Exam 2 Flashcards
Who discovered Ach
Loewi
Quantal Transmission
NT releases in fixed amounts to created a certain amount of depolarization
Change in voltage per 1 channel opened
0.25 x 10^-3 mV
Change in voltage per quanta
0.5 mV
How many ligand gated channels are opened by 1 quantum of NT?
2000 ch/q
Direct transmission
- Channel and receptor are together
- Ionotropic
Indirect transmission
- Receptor and channels are separate
- Metabotropic
Excitatory postsynaptic potentials (EPSP) are permeable to what?
Na and K
Inhibitory postsynaptic potentials (IPSP) are permeable to what?
Cl
ACh receptor
nicotinic
ACh ions
Na and K
Action of ACh
excitatory
Where are ACh receptors found
NMJ or CNS/ANS
Glutamate receptors
AMPA and NMDA
Glutamate ions in AMPA
Na and K
Main excitatory synaptic system in the CNS
Glutamate at AMPA
Glutamate ions in NMDA
Na, K, and Ca
Can NMDA and AMPA receptors be together on the same synapse?
Yes
How do you open NMDA receptors?
They are both voltage and ligand gated
Which neurotransmitter is important for learning and memory?
Glutamate
GABA receptor
GABA-A
GABA receptor ions
Cl
Are GABA receptors excitatory or inhibitory?
Inhibitory
Main inhibitory synapse in CNS
GABA
Glycine receptor
glycine
Glycine receptor ions
Cl
NT receptors found in spinal cord
Glycine
Synaptic plasticity
Neurons that fire together wire together
Molecular coincidence detector
NMDA receptor
Indicator of activity in presynaptic neuron
Binding of glutamate
Indicator of activity in postsynaptic neuron
Substantial membrane depolarization
Temporal summation
Displaced EPSPs (changes in postsynaptic potential) stack in order to reach threshold
Spatial summation
Adding EPSPs (changes in postsynaptic potential) occurring at the same time but in different places in order to reach potential
Synaptic integration
Spatial and temporal summation of many synaptic inputs to drive the membrane potential towards and above threshold
4 main types of receptor neurons
- Mechanoreceptors
- Chemoreceptors
- Photoreceptors
- Thermoreceptors
Which receptor senses pressure/stretch?
Mechanoreceptor
Which receptor senses chemicals?
Chemoreceptors
Which receptor senses light?
Photoreceptors
Which receptor senses temperature?
Thermoreceptors
Tactile
touch
Thermoceptive
temperature
Niciceptive
pain
Propioceptive
self/position
Sensory transduction
Transmits a physical signal to a biological signal through a sensory receptor neuron
Where does signaling start in a primary sensory neuron?
Terminal/end organ
Once a receptor potential passes threshold…
It becomes an action potential down the spike initiating zone
What does the accessory structure of a primary sensory neuron do?
Suppress certain features of the signal and/or enhance other features
Spike frequency adaption
In response to sustained constant stimulus the neuron doesn’t generate constant APs
Slow adaption (spike frequency)
Slowly decreases APs from start to stop of stimulus
Rapidly adapting (spike frequency)
Only sends APs at beginning and end of stimulus or when signal changes
Causes of slow/rapid adaption
- Channels inactivate during stimulus
- Activation of K channels
- Accessory structure
Sensation
Basic recognition that a stimulus has been applied
Reception
Involves integration and interpretation of multiple sensations (may involve memory)
Dimensions of sensation
- Modality (type)
- Localization (where)
- Intensity (strength)
Labeled line theory
Different types of stimuli selectively activate specific receptors –> activity is processed along separate pathways
Pattern theory
An individual pathway can convey information about multiple modalities based on the pattern of APs
Topographic organization
Systematic mapping of body parts in portions of the brain
Receptive field
Location at which a stimulus causes a location to fire
Overlap
Allows for a better (unique) understanding of stimulus identification
Divergence
Taking information and sending the same information to multiple branches –> same amount of IMPS
Convergence
Multiple inputs merge into a higher order neuron
Acuity
How precisely one can identify where a stimulus has been diverged
Type 1 muscle receptors
proprioceptors
Type 2 muscle receptors
tactile
Type 3 muscle receptors
pain/temp
Type 4 muscle receptors
pain/temp
Meissner corpuscle
- Reside near skin margin
- Small receptive fields
- Rapidly adapting
- Texture
- A Beta type axon
Merkel discs
- Reside near skin margin
- Small receptive fields
- Slowly adapting
- Awareness of touch pressure
- A Beta axon
Ruffini ending
- Deeper in skin
- Large receptive field
- Slowly adapting
- Skin stretch
- A Beta axon
Paciniam corpuscles
- Very deep
- Large receptive fields
- Fast adapting
- Detect vibration
- A Beta axon
Cold thermoreceptor axon type
A delta
Warm thermoreceptor axon type
C
Thermal neutral
Neither warm nor cold temperature (about 32 c)
First pain
Sharp, stabbing, intense, imediate pain
A delta axon
Second pain
Dull, achy, persistent pain
C-fiber axons
Caudal
Down spinal cord
Rostral
Towards nose on brain level
Ventral spinal cord
Forward
Dorsal brain
Upwards
Ventral brain
Towards jaw