Neuron Basics and Synaptic Communication

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Questions and Answers

What does overactivation of the maternal immune response increase the risk of in the fetus?

Neurodevelopmental disorders (correct)

Metabolic disorders

Respiratory issues

Cardiovascular diseases

Which statement best describes electrical communication of neurons?

It is slower than chemical communication.

It is fast and occurs at the synapse.

It allows for rapid propagation of action potentials. (correct)

It involves the release of neurotransmitters.

What is the role of negative feedback in the HPA axis?

To activate the sympathetic nervous system.

To increase cortisol production during stress.

To maintain homeostasis by reducing hormone production. (correct)

To enhance the production of CRH and ACTH.

What does allostatic load refer to?

The wear and tear on the body from chronic stress. Signup and view all the answers

Which of the following best defines electrophysiology of the neuron?

The study of the electrical properties of neurons. Signup and view all the answers

What does PANDAS stand for?

Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections Signup and view all the answers

Which of the following ventricles is located between the brainstem and cerebellum?

Fourth ventricle Signup and view all the answers

Which hormone production is reduced by the hypothalamus during high cortisol levels?

CRH (Corticotropin-Releasing Hormone) Signup and view all the answers

What is the main ion responsible for establishing the resting potential in a neuron?

Potassium (K⁺) Signup and view all the answers

Which process describes the addition of multiple EPSPs and IPSPs to determine the overall change in membrane potential?

Summation Signup and view all the answers

What occurs when the summed excitatory postsynaptic potentials (EPSPs) exceed the summed inhibitory postsynaptic potentials (IPSPs)?

The neuron is likely to fire an action potential Signup and view all the answers

Which part of the neuron is primarily responsible for the integration of potentials to determine if an action potential will be generated?

Axon hillock Signup and view all the answers

What is the result of an excitatory postsynaptic potential (EPSP)?

Depolarization of the postsynaptic membrane Signup and view all the answers

How does the sodium-potassium pump function in neurons?

Pumps sodium ions out and potassium ions in Signup and view all the answers

What is the typical time course difference between EPSPs and IPSPs?

EPSPs are typically shorter than IPSPs Signup and view all the answers

At resting potential, how is the charge inside the neuron compared to the outside?

Negatively charged Signup and view all the answers

What role does the fast response pathway (SAM) play in the body's reaction to stress?

It activates the sympathetic nervous system to prepare for immediate action. Signup and view all the answers

Why was the development of atomic theory significant in understanding chemical reactions?

It provided a framework for understanding matter at a microscopic level. Signup and view all the answers

What does the ventricle system in the brain do?

Produces and circulates cerebrospinal fluid (CSF). Signup and view all the answers

How do the structures of the cerebral cortex affect its function?

They increase the surface area, allowing for more complex processing. Signup and view all the answers

What happens during depolarization of an action potential?

Sodium ions flow into the neuron, shifting the potential to +30 mV. Signup and view all the answers

What is the primary function of a synapse?

To convert electrical signals into chemical signals. Signup and view all the answers

What are the functions primarily associated with the cerebrum?

Higher cognitive functions such as thinking and decision-making. Signup and view all the answers

What is a unique characteristic of the slow response pathway (HPA) compared to the fast response pathway (SAM)?

It is regulated by the hypothalamus and results in cortisol release. Signup and view all the answers

What is the primary function of cortical neurons compared to subcortical and brainstem neurons?

Primarily responsible for higher cognitive functions. Signup and view all the answers

Which mechanism involves the breakdown of neurotransmitters by specific enzymes?

Enzymatic degradation Signup and view all the answers

What is an Excitatory Postsynaptic Potential (EPSP) primarily caused by?

Influx of positively charged ions. Signup and view all the answers

How does a negative feedback loop function?

It counteracts the initial change to restore balance. Signup and view all the answers

Which statement best defines a positive feedback loop?

A loop that increases the effect of an initial stimulus. Signup and view all the answers

In the relationship between the cerebral cortex and subcortical structures, which is correct?

The cortex processes cognitive functions while subcortical areas manage emotional responses. Signup and view all the answers

Which of the following describes a key difference between cortical neurons and those in the brainstem?

Cortical neurons are arranged in layers. Signup and view all the answers

What process involves the reabsorption of neurotransmitters back into the presynaptic neuron?

Reuptake Signup and view all the answers

What are the primary functions of the cortical regions of the brain?

Higher-order functions such as perception and reasoning Signup and view all the answers

During which phase of an action potential does the membrane potential reach approximately +30 mV?

Depolarization Signup and view all the answers

Which statement accurately differentiates hormones from neurotransmitters?

