Motor spines that sense the environment

Sensory nerves coming from the spines

Sensory efferents to the spines

Motor nerves running to the spines

Spines that sense the environment

an increase in Cl^- permeability.

inactivation of voltage-gated Ca²⁺ channels.

inactivation of voltage-gated Na⁺ channels.

a maintained increase in K⁺ permeability.

an increase in Na⁺ permeability.

normally due to an increased rate of expulsion of Na⁺ by the Na⁺ pump.

due solely to the movement of Cl^- ions out of the cell.

due to a delayed increase in the ratio of Na⁺ permeability to K⁺ permeability.

due to a delayed increase in Na⁺ movement across the cell membrane.

speeded up by an increased rate of K⁺ leaving the cell interior.

The electrical activity of Motor neurons

The force of contraction of activated muscle fibres

The force of contraction of a whole muscle

The electrical activity of Single muscle fibres

The electrical activity of Motor units

Cockroaches

Electrodes

Filters

Amplifiers

Neurons

Propagation occurs by electrotonic current flow and saltatory conduction in all neurons

Myelinated neurons have to regenerate the action potential at every point along their length

Action Potentials are conducted only by saltatory conduction, followed by electrotonic flow into terminals

Diameter is more important than myelination in determining conduction velocity, except in smaller neurons

Regeneration of the AP  at nodes of Ranvier in myelinated neurons is possible because of their high density of voltage-gated Na+ channels

the change in axon diameters between elbow and wrist

the amount of fat under the electrode

the change in axon diameters between wrist and muscle

synaptic transmission at the neuromuscular junction

the thickness of the skin under the electrode

opening of K⁺ channels occurs after the membrane has repolarized.

voltage-gated Na⁺ channels open and then rapidly inactivate.

K⁺ channels become voltage-gated and time-dependent.

the membrane becomes immediately permeable to Na⁺ and K⁺ ions.

passive Na⁺ channels become voltage gated and open.

Vary the width of APs they produce

Increase the size of the APs they produce

Decrease the number of APs they produce

Maintain constant the number of APs they produce but decrease their size

Increase the number of APs they produce