BIOB34H3 Lecture 19: Lecture 19 Notes 2015
4 Oct 2016
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Cardiorespiratory control: the human / mammalian lung. Humans inspire (breath in) in response to contraction of the diaphragm (the major respiratory muscle). The diaphragm contracts and moves downward (towards the abdomen). This causes the chest and the lungs to expand essentially sucking air into the lungs through the mouth and nostrils. The diaphragm is controlled by the phrenic nerve which fires during inspiration. The phrenic nerve leaves the spinal cord in the region of the neck. It then travels downward through the body cavity to innervate the diaphragm which sits at the border of the chest and abdomen. A beneficial consequence of this is that a relatively high spinal injury will not prevent breathing as long as the injury is below the location that the phrenic nerve comes off the spinal cord. Breathing is generated in respiratory control centres in the brainstem (medulla and spinal cord). A basic respiratory rhythm is generated in the brainstem.
