Bozeman Circulatory System

1. What kind of system do insects have 1. What kind of system do insects have? ______________________________ How does it differ from the human body’s closed system? Describe the differences between the two. Open System / Insects have hemolymph, which is blood mixed with interstitial fluid. Humans have a closed circulatory system where blood and interstitial fluid are separated. Interstitial fluid is outside of our blood vessels throughout the body.

2. Why do endothermic organisms (warm blooded) need larger more complex hearts? Endothermic organisms require more energy making a need for a more complex system to maintain homeostasis. It is going to take more energy to pump the blood through this type of system. They have a 4 chamber heart that gives the system a double loop which is a more efficient model.

3. Why do veins have valves? Veins have valves so that the blood cannot flow backwards. It has to return to the heart against gravity, so it needs the valves to ensure it flows back towards the heart.

Diastole: Filling / Systole: Pumping 4. Define diastole. ______________________ Define Systole. _________________________ Diastole: Filling / Systole: Pumping

5. Describe how these two functions work together to allow our hearts to pump blood. An electrical impulse is sent out from the sinoatrial node into the left and right atrium causing them to contract. That same impulse is going to travel down to the bottom of the heart sending the same signal across the neurons of the left and right ventricle. The atrium and ventricle alternate contractions which is why we hear two beats. Diastole occurs when the heart muscle relaxes.

Crash Course Extension Questions

1. Name some other ways that organisms can breathe oxygen 1. Name some other ways that organisms can breathe oxygen. Why do we need lungs? ­­­­­­­­­­­­­­­Simple diffusion which allows gases to pass through a wet membrane. arthropods have little pores all over their bodies that allow the oxygen to diffuse through. They have an open circulatory system. Amphibians can take in oxygen through their skin but they can also have lungs or gills to help them respire (breathe). The bigger the animal the more oxygen it needs and we are warm blooded so we must regulate our body temperatures and that takes many calories and burning those calories takes lots of oxygen.

2. Bronchioles branch off into alveoli 2. Bronchioles branch off into alveoli. About how many alveoli are in the human lungs? _____300,000,000__________ Why are the alveoli intertwined or covered with capillaries? This is the area where the deoxygenated blood diffuses the carbon dioxide rich blood across the capillary wall and the alveoli wall, while the oxygenated blood drawn from the lungs diffuses across the alveoli cell wall and then through the capillary cell wall.

3. How do our lungs contract to allow us to breathe? Lungs work like a pump but they don’t have any muscle in them to make them contract and expand. Rather we have this large flat layer of muscles called the thoracic diaphragm When we breathe in the muscles contract and helps stretch your lungs downward and when relaxed the muscle relaxes pushing everything out.

4. What is an endotherm and an ectotherm? Endotherms are warm blooded which means we maintain a narrow internal temperature. 97-99 degrees Fahrenheit. This is good because our bodies are less vulnerable to fluctuating outside temperatures. Ectotherms are cold blooded organisms. Have slow metabolism and don’t need as much oxygen. Their circulatory systems can be far more simple with less chambers, because all of their blood does not have to be oxygenated completely as it flows through out the system.

5. Why do endotherms have to eat constantly? To maintain our high metabolisms and to create heat. This creates a need for a large supply of oxygen to all of the cells, which is why our lungs are so large and we have a complex four chambered heart.