BIO 360 - Exam 2 - Chapter 10 Summary Questions

Question 1

Sensory stimuli are divided into :

(1) ______ ______ of vision, hearing, taste, smell, and equilibrium.
(2) ______ ______ of touch, temperature, pain, itch, and proprioception.

Answer 1

special senses / somatic senses

Question 2

There are four types of sensory receptors, based on the stimulus to which they are most sensitive:

Answer 2

Chemoreceptors: Oxygen, pH, various organic molecules such as (glucose).
Mechanoreceptors: Pressure (baroreceptors), cell stretch (osmoreceptors), Vibration, acceleration, sounds
Thermoreceptors: Varying degrees of heat
Photoreceptors: Photons of light

Question 3

______ is the conversion of stimulus energy into information that can be processed by the nervous system. In many receptors, the opening or closing of ion channels converts mechanical, chemical, thermal, or light energy directly into a change in membrane potential.

Answer 3

transduction

Question 4

Each receptor type has an ______ ______, a particular form of energy to which it is most responsive.

Answer 4

adequate stimulus

Question 5

A stimulus that is above ______ creates a graded potential in the receptor.

Answer 5

threshold

Question 6

Multiple sensory neurons may converge on one secondary neuron and create a single large ______ ______. A touch-sensitive neuron in the skin responds to pressure that falls within its receptive field.

Answer 6

receptive field

Question 7

Sensory information from the spinal cord projects to the ______, then on to the sensory areas of the cerebral cortex. ______ information does not pass through the ______.

Answer 7

thalamus / olfactory / thalamus

Question 8

The central nervous system is able to modify our level of awareness of sensory input. The p______ t______ is the level of stimulus intensity necessary for us to be aware of a particular sensation.

Answer 8

perceptual threshold

Question 9

The mo______ of a signal and its location are indicated by which sensory neurons are activated. The association of a receptor with a specific sensation is called ______ ______ ______.

Answer 9

modality / label line coding

Question 10

Localization of auditory information depends on the timing of receptor activation in each ear.

Question 11

La______ in______ enhances the contrast between the center of the receptive field and the edges of the field.
In pop______ co_____, the brain uses input from multiple receptors to calculate location and timing of a stimulus.

Answer 11

Lateral inhibition / population coding

Question 12

Stimulus intensity is coded by what two things?

Answer 12

(1) number of receptors activated
(2) frequency of their action potentials

Question 13

For ______ ______, the sensory neuron fires action potentials as long as the r______ p_____ is above threshold. ______ ______ respond to a change in stimulus intensity but adapt if the strength of the stimulus remains constant.

Tonic receptors are slowly adapting receptors that fire rapidly when first activated, then slow and maintain their firing as long as the stimulus is present.

Phasic receptors are rapidly adapting receptors that fire when they first receive a stimulus but cease firing if the strength of the stimulus remains constant (Fig. 10.7b). Phasic receptors are attuned specifically to changes in a parameter. Once a stimulus reaches a steady intensity, phasic receptors adapt to the new steady state and turn off.

Answer 13

tonic receptors / receptor potential / Phasic receptors

Question 14

There are four somatosensory modalities:

Answer 14

touch, proprioception, temperature, and nociception.

Question 15

s______ s______ n_____ cross the midline so that one side of the brain processes information from the opposite side of the body. Ascending sensory tracts terminate in the ______ cortex.

Answer 15

Secondary sensory neurons / somatosensory

Question 16

______ are free nerve endings that respond to chemical, mechanical, or thermal stimuli. Their activation is perceived as pain and itch.

Answer 16

Nociceptors

Question 17

Some responses to irritants, such as the withdrawal reflex, are protective ______ ______.

Answer 17

spinal reflexes

Question 18

R______ pa_____ from internal organs occurs when multiple primary sensory neurons converge onto a single ascending tract.

Answer 18

Referred pain

Question 19

______ ______ is transmitted rapidly by small, myelinated fibers. ______ ______ is carried by small, unmyelinated fibers.
Pain may be modulated either by descending pathways from the brain or by ______ mechanisms in the spinal cord.

Answer 19

Fast pain / Slow pain / gating

Question 20

Chemoreception is divided into the special senses of:

Answer 20

smell (olfaction) and taste (gustation).

