PSYC30020 Lecture Notes - Lecture 19: External Intercostal Muscles, Peripheral Chemoreceptors, Sleep Deprivation
10 May 2018
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Lecture 19
- Why study respiration?
- Essential for life: provides oxygen and removes carbon dioxide to ensure correct
cellular functioning (gas exchange)
- Breathing is the basis for multiple critical behaviours: speaking, olfaction, emesis
[vomiting]
- Strong links to emotional centers in the brain
- Respiration = ventilation = breathing
- Inspiration = a breath in
- Expiration = breathing out
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- Respiratory System Anatomy
- How gas exchange occurs:
- Fresh air (21% O2, ~0.05% CO2) enters the lungs during inspiration.
- The low O2 and high CO2 blood entering the lungs from the body has the O2
replenished and CO2 removed by diffusion in the alveoli.
- The high CO2/low O2 (~13% O2, ~5% CO2) air is breathed out of the lungs during
expiration.
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- Respiratory muscles:
- Inspiration – Active, diaphragm and external intercostal muscle activation.
- Expiration – Passive at rest, relies on recoil of the lungs/chest wall; Active during
exercise/stress using abdominal muscles. Internal intercostal muscle contract
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- Neural innervation:
- Phrenic nerves innervate diaphragm. Cervical spinal cord (C3-C5).
- Intercostal nerves innervate intercostal muscles. Thoracic spinal cord (T1-T11).
- Accessory muscles (abdomen for example) activated during high work/cough.
Lumbar spinal cord.
find more resources at oneclass.com
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Document Summary
Essential for life: provides oxygen and removes carbon dioxide to ensure correct cellular functioning (gas exchange) Breathing is the basis for multiple critical behaviours: speaking, olfaction, emesis. Strong links to emotional centers in the brain. Fresh air (21% o2, ~0. 05% co2) enters the lungs during inspiration. The low o2 and high co2 blood entering the lungs from the body has the o2 replenished and co2 removed by diffusion in the alveoli. The high co2/low o2 (~13% o2, ~5% co2) air is breathed out of the lungs during expiration. Expiration passive at rest, relies on recoil of the lungs/chest wall; active during. Inspiration active, diaphragm and external intercostal muscle activation. exercise/stress using abdominal muscles. Accessory muscles (abdomen for example) activated during high work/cough. The main respiratory pattern generator (pacemaker) is located in the pre botzinger complex. The region of the brain that responds to co2 is the retrotrapezoid nucleus (rtn also called parafacial respiratory group - pfrg).
