Afferent Nervous System Flashcards
Stimuli is detected by
specific receptors
location of receptors
- Dendrites on Unipolar neurons
-individual cells which connect to neurons ( hair cells on internal ear)
What happens when receptors are stimulated
- Stimuli causes opening of gated channels ( usually Na) on receptor membrane
- GP occurs on receptor membrane and can either be generator potential or receptor potential
What is Generator Potential
GP that occurs on dendrites of first order neuron and directly generates AP
Receptor potential in ear (hair cells)
- in response to stimuli, receptor potential is created on hair cell
- RP cause hair cell to release nt onto associated sensory neuron
- EPSP occurs on dendrites
- EPSP generates AP on axon on sensory neuron
What is Receptor Potential
receptor cell is separate from sensory neuron and occurs on specialized receptor cell causing a release of nt onto dendrites of sensory neurons
Types of Receptors
Phasic Receptors and Tonic Receptors
What are Phasic Receptors
respond to stimulus change and adapts causing a decrease in sensitivity ( get used to it)
What are Tonic Receptors
frq and intensity of APs remain constant = no adaptation and continuous info ( feel it all the time = pain)
How does brain perceive different types of stimuli
mainly by TYPE of receptor that is stimulated
- certain stimuli will alert CNS relating to that stimuli
How does brain percieve stimuli of different strengths ( determine if feather is brick or feather on foot)
determined by the frequency of APs going to CNS
(higher stimuli = higher AP freq)
a stronger stimuli also activates more receptors
( pressure + touch)
steps for vision
- light enters pupil and image focused on retina
2.Light stimulates chemical reactions on rods and cones producing a receptor potential ( GP => AP)
Examples of how the brain uses different signals for different stimuli
- Stimulate touch receptor on right index finger
- Send signal to postcentral gyrus region for right index finger
Sensory pathways
- detect signal (GP)
AP - synapse in medulla ( EPSP)
AP - Synapse in thalamus (EPSP)
AP - Post Central Gyrus send signal for
- Identification and location
- Association Areas
pathways for Vision
- Light enters pupil
- light stimulates chemical reaction on rods and cones ( receptor potential)
- Bipolar Neuron ( Graded potential)
- Ganglion cell ( EPSP + AP)
- Optic Nerve
- Optic Tracts
- Visual Cortex of occipital love
Pathway for hearing
- Hair cells in cochlear duct stimulated ( RP)
- nt release onto associated neuron ( EPSP + AP)
- AP on axon on cochlear branch of cranial nerve VIII
- Auditory complex ( temporal lobe)
Pathway for Equilibrium
- Hair cells in semicircular duct +utricle (RP)
- nt release onto associated neuron (EPSP + AP)
- Ap on axon of vestibular branch of Cranial Nerve VIII
- goes into cerebellum, thalamus, and finally brain stem
- Brain stem sends signals to eye muscle + other muscle of neck
