Circulatory System Flashcards
Why do human bodies need circulation?
- our bodies need a way to transport nutrients to and away from cells
- because many cells do not have direct contact with the environment
- unlike amoeba (they are unicellular)
What are the three functions of the circulatory system?
- transport gases, nutrient molecules, and wastes
- regulates internal temperature and transports hormones (homeostasis)
- protects against blood loss from injury and against disease-causing microbes or toxic substances
What is the structure of the circulatory system?
- heart
- blood vessels
- blood (living tissue)
What is the cardiovascular system?
- includes the heart and blood vessels
- A closed system
- blood remains contained in the vessels
- nutrients exchange through vessel walls
What is the blood vessels function?
- The body’s transport system
What are arteries?
- blood vessels that carry blood away from the heart
What are veins?
- Blood vessels that carry blood towards the heart
What is a common misconception about veins?
- veins carry deoxygenated blood
- this is false!!
What are capillaries?
- tiny blood vessels that connect the arteries and veins
- gas and nutrient exchange occur here
What is the structure of arteries? (5)
- elastic walls that can expand and snap back as blood is pumped away from the heart
- keep blood moving in the correct direction with this motion
- Smaller arteries are called arterioles
- thick walls
- Three layers
What are the three layers of the artery walls?
- Connective (elastic) (outer)
- Muscular (elastic)
- Smooth (one cell thick, reducing friction)
What is the structure of veins? (6)
- thinner walls than arteries
- larger inner diameter
- not as elastic as arteries and cannot contract
- muscle contractions in the body push blood through veins
- one-way valves keep blood moving in the correct direction
- Smaller veins are called venules
What is the structure of capillaries? (5)
- walls are one cell thick
- Red blood cells pass-through through in single file (diameter is small)
- fine network for gas and nutrient exchange (large SA)
- most cells of the body are near capillaries, but not every cell (ex. Some fat cells)
- attached to arterioles and venules
What are precapillary sphincters?
- rings of smooth muscle at the ends of arterioles that regulate blood flow into capillaries
- if all sphincters were open, there would not be enough blood in the body to fully fill all the capillaries at once
- hence they regulate blood flow to where it is needed
What do arteries do in terms of providing blood?
- arteries that provide blood to the body from the heart and lungs, carry blood with much oxygen (oxygenated blood)
What do veins do in terms of blood?
- veins that are returning blood from the body to the heart and lungs, carry blood with little oxygen (deoxygenated blood)
How is the pulmonary circuit in the lungs an exception to arteries and veins?
- arteries carry deoxygenated blood, and veins carry oxygenated blood
What is the function of the heart? (4)
- Pumps blood
- keeps oxygenated and deoxygenated blood separate
- ensures One Direction of blood flow in the body
- rhythmic and involuntary cardiac muscle contraction allow for pumping
What is the heart’s structure? (5)
- left and right sides (left on diagram is right irl)
- four chambers [2 atria (singular: atrium) and 2 ventricles]
- left atrium on top left
- left ventricle on bottom left
- right atrium on top right and right ventricle on bottom right
What do the atria do?
- receives blood from the body through the vena cavae, And lungs (pulmonary veins)
What do ventricles do?
- receive blood from the atria
- pumps blood to the body through the aorta
- Pumps blood to the lungs through the pulmonary trunk and pulmonary arteries
What separates the left and right side of the heart?
- muscular wall (septum)