essay 37 - obstructive sleep apnea. bruxism

what is obstructive sleep apnea

pathogenesis of sleep apnea

1) Upper airway collapse during sleep

• In sleep (especially REM), muscle tone drops → pharyngeal muscles relax.

• If airway is already narrow (obesity, big tonsils, soft palate), it collapses → airflow stops.

2) Negative intrathoracic pressure

• Person tries to breathe against a blocked airway.

• This creates strong negative pressure in the chest → pulls soft tissues inward, worsening collapse.

3) Hypoxemia + Hypercapnia

• Repeated apneas → ↓ O₂ (hypoxemia) and ↑ CO₂ (hypercapnia).

• Gas exchange becomes unstable.

4) Arousal from sleep

• Brain senses low O₂ → triggers brief arousals to restore airway tone.

• These are short, not remembered, but fragment sleep.

5) Sympathetic activation

• Every arousal = fight‑or‑flight surge.

• Leads to:

  • ↑ blood pressure

  • ↑ heart rate variability

  • Long‑term: hypertension, cardiovascular disease, metabolic dysfunction

risk factors for sleep apnea

symptoms of sleep apnea

what is bruxism

pathogenesis of bruxism

1) CNS activation

• Micro‑arousals during sleep activate brain areas controlling jaw muscles → triggers grinding/clenching.

2) Autonomic nervous system involvement

• Episodes show ↑ sympathetic activity and ↑ heart rate.

3) Muscle hyperactivity

• Masseter + jaw muscles contract rhythmically or continuously → grinding/clenching movements.

4) Associations with other conditions

• Linked with:

  • Sleep disorders (especially OSA)

  • Stress, anxiety

  • Alcohol

  • Medications (e.g., antidepressants)

5) Possible protective mechanism

• Light clenching may stabilize the jaw/airway in OSA.

• But excessive bruxism → dental wear + TMJ problems.

symptoms of bruxism