Neurophysiology/Neurochemistry

Question 1

Describe the internal structures of a cell

Answer 1

-Membrane w/ lipid bilayer
-Cytoplasm
-Mitochondria for ATP
-Nucleus for chromosomes
-Cytoskeleton for structure
-Microtubules for transport

Question 2

What is neuroglia?

Answer 2

provide physical support, control nutrient flow, and are involved in phagocytosis

Question 3

Structure of glial cells “glue”

Answer 3

-Astrocytes for physical support, clean-up, and transport
-Microglia involved in phagocytosis and brain immune function
-Oligodendroglia form the myelin sheath around axons in brain
-Schwann cells form myelin for PNS axons

Question 4

Describe an action potential

Answer 4

1) A cell starts at a resting membrane potential where Na+ is high outside cell and K+ is high inside (-70 mV)

*A depolarization in which the cell becomes more positive causes an action potential

2) Sodium channels open allowing sodium to enter the cell (more positive) triggering the action potential

3) Sodium channels close, potassium channels open, potassium leaves (more negative)

4) Cell returns to resting membrane potential

Question 5

What’s the difference between ionotropic receptors and metabotropic receptors?

Answer 5

Ionotropic receptors are direct in the sense that a neurotransmitter will bind to a binding site directly on the receptor, usually allowing an ion channel to open.

Metabotropic receptors are indirect in that a chain of reactions is triggered to indirectly open an ion channel (or another change) further on in the in membrane. *think GPCR

Question 6

How are postsynaptic potentials terminated?

Answer 6

Re-uptake of the neurotransmitter

Enzyme deactivation of neurotransmitter

Question 7

Are neurotransmitters the only type of transmitter substance?

Answer 7

No
-Neuromodulators
-Hormones

Question 8

What are the effects a neurotransmitter can have?

Answer 8

1) Excitatory
2) Inhibatory

Question 9

Where is ACh synthesized?

What is its function?

Answer 9

nucleus basalis
-controls muscle contraction in PNS
-ionotropic receptors stimulated by nicotine
-AChE deactivates; can be inactivated by drugs

Question 10

Drugs that affect ACh

Answer 10

Black widow spider venom
-stimulates release of NT

Botulinum toxin
-inhibits the release of NT

Nicotine
-stimulates postsynaptic receptors

Question 11

Where is dopamine synthesized?

Answer 11

substantia nigra
-affects movement, attention, learning, and reinforcement of drugs

-Parkinson’s can be caused by degeneration of dopaminergic neurons

-cocaine blocks re-uptake of dopamine (AGO)
-L-dopa can increase dopamine concentration (AGO)

Question 12

Where is seretonin synthesized?

Answer 12

raphe
-tryptophan as important precursor

-inhibiting uptake of seretonin to treat depression (prozac)