The senses

Question 1

what does the Ears do

Answer 1

Ears provide hearing and maintain body balance

Question 2

Ear structure has 3 parts

Answer 2

• Outer ear
• Middle ear
• Inner ear

Question 3

The outer ear functions

Answer 3

• The visible part of the ear
• Protects the inner structures from damage
• The passage for sound waves

Question 4

functions of External auditory meatus - the
auditory canal

Answer 4

• Lined with ceruminous glands and hairs
• Filter out dust and foreign particles

Question 5

functions of The tympanic membrane
(eardrum)

Answer 5

separates the auditory canal from the middle ear

Question 6

The middle ear

Answer 6

1-Found within a cavity in the temporal bone
2-Has minute bones known as auditory ossicles
3-Auditory ossicles transmit sounds from
the tympanic membrane to the inner ear

Question 7

The inner ear structure

Answer 7

1- ampulla
2- oval window
3- round window

Question 8

The inner ear functions

Answer 8

• Responsible for hearing and balance
• Within the inner ear structures the vibrations of sound waves are translated into nerve impulses
• Semi-circular canals and vestibule help to maintain posture and balance

Question 9

function of The eustachian tube

Answer 9

Connects the middle ear to the throat Maintains the atmospheric pressure of air within the ear Enables eardrum to vibrate as the soundwaves reach it

Question 10

how does the inner ear work

Answer 10

The cochlea receives sound in the form of vibrations
* Vibrations cause the stereocilia to move.
* Stereocilia then convert these vibrations into nerve impulses which are taken up to the brain to be interpreted.

Question 11

Eye structures

Answer 11

Eyelids
* Layers of tissue above and below the
front of the eye
* Protect the eyes through blinking
Eyelashes
* Line the edges of the eyelids
* Filter and trap substances e.g. dust
Sebaceous and mucous secretions
lubricate the eyelids

Question 12

Lacrimal glands
secretes what

Answer 12

lacrimal fluid

Question 13

what is lacrimal fluid function

Answer 13

• keeps the surface of the
  eye moist
• Prevents the cornea from
  drying out

Question 14

Parasympathetic stimulation of the lacrimal
glands causes

Answer 14

crying

Question 15

what is The sclera

Answer 15

• A fibrous outer layer
• At the front of the eye it is continuous with the cornea

Question 16

what is Conjunctiva

Answer 16

• A mucous membrane covering he front of the eye
• Also lines the inside of the eyelids
• Helps prevent damage and drying of the eye

Question 17

• The eye is divided into 2 structures/chambers

Answer 17

1-Anterior chamber
* Between the cornea and the lens
* Contains the aqueous humour
2-Vitreous chamber
* Cavity behind the lens
* Filled with vitreous humour
* Both filled with fluids that maintain the pressure and shape of the eyeball

Question 18

what is Pathway of light through the eye

Answer 18

1-Light enters through the cornea
2-Passes through the pupil
3-Iris controls the amount of light entering the eye
4-Lens refracts light rays
5-Light rays are focused on to the retina at the back of the eye

Question 19

the lens Thickness controlled by

Answer 19

ciliary muscle

Question 20

Thick =

Answer 20

nearby objects

Question 21

Thin =

Answer 21

far away objects

Question 22

what is The retina

Answer 22

• Forms the inner layer of the eye wall
• Contains photoreceptors

Question 23

what is Macula lutea

Answer 23

• Near the centre of the retina
• Highly sensitive
• Contains millions of rods and cones
• Cones predominate in the fovea centralis
• Responsible for sharp, detailed central vision

Question 24

The retina layers

Answer 24

1-Photoreceptor layer - rods and cones
2-Bipolar cell layer: Neurons that receive neurotransmitter from the photoreceptors & Synapse with ganglion cells
3-Ganglion cell layer: axons of neurons here form optic nerve that exits eye at optic disc (“blind spot” - no rods/cones)

Question 25

what is Labyrnthitis

Answer 25

* An inflammation of the inner ear which can cause balance disorders

Question 26

Symptoms of blepharitis include:

Answer 26

* sore eyelids * itchy eyes * a gritty feeling in the eyes * flakes or crusts around the roots of the eyelashes * red eyes or eyelids * eyelids sticking together in the morning when you wake up

Question 27

types of Blepharitis

Answer 27

1-Anterior blepharitis affects the outside front of the eyelid, where the eyelashes are attached. Common causes are bacteria (Staphylococcus) and scalp dandruff. 2-Posterior blepharitis affects the inner eyelid and is caused by problems with the oil glands in this part of the eyelid.

Question 28

what is Cataracts

Answer 28

Clouding of the lens of the eye which leads to a decrease in vision

Question 29

what is Glaucoma

Answer 29

A condition that damages the eye's optic nerve Can cause permanent vision loss or even total blindness

Question 30

what is Myopia

Answer 30

Myopia (nearsightedness): can see near but not far objects - Eyeball is too long so lens cannot accommodate enough to focus images of distant objects onto retina

Question 31

what is Hyperopia - farsightedness

Answer 31

* Distant images are brought to a point of focus behind the retina. * Often due to a short eyeball * Corrected by lenses that are convex

Question 32

what is Astigmatism

Answer 32

* Asymmetry of the cornea and/or lens curvatures * Get several points of focus on the retina * Corrected by cylindrical lenses

Question 33

what Diabetic retinopathy

Answer 33

* When high blood sugar levels cause damage to blood vessels in the retina. * These blood vessels can swell and leak. Or they can close, stopping blood from passing through. * Sometimes abnormal new blood vessels grow on the retina.