U1iii: Describe the physiological consequences of acute hypoglycaemia

  • Definition: BSL < 3.0mmol/L

BSL Regulation

  • Brain = obligate glucose utiliser ∴ CNS depression → coma
  • BSL tightly regulated 4 – 8mmol/L

Negative Feedback Hormonal Control

Sensors

β cells

α cells

Messengers

Insulin

Glucagon

Effectors

Liver

Muscle + AT

Kidneys

ANS

Effector Responses

  • SNS = ↑catecholamine release → α1 & β2 stimulation
    • CNS → hunger, agitation
    • Liver → β2 → ↑glycogenolysis, ↑lipolysis
    • Muscle → β2 → ↑glycogenolysis, tremor
    • Pancreas → α1 → ↓insulin release
    • CVS → α1/β2 →
      • ↑CO, intense VC → BF diverted to brain, liver, muscle
      • Cold & clammy

Endocrine

↓ Insulin

AT

  • ↓glucose uptake
  • ↑FFA release

Liver

  • ↓glucose uptake
  • ↑FFA release
  • ↑glucose release
  • Stops glycogen synthesis
  • ↑gluconeogenesis

Muscle

  • ↓glucose uptake
  • ↓protein synthesis
  • ↓glycogen synthesis
  • ↑FFA metabolism

↑ Glucagon

  • Gluconeogenesis
  • Glycogen breakdown
  • Fat & protein catabolism

↑ Cortisol

  • ↑FFA release from AT

↑ Growth Hormone

  • ↑FFA release from AT