Exam 3 Flashcards
(30 cards)
What are Sensory Receptor Proteins?
Proteins that change in response to changes in the environment and act as transducers that convert a sensory stimulus into an electrical signal.
What are One Modality Sensory Receptor Proteins?
Sensory receptor proteins that respond to changes in one type of stimulus.
What are Sensory Receptor Cells?
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.
Types of Sensory Receptor Cells?
Mechano- ; Photo- ; Chemo- ; Thermo- ; Nociceptors.
How does Neuron Signalling work with Sensory Receptor Cells?
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.
Signal Transduction in Sensory Specialized Epithelial Receptor Cells:
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.
Signal Transduction in Sensory (Neuron) Receptor Cells:
1) Stimulus changes protein conformation –> changes ion permeability. 2) Depolarizing receptor potential (usually) leads to opening of VG Ca ion channels. 3) NT release.
Sensory Coding
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).
3 Major Characteristics About a Stimulus that are Relayed to the Brain:
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
Receptive Field
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))
Two-Point Discrimination Test
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.
Convergence
Many neurons synapsing onto one neuron –> increases size of RF
Divergence
One neuron influences many neurons –> increases processing power for RF (smaller RF)
Functions of Vestibular System
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.
Basic Structures of Vestibular System
Inner Ear: Semicircular Canals; Utricle and Saccule. Hair Cells (Modified Epithelial Cells; type of Mechanoreceptor)
Hair Cell Function
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.
Semicircular Canals
Detect head rotation and rate of movement in various directions –> eye tracking with movement
Saccule and Utricle (Otoliths)
Detect head position and changes in linear acceleration; Regulate posture; Falling reflexes; Eye movements the make surroundings stable.
Semicircular Canal - Mechanism
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.
Saccule and Utricle (Otoliths) - Mechanism
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…
Neural Pathway for Vestibular System
LOOK IT UP, GODDAMN YOU!
Sound
Alternating waves that produce changes in air pressure.
Translated from air to fluid.
Detected by mechanoreceptors.
Amplitude
Height of the wave.
Higher amplitude is proportional to loudness/perceived as loudness.
Frequency
of waves per second
Perceived as pitch.