Hormones are released by glands and neurotransmitters are released by neurons. Signup and view all the answers

What is the first step in activating the SAM (Sympathetic-Adrenal-Medullary) pathway?

Hypothalamus activation due to stress Signup and view all the answers

How does neural signaling differ from hormonal signaling?

Neural signals are much faster and localized. Signup and view all the answers

What defines the resting potential of a neuron?

A stable negative charge of -70 mV Signup and view all the answers

Which type of signaling involves the movement of ions like Na+ and K+?

Electrical signaling Signup and view all the answers

What occurs during the repolarization phase of an action potential?

Na+ channels close and K+ channels open Signup and view all the answers

Study Notes

Neuron Basics

Neuron membrane depolarizes during an action potential, changing voltage and propagating along the axon.
At resting potential, the neuron's inside is negatively charged compared to the outside.
Potassium (K+) is the main ion establishing resting potential.
The sodium-potassium pump actively moves sodium ions out and potassium ions into the neuron against the concentration gradient.
The resting potential is crucial for generating an action potential when the neuron is stimulated.
Any change in resting potential due to stimulation is a graded potential.

Synaptic Communication

An excitatory postsynaptic potential (EPSP) occurs when a neurotransmitter binds to receptors and depolarizes the postsynaptic membrane.
An inhibitory postsynaptic potential (IPSP) occurs when neurotransmitter binding hyperpolarizes the postsynaptic membrane.
The axon hillock integrates the summed potential, determining if an action potential will be generated.
Summation is the process of adding multiple EPSPs and IPSPs to determine the overall change in membrane potential.
A neuron is more likely to reach the threshold and fire an action potential if the sum of EPSPs exceeds the sum of IPSPs.
EPSPs typically involve sodium (Na+) influx, while IPSPs often involve chloride (Cl-) influx.
EPSPs are usually shorter than IPSPs.
The axon hillock has a high density of voltage-gated Na+ channels, making it sensitive to membrane potential changes.

Brain Anatomy

The cerebral cortex is divided into four main lobes.
The occipital lobe primarily processes visual information.
The frontal lobe houses the primary motor cortex.

Neuron Types And Functions

Cortical neurons are involved in higher cognitive functions, are arranged in layers.
Subcortical and brainstem neurons are involved in basic life functions, emotion, and movement regulation, lacking the layered organization of cortical neurons.

Neurotransmitter Deactivation

Two ways to deactivate a neurotransmitter: reuptake and enzymatic degradation.
Reuptake involves the presynaptic neuron reabsorbing the neurotransmitter.
Enzymatic degradation involves specific enzymes breaking down the neurotransmitter (e.g., acetylcholinesterase breaks down acetylcholine).

Excitatory Postsynaptic Potential (EPSP)

An EPSP is a temporary depolarization of the postsynaptic membrane.
It is caused by the influx of positively charged ions (usually Na+).
EPSPs make the neuron more likely to fire an action potential if the threshold is reached.

Feedback Loops

Negative feedback loop counteracts the initial change, maintaining balance.
Example: The HPA axis regulating cortisol levels.
Positive feedback loop amplifies the initial stimulus.
Example: Oxytocin release during childbirth, intensifying uterine contractions.

Cerebral Cortex vs. Subcortical Structures

The cerebral cortex handles higher cognitive functions, while subcortical structures are involved in emotion, memory, and motor control.
Together, they integrate cognitive functions with emotional and motor responses, allowing for coordinated behavior.

Neural Signaling

Signaling involves five steps:
- Resting potential: The neuron is at -70 mV.
- Depolarization: Na+ channels open, allowing Na+ to enter the neuron, raising the membrane potential.
- Repolarization: K+ channels open, causing K+ to leave the neuron, restoring the membrane potential.
- Hyperpolarization: The potential dips below -70 mV briefly.
- Return to resting potential: The Na+/K+ pump restores the resting state.

Electrical vs. Chemical Communication

Electrical communication involves transmission of action potentials along the axon through ion movement. It is fast and allows for rapid signal propagation.
Chemical communication occurs at the synapse, involving neurotransmitter release and binding to receptors on the postsynaptic neuron. It is slower but allows for greater modulation and complex signaling.

Negative Feedback

Negative feedback helps regulate processes by maintaining homeostasis.
Example: In the HPA axis, when cortisol levels rise due to stress, the hypothalamus and pituitary gland reduce CRH (Corticotropin-Releasing Hormone) and ACTH (Adrenocorticotropic Hormone) production, leading to lower cortisol production and restoring balance.

Neuron Electrophysiology

Electrophysiology studies the electrical properties of neurons, including their membrane potential and the generation of action potentials.
Neurons communicate through changes in electrical charge across their membranes, driven by the movement of ions.

