Describe and explain the series of events leading to excitatory post synaptic stimulation upon the activation of a pacinian corpuscle.
- Pacinian corpuscle is stimulated by pressure on the skin. 2) This opens stretch mediated sodium ion channels. 3) Sodium ions leak into the sensory nerve axon via facilitated diffusion thereby causing depolarisation. 4) If enough sodium ions enter to increase the voltage past the firing threshold, an action potential occurs. 5) The depolarisation stimulates voltage gated sodium ion channels to open at the nodes of ranvier along the axon. 6) The action potential is conducted along the axon via saltatory propagation. 7) When depolarisation reaches the axon terminal, calcium ion channels open. 8) The influx of calcium ions stimulates vesicles to release neurotransmitters into the synaptic cleft via exocytosis. 9) The neurotransmitters diffuse across the synaptic cleft and may then bind to receptors on the post synaptic membrane.
KD
Related Biology A Level answers
All answers ▸Explain the process of oxidative phosphorylation and the electron transport chain in the production of ATP in respiration.
How to answer an exam question such as "how might action potential transmission be affected by multiple sclerosis, a nervous system disease characterised by damage to neuronal myelin sheaths"
Explain the differences between enzyme inhibitors
The MMR vaccine gives protection against measles, mumps and rubella. How? (4 marks)