Unit 5 Lesson 4
(1) What conditions are being maintained by the cardiovascular system? Think in terms of homeostasis.
The cardiovascular system supplies the central nervous system with glucose and oxygen, assisting in the maintenance of human homeostasis. The kidneys are assisted by the cardiovascular system's maintenance of blood pressure so that wastes can be filtered out of the body. The cardiovascular system also assists in maintaining temperature. When the body overheats, blood vessels that serve the skin dilate. Warm blood is then rushed to the superficial capillaries of the skin. The heat from this blood radiates off the skins surface. When body temperature falls too low, skin capillaries restrict. This prevents warm blood from reaching the surface of the skin. - Stephen
(2) Describe the similarities and differences in structure of arteries and veins. How does their structure make them fit for their purpose?
The arteries carry blood away from the heart, but the veins carry it to the heart. The arteries are much muscular blood vessels they are much bigger and thicker than regular veins. The veins contain valves that prevent backflow of blood. The veins are smaller because they must go deeper into the body to get to the heart, but the arteries are bigger and can carry more blood from the heart.
(3) Describe the structure of capillaries and how each of the following substances are transported from blood to tissues: water, oxygen, sugars, proteins, leucocytes.
Capillaries are connected to one side of a vein and one side of an artery. Unlike the veins and arteries capillaries are very thin and very fragile. The process where oxygen is transported takes places through the thin wall. The red blood cells inside of the capillaries release their oxygen and the oxygen passes through the wall.
(4) List and describe the four processes that can be described as respiration. Which one occurs entirely within cells?
Four processes that can be described as respiration are ventilation, pulmonary gas exchange, gas transport, and peripheral gas exchange. The one that occurs entirely within cells is the peripheral gas exchange.
(5) Why can we hold our breath for only short periods of time?
We can not hold our breath for a long period of time because we have a constantly warm temperature in our body which means we need to maintain the energy to keep us warm.