The diagram below represents a part of the rib cage.

      

The diagram below represents a part of the rib cage.
Biology52201207.jpg
(a) Name the parts labeled W, Y and Z.
b) How does the part labeled Z facilitate breathing in?

  

Answers


John
(a) W - Spinal column/ vertebral column/ cervical vertebrae

Y - Sternum

Z - Intercostal muscles.

b)The external intercoastal muscles contract while the internal intercostal muscles relax. This movement pulls the ribs upwards and outwards. The diaphragm muscles contracts hence flattens. the thoracic volume increases while the pressure reduces, leading to atmospheric air rushing into the lungs through the nose and trachea hence inflating the lungs
johnmulu answered the question on May 3, 2017 at 13:18


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