Learning Objectives

Know the different Synapse Types, what makes them that way, and consequences
- Electric (aka GAP junction)
  - because the pre-synaptic axon termini is connected to post-synaptic dendrite
  - APs directly from from 1 neuron to the next
  - NO EPSP step
  - Makes much faster
  - if an AP occurs in pre-synaptic neuron it MUST occur in post-synaptic neuron (or cell)
- Chemical Direct
  - standard: Neurotransmitter (Chemical) binds to the receptor channel directly
- Chemical Indirect (aka GPCR)
  - Neurotransmitter binds to a receptor which is a separate protein from the channel
  - Many more steps = Slower
  - Enzymatic Step = Sensitivity Step = Amplification Step
  - 2nd messenger is the actual molecule that opens channel
  - 2nd messenger can have other cell responses (ex: alter gene expression)
  - Final result is STILL and EPSP or IPSP
  - blocking any step (typically) still blocks EPSP

Synapse Types

NS 4 Companion Questions

Learning Objectives

Know the steps of a neural circuit (not the same a neuron signaling)
1. Sensory Receptor (sense) - receives environmental stimuli (light, sound, touch, etc) and stimulates sensory neuron (i.e. - releases NT)
2. Sensory Neuron (aka afferent neuron) - brings signal to CNS
3. Integration - minimal 1 synapse, where decision is made
  - Central Nervous System (CNS) = Brain & Spinal Cord
  - Peripheral Nervous System (PNS) NOT integration all the portion other than integration
4. Motor Neuron (aka efferent neuron) = brings signal out of CNS
5. Effector - target of the Motor neuron
Know the types of motor neurons, their NTs and the effectors
- Somatic Neurons $LaTeX: \longrightarrow$ ACh $LaTeX: \longrightarrow$ always excitatory Skeletal Muscle
- Autonomic Nervous system / Neurons - targets Cardiac Muscle, Smooth Muscle, or Glands
  - Sympathetic $LaTeX: \longrightarrow$ NE or ACh
  - Parasympathetic $LaTeX: \longrightarrow$ Always ACh
Know the ANS concepts
- Dual vs Single Innervation
- Antagonism vs Cooperativity
- Local vs Diffuse
Know that "Tone" is the aspect that all neuron are always "on" and at a basal level. That signal intensity if adjust up or down from there.
Know the patellar (knee-jerk) reflex pathway
Understand that perception is based on connections to the brain (specific area)
- Understand the signal intensity is due to amount of stimulation (AP frequency)
Understand the receptor classifications (by specificity) and that they may refer to the cell / neuron / sensory receptor or the protein responsible for the detection
- Mechanoreceptor
- Photoreceptor
- Chemoreceptor
- Thermoreceptor
- Osmoreceptor = [solute]
- Nociceptor = Pain but any of the above
- Proprioceptor = relative location (a type of mechanorecptor)
Understand the advantages and disadvantages of relative receptive field
- small receptive fields
Understand Adaptation - sensory impules diminish over time
- Tonic - diminish slowly - ex: bright light detection
- Phasic - diminishes quickly - ex: smell

Nervous Circuit / Patellar Reflex

The Autonomic Nervous System (ANS)

Sensory Receptors pt1 - Types, Receptive Field, Adaptation

Please note - At some point in the video I incorrectly describe synesthesia as a disease. I should probably describe it as a characteristic. I am leaving it in (for now) as an example of how we can so easily be "programmed", even subconsciously to view things that are not typical as also not "right." I hope we can all use these examples as way to re-examine our thinking and to guard yourself against them.

Sensory Receptors pt2 - Mechanism