Neuroscience Unit 1 Assignments

Questions and Answers

The frontal cortex is located ____ with respect to the parietal cortex.

The temporal cortex is located ____ with respect to the frontal cortex.

inferior

What are the main stages of nervous system development? Name and briefly describe them.

Neurogenesis, Cell migration, Differentiation, Synaptogenesis, Apoptosis, Rearrangement.

What will happen if an axon of a newly developed neuron is unable to find a vacant postsynaptic cell?

Axons of about 50% of neurons will not find a vacant postsynaptic cell of the right type to synapse to, and thus die by apoptosis (also called pruning). Signup and view all the answers

The ____ is contained in the myelencephalon.

medulla Signup and view all the answers

Taking notes in class is regulated by which subdivision of the peripheral nervous system?

The somatic nervous system. Signup and view all the answers

Salivation, secretion of digestive juices, and blood flow to the GI tract are governed by the ____ nervous system.

enteric Signup and view all the answers

Describe the function of the primary cortical areas.

V1: processing visual inputs, A1: receiving input from MGN and identifying key elements of sound, S1: processing somatosensory info, motor: motor control, olfactory: receive olfactory info from tufted/mitral cells, gustatory: insula; process taste info. Signup and view all the answers

Describe the functions of the association areas.

Signup and view all the answers

Oligodendrocytes are found in the ____ nervous system and, like Schwann cells, are important for the production of myelin.

central Signup and view all the answers

During a resting potential, the force of ____ pushes potassium ions (K+) to the outside of the cell membrane.

diffusion Signup and view all the answers

Action potentials get re-generated at each _ and this jumping from node to node of the action potential is called .

node of Ranvier; saltatory conduction Signup and view all the answers

Mitochondria produce a chemical called ____, which can be used as an energy source.

ATP Signup and view all the answers

If sodium (Na+) is pushed inside the cell by both diffusion and electrostatic pressure, why is it found in greatest concentration outside of the cell?

Because it is pushed back out by the sodium-potassium pump. Signup and view all the answers

A ______ removes any extra neurotransmitters from the synapse by taking them back into the presynaptic neuron for eventual repackaging into vesicles.

transporter protein Signup and view all the answers

If the inner voltage of a cell is -70mV and the application of stimulation results in a -95mV charge, the stimulation had a effect. On the other hand, a resultant charge of +40mV would be a _ effect.

hyperpolarizing; depolarizing Signup and view all the answers

What is an autoreceptor, where is it located, and what happens when it is blocked?

An autoreceptor is a protein embedded in the cell membrane; they are located on the presynaptic terminal membrane, cell body, and/or dendrites. Their function is to moderate the amount of neurotransmitter that is released. When an autoreceptor is blocked, the release of the neurotransmitter for that neuron is no longer regulated and will be increased. Signup and view all the answers

Explain how catecholamines are synthesized.

Catecholamine synthesis begins with phenylalanine, which is then converted into tyrosine (tyrosine is also found in various foods). The enzyme tyrosine hydroxylase converts tyrosine into L-DOPA by adding a hydroxyl group. The enzyme DOPA decarboxylase then removes a carboxyl group, converting L-DOPA to dopamine. Subsequently, dopamine is converted into norepinephrine and epinephrine. Signup and view all the answers

Name the four stages of pharmacokinetics.

Absorption, Distribution, Metabolism, Excretion. Signup and view all the answers

Monica participates in an experiment where she is given a capsule filled with an inert powder and told that this powder is a powerful analgesic. She then undergoes a cold pressor test. What is her pain sensitivity likely to be on the second test compared to the first test?

Due to the placebo effect, Monica likely experienced pretty low levels of pain on the first test. However, naloxone reverses the effects of opioids - thus, on the second test, Monica would experience significantly heightened sensitivity to the pain. Signup and view all the answers

There are two main reasons for differences in the effectiveness of drugs that produce similar effects. One is the site of the drug's action, and the other is ____.

the drug's affinity for the site Signup and view all the answers

The ____ dopamine pathway projects from the ventral tegmental area to the limbic system.

mesolimbic Signup and view all the answers

Neurons that release amino acid neurotransmitters are located throughout the brain. Neurons that release other types of neurotransmitters are organized in _____?

pathways Signup and view all the answers

To which receptor does alcohol bind?

GABA Signup and view all the answers

Which monoamine has the most receptors?

