unit 3a sensory systems Flashcards
The four types of receptors
Chemo
Mechano
Photo
Thermo
definition of adequate stimulus
type of energy that a receptor responds best to
convergence of many primary neurons onto one secondary neuron increases _____ but decreases ______
sensitivity
resolution
Increased area in somatosensory cortex dedicated to the fingers rather than the arm is the caused by _______
lack of convergence in the fingertips
The two sensory pathways that do not undergo thalamic relay
olfactory pathway
equilibrium pathway
what is visceral sensory information?
gut, stomach, internal organs
How are sensations decoded in the CNS
MILD
Modality
Intensity
Location
Duration
What is modality determined by? what is another name for this type of decoding?
type of neuron activated (touch, photo…) and where the pathway terminates
also called labeled line coding
What is location determined by?
which receptive fields are activated
lateral inhibition enhances _____ and improves ________
contrast
stimulus localization
what is intensity determined by?
number of receptors activated
FREQUENCY of action potentials
what is duration determined by?
The length of time of the series of action potentials
type of receptor that turns off during a constant stimulus
phasic receptor
medulla crossing somatosensory pathways
fine touch, proprioception, vibration
spinal cord crossing somatosensory pathways
nociception, temperature, coarse touch
the superficial cutaneous sensory receptors and their adaptation
merkels disk slow
meissners corpuscle fast
the deep cutaneous sensory reseptors and their adaptations
ruffinis corpuscle slow
pacinian corpuscle fast
nociception is mediated by what types of channels?
Transient Receptor potential (TRP) channels
TRP channels do not have an adequate stimulus. Why?
mediated by a variety of sensations and non-selective ion channels
the reason wasabi tastes “hot”
The TRPV that is activated by wasabi is also activated by warm temperatures
nociception is mediated by what nerves?
free nerve endings with ion channels
three ways neural reflexes are classified
according to the effector
according to the integrating center
number of neurons in pathway
only _____ reflexes are monosynaptic
motor
skeletal muscle reflexes monitor ______, integrate in the ____, efferent pathway is _____ and the effectors are _____
proprioception, CNS, alpha motor neurons, extrafusal muscle fibers
proprioceptors sense….
changes in join movement, muscle length, muscle tension
muscle spindles monitor _____
muscle stretch
golgi tendon organs monitor
muscle tension
the ______ in the central region of intrafusal fibers are _____ and send signals to the ______
free nerve endings
tonically active 1a afferent neurons
spinal cord
1a afferent neurons will synapse in the spinal cord with ______ and ____
alpha motor neuron
inhibitory interneuron
inhibitory interneurons inhibit ________ muscles
antagonistic
alpha gamma coactivation occurs when the muscle is _______
contracting
the stretch reflex prevents over stretching by….
negative feedback loop of 1a afferent neurons synapsing with alpha motor neurons and causing contraction
compare muscle reflex with voluntary movement
muscle reflex
- integrated in spinal cord
- inherent and fast movement
-driven by external stimuli
voluntary movement
- integrated in cerebral cortex
- learned movements, can improve with practice
- driven by conscious processing
crossed extensor reflex purpose
support body weight as shift away from painful stimulus