The senses Flashcards

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1
Q

what does the Ears do

A

Ears provide hearing and maintain body balance

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2
Q

Ear structure has 3 parts

A
  • Outer ear
  • Middle ear
  • Inner ear
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3
Q

The outer ear functions

A
  • The visible part of the ear
  • Protects the inner structures from damage
  • The passage for sound waves
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4
Q

functions of External auditory meatus - the
auditory canal

A
  • Lined with ceruminous glands and hairs
  • Filter out dust and foreign particles
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5
Q

functions of The tympanic membrane
(eardrum)

A

separates the auditory canal from the middle ear

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6
Q

The middle ear

A

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

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7
Q

The inner ear structure

A

1- ampulla
2- oval window
3- round window

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8
Q

The inner ear functions

A
  • 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
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9
Q

function of The eustachian tube

A

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

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10
Q

how does the inner ear work

A

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.

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11
Q

Eye structures

A

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

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12
Q

Lacrimal glands
secretes what

A

lacrimal fluid

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13
Q

what is lacrimal fluid function

A
  • keeps the surface of the
    eye moist
  • Prevents the cornea from
    drying out
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14
Q

Parasympathetic stimulation of the lacrimal
glands causes

A

crying

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15
Q

what is The sclera

A
  • A fibrous outer layer
  • At the front of the eye it is continuous with the cornea
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16
Q

what is Conjunctiva

A
  • A mucous membrane covering he front of the eye
  • Also lines the inside of the eyelids
  • Helps prevent damage and drying of the eye
17
Q
  • The eye is divided into 2 structures/chambers
A

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

18
Q

what is Pathway of light through the eye

A

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

19
Q

the lens Thickness controlled by

A

ciliary muscle

20
Q

Thick =

A

nearby objects

21
Q

Thin =

A

far away objects

22
Q

what is The retina

A
  • Forms the inner layer of the eye wall
  • Contains photoreceptors
23
Q

what is Macula lutea

A
  • 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
24
Q

The retina layers

A

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)

25
Q

what is Labyrnthitis

A
  • An inflammation of the inner ear which can cause balance disorders
26
Q

Symptoms of blepharitis include:

A
  • 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
27
Q

types of Blepharitis

A

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.

28
Q

what is Cataracts

A

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

29
Q

what is Glaucoma

A

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

30
Q

what is Myopia

A

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
31
Q

what is Hyperopia - farsightedness

A
  • Distant images are brought to a point of focus behind the retina.
  • Often due to a short eyeball
  • Corrected by lenses that are convex
32
Q

what is Astigmatism

A
  • Asymmetry of the cornea and/or lens curvatures
  • Get several points of focus on the retina
  • Corrected by cylindrical lenses
33
Q

what Diabetic retinopathy

A
  • 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.