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Detecting the environment - Coggle Diagram
Detecting the environment
structure of the eye
cornea
transparent = allow light to pass through
curved = refracts and focuses light
choroid
black pigment = absorb light
reduce reflection of light within the eye
no light is reflected out of the eye through the pupil
helps forming a sharp image
rich in blood capillaries
supply oxygen and nutrients to the cells of the eye
retina
contain photoreceptors
cone cells
stimulated in bright light
rod cells
stimulated in dim light
optic nerve
transmit the nerve impulse generated by the photoreceptors to the cerebrum
yellow spot
high density of cone cells, no rod cells
blind spot
no photoreceptors --> image formed at the blind spot cannot be detected
no nerve impulses will be sent to the visual centre of the brain
lens
transparent = allow light to pass through
elastic = focuses on objects at different distances through adjusting its curvature
biconvex
refracts and focuses light onto the retina
size of pupil
bright light
circular muscles of iris contract
radial muscle of iris relax
pupil constricts
less light enters into the eye
dim light
circular muscles of iris relax
radial muscle of iris constract
pupil dilates
more light enters the eye
lens
focusing on near object
ciliary muscle of ciliary body contract
suspensory ligament become loosened
lens become thicker and more convex
refract light more
focus of distant object
ciliary muscle of ciliary body relax
suspensory ligament become tightened
lens become thinner and less convex
refract light less
eye defect
short sight
cause
eyeball too long
lens too thick
results in
image formed in front of the retina
correction
wear concave lens
people cannot see distant object
long sight
eyeball too short/ lens too thin
image formed behind the retina
cannot see near object
correction: wear convex lens
how do we hear
pinna
auditory canal
eardrum
earbone
oval window
cochlea
auditory nerve
auditory centre of cerebral cortex of the brain
functions of the structures
pinna: collect sound waves
auditory canal: direct sound waves into the eardrum
eardrum: change sound waves into vibration
earbone: amplify and transmit the vibration to oval window
oval window: transmit the vibration
cochlea
perilymph = transmit the vibtaion
endolymph = detect the vibration and generate nerve impulse
auditory nerve
transmit the nerve impulse
auditory centre in cerebral cortex of the brain
interpret the nerve impulse and produce hearing
Phototropism
setting up control
X make another hole on the opposite side
X remove light
the clinostat rotates so that the seedlings receive light from all sides
when light comes from one direction --> the tip will detect the unilateral light & auxins produced in the tip --> will move from the lighted side to the shaded side
phototropism in shoot
when light comes from one direction, the shoot tip will detect the unilateral light and auxins produced in the tip will move from the lighted side to the shaded side
auxins will accumulate on the shaded side than the lighted side
high concentration of auxins in the region of elongation promotes cell elongation
the shaded side grow faster than the lighted side --> causing the shoot to bend towards the unilateral light
photoropism in root
high concentration of auxins in the region of elongation inhibits the cell elongation
lighted side grow faster than the shaded side --> causing the root to bend away from the unilateral light
auxins
low concentration of auxins
promote root growth
no effect on the shoot growth
high concentration of auxins
promote shoot growth but inhibit root growth
very high concentration of auxins
inhibit both root growth and shoot growth
