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)
flow of blood through the vessel (step one)
blood flow begins at the heart, then it is carried away from the heart to the rest of the body by the arteries. Many arteries branch off from the main artery that exits the heart
flow of blood through the vessel (step two)
the more they branch off, the smaller they become and they become arterioles (smaller arteries)
flow of blood through the vessel (step three)
as the arterioles continue to branch and become smaller, they eventually become capillaries which allow them to exchange gases between the blood and body tissue (also where oxygenated blood becomes deoxygenated)
flow of blood through the vessel (step four)
capillaries merge back to become larger vessels known as venules (smaller veins) which then eventually merge back to become veins and they carry blood back into the heart
what is the coronary pathway
the arteries, veins, and capillaries that supply oxygen and nutrients to and remove waste products from the muscles of the heart itself
structure of the heart part one
composed of cardiac muscle tissue. contractions of the heart are rhythmic and involuntary.
what is the pericardium
the pericardium is a sac that surrounds the heart and is fluid filled membrane that acts as a shock absorber and prevents friction
what are the functions of the heart
- pumping the blood (between the heart and the lungs as well as between the heart and the body tissues)
- keeping oxygen rich and oxygen poor blood separate
- ensuring blood only flows in one direction
what is the atrium (atria for singular)?
the atrium are chambers that fill with blood returning to the heart either from the lungs (left atrium) or from the body (right atrium)
what are the ventricles?
the ventricles are chambers that receive blood from the atria and pump it either to the lungs (right ventricle) or the body (left ventricle)
what is your septum?
your septum is the muscular wall that separates the left and right sides of the heart and keeps oxygenated blood and deoxygenated blood from mixing
difference between superior and inferior vena cava
superior- “collects” deoxygenated blood from coming back from the head, chest, and arms, and brings it back towards the heart
inferior- “collects” deoxygenated blood from the central and lower body and towards the heart
both of them empty into the right atrium
pulmonary arteries
arteries that carry blood from the right ventricle of the heart to the lungs
pulmonary vein
veins that carry blood back from the lungs to the left atrium of the heart
what is the aorta
the largest blood vessel in the body that leaves the left ventricle carrying oxygenated blood to the body. most major arteries branch off from the aorta
valve functions
All valves function to prevent blood
from flowing backwards through the
heart (like the valves in the veins)
Right atrioventricular valve or tricuspid valve
Made up of three flaps and separates the right atrium from the right ventricle
Left atrioventricular valve or bicuspid valve
Made up of two flaps and separates the left atrium from the left ventricle
what are the AV valves held by?
Both AV valves are held in place by chordae tendinae (strong fibrous strings)
what are semilunar valves shape?
Half-mooned in shape
Pulmonary semilunar valve
Found in the pulmonary trunk. Separates right ventricle from the pulmonary
artery
Aortic semilunar valve
Found in the aorta. Separate the left ventricle from the aorta
