Chp 17 The Special Senses

Front 1

Olfaction

Back 1

Sense of Smell

Front 2

Olfactory Receptors

Back 2

First-order neurons of the olfactory pathway.

Front 3

Supporting (sustentacular) Cells

Back 3

Columnar epithelial cells of the mucous membrane lining the nose.

Fxn: to provide support for chemoreceptors

Front 4

Basal Cells

Back 4

Stem cells located between the base of the supporting cells.

Fxn: to replace dead/ damaged receptors.

Front 5

Olfactory (Bowman's) Glands

Back 5

Fxn: to secrete mucus that is carried to the surface of the epithelium by ducts. The secretion moistens the surface of the olfactory epithelium and dissolves odorants so that transduction can occur.

Front 6

Olfactory Nerve + Bulb+ Tract

Back 6

Forty (or so) bundles of axons collectively form the right and left olfactory (I) nerves. The olfactory nerves terminate in the brain in paired masses of gray matter called olfactory bulbs, which are located below the frontal lobes of the cerebrum. Axons of the olfactory bulb neurons extend posteriorly and form the olfactory tract. Some of the axons of the tract project to the primary olfactory area located in the temporal lobe.

Front 7

Gustation

Back 7

Sense of Taste

Front 8

Taste Bud

Back 8

One of a number of flask-shaped receptor cell nests located in the epithelium of the papillae of the tongue and in the soft palate, epiglottis, and pharynx that mediate the sense of taste.

Front 9

Gustatory (Taste) Receptor Cells

Back 9

Receptor cell that transduces chemical into an action potential for taste.

Front 10

Gustatory Hair (Microvillus)

Back 10

A single long microvillus that projects from each gustatory receptor cell to the external surface through the taste pore, an opening in the taste bud.

Front 11

Papillae

Back 11

Elevations on the tongue that provide a rough texture to the upper surface of the tongue.

Front 12

Vision

Back 12

Sense of Sight

Front 13

Opthalmology

Back 13

The branch of medicine dealing with the eye, including its anatomy, physiology, and pathology

Front 14

Opthalmologist

Back 14

A physician who specializes in the diagnosis and treatment of eye disorders with drugs, surgery and corrective lenses.

Front 15

Optometrist

Back 15

A specialist that is licensed to test eyes and prescribe corrective lenses. No drugs or surgery.

Front 16

Optician

Back 16

A technician who fits and adjusts corrective lenses.

Front 17

Palpebrae (eyelid)

Back 17

Shade eyes during sleep, protect eyes from excessive light and foreign objects, and spread lubricating secretions over the eyeball.

Front 18

Tarsal Plate + Glands

Back 18

A thick fold of connective tissue that gives form and support to the eyelids. Embedded in each tarsal plate is a row of elongated modified sebaceous glands that secrete a fluid that helps keep the eyelids from adhering to each other.

Front 19

Conjunctiva

Back 19

A vascular membrane that covers the sclera and lines eyelids and contains blood vessels.

Front 20

Eyelashes

Back 20

Hair projections from the border of each eyelid that help protect the eyeballs from foreign objects, perspiration and direct rays of sun. Sebaceous glands at the base of the hair follicles release a lubricating fluid into the follicles. Infection of these glands is called a Sty.

Front 21

Eyebrows

Back 21

Transversely-arched group of hair above the upper eyelids that help the eyelashes with protection.

Front 22

Lacrimal Apparatus

Back 22

A group of structures that produces and drains lacrimal fluid or tears.

Front 23

Lacrimal Gland

Back 23

About the shape and size of an almond, these glands secrete lacrimal fluid.

Front 24

Lacrimal Fluid

Back 24

Tears - made of lysozymes - an anti-bacterial enzyme to sterilize surface of the eye.

Front 25

Excretory Lacrimal Ducts

Back 25

6-12 ducts that empty tears on the surface of the conjunctiva of the upper lid.

Front 26

Lacrimal Puncta

Back 26

The minute circular opening of the lacrimal duct on the margin of each eyelid near the medial commissure.

