Sensory Physiology

Front 1

What is the function of group B fibers?

Back 1

Motor: preganglionic autonomic

Front 2

What is the stimuli for chemoreceptors?

Back 2

Chemoreceptors include receptors for taste, smell, and internal stimuli such as pH, metabolite, concentrations

Front 3

What is receptor potential?

Back 3

The change in membrane potential of the receptor as a result of the interaction with the stimulus

a. can be produced by several different mechanisms depending on the receptor being activated

b. graded response - the amplitude of the receptor potential increases with increasing stimulus intensity over a wide range.

Front 4

What are phasic receptors and tonic receptors?

Back 4

Rapidly Adapting (Phasic) Receptors - receptor response diminishes quickly, best suited for detecting rate of change of a stimulus, they stop firing when stimulus us constant

Slowly adapting (tonic) Receptors - receptor response maintained

Front 5

What is modality?

Back 5

Modality is the type of sensation. This is accomplished by the wiring of nerves to the CNS and has been given the name "Labeled Line"

Front 6

What type of mechanoreceptor occurs especially in the fingertips an participates fine tactile discrimination?

Back 6

Meissner's Corpuscle

Front 7

What type of mechanoreceptor is a good sensor of vibrations?

Back 7

Pacinian corpuscles

Front 8

What type of mechanoreceptor is associated with nondiscriminatory touch?

Back 8

free nerve endings

Front 9

What type of fibers are associated with secondary afferents for mechanoreceptors ( spindles, touch, pressure, Pacinian Corpuscles)

Back 9

myelinated A-Beta-II

Front 10

What type of fibers are associated with cold receptors?

Back 10

Axons mostly myelinated A-delta, but some C fibers

Front 11

What kind of fibers are warm receptors?

Back 11

C fibers

Front 12

Which types of fibers are responsible for detecting noxious stimuli in the pulp?

Back 12

A-delta and C fibers

- Some A-delta fibers respond to mechanical stimulation of dentin (drilling, probing), while others respond to thermal stimuli

- C fibers are polymodal and respond to mechanical, chemical, and thermal stimuli

Front 13

What causes hyperalgesia in pulp?

Back 13

inflammation

Front 14

T/F: Classification of peripheral nerve fibers by microscopic measurement of diameter is for SENSORY FIBERS ONLY.

Back 14

True

Front 15

T/F: Spinal reflexes are not dependent on input from higher centers, however they are modified by higher centers.

Back 15

True

Front 16

What is the receptor for stretch reflexes ( myotactic reflex) ?

Back 16

muscle spindles made up of motor neurons and specialized sensory nerve endings embedded in two types of modified striated muscles fibers called intrafusal fibers.

Front 17

What are the two types of fibers in a muscle spindle?

Back 17

(1) nuclear bag fibers - intrafusal fibers which contain numerous nuclei packed in a center bag area. DYNAMIC RECEPTORS which relay information about the RATE of change of length.

(2) nuclear chain fibers - shorter thinner intrafusal fibers containing a single row of nuclei. Static receptors which relay information about overall LENGHT

Front 18

What type of fibers are in the primary ending of intrafusal fibers? secondary ending?

Back 18

primary ending - group Ia afferent, relays both dynamic and static

secondary ending - group II afferent, found chiefly on nuclear chain fibers (relay static info)

Front 19

What is the type and function of motor nerve ending of intrafusal fibers ?

Back 19

Motor nerve endings of intrafusal fibers are y-motorneurons.

They function to control the length of intrafusal fibers and set and maintain the sensitivity of the spindle.

Front 20

T/F: During a knee jerk reflex, Ia fibers have an EXCITATORY effect on a-motorneurons to EXTENSORS. Collateral groups of Ia fibers synapse on INHIBITORY interneurons to a-motorneuron of antagonistic muscle (FLEXOR)

Back 20

TRUE.

note: this arrangement is known as reciprocal innervation

Front 21

What is the role of gamma-motorneurons in the Knee-Jerk Reflex?

Back 21

to MAINTAIN TENSION (not inhibitory) of intrafusal fibers and help set sensitivity.

Front 22

Describe the two synaptic pathway of the Inverse stretch receptor mechanism.

