Sensory physiology Flashcards
What 2 kinds of sensory neurons are there?
1) sensory receptors attached to neurons
2) Receptor cell as a separate entity
What are receptor potentials?
graded potentials that initiate AP (allow the passage of ions in order to change membrane potential)
What are transductions?
Transmission of stimulus through an axon
what are the major types of receptors?
Chemo
Mechano
Photo
Thermo
Noci-pain
What are the 4 properties of all stimuli?
Modality (type of stimulus) , Location, Intensity and Duration
what does adequate stimulus mean?
The perception of a receptor to other stimuli
ex) when feeling heat it activates thermoreceptors, however, if hot enough it will also activate nociceptors
how does the size of the receptive field affect perception of a stimulus?
smaller and more numerous receptive fields increase sensitivity in a region
larger receptive fields are seen in less sensitive areas
explain the concept of lateral inhibition
Lateral inhibition occurs when a secondary neuron inhibits its lateral neurons, preventing them from sending stimuli to the lateral tertiary neurons
-this allows the brain to localize sensory input
what are the 2 properties of a stimulus?
Intensity
-population coding (number of receptors activated)
-frequency coding (frequency of AP)
Duration (duration of AP)
-Tonic receptors
-Phasic receptors
what is a phasic receptor?
a rapidly adapting receptor where signals come and go
-thermoreceptor
-chemoreceptor
what is a tonic receptor?
a slowly acting receptor in which signals are constantly sent (needed for survival)
-nociceptors
-proprioception
Tonic
what are somatic receptors?
variety of sensory receptors from the skin, skeletal muscles, bones, tendons, and joints
What is the Meissner’s Corpuscle receptor?
(A)
-rapidly adapting mechanoreceptor
-sensitive to touch / pressure
-located in dermis
What is the merkel’s Corpuscle receptor?
(B)
-slowly adapting mechanoreceptor
-located in the dermis
-sensitive to touch /pressure
-usually for grip
What is the free neuron ending receptor?
(C)
-slowly adapting nociceptor, itch, thermo and mechanoreceptor
-mostly located in the dermis
What is the Pacinian Corpuscle receptor?
(D)
-rapidly adapting mechanoreceptor
-sensitive to vibration and deep pressure
What is the Ruffini Corpuscle receptor?
(E)
-slowly adapting mechanoreceptor
-sensitive to stretching of skin
what 2 things does visual perception require?
-an organ (the eye)
-neural pathways
name the parts of the eye
PISCAL
what is the optic disk?
the blind spot where neurons join to the optic nerve
what is the macula?
the round area at the center of the retina
-contains the fovea
what is the fovea?
Fovea is the region of sharpest vision
-highest [photoreceptors]