Question 21

______ ______ ______ in the nasal cavity are bipolar neurons whose pathways project directly to the olfactory cortex.

Answer 21

Olfactory sensory neurons

Question 22

______ ______ are G protein-coupled membrane proteins.The combination of most odorant molecules with their olfactory receptors activates a special G protein, Golf, which in turn increases intracellular cAMP.

Answer 22

Olfactory receptors

Question 23

Taste is a combination of five sensations: sweet, sour, salty, bitter, and ______, a taste associated with the amino acid glutamate and some nucleotides.

Sour taste is triggered by the presence of H+ and salty by the presence of Na+. The other three taste sensations result from organic molecules. Sweet and umami are associated with nutritious food. Bitter taste is recognized by the body as a warning of possibly toxic components. If something tastes bitter, our first reaction is often to spit it out.

Answer 23

umami

Question 24

______ ______ ______ are nonneural cells with membrane channels or receptors that interact with taste ligands. This interaction creates an intracellular Ca2+ signal that ultimately activates the primary sensory neuron.

Answer 24

Taste receptor cells

Question 25

______ is our perception of the energy carried by sound waves. Sound transduction turns air waves into mechanical vibrations, then fluid waves, chemical signals, and finally action potentials.

Answer 25

Hearing

Question 26

The ______ of the inner ear contains three parallel, fluid-filled ducts. The ______ ______ contains the ______ ______ ______, which contains hair cell receptors.

Answer 26

cochlea / cochlear duct / organ of Corti

Question 27

When sound bends hair cell cilia, the hair cell membrane potential changes and alters release of neurotransmitter onto sensory neurons.

Question 28

The initial processing for pitch, loudness, and duration of sound takes place in the ______. Localization of sound is a higher function that requires sensory input from both ears and sophisticated computation by the brain.

Answer 28

cochlea

Question 29

The auditory pathway goes from ______ nerve to m______, p______, m______, and t______ before terminating in the a______ c______. Information from both ears goes to both sides of the brain.

Answer 29

cochlear / medulla / pons / midbrain / thalamus / auditory cortex.

Question 30

E______ is mediated through hair cells in the v______ a______ and s______ c______ of the inner ear.

______ and ______ provide the force that moves the cilia.

Answer 30

Equilibrium / vestibular apparatus / semicircular canals

gravity & acceleration

Question 31

______ is the translation of reflected light into a mental image. Photoreceptors of the retina transduce light energy into an electrical signal that passes to the visual cortex for processing.

Answer 31

Vision

Question 32

The amount of light entering the eye is altered by changing the size of the ______.

Answer 32

pupil

Question 33

Light waves are focused by the lens, whose shape is adjusted by contracting or relaxing the ______ muscle.

Answer 33

ciliary

Question 34

Light is converted into electrical energy by the ______ of the retina. Signals pass through bipolar neurons to ganglion cells, whose axons form the optic nerve.

Answer 34

photoreceptors

Question 35

The ______ has the most acute vision because it has the smallest receptive fields.

Answer 35

fovea

Question 36

______ are responsible for monochromatic nighttime vision. ______ are responsible for high-acuity vision and color vision during the daytime.

Answer 36

Rods / Cones

Question 37

Light-sensitive vi_____ pi_____ in photoreceptors convert light energy into a change in membrane potential. The visual pigment in rods is r______. Cones have three different visual pigments.

Answer 37

visual pigments / rhodopsin

Question 38

Rhodopsin is composed of ______ and ______. In the absence of light, retinal binds snugly to ______.

Answer 38

opsin / retinal / opsin

Question 39

When light bleaches rhodopsin, ______ is released and ______ begins a second-messenger cascade that hyperpolarizes the rod so that it releases less glutamate onto the bipolar neurons.

Answer 39

retinal / transducin

Question 40

Signals pass from photoreceptors through bipolar neurons to ganglion cells, with modulation by horizontal and amacrine cells.

Question 41

Ganglion cells called ______ ______ convey information about movement. Ganglionic ______ ______ transmit signals that pertain to the form and texture of objects in the receptive field.

Answer 41

M cells / P cells

Question 42

Information from one side of the visual field is processed on the opposite side of the brain. Objects must be seen by both eyes to appear three-dimensional.