Edexcel IAL Biology 8.6 Synaptic transmission and pupil response

A description that includes four of the following points:

- pupil \{contracts / constricts / gets smaller\} in high light intensity / pupil \{dilates / enlarges\} in low light intensity (1)

- involves circular and radial muscles which are antagonistic (1)

- impulse transmitted along \{motor neurone/ sympathetic nervous system/ parasympathetic nervous system/ nerve\} (to muscle) (1)

- (in bright light / high light intensity) circular muscle contract and radial muscle relax to make pupil \{contract / constrict / get smaller\} (1)

- (in dim light / low light intensity) circular muscle relax and radial muscle contract to make pupil \{dilate / enlarge\} (1)

Can piece together mp1

accept pupil \{contracts / constricts / gets smaller\} to allow less light to enter / pupil \{dilates / enlarges \} to allow more light to enter accept pupil dilates in the dark

ignore optic

accept circular muscle contract and radial muscle relax in \{bright light / high light intensity\}

accept circular muscle relax and radial muscle contract in \{dim light / low light intensity\}