In this video I do an overview of how animals breathe via the respiratory system. Oxygen is absorbed from the air via millions of small air sacs called alveoli (atria in birds), and pumped to the heart as oxygen rich blood, which then gets pumped throughout the body. I also go over the fetal circulation system, which is facilitated by the placenta, as well as discuss the unique respiratory system of birds, which absorb oxygen from air before expelling it out in the same direction.
Breathing: Gas exchange in the lungs occurs in millions of small air sacs called alveoli: 0:00
Respiration is the movement of oxygen from outside the environment to the cells. Breathing is moving air out and in the lungs: 2:26
Diagram of the respiratory system in humans: 5:57
Human lungs and heart diagram: 8:44
Pulmonary veins transfer oxygenated blood from the lungs to the heart. Pulmonary artery carries deoxygenated blood from the heart to the lungs: 12:15
Fetal circulation: umbilical vein carries oxygenated blood from the placenta to the child. Umbilical artery carry deoxygenated blood from the child to the placenta: 15:58
Diagram of the fetal circulatory system: 18:48
Diagram of the human heart showing valves, arteries, and veins: 22:10
Diagram of aorta artery, which is the main and largest artery directing oxygenated blood from the heart to all parts of the body: 27:12
Another fetal circulation diagram: 29:18
Animated schematic of the mother and fetus circulation systems: 31:54
Diagram of blood circulation around the alveoli. Close up of the alveolar sacs and capillaries: 37:23
Muscles of respiration help in inhalation and exhalation. The diaphragm drives quiet breathing: 42:54
Diagram of the body cavities: 47:08
Respiratory system of birds: 49:08
Diagram of human sinuses, which are still not fully understood: 52:06
Inhalation and exhalation cycle in birds: 53:36
Diagram of the parabronchus gas exchanger in birds: 55:53
Diagram of a closer view of the parabronchus: 1:01:18
