Understanding Neurons and the Nervous System

What are neurons?

Neurons are the building blocks of the brain responsible for everything you think, feel, and do.

How do neurons function similarly to computers?

Neurons accept inputs, operate on them, and produce outputs, much like a computer running a program.

What are the key parts of a neuron?

The key parts of a neuron include the cell body, dendrites, axon, cell membrane, and terminal buttons.

What occurs when a neuron is at rest?

When at rest, a neuron maintains a negative charge due to the distribution of positively and negatively charged atoms.

What triggers a neuron to fire?

A neuron fires when its dendrites or cell body receive appropriate inputs from other neurons.

What happens during the firing of a neuron?

Channels in the axon membrane open, allowing an exchange of atoms that changes the electrical charge inside the axon.

What is the all-or-none law in neural firing?

The all-or-none law states that a neuron either fires and releases chemicals or it does not fire at all.

How often can many neurons fire?

Many neurons can fire hundreds of times a second due to rapid chemical reactions that reset them.

What is the synapse?

The synapse is the junction where sending and receiving of signals between neurons takes place.

What is the role of neurotransmitters in neural communication?

Neurotransmitters function as signals that bridge the gap between neurons at the synapse.

What happens after a neuron fires?

After firing, the neuron releases neurotransmitters that affect other neurons.

What is the significance of the negative charge in a resting neuron?

The negative charge is crucial for the neuron's ability to fire and transmit signals.

What is the structure of a neuron?

A neuron consists of a cell body with a nucleus, dendrites that branch out, and an axon that connects to other neurons.

What initiates the exchange of atoms in a neuron?

The opening of channels in the axon membrane initiates the exchange of atoms.

How do neurons reset after firing?

Chemical reactions within the neuron allow it to reset and be ready to fire again.

What is the function of terminal buttons?

Terminal buttons release neurotransmitters that act as signals to other neurons.

What is the role of inputs in neural firing?

Inputs must reach adequate levels for a neuron to fire and release neurotransmitters.

How does the electrical charge change during neural firing?

The electrical charge changes due to the influx and efflux of ions across the neuron's membrane.

What is the relationship between neurons and the nervous system?

Neurons are the basic units of the nervous system, forming a coordinated network with other cell types.

What is the significance of the axon in a neuron?

The axon is the cable-like structure that transmits signals from the cell body to other neurons.

What happens to the electrical charge inside the axon during firing?

The electrical charge becomes positive as ions flow into the axon during firing.

What is the function of dendrites?

Dendrites receive signals from other neurons and transmit them to the cell body.

What are the three parts of a synapse?

1. The portion of the axon that sends the message. 2. The portion of the receiving neuron that receives the message. 3. The space between the axon and receiving neuron, known as the synaptic cleft.

What is the synaptic cleft?

The space between the sending and receiving neurons where they do not physically touch.

What are vesicles in the context of neurotransmission?

Small sacs that contain neurotransmitter substances and transport them across the synaptic cleft.

What role do neurotransmitters play in the brain?

They act as chemical messages that transmit signals between neurons.

What is the function of acetylcholine?

It causes muscles to contract and is involved in memory and arousal.

What disorders are associated with a shortage of acetylcholine?

Alzheimer's disease and delusions.

What drugs affect acetylcholine?

Physostigmine (increases) and scopolamine (blocks).

What is the primary function of dopamine?

It is involved in motivation, reward, movement, thought, and learning.

What disorders are linked to dopamine shortages?

Parkinson's disease, depression, and ADHD.

Which drugs alter dopamine levels?

Amphetamine and cocaine (cause release), chlorpromazine (blocks at receptors), and methylphenidate (Ritalin, blocks reabsorption).

What is the role of noradrenaline (norepinephrine)?

It is involved in dreaming and attention.

What symptoms are associated with a shortage of noradrenaline?

Depression, fatigue, and distractibility.

What drug class affects noradrenaline levels?

Tricyclic antidepressants like amitriptyline (keeps more available at the synapse).

What is glutamate's primary function?

It is the primary excitatory neurotransmitter involved in learning and memory.

What disorders are associated with glutamate?

Schizophrenia and possibly mood disorders.

What drugs block glutamate?

PCP and ketamine.

What is the function of endorphins?

They are involved in modulating pain perception.

What disorders are linked to excess endorphins?

Anxiety disorders and substance use disorder.

What drugs mimic endorphins?

Opium, morphine, heroin, and prescription pain medications.

What is serotonin's primary role?

It is the primary inhibitory neurotransmitter that regulates mood and sleep.

What disorders are associated with serotonin shortages?

Obsessive-compulsive disorder, insomnia, and depression.

What drugs affect serotonin levels?

Fluoxetine (Prozac) and tricyclic antidepressants.

What is the function of gamma-aminobutyric acid (GABA)?

It inhibits the sending neuron.

What disorders are linked to GABA shortages?

Anxiety, panic, epilepsy, and Huntington's disease.

What substances mimic GABA's effects?

Sedatives like phenobarbital, alcohol, and benzodiazepines.

What role do endogenous cannabinoids play?

They are involved in memory, attention, emotion, movement, and appetite.

What disorders are associated with endogenous cannabinoid imbalances?

Chronic pain (shortage) and schizophrenia (excess).

What are SSRIs and name three examples?

SSRIs are selective serotonin reuptake inhibitors. Examples include Prozac, Zoloft, and Paxil.

What are SNRIs and name two examples?

SNRIs are serotonin-norepinephrine reuptake inhibitors. Examples include Cymbalta and Effexor.

What is the function of Naltrexone?

Naltrexone blocks the effects of alcohol and opiates and is used to treat substance abuse.

