Neuroanatomy Overview

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Questions and Answers

What is the role of myelin in neurons?

It converts chemical signals into electrical signals.

It forms synaptic connections between neurons.

It speeds up signal propagation along the axon. (correct)

It maintains the ionic environment for neuronal signaling.

Which type of neuron has one axon that splits into two branches?

Bipolar neurons

Pseudounipolar neurons

Unipolar neurons (correct)

Multipolar neurons

What is one of the main functions of astrocytes in the central nervous system?

Facilitating neurotransmitter release

Producing myelin around axons

Creating synaptic connections in the brain

Modulating the propagation of nerve cell signals (correct)

Which type of neuron is primarily found in sensory systems like the retina and olfactory system?

Bipolar neurons Signup and view all the answers

What do oligodendrocytes primarily contribute to in the nervous system?

Myelin production for axons Signup and view all the answers

How do glial cells support neurons during injury recovery?

By providing a scaffold and removing pathogens Signup and view all the answers

Which part of the neuron converts electrical signals into chemical signals?

Axon terminals Signup and view all the answers

What is the function of the Node of Ranvier in myelinated axons?

To facilitate the exchange of ions Signup and view all the answers

What ion is primarily responsible for the hyperpolarization of a neuron when GABA binds to GABA-A receptors?

Chloride (Cl⁻) Signup and view all the answers

Which neurotransmitter is primarily excitatory due to its ability to increase sodium and calcium influx?

Glutamate Signup and view all the answers

What role does magnesium play in the NMDA receptor's function?

Blocks ion flow until displaced Signup and view all the answers

Which type of ion channel do GABA-A and glycine receptors represent?

Ligand-gated chloride channels Signup and view all the answers

What is the primary effect of excitatory neurotransmitters on a neuron?

Depolarization of the neuron Signup and view all the answers

What mechanism allows for direct ion flow between presynaptic and postsynaptic membranes?

Electrical synapse Signup and view all the answers

What effect do drugs like benzodiazepines have on GABA-A receptors?

Enhance GABA's inhibitory effect Signup and view all the answers

Which statement accurately describes ion channel selectivity for inhibitory neurotransmitters?

They increase potassium efflux to hyperpolarize the neuron. Signup and view all the answers

What defines the length constant (λ) in the context of dendritic signal propagation?

The distance until the signal decreases to 37% Signup and view all the answers

Which type of ion channel remains open at all times?

Non-gated ion channels Signup and view all the answers

How do dendrites behave in transmitting electrical signals?

They transmit signals passively like electrical cables Signup and view all the answers

What kind of ion channels are responsible for generating action potentials?

Voltage-gated ion channels Signup and view all the answers

What factor contributes to the decay of a signal in a dendrite according to cable theory?

Resistance and capacitance within the membrane Signup and view all the answers

What role do non-gated ion channels play in nerve cells?

Maintain the resting membrane potential Signup and view all the answers

Which of the following is NOT a type of gated ion channel?

Non-gated channels Signup and view all the answers

What determines the flux of ions through gated ion channels?

The electro-chemical driving force Signup and view all the answers

What is the primary purpose of the cell-attached configuration in the patch clamp technique?

To measure currents through ion channels still embedded in the cell membrane Signup and view all the answers

In which patch clamp configuration is the intracellular side of the ion channel exposed to the external solution?

Inside-Out Configuration Signup and view all the answers

Which configuration is most suitable for studying the overall cellular properties, such as membrane potential and action potentials?

Whole-Cell Configuration Signup and view all the answers

What is the main application of the outside-out configuration in patch clamp techniques?

Investigating the effects of extracellular ligands on ion channel function Signup and view all the answers

Which method in the patch clamp technique involves applying gentle suction to break through the cell membrane?

Whole-Cell Configuration Signup and view all the answers

What distinguishes the perforated patch clamp technique from traditional patch clamp methods?

