The events of inspiration begins with the;
Impulses are conducted on the phrenic nerve to muscle fibers in the diaphragm contracting them.
As the dome shaped diaphragm moves downward the thoracic cavity expands.
At the same time the external intercostal muscles may contract raising the ribs and expanding the thoracic cavity further.
The intra-alveolar pressure decreases
Atmospheric pressure greater than intra-alveolar pressure forces the air into the respiratory tract through the air passages.
The lungs fill with air.
The Nucleolus helps function the cell.
<u>Answer:</u>
internal carotid and vertebral; internal jugular
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Blood flows to the brain through the<u> internal carotid and vertebral </u>arteries and away from the brain through the <u>internal jugular</u> veins.
