Exam 3

Question 1

What are Sensory Receptor Proteins?

Answer 1

Proteins that change in response to changes in the environment and act as transducers that convert a sensory stimulus into an electrical signal.

Question 2

What are One Modality Sensory Receptor Proteins?

Answer 2

Sensory receptor proteins that respond to changes in one type of stimulus.

Question 3

What are Sensory Receptor Cells?

Answer 3

1) Either a neuron itself OR a specialized epithelial cell that then interacts with a neuron. 2) Generate an electrical signal following adequate environmental stimulus.

Question 4

Types of Sensory Receptor Cells?

Answer 4

Mechano- ; Photo- ; Chemo- ; Thermo- ; Nociceptors.

Question 5

How does Neuron Signalling work with Sensory Receptor Cells?

Answer 5

1) Stimulation of Sensory Receptor Proteins generates receptor potential (type of electrotonic potential) –> depol or hyperpol. 2) Generates electrical signal following stimulus interaction on sensory receptor protein. 3) Amplitude (proportional to) Intensity of stimulus. 4) Not initiated by presynaptic neuron.

Question 6

Signal Transduction in Sensory Specialized Epithelial Receptor Cells:

Answer 6

1) Stimulus changes protein conformation –> changes ion permeability. 2) Depol or Hyperpol. 3) Depolarizing receptor potential (usually) leads to opening of VG Ca ion channels. 4) NT release.

Question 7

Signal Transduction in Sensory (Neuron) Receptor Cells:

Answer 7

1) Stimulus changes protein conformation –> changes ion permeability. 2) Depolarizing receptor potential (usually) leads to opening of VG Ca ion channels. 3) NT release.

Question 8

Sensory Coding

Answer 8

Process of how converted stimulus energy relays information about stimulus (sensory changes) to the CNS (aka Sensory Transduction to the cortex, where info. is processed and generate perception).

Question 9

3 Major Characteristics About a Stimulus that are Relayed to the Brain:

Answer 9

1) What modality/kind? –> labelled lines; labelled by neuron type
2) How intense/strong? –> firing patterns of AP (less AP … less intense)
3) Where is the info. coming from in the organ? –> sensory organs are mapped; vision, audition, and olfaction have addition CNS processing to determine

Question 10

Receptive Field

Answer 10

A region of the body that, when stimulated, leads to firing changes in one particular neuron. (1st Order Neuron RF = (size of dendritic tree) / (no of modified epithelial cells that dump info on it))

Question 11

Two-Point Discrimination Test

Answer 11

A measure of the size of the receptive field: the greater the distance between the 2 points to feel separate, the greater the receptive field.

Question 12

Convergence

Answer 12

Many neurons synapsing onto one neuron –> increases size of RF

Question 13

Divergence

Answer 13

One neuron influences many neurons –> increases processing power for RF (smaller RF)

Question 14

Functions of Vestibular System

Answer 14

Balance; Relays info to the brain used to compute head position and movement; Allows eyes to stay fixed with head movement; Helps body remain upright.

Question 15

Basic Structures of Vestibular System

Answer 15

Inner Ear: Semicircular Canals; Utricle and Saccule. Hair Cells (Modified Epithelial Cells; type of Mechanoreceptor)

Question 16

Hair Cell Function

Answer 16

Kinocilia (tall one), connected to stereocilia (smaller ones). Lots of K+ and Ca(2+) outside cell. As pressure is applied to hair cell, stereocilia deformed/bend toward kinocilia –> opens cation channels –> influx of K+ and Ca(2+) –> depol of hair cell (if large enough)–> VG-Ca(2+) channels open –> NT exocytocysis.

Question 17

Semicircular Canals

Answer 17

Detect head rotation and rate of movement in various directions –> eye tracking with movement

Question 18

Saccule and Utricle (Otoliths)

Answer 18

Detect head position and changes in linear acceleration; Regulate posture; Falling reflexes; Eye movements the make surroundings stable.

Question 19

Semicircular Canal - Mechanism

Answer 19

Surrounds with Endolymph. In Ampulla, there is a Crista (substructure filled with hair cells) and Cupula (large potion of Ampulla). Hair cells interact with Cupula (gelatinous mixture, surrounded by Endolymph). With movement of head, endolymph movement lags –> pressure to cupula –> bending stereocilia… –> receptor potentials in hair cells.

Question 20

Saccule and Utricle (Otoliths) - Mechanism

Answer 20

1) Contain Macula (specialized sensory epithelia; where hair cells live). Hair cells project cilia into otolith membrane (gelatinous mixture); gelatinous cap is covered in otoliths (Ca-carbonate stones… very heavy). Movements of head cause shifting of otoliths –> pulls on cilia of hair cells –> We know…

Question 21

Neural Pathway for Vestibular System

Answer 21

LOOK IT UP, GODDAMN YOU!

Question 22

Sound

Answer 22

Alternating waves that produce changes in air pressure.

Translated from air to fluid.

Detected by mechanoreceptors.

Question 23

Amplitude

Answer 23

Height of the wave.

Higher amplitude is proportional to loudness/perceived as loudness.

Question 24

Frequency

Answer 24

of waves per second

Perceived as pitch.

Question 25

Outer Ear

Answer 25

Localize sound and Conduct sound waves to middle ear.

Pinna -> Ear canal -> Tympanic Membrane

Question 26

Middle Ear

Answer 26

Translate air-borne sound waves to liquid-base ones.

Ossicles. (Smallest bones in the body)

Question 27

Inner Ear

Answer 27

Sensory transduction and the beginnings of sensory coding.

Coche a, Semicircular Canals, Otoliths.

Question 28

Ossicles

Answer 28

Translate sound waves from air to liquid.

Without the bones, much of the sound waves would be lot between tympanic and oval membrane.

Focus and more forcefully apply sound waves to oval window.

Vibrations in tympanic membrane moves the bones which then tap on oval window.

Question 29

Cochlea

Answer 29

Oval Window: transfers sound waves to liquid-form

Round Window: pressure equalization

Three fluid-filled canals:
Scala Vestibuli
Scala Media: organ of Corti with receptor cells, basilar membrane, and tectorial membrane.
Scala Tympani: sound waves travel

Question 30

Cochlear Mechanoreceptors

Answer 30

Contain proteins that allow ion movement when stimulated by mechanical force.

IHC: Relay information about sound to CN VIII, Afferent, depol leads to glutamate release to depol of CN VIII.

OHC: more responsive to efferent info, comes from CN VIII. Depol/Hyperpol leads to motor protein movement