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Anatomy (BKS) The Special Senses Part A

Terms in this set (47)

Chemical senses
gustation (taste) and olfaction (smell)
(Chemical senses) Their chemoreceptors respond to
chemicals in aqueous solution
(chemoreceptors) Taste
to substances dissolved in saliva
(chemoreceptors) Smell
to substances dissolved in fluids of the nasal membranes
Most of the 10,000 or so taste buds are found on
the tongue
Taste buds are found in papillae
of the tongue mucosa
Papillae come in three types:
filiform, fungiform, and circumvallate
Fungiform and circumvallate papillae contain
taste buds
There are five basic taste sensations:
-Sweet - sugars, saccharin, alcohol, and some amino acids
-Salt - metal ions
-Sour - hydrogen ions
-Bitter - alkaloids such as quinine and nicotine
-Umami - elicited by the amino acid glutamate
Taste is 80% what?
smell
Thermoreceptors, mechanoreceptors, nociceptors also influence
tastes
What are enhanced or detract from taste?
Temperature and texture
70% of all sensory receptors are in
the eye
Most of the eye is protected by
a cushion of fat and the bony orbit
Accessory structures include
eyebrows, eyelids, conjunctiva, lacrimal apparatus, and extrinsic eye muscles
Lacrimal Apparatus Consists of
the lacrimal gland and associated ducts
Lacrimal Apparatus - Lacrimal glands do what?
secrete tears
Lacrimal Apparatus - Tears contain
mucus, antibodies, and lysozyme
Lacrimal Apparatus - Tears drain into the
nasolacrimal duct
Six straplike extrinsic eye muscles Enable the eye to
follow moving objects
Six straplike extrinsic eye muscles Maintain the shape of
the eyeball
Four rectus muscles originate from
the annular ring
Two oblique muscles move the eye in the
vertical plane
the eyeball is a
A slightly irregular hollow sphere with anterior and posterior poles
Structure of the Eyeball -The wall is composed of three tunics
fibrous, vascular, and sensory
Structure of the Eyeball - The internal cavity is filled with
fluids called humors
Structure of the Eyeball - The lens separates the internal cavity
into anterior and posterior segments
Fibrous Tunic Forms the
outermost coat of the eye and is composed of:
-Opaque sclera (posteriorly)
-Clear cornea (anteriorly)
(Fibrous Tunic) The sclera protects the
eye and anchors extrinsic muscles
(Fibrous Tunic)The cornea lets
light enter the eye
Choroid Region Has three regions:
choroid, ciliary body, and iris
Vascular Tunic (Uvea): Choroid region Supplies
blood to all eye tunics
Vascular Tunic: Ciliary Body is A thickened
ring of tissue surrounding the lens
Vascular Tunic: Ciliary Body is Composed of
smooth muscle bundles (ciliary muscles)
Vascular Tunic: Ciliary Body Anchors the
suspensory ligament that holds the lens in place
Vascular Tunic: Iris is The colored part of
the eye
Vascular Tunic: Iris - Pupil is...
central opening of the iris
Vascular Tunic: Iris - Pupil Regulates the amount of
light entering the eye during:
Close vision and bright light
pupils constrict
Distant vision and dim light
pupils dilate
Sensory Tunic: Retina contains
A delicate two-layered membrane
Sensory Tunic: Retina -Pigmented layer
the outer layer that absorbs light and prevents its scattering
Sensory Tunic: Retina -Neural layer, which contains:
-Photoreceptors that transduce light energy
-Bipolar cells and ganglion cells
-Amacrine and horizontal cells
The Retina: Ganglion Cells and the Optic Disc - Ganglion cell axons:
-Run along the inner surface of the retina
-Leave the eye as the optic nerve
The optic disc:
Is the site where the optic nerve leaves the eye
Lacks photoreceptors (the blind spot)
The Retina: Photoreceptors-Rods:
-Respond to dim light
-Are used for peripheral vision
The Retina: Photoreceptors-Cones:
-Respond to bright light
-Have high-acuity color vision
-Are found in the macula lutea
-Are concentrated in the fovea centralis
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