KINESIOL 1YY3 Lecture Notes - Lecture 11: Breathing, Pulmonary Vein, Tidal Volume
20 Apr 2016
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Document Summary
As branches decrease in size, they increase in number. After the first branch, it divides 16-18 times. Progressive loss of cartilage replaced with smooth muscle: first it becomes cartilage plates and then the smooth muscle, with smooth muscle, amount of air is controlled coming in and out of gas exchange area. Vasodilation in exercising allows more air into gas exchange. Vasoconstriction (asthma attack, for example) > less air going into the airways/gas exchange regions. Diaphragm muscle fibers run in upwards direction > flattens when breathing. Base of lungs > convex shape, sits on diaphragm. Apex is the top pointy part at clavicle level. Terminal bronchiole lined with smooth muscle on outside, which can change diameter to control amount of air entering gas exchange area. Like blood vessels, the outside structures here need blood supply: bronchial vein and bronchial artery. It"s just a supply, no gas exchange happening here. Smooth muscle has the nervous system supply to control vasoconstriction and dilation.
