PART 1 (Taste, Smell, Vision)

What type of receptors are used for taste?

Chemoreceptors

What must happen for taste to occur?

Chemicals must dissolve in saliva

What percentage of taste is actually smell?

80%

Where are taste buds located?

Papillae on tongue, cheeks, soft palate

What do taste buds contain?

Gustatory receptor cells and a taste pore

Which cranial nerves carry taste information?

VII Facial, IX Glossopharyngeal, X Vagus

What other receptors are in the mouth besides taste receptors?

Mechanoreceptors, thermoreceptors, nociceptors

What type of receptors detect smell?

Chemoreceptors

What must happen for smell to occur?

Chemicals must dissolve in nasal mucus

How many odors can humans detect?

About 10,000

How many olfactory receptors do humans have?

About 400

What is the only sensory pathway that does NOT pass through the thalamus?

Olfactory nerve (Cranial Nerve I)

Where do olfactory receptor axons synapse?

Olfactory bulb

What are the accessory eye structures?

Eyebrows, eyelids, eyelashes, conjunctiva, lacrimal apparatus, extrinsic eye muscles

What structures make up the lacrimal apparatus?

Lacrimal gland and lacrimal sac

What are the three layers of the eye?

Fibrous layer, vascular layer, inner layer (retina)

What are the components of the fibrous layer?

Sclera and cornea

What is the function of the sclera?

Protects and shapes eye; anchors muscles

What is the function of the cornea?

Lets light in and refracts light

Is the cornea vascular?

No, it is avascular

What is the function of the choroid?

Blood-rich layer that nourishes eye and absorbs light

What does the ciliary body do?

Controls lens shape via suspensory ligaments

What muscles does the iris contain?

Sphincter pupillae and dilator pupillae

What is the pupil?

Opening that allows light to enter the eye

What are rods responsible for?

Dim light, black/white vision, peripheral, fuzzy images

What are cones responsible for?

Bright light, color, sharp images

What is the optic disc?

Blind spot where optic nerve exits the eye

What is the fovea centralis?

Area with the highest concentration of cones; sharpest vision

What is the lens made of?

Biconvex, clear, flexible, avascular tissue

What are cataracts?

Clouding of the lens

What does the anterior segment contain?

Aqueous humor (regenerates)

What does the posterior segment contain?

Vitreous humor (lifelong, gel-like)

What is glaucoma?

Blocked aqueous humor causing increased pressure and optic nerve damage

What is refraction?

Bending of light entering a different density medium

What is astigmatism?

Unequal curvature of cornea or lens causing blurry vision

What are opsins?

Proteins sensitive to specific wavelengths of light

What is rhodopsin?

Light-sensitive pigment found in rods

Where are cones most concentrated?

Fovea centralis

What percent of the visual cortex is devoted to the fovea?

Over 50%

What is binocular vision?

Using both eyes to perceive depth (stereoscopic vision)

What does binocular vision help with?

Depth perception and 3D vision

What is visual acuity?

Sharpness of vision; ability to see fine detail

Which part of the eye provides the highest visual acuity?

Fovea centralis