Chapter 14

Front 1

What is sensory adaptation?

Back 1

It occurs once you have adjusted to a change in the environment; sensory receptors become less sensitive when stimulated repeatedly.

Front 2

What are/is the function of sense receptors?

Back 2

Sense receptors convert energy into other forms. They are modified dendrites of sensory neurons and are generally grouped within specialized sensory organs. This grouping amplifies the energy of stimulus, ensuring the stimulus can reach threshold levels.

ex. taste receptors convert chemical energy --> electrical energy (action potential)

Front 3

What are/is the function of pain receptors?

Back 3

Pain receptors have naked dendrites in the epidermis and are extremely important because pain makes you move away from the stimulus source. This protects you from hurting yourself further. Pain receptors release impulses to the brain and can be blocked by pain medication.

Front 4

Where do sensations occur?

Back 4

Sensations occur in the brain not the receptor. The brain registers and interprets the sensation when the sensory region of the cerebral cortex is excited by an electrical shock. The sensation returns even if there's no stimulus.

Front 5

Explain why you don't detect everything in your environment.

Back 5

Most of our environment is undetected because we detect stimuli relevant to survival.

Ex. we only detect light of wavelengths from 350mm-800mm, and no sensations occur from radio/infrared/UV rays.

Front 6

What are/is the function of sensory adaptation?

Back 6

Sensory adaptation happens when receptors become accustomed to a stimulus. The neuron stops firing even though the stimulus is present. The adaptation recognizes that the new environmental condition is not harmful.

Front 7

Explain taste as a sense.

Back 7

Taste allows you to differentiate between edible and inedible. Specific chemicals dissolve on the tongue and stimulate taste receptors in the taste buds. Each cell is responsive to chemicals for all taste types but most responsive to one channel. The five parts to taste are: sweet, sour, salty, bitter, and savoury.

Front 8

Explain smell as a sense.

Back 8

Taste and smell work together. When airborne chemicals combine with molecules of a certain geometry, you smell. These combine with smell receptors and the messages produced by receptors go to the olfactory bulb.

Front 9

What is sensory reception?

Back 9

When sense receptors convert energy ---> neural impulses ---> brain.

Front 10

What is sensation?

Back 10

When sense receptions absorb energy from physical/chemical simtuli in the environment.

Front 11

What is perception?

Back 11

When the brain organizes info and translates it into something meaningful.

Front 12

What is the purpose of senses?

Back 12

Senses allow our body to maintain homeostasis by giving information to our body on how to act.

Front 13

Explain touch as a sense.

Back 13

There are mechanoreceptors throughout our body for touch. Different receptors are sensitive to things like pain, temperature, and light touch.

Front 14

What is the scerla?

Back 14

The outer covering of the eye that supports and protects the eyes inner layer; usually referred to as the white of the eyes.

Front 15

What is the cornea?

Back 15

The transparent part of the sclera that protects the eye and refracts light towards the pupil of the eye.

Front 16

What is the aqueous humour?

Back 16

The watery liquid that protects the lens of the eye and supplies the cornea with nutrients.

Front 17

What is the choroid layer?

Back 17

The middle layer of tissue in the eye that contains blood vessels that nourish the retina.

Front 18

What is the iris?

Back 18

The opaque disk of tissue surrounding the pupil that regulates the amount of light entering the eye.

Front 19

What is the retina?

Back 19

The innermost layer of tissue at the back of the eye containing photoreceptors.

Front 20

What are rods?

Back 20

Photoreceptors that operate in dim light to detect light in black and white.

Front 21

What are cones?

Back 21

Photoreceptors that operate in bright light to identify colour.

Front 22

What is the fovea centralis?

Back 22

The area at the centre of the retina where cones are most dense and vision is sharpest.

Front 23

What is accommodation?

Back 23

Adjustments made by the lens and pupil of the eye for near and far objects.

Front 24

What is glaucoma?

Back 24

A disease of the eye in which increased pressure within the eyeball causes a gradual loss of sight.

Front 25

What is cataract?

Back 25

A condition that occurs when the lens or cornea becomes opaque, preventing light from passing through.

Front 26

What is astigmatism?

Back 26

A vision defect caused by abnormal curvature of the surface of the lens or cornea.

Front 27

What is nearsightedness?

Back 27

A condition that occurs when the image is focused in front of the retina.

Front 28

What is farsightedness?

Back 28

A condition that occurs when the image is focused behind the retina.

Front 29

What are the three layers of the eye?

Back 29

Outermost = Sclera

Middle = Choroid Layer

Innermost = Retina

Front 30

Which parts of the eye are in the outermost layer?

Back 30

Cornea

Front 31

What is/is the function of the sclera?

Back 31

Protective layer and maintains shape.

Front 32

What is/is the function of the cornea?

Back 32

The cornea is the front of the sclera. It bends light towards the pupil and contains no blood vessels. Oxygen is absorbed from gases dissolved in tears.

Front 33

What is/is the function of the aqueous humour?

Back 33

The aqueous humour is the transparent fluid in the chamber behind the cornea that supplies nutrients to the cornea and lens. It also refracts light towards the lens.

