The Circulatory System By Alex Kannel, Anya Novikova, Carolyn Gee, and Jacob Mingolla

The Circulatory System includes... - blood: a circulating connective tissue, and is made up of liquid plasma (water and dissolved materials) and cells - blood + interstitial fluid = internal environment (5) -blood vessels (vascular system): "channels" that carry blood around the body, to and from all tissues -arteries, veins, capillaries -valves: keep blood moving in one direction; prevent backflow in veins -heart: muscular pump that moves blood

Function of the Circulatory System: - rapid internal transport of substances (food, hormones, metabolic wastes, and gases) to and from tissues, "highway system" (5) - blood is the transport medium of circulatory systems(5) - maintains favorable internal conditions (the volume/composition/temp of interstitial fluid) (5)

Parts of the Circulatory System: Pulmonary Circulation: o delivers blood to and from lungs (oxygenates blood) o travels in a short loop from the heart's right side to capillary beds in both lungs, then returns to the left side o driven by right side of the heart(5) Systemic Circulation: o travels in a longer loop o carries oxygenated blood away from the left side of the heart to the rest of the body, returns oxygen-poor blood to the right side of the heart o driven by left side of the heart Lymphatic System: flow of blood removes products of cellular breakdown and bacterial invasion from the body

Circulatory System Structure:

Structure of the Human Heart:

Circulatory System Video:

Type of Blood Vessel:Structure:Function: Arteries: - Comprised of smooth muscle fiber cells that relax/contract based on signals from the nervous system to help keep blood moving(1). -thick wall -branch into arterioles, then capillaries -Transports oxygenated blood away from the heart. -control blood flow Capillaries: - Blood vessels of about 5-20 micrometers - Found in every major organ - Thin walls (only one cell thick), made of endothelium cells (5) -converge to form venules - diffusion zones b/w blood and interstitial fluid where gases are exchanged - provide Surface Area for gas exchanges - close to cells to increase diffusion rate Veins: -The outer layers consist of 3 layers of tissue, while the interior consists of a series of valves which aid in it's function. -thin, stretchy, not as much muscle -muscular to transport low pressured blood -Transports deoxygenated blood to the heart; after gases, nutrients, and wastes are exchanged -can store blood if flow slows down

Main Types of Blood Vessels Cont.

Both Arteries and Veins are composed of... endothelial cells(6) elastin smooth muscle loose fiberous connective tissue epithelial cells

Arteries: carry blood away from heart(1). carry oxygenated blood more muscle/elastic tissue carry blood under higher pressure do not have valves Veins: carry blood towards heart (1). carry deoxygenated blood less muscle/elastic tissue carry blood under lower pressure have valves, which help prevent blood from moving backwards in the vein

Gas Exchange Diagram:

Gas Exchange in the Circulatory System: Diffusion: oxygen (carried in red blood cells) diffuses across capillary walls into cells if <1mm away, while carbon dioxide diffuses into blood in capillaries to be returned to the heart(5). o If too far away (in non-optimal places) diffusion will not occur, but since capillaries are so small, red blood cells are forced to be close to the walls o Hemoglobin - transfers oxygen in the blood from the lungs to the rest of the body, diffuses into the cells o When the blood moves closer to its destination, the size of the blood vessels decreases to the point that gases can freely move across and out of the blood stream

Factors increasing gas exchange: o lower pH (blood has a pH range of ) o temperature increases o increased levels of CO 2 For example, when skeletal muscles become more active, they increase the temperature and lower the pH, changing the structure of the hemoglobin and increasing the amount of oxygen diffused to the cell (3). o the thickness of the non-capillary blood vessels stops gas exchange by being too thick to allow gas to diffuse through

Gas Exchange in the Circulatory System (continued): Bulk Flow: water and solutes moved across capillary wall because of ultrafiltration and reabsorption(5). o Ultrafiltration: at beginning, small amount of protein-free plasma is pushed out through clefts in capillary wall because outward- directed force of blood pressure greater than inward-directed osmotic force o Reabsorption: at end, there is less blood pressure so inward- osmotic force greater than outward force of blood pressure, so moves through clefts into capillaries o net outward movement o important in maintaining distribution of extracellular fluid between blood and interstitial fluid

Bibliography 1."Blood Vessels." Ivy-Rose. IvyRose.ltd, n.d. Web. 8 Nov < rose.co.uk/HumanBody/Blood/Blood_Vessels.php>. 2. "Circulatory and Gas Exchange Systems." LSU. Web. 8 Nov "Human Physiology - Respiration." Eastern Kentucky University. Biology 301. Harvey Project, n.d. Web. 9 Nov "Cardiovascular System." Rose, Lane P. Partners In Assistive Technology Training and Services. N.p., 1 Oct Web. 9 Nov Starr, Cecie, and Ralph Taggart. Biology: The Unity and Diversity of Life. 9 Har/Cdr ed. New York: Brooks/Cole Pub Co, Print. 6. "High Blood Pressure." Weber, Craig. Web. 9 Nov "Circulatory and Respiratory Systems." Bellermine. Web. 9 Nov