Front 27

Lacrimal Canals

Back 27

Tears pass into these two ducts which lead into the lacrimal sac.

Front 28

Nasolacrimal Duct + Sac

Back 28

A duct that carries lacrimal fluid into the nasal cavity just inferior to the inferior nasal concha. An infection of the lacrimal sacs is called Dacryocystitis.

Front 29

Fibrous Tunic

Back 29

The superficial layer of the eyeball and consists of the anterior cornea and posterior sclera.

Front 30

Cornea

Back 30

A transparent coat that covers the colored iris. Its outer surface consists of nonkeratinized stratified squamos epithelium.

Front 31

Sclera

Back 31

A layer of dense CT made up mostly of collagen fibers and fibroblasts. It covers the entire eyeball except the cornea; it gives shape to the eyeball, makes it more rigid, protects its inner parts and serves as a site of attachment for the extrinsic eye muscles.

Front 32

Vascular Tunic

Back 32

The middle layer of the eyeball. It is composed of three parts: choroid, ciliary body and iris.

Front 33

Choroid

Back 33

This lines most of the internal surface of the sclera. Its numerous blood vessels provide nutrients to the posterior surface of the retina. The choroid also contains melanocytes that produce the pigment melanin, which gives it the dk brown color.

Front 34

Ciliary Body

Back 34

In the anterior portion of the vascular tunic, the choroid becomes this. The ciliary body consists of ciliary processes and ciliary muscles.

Front 35

Iris

Back 35

The colored portion of the eyeball. Shaped like a flattened donut. It is suspended between the cornea and the lens. The amt of melanin in this determines eye color.

Front 36

Pupil

Back 36

The hole in the center of the iris.

Front 37

Retina (Nervous Tunic)

Back 37

The third and inner layer of the eyeball that lines the posterior 3/4 of the eyeball and is the beginning of the visual pathway. Can be viewed with an Ophthalmoscope.

Front 38

Optic Disc

Back 38

The site where the optic (II) nerve exits the eyeball.

Front 39

Photoreceptor Layer

Back 39

The layer of the retina where light is transduced into action potentials.

Front 40

Ganglion Cell Layer

Back 40

The axons of these cells make up the optic nerve.

Front 41

Rod

Back 41

Allow us to see in dim light, such as moonlight. These do not provide color vision, so in dim light, we can only see black, white and shades of gray.

Front 42

Cone

Back 42

Allow us to see color. Three types are present: blue, green and red. Color vision results from the stimulation of various combinations of these three types.

Front 43

Macula Lutea

Back 43

The bull's eye. The exact center of the posterior portion of the retina.

Front 44

Fovea Centralis

Back 44

Middle of the Bull's Eye that contains only cones.

Front 45

Blind Spot

Back 45

The optic disc, where there are no photoreceptors.

Front 46

Lens

Back 46

The transparent, biconvex body separating the posterior chamber and vitreous body, and constituting part of the refracting mechanism of the eye.

Front 47

Suspensory Ligaments (Ciliary Zonule)

Back 47

A series of fibers connecting the ciliary body and lens of the eye

Front 48

Anterior Cavity

Back 48

The space anterior to the lens.

Front 49

Canal of Schlemm

Back 49

An opening at the junction of the sclera and the cornea. Aqueous humor drains into this sinus.

Front 50

Aqueous Humor

Back 50

A transparent watery fluid that nourishes the lens and cornea. It continually filters out of blood capillaries in the ciliary processes and into the posterior chamber of the anterior cavity. It is completely replaced about every 90 minutes.

Front 51

Glaucoma

Back 51

A group of eye diseases characterized by damage to the optic nerve usually due to excessively high intraocular pressure (IOP).This increased pressure within the eye, if untreated can lead to optic nerve damage resulting in progressive, permanent vision loss, starting with unnoticeable blind spots at the edges of the field of vision, progressing to tunnel vision, and then to blindness.

Front 52

Intraocular Pressure

Back 52

The pressure exerted against the outer coats by the contents of the eyeball. Normally 16 mmHg. Maintains the shape of the eyeball and prevents it from collapsing.