It preserves the integrity of the cell membrane while measuring currents. Signup and view all the answers

What is the primary mechanism of action of botulinum toxin (BoTx) at the neuromuscular junction?

Inhibits acetylcholine release Signup and view all the answers

Which patch clamp configuration is ideal for studying intracellular factors like calcium and phosphorylation?

Inside-Out Configuration Signup and view all the answers

What happens to the patch during the outside-out configuration when the pipette is pulled away?

The patch re-seals with the extracellular side exposed to the bath. Signup and view all the answers

How does tetanus toxin (TeTx) lead to spastic paralysis?

By inhibiting inhibitory interneurons Signup and view all the answers

Which of the following symptoms is NOT commonly associated with myasthenia gravis?

Muscle twitching Signup and view all the answers

Nerve gas poisoning primarily affects which aspect of synaptic transmission?

Prevent the breakdown of acetylcholine Signup and view all the answers

What is the primary purpose of using a glass microelectrode in neuronal activity registration?

To measure voltage changes inside an axon Signup and view all the answers

In voltage clamping, what is maintained constant while measuring ionic currents?

Membrane potential Signup and view all the answers

What is a key characteristic of the paralysis caused by botulism?

It results in flaccid paralysis Signup and view all the answers

Which neurotransmitters are blocked by tetanus toxin leading to spastic paralysis?

GABA and glycine Signup and view all the answers

What is the initial condition for NMDA receptors in the postsynaptic neuron when glutamate is released?

They are inactive due to being blocked by magnesium. Signup and view all the answers

What triggers the removal of the magnesium block from the NMDA receptor?

High levels of glutamate combined with postsynaptic depolarization. Signup and view all the answers

What is a key outcome of calcium influx into the postsynaptic neuron during LTP?

Insertion of more AMPA receptors into the synapse. Signup and view all the answers

What does LTP primarily represent in the context of neural functioning?

A stronger synaptic connection that enhances learning and memory. Signup and view all the answers

In terms of synaptic strength, how does LTP affect the postsynaptic response to glutamate after it occurs?

It causes a larger postsynaptic response for the same amount of glutamate. Signup and view all the answers

What role does associativity play in LTP?

It allows weakly stimulated synapses to also undergo LTP if activated simultaneously with strong stimuli. Signup and view all the answers

Which synapse is strengthened by LTP when it receives a weak stimulus alongside a strong stimulus?

The weak synapse can strengthen due to associativity with the strong synapse. Signup and view all the answers

Which of the following accurately describes the pathway of LTP induction?

LTP is induced when a strong stimulus depolarizes the neuron while a weak stimulus activates another synapse. Signup and view all the answers

Study Notes

Neuroanatomy

Be able to describe the nervous system's macroscopic anatomy, including major core areas and pathways.
The nervous system includes the brain, spinal cord, and major pathways.
The brain is divided into sections like the telencephalon, diencephalon, brainstem, and cerebellum.
The cerebrum includes the corpus callosum, which connects the two hemispheres.
The diencephalon includes the thalamus and hypothalamus.
The brainstem comprises the midbrain, pons, and medulla oblongata.
The cerebellum is responsible for coordinating movement.
Gyri and sulci are folds and grooves in the cerebral cortex respectively.
Gyrus precentralis is related to motor functions, and gyrus postcentralis is related to sensory functions.
Specific areas, like Broca's and Wernicke's areas, are involved in language processing

The Cerebral Cortex

The cerebral cortex is divided into four lobes: frontal, parietal, temporal, and occipital.
Each lobe has specific functions.
The frontal lobe is associated with motor functions, Broca's area, and higher-level cognitive functions.
The parietal lobe is associated with sensory processing.
The temporal lobe is associated with auditory processing and Wernicke's area.
The occipital lobe is associated with visual processing.

The Basal Ganglia

The basal ganglia are a group of nuclei deep within the brain involved in motor control.
Components include the caudate nucleus, putamen, and globus pallidus.
They are involved in motor control and learning.

