Page 215-238: Cardiovascular System
• Transports nutrients, respiratory gases, wastes and heat.
• Transports immunecells and antibodies
• Transports hormones
• Blood is carried AWAY from the heart in ARTERIES
• Blood is carried TOWARDS the heart in veins
Heart-->Arteries-->Arterioles-->Capillaries( Allowsexchange of materialsbetween blood and cells)
• Lining of blood vesselsis the ENDOTHELIUM. Interior of blood vesselsis the LUMEN.
• Inner endothelium wall.
• Middle elasticfiber and smooth muscle layer. Allowsartery to stretch and adapt to pressure
changes to keep a relativelyeven pressure within the artery.
• Outer layeris sheath of connective tissue containing fibers and collagen. Outer layeradds
strength to wall and anchors to tissue.
• Our pulse is created by this expansion and recoil of arteries.
• Aneurysm: Weakenedarterial wall leading to the artery wall swellingoutwards. Biggestriskis
that the aneurysm will burst or clot.
• Connects arteriolesand venules
• Thin wallsto allow substances to move between the blood and fluidoutside capillary.
• Plasmamembranein endothelial cells is selectivebarrier
• Network of capillariesfor a particular area are the CAPILLARY BED.
• PRECAPILLARY SPHINCTERS: Valves that open and close capillarybeds
• Blood flows slowerthrough capillariesbecause of the small size, but largecross sectional area
• Wallsare thinner then arteries with lumenlargerto allow veinsto hold a large volumeof
• Valvesin veins prevent backflow of blood to allowblood from lower parts of the body to make
it back up to heart.
• Skeletal muscle contractions squeezesveins to push it up towards heart.
• Breathing changes pressure. Chest cavity increase in inhalation reduces pressures in thoracic
cavity causing blood to move towards the area of lowerpressure (towards heart).
• MYOCARDIUM is the wall of the heart
• ENDOCARDIUM is the thin lining in heart cavities
• PERICARDIUM is thick sac that holds the heart in the center of the thoracic cavity
• RIGHT SIDE-->Lungs to be oxygenated. Through the pulmonary circuit.