Allostatic Load

Allostatic load refers to the cumulative "wear and tear" on the body resulting from chronic exposure to stress and physiological responses.
It can lead to health problems like cardiovascular disease and cognitive decline.

PANDAS

PANDAS stands for Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections.
It is a condition where streptococcal infections trigger an autoimmune response that affects the brain, leading to sudden-onset OCD and tics in children.

Ventricles of the Brain

The ventricles are interconnected cavities producing and circulating cerebrospinal fluid (CSF).
The major ventricles are:
- Lateral ventricles (1st and 2nd): Located in each cerebral hemisphere.
- Third ventricle: Located in the diencephalon.
- Fourth ventricle: Located between the brainstem and cerebellum.

DSM

The Diagnostic and Statistical Manual of Mental Disorders (DSM) is a manual used by healthcare professionals to diagnose and classify mental health conditions.
It provides standardized criteria for diagnosing various mental disorders.

SAM Pathway

Fast response pathway (SAM): This involves the sympathetic nervous system and the adrenal medulla, which releases epinephrine and norepinephrine. This prepares the body for immediate action (fight or flight).
Slow response pathway (HPA): This involves the hypothalamus, pituitary gland, and adrenal cortex, which releases cortisol for long-term stress adaptation.

Atomic Theory

Before the atomic theory, it was not possible to explain chemical reactions in terms of indivisible units (atoms).
The atomic theory provided a foundation for understanding the composition and behavior of matter at the microscopic level.

Ventricle System

The ventricle system consists of interconnected cavities in the brain producing and circulating cerebrospinal fluid (CSF).
It helps cushion the brain, maintain pressure, and remove waste.

Brain Structure and Function

The appearance of a brain region affects its function. Folds (gyri) and grooves (sulci) of the cerebral cortex increase surface area, allowing for more complex processing.
Distinct structures, like the cerebellum, are specialized for specific tasks like motor coordination.

Action Potential

Resting potential: -70 mV.
Depolarization: +30 mV (due to Na+ influx).
Repolarization: Drops back to negative values (due to K+ outflow).
Hyperpolarization: Potential dips below -70 mV briefly.
Return to resting potential: Na+/K+ pump restores balance.

Synapse

A synapse is the junction between two neurons where electrical signals are converted into chemical signals through the release of neurotransmitters.
It allows communication between neurons.

Cerebrum vs. Cerebellum

Cerebrum: Responsible for higher cognitive functions (thinking, decision-making, voluntary movement). It consists of two hemispheres with four lobes: frontal, parietal, occipital, and temporal.
Cerebellum: Involved in motor coordination, balance, and learning new motor skills. It is located at the back of the brain, beneath the cerebrum.

Cortical vs. Subcortical Regions

Cortical regions: The cerebral cortex is responsible for higher-order functions. It consists of four lobes: frontal, parietal, temporal, and occipital.
Subcortical regions: Located beneath the cortex, they are involved in more fundamental processes (emotion, memory, basic survival functions).

Action Potential Process

Resting potential: Neuron is at -70 mV.
Depolarization: Na+ channels open, causing Na+ to enter the neuron, raising the membrane potential to +30 mV.
Repolarization: K+ channels open, allowing K+ to leave the neuron, restoring the membrane potential.
Hyperpolarization: The potential dips below -70 mV briefly.
Return to resting potential: The Na+/K+ pump restores the resting state.

Action Potential vs. Resting Potential

Action potential: A rapid, temporary change in membrane potential due to depolarization, leading to signal transmission (+30 mV).
Resting potential: The stable, negative charge of the neuron when not transmitting signals (-70 mV).

Hormones vs. Neurotransmitters

Hormones: Released by glands, travel through the bloodstream, slower, affect distant organs.
Neurotransmitters: Released by neurons at synapses, fast-acting, affect nearby cells.

Hormonal vs. Neural Signaling

Speed: Neural signaling is much faster than hormonal signaling.
Distance: Neural signals are localized, whereas hormones travel throughout the bloodstream.

Chemical vs. Electrical Signaling

Electrical signaling: Action potentials, fast, involves ion movement (Na+, K+).
Chemical signaling: Involves neurotransmitter release at synapses, slower but allows for greater modulation.

Activating the SAM Pathway

Stress activates the hypothalamus.
The sympathetic nervous system is stimulated.
The adrenal medulla releases epinephrine and norepinephrine, triggering the fight-or-flight response.

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Description

Explore the fundamental principles of neuron function and how synaptic communication operates. Learn about resting potential, action potentials, and the role of neurotransmitters in excitatory and inhibitory responses. This quiz is essential for understanding the mechanisms of neural signaling.