PNS Afferent Division

afferent is also known as

sensory

some sensory neurons travel to the cerebrum for _____ perception

other sensory neurons travel to the spinal cord for ____ perception

conscious

unconscious

conscious processing has ______ and _____ senses

special and somatic

special senses are only located where?

the head

what are the special senses?

gustation
olfaction
vision
equilibrium
hearing

is proprioception (related to the body’s position and movement) somatic sensory and somatic stimuli?

yes

subconscious is divided into what two stimuli

somatic and visceral

sensory receptor types

simple receptors: neurons with free nerve endings

complex receptors: nerve endings enclosed in connective tissue capsules (examples: pacininan corpuscles, meissner’s corpuscles)

special receptors: release neurotransmitters onto sensory neurons

mechanoreceptors

thermoreceptors

chemoreceptors

photoreceptors

nociceptors

baroreceptors

mechanoreceptors respond to mechanical pressure

thermoreceptors respond to temperature changes

chemoreceptors respond to chemical changes

photoreceptors convert light into electrical signals

nociceptors respond to damaging stimuli, pain

baroreceptors are stretch receptors that sense blood pressure

vomiting is an example of what type of receptor

visceral receptor

do olfactory pathways travel to the thalamus

no, they go straight to the olfactory cortex

do equilibrium pathways travel to the thalamus?

no, they travel straight to the cerebellum

which two pathways do not travel to the thalamus

olfactory and equilibrium

sensation is the ______ of stimuli

awareness

perception is the _____ of stimuli

conscious interpretation

Principles of Sensory Coding

when a stimulus reaches a receptor, the following events take place:

1. reception: specialized cells (receptors) absorb physical energy

2. transduction: physical energy is converted into electrochemical energy

each receptor is specialized to absorb and transduce only one kind of energy

the strength of the receptor potential determines how strongly the receptors are activated. These are graded potentials, not action potentials

sensory receptors encode 4 types of information

modality- the specific form of energy of a stimulus

location- the receptive fields (smaller receptive fields = higher acuity aka precision)

intensity- intensity of the stimulus

duration- how long a stimulus lasts

what does a stronger stimulus do to the action potential

increases the frequency of action potentials

how do tonic receptors react to a prolonged stimulus?

show little adaptation

how do phasic receptors react to changes in the intensity of a stimulus?

adapts quickly to changes in stimulus

a strong stimulus that is applied to one neuron and results in the inhibition of transmission to neighboring neurons is called?

lateral inhibition

lateral inhibition increases/ decreases acuity?

increases

two point discrimination

the ability to distinguish two fine points against the skin rather than perceiving them as one

1

tonic

2

phasic