Circulatory system Flashcards
main function of the circulatory system (transport)
transport- transport gases, nutrients, molecules, and wastes
main function of the circulatory system (homeostasis)
homeostasis- regulates internal temperature, and transport hormones
main function of the circulatory system (protection)
protection- protects against bacteria/viruses, toxic substances, and blood loss from injury (via clotting)
what is the heart
muscular organ that pumps blood through the body to generate blood flow
what are blood vessels
veins, arteries, and capillaries that act as roadways for blood
what is blood
carries nutrients, oxygen, carbon dioxide, water, and other materials through the body
arteries (function)
typically carry oxygenated or oxygen rich blood and carries it away from the heart
arteries (movement)
thick, highly elastic walls that keep blood flowing in the correct direction by providing a pumping motion to help force blood through the vessel
- artery expands when a surge of blood rushes through
- artery snaps back when the heart relaxes
arteries (structure)
three layers
- outer layer- connective tissue and elastic tissue
- middle layer- circular bands of elastic tissue and smooth muscle tissue
- inner layer- one cell thick; flat, smooth cells to reduce friction
veins (function)
typically carry deoxygenated or oxygen poor blood and carries it towards the heart
veins (movement)
thin, rigid, non-elastic walls. Larger internal circumference than arteries
veins (structure)
composed of the same three layers like arteries, but they come in different proportions. Have one way valves to prevent blood from flowing backwards (important for when blood needs to flow against gravity, like in legs)
what are varicose veins
when the one way valves become weak and do not close properly, blood can accumulate below the valve and causes them to bulge and become bigger. Factors include age, obesity, poor nutrition, pregnancy and poor posture
capillaries part one
capillaries are extremely small vessels and their walls are one single layer. The diameter is wide enough for a single blood cell to pass through at a time
capillaries part two
much smaller but more abundant than arteries and veins (they spread throughout the entire body in a fine network) they connect arteries and veins to tissues. this is also where gas exchange takes place (the transitions where oxygenated blood transitions to deoxygenated blood)