Sensory And Motor Mechanisms

Front 1

Sensory receptor –

Back 1

respond to specific stimuli either from outside or from within the body

Front 2

Sensory transduction –

Back 2

the conversion of stimulus energy into a change in the membrane potential of a sensory receptor
This change in membrane potential is called a receptor potential

Front 3

Sensory amplification –

Back 3

the strengthening of stimulus energy by cells in sensory pathways

Front 4

Sensory adaptation –

Back 4

a decrease in responsiveness to continued stimulation

Front 5

Organ of Corti –

Back 5

the organ in the inner ear of mammals that contains auditory sensory cells, or “hair cells

Front 6

Gustation –

Back 6

(taste) is dependent on the detection of chemicals called tastants

Front 7

Olfaction –

Back 7

(smell) is dependent on the detection of odorant molecules

Front 8

Tastant –

Back 8

any chemical that stimulates the sensory cells in a taste bud

Front 9

Visual pigment –

Back 9

any of a number of related substances that function in light reception by animals by transforming light energy into electrical (nerve) potentials

Front 10

Horizontal cells and amacrine cells –

Back 10

integrate visual information before it is sent to the brain

Front 11

z-line –

Back 11

in electron micrographs of cross-striated muscle, the Z-line appears as a series of dark lines. A sarcomere is defined as the segment between two neighboring Z-lines. (sarcomere is the basic unit of a muscle)

Front 12

What is a sensation and how is it produced?

Back 12

Sensation involves converting energy into a change in the membrane potential of sensory receptors
Sensations are action potentials that reach the brain via sensory neurons

Front 13

Sensory pathways have four basic functions in common; what are they?

Back 13

a. Sensory reception
b. Transduction
c. Transmission
d. Integration

Front 14

Are receptor potentials graded potentials?

Back 14

Receptor potential is a type of graded potential
It is the transmembrane potential difference of a sensory receptor

Front 15

In what form is sensory information transmitted through the nervous system?

Back 15

Sensory receptor cells release neurotransmitters at synapses with sensory neurons

Front 16

What controls the rate of AP production by a sensory receptor?

Back 16

The magnitude of the receptor potential controls the rate of AP production by a sensory receptor.

Front 17

What is the sensory information received in the brain interpreted as?

Back 17

The brain interprets sensory stimuli received as a perception – a color, smell, sound, taste, etc.
The brain distinguishes sensory stimuli from different receptors by the area in the brain where the action potentials arrive

Front 18

What are the five categories of sensory receptors and what is the nature of the stimuli detected by each?

Back 18

a. Mechanoreceptors – sense physical deformation caused by stimuli such as pressure, stretch, motion, and sound
b. Chemoreceptors – transmit information about the total solute concentration
c. Electromagnetic receptors – detect different forms of electromagnetic energy such as light, electricity, and magnetism
d. Thermoreceptors – detect heat and cold
e. Pain receptors – detect pressure, temperature, or certain chemicals that can damage animal tissues

Front 19

How are hearing and equilibrium in mammals related?

Back 19

Mechanoreceptor cells produce receptor potentials when settling particles or moving fluid cause deflection of cell surface structures
In most terrestrial vertebrates, sensory organs for hearing and equilibrium are closely associated in the ear

Front 20

What three bones comprise the inner ear? What is their role in hearing?

Back 20

a. Cochlea – auditory portion
b. Semicircular canal – interconnected tubes located inside each ear. Helps maintain balance
c. Vestibule – contains the sense organs responsible for balance

Front 21

Draw the chohlea and label the following structures: vestibular canal, organ of Corti, tympanic canal, cochlear duct, auditory nerve.

Back 21

Look at picture

Front 22

Explain how the human ear works to convert pressure waves in the air to nerve impulses that the brain perceives as sound.

Back 22

a. Moving air causes the tympanic membrane to vibrate
b. Three bones in the middle ear transmit and amplify this vibration to the oval window
c. Vibration of the oval window causes pressure waves in the fluid inside the cochlea
d. Pressure waves in the fluid of the vestibular canal push down on the cochlear duct and basilar membrane
e. Hair cells attached to the basilar membrane vibrate up and down
f. Hairs are bent against the tectorial membrane
g. In response, mechanoreceptors in the hair cells open or close ion channels in the plasma membrane
h. Bending in one direction depolarizes, while bending in the opposite direction hyperpolarizes hair cells
i. The fluid waves dissipate when they strike the round window at the end of the tympanic canal

Front 23

How is the volume and pitch of a sound wave conveyed to the brain?

Back 23

Volume is determined by the amplitude of the sound wave and the corresponding movement of the basilar membrane
Pitch – because the basilar membrane is not uniform along its length, each region vibrates most vigorously at a particular frequency

Front 24

What prevents pressure waves from reverberating within the ear and causing prolonged sensation?

Back 24

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Front 25

What is the function of the utricle and saccule?

Back 25

Allow us to detect gravity and linear movement

Front 26

Why are there three semicircular canals? (hint: How are they arranged?)

Back 26

a. Horizontal semicircular canal
b. Superior semicircular canal
c. Posterior semicircular canal

Front 27

What are the five types of tastants?

Back 27

a. Sweet
b. Sour
c. Salty
d. Bitter
e. Unami

Front 28

How does a taste receptor work?

Back 28

The sensation of sweet, unami, and bitter tastes employ G protein coupled receptors (GPCR)

Front 29

How does the receptor for sour taste differ from the receptors for the other four tastants?

Back 29

The receptor for sour taste belongs to the transient receptor potential family

Front 30

How does olfaction differ from gustation? How is it similar?

Back 30

Both rely on similar sets of sensory receptors
Gustation (taste) is dependent on the detection of chemicals called tastants
Olfaction (smell) is dependent on the detection of odorant molecules
In aquatic animals there is no distinction between taste and smell
Taste receptors of insects are in sensory hairs called sensilla, located on feet and in mouth parts
Olfactory receptor cells are neurons that line the upper portion of the nasal cavity

Front 31

What are the main parts of the vertebrate eye?

Back 31

a. The sclera
b. The choroid
c. The iris
d. The retina
e. The lens
f. The optic disk

Front 32

What are the two main cavities of the eye and what are they filled with?

Back 32

The anterior cavity is filled with watery aqueous humor
The posterior cavity is filled with jellylike vitreous humor

Front 33

How is light focused in the human eye?

Back 33

Humans and other mammals focus light by changing the shape of the lens

Front 34

What are the two basic types of photoreceptors that make up the human eye? How do they differ?

Back 34

Rods are light-sensitive but don’t distinguish colors
Rods are more concentrated around the periphery of the retina
Cones distinguish colors but are not as sensitive to light
In humans, cones are concentrated in the fovea, the center of the visual field

Front 35

Where is the highest concentration of cones found in the human eye?

Back 35

In humans, cones are concentrated in the fovea, the center of the visual field

Front 36

Describe the sensory transduction pathway in the eye?

Back 36

Each rod or cone contains visual pigments consisting of a light-absorbing molecule called retinal bonded to a protein called an opsin
Rods contain the pigment rhodopsin (retinal combined with a specific opsin), with changes shape when light is absorbed

Front 37

Why are there three types of cones in the human eye?

Back 37

a. Red
b. Green
c. Blue