Who first described Parkinson's disease and in what year?

James Parkinson first described Parkinson's disease in 1817.

How many Americans are affected by Parkinson's disease?

About half a million Americans.

What are some symptoms of Parkinson's disease?

Symptoms include shaking hands, sluggish movement, stooped posture, shuffling walk, and frozen limbs.

What neurotransmitter's cell death is associated with Parkinson's disease?

Dopamine.

What is L-dopa and what effect does it have on Parkinson's symptoms?

L-dopa helps produce dopamine and decreases Parkinson's symptoms, but its effectiveness diminishes over time.

What are dopamine agonists?

Dopamine agonists are new drugs being developed to treat Parkinson's disease.

What is the role of neurotransmitter receptors?

Neurotransmitter receptors are sites where neurotransmitter molecules attach to affect receiving neurons.

What analogy is used to describe neurotransmitter receptors?

The analogy of a lock and key, where the receptor is the lock and the neurotransmitter is the key.

What are the two general types of effects neurotransmitters can have after binding to receptors?

Excitatory inputs, which increase the likelihood of a neural impulse, and inhibitory inputs, which decrease it.

How do neurons receive multiple inputs?

Neurons can receive thousands of different inputs due to the branching of axons and the presence of many dendrites.

What happens to excess neurotransmitters not taken up by receptors?

Excess neurotransmitters remain in the synaptic gap and require special mechanisms for reabsorption into the sending neuron.

What is the function of glial cells in the brain?

Glial cells support neural functioning in several ways and outnumber neurons by about ten to one.

Who is credited with increasing interest in glial cells?

Albert Einstein, after his brain was studied posthumously.

What was initially observed about Einstein's brain?

It was not larger than average and did not have more neurons than a typical brain.

What did researchers at the University of California, Berkeley discover about Einstein's brain in 1985?

Einstein had a greater ratio of glial cells to neurons compared to donated brains of other doctors.

In which area of the brain did researchers find an increased number of glial cells in Einstein's brain?

In the area involved with imagination and complex thinking.

What are glial cells known to help neurons do during brain development?

Glial cells help neurons create synapses and form appropriate connections.

What traditional functions of glial cells are acknowledged in their role supporting neurons?

Glial cells cushion neurons, clean up dead neurons, dispose of extra neurotransmitters, and provide nutrients.

How do neurons and glial cells influence each other?

Neurons stimulate glial cells to release specific chemicals, and glial cells can regulate how strongly one neuron affects another.

What role do glial cells play in brain circuits?

Glial cells coordinate the activity of vast sets of brain circuits.

What is a unique way that glial cells communicate?

Glial cells pass chemicals directly through their walls to adjoining glial cells or release molecules into the surrounding brain fluid.

What are some functions that glial cells are believed to influence?

Glial cells may play a role in drug addiction and controlling the internal clock that governs daily rhythms.

What are the two main parts of the human nervous system?

The peripheral nervous system and the central nervous system.

What are the two parts of the peripheral nervous system (PNS)?

The autonomic nervous system and the somatic nervous system.

What does the autonomic nervous system (ANS) control?

The ANS controls smooth muscles and glandular functions, as well as self-regulating activities like digestion and circulation.

Where are smooth muscles found in the body?

Smooth muscles are found in blood vessels, stomach lining, and intestines.

Are the activities controlled by the autonomic nervous system usually under conscious control?

No, many activities controlled by the ANS, such as digestion and circulation, are not under conscious control.

What is the primary function of neurons in the brain?

Neurons take inputs and, when enough inputs are received, they fire along their axon to create new inputs.

How do billions of neuron firings contribute to human experience?

They create complex thoughts and actions, such as speaking or calculating the path of a moving object.

What is the significance of glial cells in relation to personal performance?

Glial cells are essential for optimal functioning as a parent, student, or employee.

What is the role of glial cells in synapse formation?

Glial cells can encourage neurons to form additional synapses.

What is a key difference between glial cells and neurons in terms of neural impulses?

Glial cells do not produce neural impulses and do not fire like neurons.

What is the relationship between glial cells and neurotransmitters?

Glial cells help dispose of extra neurotransmitters in the fluid surrounding neurons.

What is the impact of glial cells on brain functions?

Glial cells are important in a remarkably wide range of brain functions.

What is the purpose of the lesson mentioned in the notes?

To identify the major areas of the brain and the function of each area.

What happens when a neuron receives enough of the right inputs?

The neuron will fire along its axon, creating a new input.

How do glial cells contribute to the development of the brain?

They assist in creating synapses and forming connections during prenatal development and childhood.

What are the two branches of the autonomic nervous system (ANS)?

The sympathetic and parasympathetic nervous systems.

What is the primary function of the sympathetic nervous system?

To prepare an animal to cope with an emergency by increasing oxygen flow to muscles and improving vision.

What role does the parasympathetic nervous system play after an emergency?

It calms down the muscles and directs oxygen back to slower processes like digestion.

What is the somatic nervous system (SNS) responsible for?

Receiving information from the body and the outside world and enabling actions based on that information.

What does the central nervous system (CNS) consist of?

The brain and the spinal cord.

How does the spinal cord function in relation to the brain?

It serves as the largest conduit for information going to and from the brain.

What are the two large tracts of the spinal cord responsible for?

One tract sends the brain's commands to the body, while the other registers information about the body and conveys it to the brain.

How many pairs of spinal nerves connect the spinal cord to the body?

31 pairs of spinal nerves.

What are the three protective membranes that cover the brain called?

Meninges.

What separates the left and right hemispheres of the brain?

A deep crease down the middle.

Which hemisphere of the brain controls the right hand in a right-handed person?

The left hemisphere.