Back 22

Ib fibers from contracting muscle synapse on inhibitory interneuron which then inhibits a-motoneurons to the contracting muscle.

note: unlike stretch receptors, Inverse stretch receptors will have Ib fibers that inhibit contracting muscles and collaterals fibers which will excite antagonist muscles.

Front 23

What is the function of the Golgi Tendon Organ?

Back 23

It is a stretch receptor of group Ib fibers located in a tendon at the end of a muscle and activated by muscle contraction. Functions to inhibit contracting muscle.

Front 24

What kind of receptors are seen in Flexor Withdrawal reflex ?

Back 24

Receptors are nociceptive endings and function to withdraw limb from noxious stimulus.

Front 25

T/F The Crossed Extensor reflex is BILATERAL because it involves a flexor withdrawal reflex on one side and an extensor reflex on other (like when you step on a tack)

Back 25

TRUE

Front 26

What causes gamma-rigidity?

Back 26

gamma rigidity is also known as DECEREBRATE rigidity and it is caused by transection of the brainstem at the level on superior and inferior colliculus. The resulting state is characterized by tremendous increase in extensor tone since there is loss of inhibition from brain to brainstem and thus, motor output activity of brainstem increases.

Front 27

T/F: Cones are responsible for DAYLIGHT and COLOR vision. They are called PHOTOPIC and have high visual acuity.

Back 27

TRUE.

"Ice cream trucks drive around in the DAY carrying ice cream CONES and have a lot of COLORS to attract kids"

Front 28

T/F: Rods are responsible for DIM LIGHT and COLORLESS vision. They have low visual acuity but high sensitivity.

Back 28

TRUE.

"NIGHT-time fishing with RODS, at night everything is COLORLESS and you have to be very SENSITIVE to know when fish bite the rods"

Front 29

What is the function of horizontal cells in the bipolar layer of the Retina?

Back 29

They make horizontal photoreceptor to photoreceptor connections

note: bipolar cells connect rods and cones

Front 30

Axons of what type of cells for the optic nerve and optic tract?

Back 30

axons of ganglion cells in the ganglion cell layer of the retina

Note: cell laters..

Pigment - melanin and Vit A
Photoreceptor - rods and cones
Biporal - bipolar, horizontal, amacrine
Ganglion - ganglion cells

Front 31

T/F The FOVEOLA is the region in the Macula Lutea of HIGHEST VISUAL ACUITY and contains rods and cones.

Back 31

FALSE!!!

Faveola contains ONLY CONES!!

note: it is also the only place in the retina where light has direct access to photoreceptors without having to pass through the layers

Front 32

What are the visual pigments in Rods and how do they differ from the visual pigments in Cones?

Back 32

ALL visual pigments have 11-Cis Vitamin A aldehyde which absorbs light

Rods: also contain Opsin (Scotopsin)

Cones: contains a different Opsin for color (red, green, and blue)

Front 33

T/F: Metarhodosin II (activated rhodopsin) reduces the dark current in the outer membrane caused by high conductance to Na+. Reduction of dark current produces HYPERPOLARIZATION as membrane potential moves closer to K.

Back 33

TRUE.

Front 34

How does Metarhodopsin II reduce the dark current?

Back 34

It activates a G-Protein called Transducin which stimulates Phosphodiesterase molecules --> Phosphodiesterase molecule hydrlyzes cGMP molecules --> withouth cGMP the Na channels close.

Front 35

What effect does light have on Rods?

Back 35

Capture of light produces a GRADED HYPERPOLARIZATION response.

more light = more hyperpolarization

Front 36

Response of ganglion cells to light is dependent on what other cell?

Back 36

Dependent of bipolar cells.

If bipolar cell is depolarized => increases excitatory transmitter to ganglion cells

If bipolar cell is hyperpolarized => excitatory neurotransmitter to ganglion cells decreases

Front 37

What is the ratio of Cones to to Ganglion Cells in the foveola?

Back 37

1:1

*remember! - NO RODS PRESENT so high visual acuity but low sensitivity

Front 38

T/F: Each Geniculate Cell receives input from both eyes.

Back 38

FALSE!!

Each Geniculate Cell receives input from ONLY ONE EYE!!

Front 39

What is the ratio on [K] to [Na] of the endolymph in the membranous labyrinth?

What is the ratio in the perilymph which is located between the bony labyrinth and the membranous labyrinth?

