscle and elastic fibers as it is low pressure● valves to prevent backflow● wide lumen for easy flow, less resistance against the

blood flow

Veins

Capillaries● slow downs the blood that enters them● smallest of the blood vessels ● connect arteries and veins● so narrow that the walls are only one cell thick● allow nutrients, oxygen, and fluids to pass into tissue,● collect carbon dioxide waste materials and fluids for

return through the veins to the lungs and the lymph system

Capillaries continued● strong walls are not required due to low blood pressure● thin walls and narrow lumen allow blood to come in

close contact with tissues, just large enough for red blood cells to pass through

- allows diffusion between capillaries and surrounding tissues, white blood cells can squeeze between cells of the wall

Gas Exchange● Hemoglobin, a protein in Red Blood Cells, create weak bonds with Oxygen

to transfer the nutrient through the circulatory system to nourish other cells. Hemoglobin with or without oxygen determines color of RBC

● Blood also transfers CO2, hormones, and other waste collected from cells through the circulatory and into our lungs to be exhaled out of our body.

● This process exchanges O2 (hypotonic) into cells that are hypertonic with CO2 -- vice versa

http://www.youtube.com/watch?v=9fxm85Fy4sQ3:15-4:15

Gas Exchange

Gas Exchange in Non-Optimal Places

● Gas exchange cannot take place in areas of the body in which there are veins or arteries because the exchange can only happen in blood vessels with small diameters and a slow blood flow. In large veins, the blood flow is too fast for a reaction to take place and the vessel walls are too thick for diffusion to take place.

Concentration of Oxygen● concentration of oxygen is highest in the lungs● capillaries are where the diffusion takes place to exchange the oxygen● the further away from the heart, the less oxygen as it is being used up and

diffused through the capillaries into the body’s tissues● that is why the oxygen poor blood must go through the veins and return to

the heart then to the lungs for oxygen to be restored● right side of the heart is low in oxygen concentration● left side is rich in oxygen

Nascar Pit Stop: https://www.youtube.com/watch?v=qj-BLx922OI

Heart Diagram

Bibliography● "Arteries, Veins and Capillaries - Structure and Functions." Biology Notes for IGCSE 2014. N.p., n.d. Web. 17 Nov. 2014.

<http://biology-igcse.weebly.com/arteries-veins-and-capillaries---structure-and-functions.html>.● "Blood Vessels." -TheHumanHeart:AnOnlineExplorationfromTheFranklinInstitute,MadePossiblebyUnisys. Franklin

Institute, n.d. Web. 17 Nov. 2014. <http://learn.fi.edu/learn/heart/vessels/vessels.html>.● "Human Heart Diagram - Human Body Pictures - Science for Kids." Human Heart Diagram - Human Body Pictures -

Science for Kids. N.p., n.d. Web. 16 Nov. 2014. <http://www.sciencekids.co.nz/pictures/humanbody/heartdiagram.html>.● "PBS LearningMedia." Red Gold: Blood Journey. PBS, n.d. Web. 17 Nov. 2014.

<http://www.pbslearningmedia.org/resource/pbs_org14_rgesblo_sci_8/red-gold-blood-journey-creation-of-blood-the-circulatory-system/>.

● Wilson, Sue. "Blood in the Body." PBS. PBS, 2002. Web. 17 Nov. 2014. <http://www.pbs.org/wnet/redgold/basics/circulation.html>.