Front 34

Which parts of the eye are in the middle layer?

Back 34

Iris, pupil, lens, and ciliary muscles.

Front 35

What is/is the function of the iris?

Back 35

The iris is thin muscle at the front of the choroid layer that acts like a diaphragm by controlling the size of the pupil.

Front 36

What is/is the function of the pupil?

Back 36

The pupil is the opening formed by the iris that allows light to enter the eye.

Front 37

What is/is the function of the lens?

Back 37

The lens is immediately behind the iris and focuses the image on the retina.

Front 38

What is/is the function of the ciliary muscles?

Back 38

The ciliary muscles are attached to ligaments suspended from the lens that alters the shape of the lens. It's functions include focusing and accommodation.

Front 39

What is/is the function of the vitreous humour?

Back 39

The vitreous humour is a cloudy, jellylike material that maintains the shape of the eye and permits light transmission to the retina by further refracting light.

Front 40

What are the 3 layers of the retina?

Back 40

Pigmented epithelium, bipolar cells, and light sensitive cells.

Front 41

What is/is the function of the pigmented epithelium?

Back 41

Pigmented granules prevent light from scattering.

Front 42

What are the two types of light-sensitive cells?

Back 42

Rods and cones.

Front 43

What is/is the function of the fovea centralis?

Back 43

The fovea centralis is a tiny depression in the centre of the retina that is the most sensitive part of the eye. This is where the sharpest colour images occur because cones are packed closely and absorb most of the light rays. Rods surround the fovea, explaining how we have peripheral vision but no colour.

Front 44

What is/is the function of the blind spot?

Back 44

The blind spot occurs when the optic nerve touches the retina, therefore no rods or cones exist. Since there are no photosensitive cells, the blind spot exists.

Front 45

What is flow chart that illustrates the process by which light enters the eye and an image is processed.

Back 45

cornea ---> pupil ---> aqueous humour ---> lens ---> vitreous humour ---> retina ---> pigmented epithelium ---> rods and cones ---> bipolar cells ---> ganglion cell layer ---> optic nerve ---> thalamus ---> occipital lobe

Front 46

What is/is the function of rhodopsin?

Back 46

Rhodopsin is composed of a form of vitamin A and a large protein molecule cause "opsin." When a photon strikes a rhodopsin molecule it divides into retinene and opsin. This division alters the cell membrane of the rods and produces an action potential. Neurotransmitters are released from the end plates, and the nerve message moves across the synapse to bipolar cells, then to the optic nerve.

Front 47

Why does a vitamin A deficiency damage rods?

Back 47

Rods can only work when rhodopsin levels are maintained.

Front 48

What causes afterimages?

Back 48

Rhodopsin is extremely sensitive and in bright light rhodopsin breaks down faster than it can be restored.

Front 49

When are rods most effective?

Back 49

Since only rods are active during times of low light intensity, images are grey. So, rods are most effective at dusk and dawn.

Front 50

What are/is the function of cones?

Back 50

Cones are responsible for colour vision, and each cone is sensitive to one of 3 primary colours of source light (red, blue, green). Combinations of cones allows the brain to perceive different shades of colours.

*white is when all three wavelengths are stimulated

Front 51

What causes colour blindness?

Back 51

When one or more types of cones are defective.

Front 52

What are the type types of after images, and what are they/

Back 52

Positive: After you look into a bright light then close your eyes the image can still be seen even though your eyes are close.

Negative: When your eyes are exposed to bright light for extended periods of time.

Both are caused by a breakdown of rhodopsin.

Front 53

What is refraction?

Back 53

The slowing of light by a denser medium.

Front 54

Describe accommodation on near and far objects.

Back 54

Near: Ciliary muscles contract, the lens thickens allowing an increased refraction of light, and the pupil constricts.

Far: Ciliary muscles relax, the lends thins to decrease the refraction of light, and pupil dilates.

Front 55

What is the pinna?

Back 55

The outer part of the ear that acts like a funnel, taking sounds from a large area and channeling it into a small canal.

Front 56

What is the auditory canal?

Back 56

Carries sound waves to the eardrum.

Front 57

What is the tympanic membrane?

Back 57

The think layer of tissue that receives sound vibrations, also known as the eardrum.

Front 58

What are the osicles?

Back 58

Tiny bones that amplify and carry sound in the middle ear.

Front 59

What is the oval window?

Back 59

The oval shaped hole in the vestibule of the inner ear, covered by a thin layer of tissue.

Front 60

What is the eustachian tube?

Back 60

The air-filled tube of the middle ear that equalizes pressure between the external and internal ear.

Front 61

What is the vestibule?

Back 61

The chamber found at the base of the semicircular canals that provides information about static equilibrium.

Front 62

What are the semicircular canals?

Back 62

The fluid-filled structures within the inner ear that provide information about dynamic equilibrium.

Front 63

What is the cochlea?

Back 63

The coiled structure of the inner ear that responds to various sound waves and converts them into nerve impulses.

Front 64

What is the Organ of Corti?

Back 64

The primary sound receptor in the cochlea?

Front 65

What is the basilar membrane?

