Respiratory and Circulatory Systems

These two systems work together to provide oxygen and food to cells.

Respiratory System Cells of living things require oxygen and food. The respiratory system of some animals is made of the lungs and the passageways that lead to them. Different structures are used for gas exchange in other animals, such as the gills of fish.

Respiratory System A tiger’s respiratory system: As a tiger breathes in air, it enters through the nose and mouth. Air travels through a tube and this tube branches into two smaller tubes called bronchi. Bronchi have branches like a tree. These branches empty into thin- walled sacs called alveoli. The walls of the alveoli are so thin that gases such as oxygen and carbon dioxide pass through them.

Respiratory and Circulatory Systems A tiger’s circulatory system: Circulation begins as oxygen-poor blood gets pumped by the tigers heart to its lungs. In the lungs, the blood carrying carbon dioxide picks up oxygen from the air in the alveoli. At the same time, the blood releases carbon dioxide (a waste product of cells). As the tiger breathes out, carbon dioxide leaves the body.

Respiratory and Circulatory Systems The oxygen-rich blood flows back to the heart. The heart pumps the blood around the body. When it reaches the small intestine, it picks up nutrients. This nutrient-rich and oxygen-rich blood can be delivered to the tiger’s body cells. The blood moves through the body, traveling through blood vessels. As the blood reaches tiny vessels, or capillaries, dissolved nutrients and oxygen can pass through the thin walls and enter cells. Cells pass their waste materials back through the capillaries and into the blood. Oxygen-poor blood gets pumped back to the heart, and the process continues.

What is the main respiratory organ in a mammal? The lungs How are the bronchi related to the alveoli? The bronchi are small tubes that empty into thin-walled air sacs called alveoli.

Could the lungs supply oxygen to your body cells without the circulatory system? No Why? The lungs need a way to transport the oxygen to other parts of the body.

Let’s name the parts of each organ. What is the main function of the lungs? The main function of the lungs is to exchange oxygen and carbon dioxide with the blood.

Where is the oxygen-poor blood pumped?. Oxygen-poor blood is pumped to the lungs where the blood picks up oxygen and rids itself of carbon dioxide.

What steps does the circulatory system take to deliver blood to the body? The heart pumps oxygen-rich blood to the body cells. Blood vessels return carbon dioxide-rich blood to the heart and then the lungs, where the blood picks up oxygen and gets rid of carbon dioxide. The oxygen-rich blood returns to the heart and is pumped back to the body cells.

Is the respiratory system part of the excretory system? Explain. The respiratory system is part of the excretory system because it removes carbon dioxide from the body. Carbon dioxide is a cellular waste product.