Option E2 Perception of Stimuli
Assessment Statements:
E.2.1 Outline the diversity of stimuli that can be detected by human sensory receptors.
E.2.2 Label a diagram of the structure of the human eye.
E.2.3 Annotate a diagram of the retina to show the cell types and the direction in which light
moves.
E.2.4 Compare rod and cone cells.
E.2.5 Explain the processing of visual stimuli, including edge enhancement and contralateral
processing.
E.2.6 Label a diagram of the ear.
E.2.7 Explain how sound is perceived by the ear
Human Sensory Receptors
Complete the table:
Receptor
Stimulus
Location
Mechanoreceptor
Chemoreceptor
Thermoreceptor
Photoreceptor
The Human Eye
Label the diagram:
Match the structure to its function:
Structure
Function
Sclera
Photoreceptive tissue and neurons of the eye
Choroid
Mucus secreting epithelia that provides moisture to the eye
Retina
Jelly like filling of the anterior section of the eye
Fovea
Coloured part of the choroid layer that regulate the light entering the eye
Blind spot
The collection of nerves from the photoreceptors
Optic nerve
Tough white outer layer of connective tissue
Vitreous humour
Transparent layer formed from the sclera, focuses the light
Aqueous humour
High concentration of cone cells and centre of field of vision
Lens
Thin pigmented layer that absorbs scattered light in the eye
Iris
Hole in the centre of the iris through which light reaches the retina
Pupil
Region of no photoreceptors where axons of neurons leave the eye
Cornea
Jelly like filling of the posterior cavity of the eye
Conjunctiva
Transparent protein disc suspended from ligaments, for fine focus
The retina
Label the diagram:
Rods and Cones
Complete the table:
Feature
Rods
Cones
Location in retina
Optimal light conditions
Visual acuity (resolution)
Connection to nerve fibre
Colour sensitivity
Type of vision
Number of types
Relative abundance
Define:
Edge enhancement
Contralateral processing
What do you see? Explain this optical illusion:
The Ear
Add labels to the diagram:
How Sound is Perceived
Rearrange the sentences to describe how sound is perceived:
Movement of the cochlear fluid affects the position of cilia on sensory hair cells.
The ossicles push against the oval window,
The degree of vibration will vary according to the frequency
Sound travels as pressure waves in the air
displacing fluid within the cochlea.
transmitted via the auditory nerve to the brain.
and amplitude of the sound waves.
which magnify the vibrations up to 20 times.
Cilia on hair cells vary in length and each resonates to a different frequency of sound.
which push the membrane of the eardrum causing it to vibrate.
Activation of the hair cells generates nerve impulses which are
The kinetic motion of the cochlear fluid is dissipated by the movement of the round window.
The ear drum pushes on the bones of the middle ear (ossicles)
1. List two groups of sensory receptors, giving the stimulus each perceives (2)
2. Explain the role of receptors, sensory neurons and motor neurons in the response of animals
to stimuli (3)
3. Label structures I to IV (4 marks)
4. Outline contralateral processing of visual stimuli (3)
5. Compare the functions of rod and cone cells (3)
6. Identify structures A to D (2)
7. Explain how sound is perceived by the ear (6)