How do field mice breathe? - briefly
Field mice inhale and exhale via a diaphragm and intercostal muscles that quickly expand and contract the lungs. Their elevated metabolic demand drives a respiration rate of roughly 80–120 breaths per minute, ensuring rapid oxygen uptake and carbon‑dioxide removal.
How do field mice breathe? - in detail
Field mice possess a respiratory system adapted for rapid, efficient gas exchange. Air enters through the nostrils, passes the nasal turbinates where it is warmed and filtered, then moves to the larynx, trachea, and bifurcates into the primary bronchi. Each bronchus subdivides into progressively smaller bronchioles, terminating in clusters of alveolar sacs surrounded by a dense capillary network.
Breathing is driven primarily by the diaphragm, a thin muscle separating the thoracic and abdominal cavities. Contraction of the diaphragm expands the thoracic volume, creating sub‑atmospheric pressure that draws air into the lungs. Simultaneously, external intercostal muscles lift the rib cage, further increasing lung capacity. Relaxation of these muscles reverses the pressure gradient, expelling air through the same pathway.
Within the alveoli, oxygen diffuses across the thin epithelial barrier into the pulmonary capillaries, while carbon dioxide moves in the opposite direction. The diffusion gradient is maintained by the high surface‑area‑to‑volume ratio of the alveolar walls and the thinness of the respiratory membrane. Hemoglobin in red blood cells binds the incoming oxygen, forming oxyhemoglobin, and transports it to peripheral tissues. Carbon dioxide generated by cellular metabolism is carried back to the lungs primarily as bicarbonate ions, then released into the alveolar space for exhalation.
Regulation of ventilation involves several feedback mechanisms:
- Central chemoreceptors in the medulla detect changes in arterial CO₂ and pH, adjusting the rate and depth of breathing.
- Peripheral chemoreceptors in the carotid and aortic bodies respond to drops in arterial O₂, providing rapid corrective signals.
- The autonomic nervous system modulates diaphragmatic and intercostal muscle activity, coordinating respiratory rhythm with locomotor demands.
These physiological features enable field mice to sustain high metabolic rates during foraging, escape responses, and thermoregulation, ensuring continuous oxygen supply and efficient removal of metabolic waste gases.