Exam Two - Special Senses

Photoreceptors

rods and cones

rods

black and white (grey)/ night vision (dim light)

• Scotopic vision and rhodopsin pigment

cones

color, bright light, good acuity, and shapes

• Photopic vision and photopsin pigment

Astigmatism

Irregular shaped cornea or lens

What are rods most sensitive to on the color spectrum?

blue and green

Horizontal cells (GABA)

Modulator between rods and cones

Amacrine cells

between bipolar and ganglion modulator

Taste buds

salt, sweet, bitter, sour, umami

Stimulates salt taste bud

sodium

Stimulates sweet taste bud

glucose

Stimulates bitter taste bud

poison

Stimulates sour taste bud

acid, H+ ions

Stimulates umami taste bud

glutamate (msg)

hyperopia

light lands past retina (far sighted)

Lens used to correct hyperopia

convex

Convex lens

bends light inwards bringing rays closer together

Myopia

light lands before retina (near-sighted)

Lens used to correct myopia

concave

Concave lens

bends light farther apart

Inner hair cells

responsible for transmitting sound info to the brain (hearing the sound)

Outer hair cells

responsible for modulating sound (adjusts sound)

How does the organ of corti work

The fluid waves move basilar membrane > endolymph rushes between TM and hair cells causing them to shear > bending opens K and Ca channels, causing depolarization and trigger of nerve impulses

Basilar membrane

has different sensitivity to sound along its length, the frequency of sound determines the displacement of the membrane

Treble

thicker and stiffer region of basilar membrane, base of cochlea

Bass

Thinner and flexible region of basilar membrane, apex of cochlea

Utricle

sense acceleration; change in forward or backward direction

Saccule

change in up in down movement

Semicircular canals

superior, posterior, lateral

Superior

detects nodding movement

Posterior

detects tilting

Lateral

detects lateral movement

Muscles and nerves activated in eyes: turn head to left

left eye activates medial rectus and oculomotor nerve

right eye activates lateral rectus and abducens nerve

Muscles and nerves activated in eyes: turn head to right

right eye activates medial rectus and oculomotor nerve

left eye activates lateral rectus and abducens nerve