The Limbic System

The anatomical view of the limbic system focuses on emotions and memory.
Different brain areas are involved in both: anterior structures involved with emotions, and posterior with memory.

The Brainstem

The brainstem is a continuous structure connecting the pons to the medulla oblongata.
Relays signals and coordinates many functions.

The Reticular Formation

The Reticular Formation (RF) is a group of nuclei that plays a significant role in consciousness.
The RF has ascending and descending components which are involved in consciousness and motor functions, respectively.

The Spinal Cord

The spinal cord is part of the central nervous system, situated within the vertebral column.
The spinal cord has white and gray matter, with white matter carrying sensory and motor tracts, and gray matter including cell bodies.
Sensory and motor functions are connected to the spinal cord through various tracts.

The Meninges

The meninges are three protective layers surrounding the brain and spinal cord (dura mater, arachnoid mater, pia mater)
The cerebrospinal fluid (CSF) circulates within the subarachnoid space.
Blood supply to the brain comes from internal carotid arteries and vertebral arteries.

Neuron & Glial Cells

Neurons: Basic functional units of the nervous system.
Types of neurons include bipolar, unipolar, and multipolar neurons which perform different roles.
Glial cells (astrocytes, oligodendrocytes, microglia): Support and protect neurons.

Axon Guidance Cues

Axon growth and synapse formation are controlled by chemoattractive and chemorepulsive cues.
Guidance cues play critical roles in developing neural circuits.

Ion Channels & Membrane Potentials

Ion channels regulate ion movement across the membrane.
The Nernst equation determines the equilibrium potential for a specific ion.
The Goldman equation calculates the resting membrane potential, considering multiple ions.
The rate of passive current depends on the length and time constants.
Active currents involve the opening of voltage-gated ion channels to generate and spread an action potential.

Action Potentials

Action potentials are rapid changes in membrane potential that transmit electrical signals along axons.
Steps include resting potential, threshold, depolarization, repolarization, and after-hyperpolarization.
Refractory periods prevent backward conduction.

Synaptic Transmission

Synapses are specialized junctions between neurons.
Chemical synapses involve neurotransmitters released from presynaptic vesicles and binding to receptors on postsynaptic neurons.
Different types of receptors exist (ionotropic and metabotropic).
Synaptic plasticity refers to changes in synaptic strength over time (short term and long term).
Synaptic transmission is essential for information processing in the nervous system.

Postsynaptic Receptors

Postsynaptic receptors are proteins in the membrane of a neuron or muscle cell capable of receiving neurotransmitters.
Signal transduction mechanisms involving receptors vary by the NT being received.
Different types of receptors (ionotropic and metabotropic) respond to certain neurotransmitters
Different mechanisms for signal transduction exist in both of these types.

Synaptic Plasticity

Short-term plasticity is influenced by changes in presynaptic calcium inflow.
Depression and facilitation affect the duration and intensity of the response.
Long-term plasticity involves both pre and postsynaptic changes.

Neural Recording

Electrophysiology methods (e.g., patch-clamp) allow measuring currents across neural membranes.

Neurotransmitters

Small molecule (e.g., acetylcholine, amino acids, amines)
Peptides (e.g., endorphins) have a broad scope affecting many processes.
Synthesis and storage mechanisms are unique to each form.

Toxins and Diseases Affecting Synapses

Botulism, tetanus, myasthenia gravis, and nerve gas poisoning cause dysfunction in synaptic transmission and various pathways of the neuromuscular junction.

Neuroanatomy-Experimental Techniques

Describes commonly used experimental techniques (e.g., patch-clamp, whole-cell clamp, etc) used to study the nervous system.

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Description

This quiz explores the macroscopic anatomy of the nervous system, detailing its major structures such as the brain, spinal cord, and key pathways. Students will learn about the divisions of the brain, including the telencephalon, diencephalon, brainstem, and cerebellum, along with their functions and anatomical features.