Front 53

Posterior Cavity

Back 53

A cavity that lies between the lense and retina and is filled with vitreous humor.

Front 54

Vitreous Humor

Back 54

A transparent jellylike substance that holds the retina flush against the choroid, giving the retina an even surface for the reception of clear images. Occupies 4/5s of the eyeball. Does not undergo constant replacement.

Front 55

Refraction

Back 55

As light rays enter the eye, they are refracted at the anterior and posterior surfaces of the cornea. Both surfaces of the lens of the eye further refract the light rays, so they come into exact focus on the retina.

Front 56

Accommodation

Back 56

The increase in the curvature of the lens for near vision.

Front 57

Convergence

Back 57

When both eyes focus on only one set of objects. This allows for the perception of depth and an appreciation of the the 3D nature of objects.

Front 58

Photopigment

Back 58

A colored protein that undergoes structural changes when it absorbs light, in the outer segment of a photoreceptor.

Front 59

Rhodopsin

Back 59

The only type of photopigment found in rods.

Front 60

Opsin

Back 60

A glycoprotein found in photopigments.

Front 61

Retinal (Vitamin A)

Back 61

A derivative of Vit A found in photopigments. They are formed from carotene.

Front 62

Nyctalopia

Back 62

Night blindness. An inability to see well at low light levels. Caused by a prolonged Vit A deficiency.

Front 63

Light Adaptation

Back 63

When your visual system adjusts in seconds to the brighter environment by decreasing its sensitivity.

Front 64

Dark Adaptation

Back 64

When your visual system adjusts to the darker environment by increasing its sensitivity slowly over several minutes.

Front 65

Optic Chiasm

Back 65

The axons within the optic nerve pass through the optic chiasm, a crossing point of the optic nerves.

Front 66

Optic Tract

Back 66

After passing through the chiasm, the axons now become a part of this and enter into the brain and terminate at the thalamus.

Front 67

Optic Radiations

Back 67

The axons from the optic tract synapse with neurons whose axons form this, which project to the primary visual areas in the occipital lobe and visual perception occurs.

Front 68

Auditory

Back 68

The sense of hearing.

Front 69

External (Outer) Ear

Back 69

Consists of the auricle, external auditory canal, and eardrum.

Front 70

Auricle

Back 70

A flap of elastic cartilage shaped like the flared end of a trumpet and covered by skin.

Front 71

Pinna

Back 71

Another name for the auricle.

Front 72

Helix

Back 72

The upper rim of the auricle.

Front 73

Lobule

Back 73

The inferior portion of the external ear.

Front 74

External Auditory Canal

Back 74

A curved tube about 2.5cm long that lies in the temporal bone and leads to the eardrum.

Front 75

Eardrum (Tympanic Membrane)

Back 75

A thin, semitransparent partition between the external auditory canal and middle ear. It is covered by epidermis and lined by simple cuboidal epithelium. Tearing of this results in a perforated eardrum.

Front 76

Ceruminous Glands

Back 76

Specialized sweat glands that secrete earwax or cerumen. The combination of hairs and cerumen helps prevent dust and foreign objects from entering the ear.

Front 77

Middle Ear

Back 77

A small, air-filled cavity in the petrous portion of the temporal bone that is lined by epithelium. It is separated from the external ear by the tympanic membrane.

Front 78

Eustachian Tube

Back 78

A tube that consists of both bone and elastic cartilage and connects the middle ear with the nasopharynx. It is normally closed at its medial end and assists with equalizing pressure.

Front 79

Auditory Ossicles

Back 79

Malleus, Incus and Stapes.

Front 80

Oval Window

Back 80

Where the base of the stapes fits into.

Front 81

Round Window

Back 81

An opening that is enclosed by the Secondary Tympanic Membrane.

Front 82

Tensor Tympani Muscle

Back 82

A muscle supplied by the Trigeminal (V) Nerve limits movement and increases tension on the eardrum to prevent damage to the inner ear from loud noises.

