1. A3: Perception of Stimuli
Use your IB book ~ Option E Chapter along with this PowerPoint to complete the A3 reading/handout guide Info taken from: BioNinja HL Biology 2nd Edition, Daman, McGongegal, Tosto & Ward

2. Eye Functions Iris: Regulates the size of the pupil
Pupil: Admits light
Retina: Contains receptors for vision
Aqueous Humor: Transmits light rays and supports the eyeball
Vitreous Humor: Transmits light rays and supports the eyeball
Rods: allow black and white vision in dim light
Cones: allow color vision in bright light
Fovea: Area of densely packed cone cells where vision is most accurate
Lens: Focuses the light rays
Sclera: Protect and supports the eyeball
Cornea: focusing begins here
Choroid: Absorbs stray light
Conjunctiva: covers the sclera and cornea and keeps the eye moist
Optic Nerve: transmits impulses to the brain
Eye Lid: Protects the eye

4. Vision Pathway in the Retina
Rods and cones receive light stimulus
Rods and cones synapse with the bipolar neuron
Bipolar neuron carries the impulse to the ganglion cell
The ganglion cell is located in the optic nerve
The optic nerve carries the impulse to the brain

6. The Ear

7. Transmitting and Amplifying Sound
-The bones of the middle ear receive vibrations from the tympanic membrane. Vibrations are multiplied. -The stapes strikes the oval window causing it to vibrate. -The vibration is passed to the fluid in the cochlea. -The fluid in the cochlea causes sensory hair cells to vibrate. -The hair cells release neurotransmitter across the synapse to the auditory nerve. -Vibrations are transformed into nerve impulse -nerve impulse is transmitted to the brain by the auditory nerve