C2.2 Neural Signalling

Interaction and Interdependence

Genetic Variation

Cell Division

Photosynthesis

To transmit information rapidly between cells

To provide structural support to tissues

To store genetic information

To produce energy for cellular activities

It generates action potentials directly.

It maintains concentration gradients of sodium and potassium ions.

It releases neurotransmitters into the synaptic cleft.

It insulates axons to speed up impulse transmission.

Neuron

Resting Potential

Photosynthesis

Myelin

Sensory neuron

Motor neuron

Interneuron

Glial cell

Dendrites

Cell body (soma)

Axon

Myelin sheath

To generate action potentials

To maintain the resting potential by using ATP to pump Na+ out and K+ in

To transmit nerve impulses directly

To produce neurotransmitters

It transports Na+ out of the axon and K+ into the axon.

It works against the concentration gradients of Na+ and K+.

It is an example of passive transport.

It helps maintain the resting potential of neurons.

Sodium (Na+) and potassium (K+) ions

Calcium (Ca2+) and chloride (Cl-) ions

Magnesium (Mg2+) and phosphate (PO4-) ions

Iron (Fe2+) and copper (Cu2+) ions

Wider diameter of axons and myelination of axons

Longer axons and increased number of dendrites

Higher concentration of sodium ions and thicker cell membranes

Increased number of synapses and more neurotransmitters

As animal size increases, the speed of nerve impulses decreases.

As animal size increases, the speed of nerve impulses increases.

There is no correlation between animal size and speed of nerve impulses.

As animal size decreases, the speed of nerve impulses decreases.