What are the four basic morphological types of neurons?
Which is most common?
Which is associated with dorsal root ganglia?
–Dorsal root ganglia
Identify the types of neurons shown.
What does myelin do? How?
Insulates the axon, by blocking ion channels. Enabling saltatory conduction.
A unipolary neuron has how many dendrites?
Do humans have many unipolar neurons?
No, they are mostly in invertebrates
How are the branches of neurons classified?
Primary, secondary, tertiary, etc
How many dendrites do pseudounipolar neurons have?
Zero, but one end of the axon works essentially as a dendrite.
What is the myelinating cell of the CNS?
How do Schwann cells do their thing?
Kool-aid man style. Sacrifices self to myelinate target
What role does an astrocyte have in the tri-partite synapse?
enables the synapse to exist, provides nutrients, mediates neurotransmitter levels, vasculature, etc.
What is a quanta of NT?
What ever amount of NT that is released by a neuron in response to an action potential.
What is the most prevelant excitatory NT?
What are the two main ways glutamate serves as an NT?
Glutamate is ionotropic for what three receptors?
–NMDA—Requires depolarization, some Mg2+ and then Na+ and Ca2+ influx in addition to glutamate binding
What receptors is glutamate metabotropic for?
What is an important clinical correlate for glutamate?
It can be excitotoxic
NMDA receptors are currently a hot topic for what two things?
Memory formation and epilepsy
What is the most prevalent inhibitory NT?
What happens due to long term use of antiepileptics?
GABA can act ionotropically or metabotropically. What are the receptors it associates with in each way?
–GABA A—Cl- influx
–GABA B—GPCR and 2nd messengers
–GIRK channels trigger IPSPs by expelling K+
What are two examples of agonists of Ionotropic GABA A receptors?
Glycine is a NT found all throughout the body, where is it particularly active?
Ach is synthesized from coA and choline with the CHAT enzyme, and degraded by acetyl cholinesterase. What are the ionotropic and metabotropic receptors?
Ionotropic - Nicotinic (skeletal muscle, primarily found in PNS)
Metabotropic - Muscarinic (mostly in CNS)
Where are GABA receptors concentrated on the neuron?
The axon hillock
Is glycine inhibitory or excitatory?
All motoneurons use what NT?
Myasthenia gravis is an autoimmune disorder, what is it against?
What is a treatment target for myastheia gravis?
Acetyl cholinesterase inhibitors
Dopamine receptors are metabotropic. What are the excitatory and inhibitory receptors?
»D1 (Excitatory) and D2 (Inhibitory) receptors
Dopamine works in two major areas: SUBSTANTIA NIGRA and VENTRAL TEGMENTAL AREA (VTA).
What do each of these do?
»Substantia nigra is involved with basal ganglia circuit and loss of dopamine here is cause of Parkinson’s Disease (Mostly motor component)
»VTA involved with both addiction and schizophrenia (Mostly mental part)
Where is norepinephrine produced in the pons?
NE is the PNS ________________ NT.
What are the two indoleamines?
Serotonin and melatonin
Serotonin has at least 7 different receptor subtypes. What is it related to clincially?
Related to depression. Common RX is SSNRI
Where is histamine primarily made?
–Predominantly made in the hypothalamus, in the tuberomamillary nucleus
(Also from mast cells in brain)
Neuropeptides are co-released with other NT's, what are some examples?
Adenosine is co-released with glutamate, what is it's function generally? What is an antagonist? What are the receptors types?
–Tends to be more sedative
–Antagonist is caffeine
–Receptors are GPCRs
NO is a gaseous NT, that diffuses quickly across and between cells, traveling in many directions. When is it synthesized?
Immediately before use
What are two important components of an electrical synapse?
Connexon and connexin
What is a tract?
•axons clustered in the central nervous system
What are axons clustered and ensheathed in the peripheral nervous system called?
Nissl body stains rough ER—what part of neuron are we looking at?
Purple areas are grey matter (collections of cell bodies)
What is the black portion? Stain type?
Silver stain. White matter
Describe the continuous division of neurons.
They do not continually divide
What are the intermediate filaments of the nervous system?
Microtubules provide anterograde and retrograde transport. Where do they sit?
The axon terminal, from where they extend via an axon growth cone which determines the path of growth.
How do manufactured products of the neuron get from the cell body to the axon terminal?
Axonal transport via kinesin (anterograde) and dynein (retrograde)
What functions does anterograde axonal transport serve?
•Sending materials, nutrients from the cell body down to the axon terminal (anterograde)
–Synthesis of some neurotransmitters, synthesis of vesicles
Neurotrophins help nerve growth and migration through what kind of transport?
Retrograde transport is important for what?
–Recycling of released materials
Define these terms
•Sulcus = groove
•Fissure = a really big groove
•Gyrus = Ridge
•Pole = the end
•Notch = an angular cut
•Allocortex = older, less-developed cortex of olfactory system and hippocampus (3-4 layers)
•Neocortex = more recent cortex with 6 layers
The neocortex can be divided into what 5 lobes?
What divides the lobes of the cerebral cortex?
–Sulcus of Rolando
What is the easiest sulcus to find?
Lateral sulcus (Sylvian fissure)
What does the cingulate sulcus divide?
The limbic from the other lobes
What are the four major gyri of the frontal lobe?
What is the precentral gyrus involved in?
•Primary Motor Cortex (voluntary motor control)
•Premotor and Supplementary Motor Cortex (motor planning)
What is the superior gyrus involved in?
•Frontal eye fields (eye tracking)
What are the two subcomponents of the Inferior gyrus?
Where is Broca's area nearly always located?
What is the prefrontal cortex involved in?
•Executive function, decision-making
What area is damaged here?
What is the parietal lobe divided into?
What are the two portions of the inferior parietal lobule?
What are the main associations of the parietal lobe?
•Primary somatosensory cortex (somato-sensation)
• Language comprehension (around border with temp., frontal)
•Spatial orientation and perception
- Hugely important in vision - information regarding movement of objects
What are the components of the temporal lobe?
Where is the primary auditory cortex?
Superior temporal lobe
What are the two portions of the superior temporal lobe?
•Primary auditory cortex
•Wernicke’s Area (understanding speech)
What part of your temporal lobe is lighting up right now?
Wernike's aphasia presents as? Where is Wernicke's area?
Word salad, not forming words in mind. Feels like they are making sense.
Left temporal lobe
Where is the primary visual cortex found?
What is your inferior visual field related to in the occipital lobe?
what is the superior visual field associated with in the occipital lobe?
What is V2?
Visual Association cortex. Also called area 18
What is V1?
Primary visual cortex, AKA Area 17
The occipital pole is responsible for vision where?