Serotonin (13) Signup and view all the answers

What is the difference between drug tolerance and drug sensitization?

Drug tolerance describes a reduced effect with repeated administration, whereas drug sensitization refers to an amplified effect with repeated administration. Signup and view all the answers

Describe one mechanism whereby a drug can produce an agonist effect on neurotransmission.

Stimulating postsynaptic receptors (e.g., nicotine and muscarine on ACh). Signup and view all the answers

Describe one mechanism whereby a drug can produce an antagonist effect on neurotransmission.

Stimulating the autoreceptors, inhibiting the synthesis and release of the transmitter substance (e.g., apomorphine on dopamine). Signup and view all the answers

Study Notes

Nervous System Structures and Functions

The frontal cortex is located anteriorly to the parietal cortex.
The temporal cortex is located inferiorly to the frontal cortex.
The peripheral nervous system lacks the arachnoid membrane and the subarachnoid space in its meninges.

Development of the Nervous System

Neurogenesis: Progenitor cells divide to produce neurons through symmetrical and asymmetrical division.
Cell migration: Neurons utilize radial glial cells for movement to designated locations.
Differentiation: Chemical signals guide neurons to develop into specific types (e.g., sensory, motor, interneurons).
Synaptogenesis: Formation of synaptic connections between neurons.
Apoptosis: Pruning occurs with massive cell death.
Rearrangement: Strengthening of active synapses and elimination of inactive ones.

Neuron Function and Maintenance

Approximately 50% of newly developed neurons die by apoptosis if their axon does not connect with a suitable postsynaptic cell.
The medulla is housed within the myelencephalon.
The somatic nervous system controls activities like note-taking in class.
The enteric nervous system regulates functions such as salivation and digestion.

Primary and Association Cortical Areas

Primary cortical areas include:
- V1: Processes visual inputs.
- A1: Analyzes sound elements receiving input from MGN.
- S1: Processes somatosensory information.
- Motor cortex: Responsible for motor control.
- Olfactory area: Receives olfactory information.
- Gustatory area: Processes taste information from insula.

Central Nervous System Components

Oligodendrocytes, found in the central nervous system, produce myelin similar to Schwann cells.
Resting potential is maintained as diffusion drives potassium ions (K+) outside the membrane.

Action Potentials and Neurotransmitter Dynamics

Action potentials rejuvenate at each node of Ranvier via saltatory conduction.
Mitochondria generate ATP, serving as an energy source for cells.
Sodium (Na+) concentration is higher outside the cell due to the sodium-potassium pump despite diffusion and electrostatic pressure pushing it inward.

Neurotransmitter Regulation

A transporter protein reabsorbs excess neurotransmitters from the synapse back into the presynaptic neuron.
Hyperpolarizing stimulus shifts the voltage from -70mV to -95mV, while a depolarizing effect results in a +40mV charge.

Autoreceptors and Catecholamines

Autoreceptors are proteins that moderate neurotransmitter release, located in the presynaptic terminal, cell body, and dendrites. Blockage results in unregulated neurotransmitter release.
Catecholamines are synthesized from phenylalanine through several enzymatic steps: phenylalanine → tyrosine → L-DOPA → dopamine → norepinephrine → epinephrine.

Pharmacokinetics

The four stages of pharmacokinetics include absorption, distribution, metabolism, and excretion.

Placebo and Drug Responses

The placebo effect observed in Monica's experiment resulted in low pain sensitivity initially. Naloxone, an opioid antagonist, likely heightened pain sensitivity in subsequent tests.
Differences in drug effectiveness can stem from the drug's action site and its affinity for that site.

Pathways and Receptors

Mesolimbic dopamine pathway connects from the ventral tegmental area to the limbic system.
Neurons releasing amino acid neurotransmitters are dispersed throughout the brain, whereas other neurotransmitter types are organized in pathways.
Alcohol binds primarily to GABA receptors.
Serotonin has the highest number of receptors (13).

Drug Tolerance and Sensitization

Drug tolerance leads to reduced effects after repeated use, while drug sensitization results in amplified effects from repeated administration.
Drugs can exert agonist effects by stimulating postsynaptic receptors, while antagonist effects can stem from activating autoreceptors, inhibiting neurotransmitter synthesis and release.

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Test your knowledge on the structure of the brain and nervous system with these flashcards from Unit 1. Explore terms related to the location of various cortices and the meninges in both the central and peripheral nervous systems. Perfect for students studying neuroscience!