PSYC 360 - Unit 1

CNS/PNS Anatomy

100

Describe the location of the tegmentum in relation to the tectum in the midbrain.

The tegmentum is inferior to the tectum.

200

Name the midbrain structure consists of dense dopamine producing neurons and plays an important role in both conscious and unconscious motor control.

Substantia nigra (tegmentum)

300

Cranial nerves serve head and neck functions except for one. Name the nerve that is the exception and what it serves. 

Vagus nerve serves all organs

400

Describe where the sympathetic and parasympathetic nerves originate. 

• Sympathetic – originates in thoracic spine - reduces digestion, focus on prep for fight/flight
• Parasympathetic – originates at cranial and sacral extremes - “destress and digest”

500

Name two  specific structures in the forebrain and their functions.

• Thalamus – superior to midbrain, sensory information hub or relay station
• Hypothalamus – metabolism, stress, reproductive function
• Pituitary – regulates and produces a wide variety of hormones
• Basal ganglia – memory, includes substantia nigra
• Corpus callosum – highway of signals and information between hemispheres

Support Cells and Nervous System development

100

Name the support cells that form myelin in the central nervous system and insulate many axons simultaneously.

Oligodendrocytes

200

Name what structures you would expect to find within the soma of a neuron.

• Nucleus (where the DNA resides)
• Organelles (e.g., mitochondria, microtubules, ribosomes)

300

At what point in neurodevelopment (days) does maturation occur and give an example of one development within this period. 

After 24 days

• Maturation – synapses form, unneeded cells die off and myelinization begins

400

Name a developmental step that differentiates development into the central nervous system or the peripheral nervous system.

Neural plate > neural groove > neural tube = CNS

• Neural plate > neural crest = PNS

500

Name the condition that occurs if the posterior of the neural tube doesn not close during development.

• Spina bifada – posterior doesn’t close
• Anecephaly – anterior doesn’t close

Action Potentials

100

Describe the two principles of ion movement.

• Diffusion – concentration, particles want to create even dispersion
• Electrostatic pressure - Opposites attract, Same charge repels

200

Describe resting potential and how it maintained.

• The electrochemical state of a neuron when it is not conducting an action potential.  (banana in a salty milk pool) - At rest, there is a  -70 mV membrane potential in the neuron (inside is more negative than outside) - Lots of positive sodium outside and negative potassium inside

• Resting potential is maintained by: closed voltage gated Na+ and K+ channels, open NON-voltage gated K+ and Na+ channels (K+ leaks passively out; Na+ leaks passively in), sodium-potassium pump uses energy to reverse leaks (sodium out, potassium in)

300

Describe what happens when an action potential reaches the end feet of an axon.

• calcium channels in the end feet open
• synaptic vesicles that reside in the end feet are pushed to the edge and release neurotransmitter into the synaptic cleft (the space between two neurons)

400

Explain the role of myelin in saltatory conduction.

• Action potential cycle happens in sequence down the length of the neuron between myelinated areas
• Myelination keeps positive charge inside the axon and allows the signal to travel farther
• Node of Ranvier – where the action potential happens between myelinated segments

500

List the basic steps (4 or 5) of an action potential once the threshold is reached.

• Na+ gates along the entire axon open (sodium enters cell, depolarization begins)
• gated K+ channels open along axon (potassium slowly starts to leave cell)
• Na+ gates close at ~ +30 Mv (potassium leaves faster)
• K+ gates close (repolarization to just below resting voltage)
• pump restores the resting state

Receptors & NTs

100

Describe the main difference between Ionotropic and Metabotropic receptors.

Ionotropic: receptor is directly associated with and controls ion channels - NT binds and opens ion channel

Metabotropic (G-protein coupled receptor): receptor is indirectly associated with ion channels - mediated by either a G-protein or an enzyme

200

Describe one way neurotransmitters are deactivated.

• Reuptake via transporters - Separate transporters exists for each type of neurotransmitter
• Enzymatic breakdown/regulation/degredation - example: acetylcholinesterase (AChE) - floats around in the synaptic cleft, if contacts acetylcholine, breaks it down into its components and prevents rebinding - example: monoamine oxidase (MAO) - monoamine is a class of neurotransmitter including dopamine and serotonin, exists in presynaptic neuron and breaks down enzymes returned through the transporters

300

Describe the difference in ACh function in the CNS as compared to the PNS.

In the PNS

neuromuscular junction and sympathetic nervous system (nicotinic receptor type-ionotropic, excititory)

Autonomic - parasympathetic nervous system (muscarinic receptor type) – connects to internal organs

In the CNS (both nicotinic and muscarinic are in the CNS)

CNS ACh is produced mainly from the basal forebrain and brainstem nyclei - Involved in arousal, sleep, attention, and memory

400

Name one of the three types of Catecholamine NTs and describe its function.

dopamine- motor, emotional/reward, cognitive pathways - created in substantia nigra for motor, VTA to nucleus accumbens for pleasure or to prefrontal cortex for cognition

norepinephrine (aka noradrenaline) - hindbrain generated – promotes vigilance and alertness and cognitive aspects of sympathetic nervous system

epinephrine – stress response AKA adrenaline

500

Name the unusual function of serotonin that does not involve brain activity.

Also exists in intestines—critical for digestive function and even mood!

Drugs

100

Describe the difference between agonist and antagonist drug effects.

Agonist facilitates intended NT action versus antagonist which interferes with intended NT action.

200

Name two ways that psychoactive drugs can affect neurotransmission.

• production/storage of NT
• release of NT
• actions on postsynaptic receptors
• increase or decrease reuptake or degradation

300

Describe the main difference between newer (SSRIs) and older (MAOIs or Tricyclics) types of antidepressants in terms of their effects on neurotransmission.

• older: MAOIs, Tricyclics – act on many types of receptors and cause side effects
• newer: SSRIs selective serotonin reuptake inhibitors, SNRIs selective norepinephrine reuptake inhibitors, act on very specific NTs and have fewer side effects

400

Give an example of a drug that acts on the neurotransmitter dopamine and describe its effect.

• antipsychotics (e.g., Clonopin (clozapine), Risperdal (risperidone)) – block dopamine receptors, newer drugs block more receptor types and cause side effects - side effects related to motor problems from prolonged use
• Addictive drugs – most target dopamine reward pathway
• Cocaine – blocks reuptake of dopamine
• amphetamines (sink and drain metaphor) – blocks and reverses dopamine transporters and promotes release by facilitating dopamine packaging in vesicles

500

Give an example of a drug that impacts the neurotransmitter Acetylcholine  (ACh) and describe it effects.

• nicotine – stimulates receptors (other NT systems too)
• spider venom- promotes release
• botulin toxin (found in poorly canned goods) – blocks ACh release; curare – blocks receptors
• drugs for Alzheimer’s disease (receptor agonists and AChE inhibitors) – stops enzymes from breaking down Ach and increase NT prevelance