Sensory Receptors and Exteroception Flashcards
Weak left hand, clumsy left leg. Abnormal temperature and pinprick sensation in right leg. Loss of vibration sense in left hand. Left plantar response extensor (Babinski)
Hemisection of the left spinal cord (Brown-Séquard)
Hand grips weak bilaterally. Bilateral decreased touch and vibration below his knees. Normal pinprick, except in the palm of his hands. No truncal sensory level.
Acute inflammatory demyelinating polyneuropathy (Guillain-Barré)
Special Sensory Systems
Light- seeing
Air Pressure- hearing
Chemical- olfaction; taste
sensory receptor cells depolarization of the membrane in the synaptic region causes opening of ______________ eliciting an increase in intracellular calcium, which triggers synaptic vesicle fusion and release of chemical transmitter(s) to which the second order cell is sensitive.
voltage-dependent calcium channels
Exteroception Somatosensory system
vibration- touch
Pain/Temp-
Depolarizing receptor potentials. Receptors that depolarize to their adequate stimulus
generally do so as a result of an increase in:
nonspecific cation conductance in the receptive area membrane.
Sensory receptor cell characteristics
have somas/ nucleus, synapse, second order neuron, sensory ending
The process of detection of a sensory input and transformation of information into a change in neuronal action potential – a neural signal - is called :
transduction.
Stimulus–> voltage change
transduction channels are not voltage-dependent
Sensory endings are _____ dependant
Stimulant
Not voltage
An example of a receptor that hyperpolarizes upon stimulation is the
rod photoreceptor
resting membrane potential of
approximately –40 mV due to a substantial resting cation conductance
Voltage dependant channels with 2 gates:
Na channel
Some receptors, such as hair cells of the auditory system, respond to stimulation with an oscillatory change in generator potential alternating between:
depolarization and
hyperpolarization
Retina has 2 cell types
Cone cells, color
rod cells, light
Receptors that hyperpolarize in response to stimulation have resting potentials that lie between 0 mV and Ek (-70 mV), generally:_____
-30 to -40 mV
Proprioception
you do not need to think a lot to move. Brain knows where hand is by: Detecting stretch of muscles (muscle spindles)