Back 39

endolymph = high [K], low [Na]
(kinda like what's inside cells)

perilymph = high [Na], low [K]

Front 40

Where does impedance matching of sound in air and liquid of inner ear occur?

Back 40

in the middle ear

Front 41

What structure is responsible for transduction of mechanical vibration to electrical signals? Where is it located?

Back 41

The Organ of Corti is located in the middle ear, inside the Scala Media

Front 42

T/F: The Scala Media is a structure in the Cochlea that contains the Organ of Corti.

Back 42

True.
It contains endolymph (high K+, low Na) secreted by stria vascularis and the Basilar Membrane supports the Organ of Corti and seperates scala media from Scala Tympani

Front 43

The basilar membrane vibrates in response to what?

Back 43

It moved in response to frequency

Front 44

T/F The Basilar Membrane, in response to high frequencies, produces large movements closer to the apex. In response to low frequencies it will produce movements closer to the base.

Back 44

TRUE.

Front 45

Where are hair cells located?

Back 45

Organ of Corti

Front 46

T/F : Inner hair cells are responsible for detection of sound and Outer hair cells act as amplifiers and produce otoacustical emmisions?

Back 46

TRUE

INNER => sounds
OUTER => amplifiers

Front 47

T/F: Bending of hair cells in one direction causes depolarization and an increase in the release of transmitter, beding in the other direction produces inhibition and decrease in transmitter release.

Back 47

TRUE

Front 48

T/F Each frequency produces a characteristic maximal displacement of the basilar membrane.

Back 48

TRUE

Front 49

What is the function of the semicircular canals?

Back 49

Function to detect rotation or angular acceleration

Front 50

What is the name of the sensory portion of the semicircular duct that contains SENSORY HAIR CELLS?

Back 50

Ampullary Crest

Front 51

T/F : Bending cilia in one direction increases activity in CN 5, whereas bending them in the other direction inhibits activity.

Back 51

FALSE! It stimulated CN 8 !!

Front 52

What is the function of the Utricle and Saccule?

Back 52

functions to detect position of the head in space and linear acceleration. The receptor region is the macula.

Front 53

The otholitic membrane contains something which function to increase the density around haircells. What is it?

Back 53

contains OTOCONIA which is CaCO3 (Calcium Carbonate Hair Cells)

Front 54

What is the function of the macula of the Utricle?

Back 54

Macula of Utricle lies in horizontal plane and detects acceleration (like when in a car)

Front 55

What is the function of the macula of the Saccule ?

Back 55

Macula of Saccule is oriented vertivally and function when lying down or when moving in an elevator

Front 56

As the frequency of sound increases, the location of maximal displacemnt of basilar membrane moves towards ___ ?

Back 56

the BASE of the cochlea

Front 57

You are seated in a chair and spin in the leftwards direction. The eye movement that is produced as a result of spinning is due to stimulation of what?

Back 57

The Ampullary Crest

Front 58

What is common to both stretch and inverse stretch reflex?

Back 58

The reflex opposes action of muscle

Front 59

What is the difference between row of inner hair cells and outer hair cells of the cochlea?

Back 59

Outer hair cells can change their length and augment basilar membrane motion.

Front 60

Person falls in the elevator, which part of ear is activated?

Back 60

Macula of Saccule

Front 61

Most axons of receptors (except free nerve endings) are primarily ___ ?

Back 61

mylinated AB type fibers

Front 62

What fibers are associated with noxious stimuli ?

Back 62

both A-delta and C

Front 63

What senses a change in muscle length?

Back 63

nuclear bag fibers

Front 64

What is the function of gamma-motorneurons?

Back 64

help set sensitivity of stretch reflex by maintaining tension of intrafusal fibers

Front 65

Brainstem damage produces muscle rigidity, which is relieved by anesthetizing dorsal roots. This rigidity results from...?

Back 65

excessive drive of both alpha and gamma motorneurons of higher centers

Front 66

What is the direct action of transducin?

Back 66

activation of c-GMP phosphodiesterase

Front 67

T/F Dark current is DEPOLARIZED in the dark.

Back 67

True

Front 68

What is the direct response of retinal rod to light?

Back 68

hyperpolarization

Front 69

Response of ganglion cells is dependent on what other type of cells?

Back 69

Bipolar cells