Front 83

Stapedius Muscle

Back 83

A muscle supplied by the Facial (VII) Nerve is the smallest skeletal muscle in the human body. It dampens large vibrations of the stapes due to loud noises, it protects the oval window, but also decreases the sensitivity of hearing.

Front 84

Internal (Inner) Ear

Back 84

Also called the Labyrinth. Consists of two main divisions: an outer bony labyrinth that encloses an inner membranous labyrinth.

Front 85

Bony Labyrinth

Back 85

A series of cavities in the petrous portion of the temporal bone divided into three areas: semicircular canals, vestibule and cochlea.

Front 86

Membranous Labyrinth

Back 86

A series of epithelial sacs and tubes inside the bony labyrinth that have the same general form as the bony labyrinth.

Front 87

Endolymph

Back 87

The fluid contained in the membranous labyrinth of the inner ear.

Front 88

Perilymph

Back 88

The fluid contained in the bony labyrinth of the inner ear. Chemically similar to CSF.

Front 89

Vestibule

Back 89

The oval portion of the bony labyrinth. Consists of two sacs called the Utricle and the Saccule, which are connected by a small duct.

Front 90

Macula

Back 90

A thickened region in the walls of the utricle and the saccule. The receptors for static equilibrium.

Front 91

Semicircular Canals

Back 91

Three bony projections from the vestibule.

Front 92

Ampulla

Back 92

A swollen enlargement at the end of each semicircular canal.

Front 93

Crista

Back 93

A small elevation in the ampulla of the semicircular ducts.

Front 94

Cupula

Back 94

A mass of gelatinous material in the semicircular ducts.

Front 95

Cochlea

Back 95

A bony spiral canal that resembles a snail's shell and makes almost three turns around a central bony core.

Front 96

Scala Vestibuli

Back 96

The channel above the cochlear duct, which ends at the oval window.

Front 97

Scala Tympani

Back 97

The channel above the cochlear duct, which ends at the round window.

Front 98

Helicotrema

Back 98

The opening at the apex of the cochlea.

Front 99

Cochlear Duct (Scala Media)

Back 99

A continuation of the membranous labyrinth into the cochlea and is filled with endolymph.

Front 100

Vestibular Membrane

Back 100

The separation of the cochlear duct from the scala vestibuli.

Front 101

Basilar Membrane

Back 101

The separation of the cochlear duct from the scala tympani.

Front 102

Organ of Corti

Back 102

A coiled sheet of epithelial cells, including supporting cells and about 16,000 hair cells.

Front 103

Hair Cells

Back 103

Receptors for hearing

Front 104

Tectorial Membrane

Back 104

A flexible, gelatinous membrane that covers the hair cells of teh spiral organ (Organ of Corti).

Front 105

Pitch

Back 105

The quality of sound dependent principally on its frequency

Front 106

Hertz

Back 106

A unit of frequency equal to one cycle per second. Humans can hear a range of 20 to 20,000 Hz.

Front 107

Intensity

Back 107

Size or amplitude of sound

Front 108

Decibel

Back 108

The measurement of sound intensity.

Front 109

Static Equilibrium

Back 109

A type of balance that refers to the maintenance of the position of the body (mainly the head) relative to the force of gravity.

Front 110

Dynamic Equilibrium

Back 110

A type of balance that refers to the maintenance of body's position (mainly the head) in response to rotational acceleration or deceleration.

Front 111

Stereocilia

Back 111

Though their name is more similar to cilia, they are actually more closely related to microvilli, and some sources consider them to be a variant of microvilli rather than their own distinct type of structure. It is a long projection of cell membrane, similar in structure to microvillus

They are characterized by their length (distinguishing them from microvilli) and their lack of motility (distinguishing them from cilia).

Front 112

Kinocilium

Back 112

A special structure on the apex of hair cells located in the sensory epithelium of the vertebrate inner ear.

Front 113

Otolithic Membrane

Back 113

The thick, gelatinous glycoprotein layer that rests on the hair cells within the macula.