Eye and ear and waves Flashcards
Why is it better to have 2 ears rather than just one?
Having two ears rather than one makes judging the direction of sound more accurate.
Describe the eardrum (form & function).
a thin membrane which picks up the vibrations of sound waves
What is the structure of the inner ear?
Made up of 3 small bones: the hammer, the anvil & the stirrup. The three bones form a chain.
What is the function of the inner ear?
The chain of small bones amplify the vibrations passed to them from the eardrum. They then conduct the amplified vibrations to the cochlea in the inner ear.
For teaching:
Describe the transformation of engery inside the ear.
Sound energy travels through the air
(*medium = gas)
and is funnelled by the outer ear into the air-filled ear canal until it reaches the ear drum.
The eardrum acts as a natural boundary between the air-filled middle ear and the ear canal.
The thin membrane of the eardrum vibrates and the vibrations are conducted
(*medium = solid)
by the small bones in the middle ear.
The sound pressure patterns
(energy form = sound)
reaches the fluid-filled cochlea
(medium = liquid)
in the inner ear and is converted into electrochemical impulses
(*energy form = electrical and chemical)
which travel through the auditory nerve and reach the brain.
note: KS3 will usually only name “electrical signals” or “electrical impulses”. KS4 and above should use the phrase “electrochemical signals” or “electrochemical impulses”.
KS4 and above:
What is happening when ears “pop” in an aeroplane?
KS4 and above:
Pressure in the middle ear is maintained through the Eustachian tubes, which are closed when not in use.
Each time a person swallows, the Eustachian tubes open and allow fresh air to enter into the cavity.
This maintains a constant pressure gradient.
Sometimes, this pressure is not equalized with the environment outside the head, and this is often the reason why some people experience discomfort in airplanes and at higher elevations.
Your ears pop in airplanes because the air high above the surface of Earth is less dense than air near the surface, because air near the surface has all the air above it pushing down.
Your inner ear has air trapped in it and as the atmospheric pressure changes, it causes pressure on your ear drum.
In vertebrates, what is the function of the inner ear?
In vertebrates, the inner ear is mainly responsible for sound detection and balance.
Describe what role the cochlea has for hearing.
The cochlea is the part of the inner ear dedicated to hearing. It is where sound pressure patterns from are converted into electrochemical impulses, which are then passed on to the brain through the auditory nerve.
What is the structure (form) and function of the cochlea?
It is a long coiled tube in the inner ear filled with fluid - it picks up the vibrations and changes them to electrical signals
note: KS3 will usually only name “electrical signals” or “electrical impulses”. KS4 and above should use the phrase “electrochemical signals” or “electrochemical impulses”.
What connects the inner ear to the brain?
the auditory nerve
What is the function of the auditory nerve?
Connects the inner ear to the brain and it carries the electrical signals from the cochlea
note: KS3 will usually only name “electrical signals” or “electrical impulses”. KS4 and above should use the phrase “electrochemical signals” or “electrochemical impulses”.
KS4 and above:
Describe the structure (form) and function of the vestibular system in the ear?
KS4 and above:
Balance is controlled in the inner ear by the Semi-Circular Canals.
The Semi-Circular Canals are 3 tubes at right angles to each other - they pick up movements of the head by detecting movements of the fluid they contain.
These movements are turned into electrochemical signals - since there are 3 canals at right angles the brain can use these signals to give 3-dimensional information to help control balance and tell us which way up we are.
GCSE and above:
What are the 10 key assessment areas
for “COORDINATION” in the human body?
GCSE and above:
A) state that two eyes help to judge distances
B) give the functions for the main parts of the eye
C) state that two ears help to tell the direction of sounds
D) give the functions for the main parts of the ear
E) explain the arrangement of the semi-circular canals with relation to their function
F) state the parts of the central nervous system
G) state that nerves carry information from the senses to the CNS then to the muscles
H) describe the reflex arc
I) identify the 3 main sections of the brain and state their functions
J) give functions for the cerebrum, cerebellum and medulla in the brain
http://bbc.in/2Ftz6OH
What is binocular vision and what advantages and disadvantages?
This is a type of vision in which an animal has two eyes
with overlapping fields of view.
Advantages: allows good perception of depth and gives the animal the ability to perceive a single three-dimensional image of its surroundings.
Disadvantages: a smaller field of view.
Alternative: Prey animals tend to have monocular vision. The eyes of an animal with monocular vision are usually positioned on opposite sides of the animal’s head, giving it the ability to see two objects at once.
cornea
KS3:
This is the clear layer on the front of the eye that covers the iris and pupil.
KS4 and above:
It refracts light (focus) and accounts for approximately two-thirds of the eye’s total optical power.