Back 65

The structure that anchors the receptor hair cells in the Organ of Corti.

Front 66

What are otoliths?

Back 66

Tiny stones of calcium carbonate embedded in gelatinous coating within the saccule and utricle.

Front 67

What are the two function of the ear?

Back 67

Hearing and equilibrium.

Front 68

Which structures are in the outer ear?

Back 68

Pinna and auditory canal.

Front 69

What is/is the function of the pinna?

Back 69

The pinna is the external ear flap that collects sound and directs it towards the auditory canal.

Front 70

What is/is the function of auditory canal?

Back 70

The auditory canal carries sound to the eardrum. It is lined with sweat glands that produce ear wax, which traps foreign particles and prevents them from entering the ear.

Front 71

Which structures are in the middle ear?

Back 71

Tympanic membrane, ossicles, oval window, and eustachian tube.

Front 72

What is/is the function of the tympanic membrane?

Back 72

The tympanic membrane is also known as the eardrum. Sound waves cause it to vibrate and transmit the waves to the air-filled chamber.

Front 73

What is/is the function of the ossicles?

Back 73

They are three small bones that amplify and carry sound to the inner ear. The three bones are the malleus/hammer ---> incus/anvil ---> stapes/stirrup. It is able to amplify the sound up to 3x the amount because it is small, so it moves a shorter distance but with greater force.

Front 74

What is/is the function of the oval window?

Back 74

Further amplifies sound.

Front 75

What is/is the function of the Eustachian Tube?

Back 75

The Eustachian tube extends from the mid ear to the mouth and nose. It permits equalization of air pressure of either side of the ear drum. This can result in discomfort, temporary hearing loss, and poor balance.

Front 76

Which structures are in the inner ear?

Back 76

Vestibule (utricle and saccule), semicircular canals, and cochlea.

Front 77

What is/is the function of the vestibule?

Back 77

The vestibule houses two small sacs : the utricle and saccule (which encase the otoliths), which establishes head position. It is vital in the maintenance of static movement equilibrium along one plane.

Front 78

What is/is the function of the semicircular canals?

Back 78

The movement of fluid within the semicircular canals help identify body movement. Three canals provide information about dynamic equilibrium.

Front 79

What is/is the function of the cochlea?

Back 79

The cochlea contains rows of specialized hair cells along the inner canal. The hair cells convert sound waves to nerve impulses.

Front 80

Draw a flowchart that illustrates the process by which sound is heard.

Back 80

pinna ---> auditory canal --->tympanic membrane ---> ossicles (hammer ---> anvil ---> stapes) ---> oval window ---> cochlea (organ of corti) ---> auditory nerve ---> temporal lobe

Front 81

What protects the inner ear against excessive noise?

Back 81

Muscles that join the bones of the middle ear protects the inner ear against excessive noise. Intense sound causes tiny muscles to contract, restricting movement of the malleus and decreasing the intensity of movement. The second muscles pulls the stapes away from the oval window, protecting the inner ear from vibrations. This may not work in the case of sudden sound.

Front 82

What are the three structures of the Cochlea?

Back 82

1. Basilar membrane - many hair cells

2. Hair cells - many tiny projections

3. Tectorial membrane - embedded on ends of hair cells

Front 83

How do we distinguish between different pitches?

Back 83

Each pitch has a different frequency, which resonates on different lengths/positions of the cochlea. High frequency pitches die quicker in the cochlea, while low sounds resonate deeper in the cochlea, as the cochlea becomes wider and more elastic. These vibrations trigger the cilia to create action potentials that are carried back to your temporal lobe, which allows you to differentiate between pitches.

Front 84

How do we differentiate between different sound intensities?

Back 84

Sound intensity is depends on the strength of vibrations, meaning amount of cilia triggered, and frequency/number of neural impulses, resonate within the cochlea/organ of corti, generating action potentials to be transferred and translated to the temporal lobe.

Front 85

What are the two components of balance?

Back 85

Static and dynamic equilibrium?

Front 86

How does the ear maintain static equilibrium?

Back 86

Head position is monitored by saccule and utricle - two fluid filled sacs. Cilia are suspended in gelatinous material with otoliths - small calcium carbonate granules. If the head is bent forward, gravity pulls the otoliths down , causing the gelatine to shift, and the cilia to bend. The movement of cilia stimulates sensory nerves , which are sent to the cerebellum for interpretation.

Front 87

How does the ear maintain dynamic equilibrium?

Back 87

During movement, balance is maintained by three fluid filled semicircular canals. Each canal has an ampulla which holds a cupula. Rotational stimuli cause fluid in semicircular canals to move, bending cilia attached to hair cells in the cupulas. When the hair bends they generate nerve impulses which are sent to the cerebellum.

Front 88

Label all parts of the ear.

Back 88

Front 89

Label all parts of the eye.

Back 89

Front 90

How does sound register in the cochlea?

Back 90

Hair cells respond to vibrations of the basilar membrane. Vibrations in the fluid surround ing BM cause the membrane to move, hairs bend against the tectorial membrane. Movement of hair cells stimulate sensory nerves in the BM.