Chapter 5: Neurons, Neural Communication, and Behavioral Genetics

Neurons

The basic units on which the entire brain and nervous system are built: no neurons, no brain.

Axons

Slender protrusions from the cell body, outside of the brain and spinal column.

Cranial nerves

They are nerves that come out of the brain and generally send messages to the head and neck

Spinal cord

A long, column-shaped bundle of nerve tissue that extends from the base of the brain down the center of the back, acting as a crucial communication highway for the central nervous system.

Glial cells

Provide nutrition and protection for the neurons.

Sensory neurons

Take input received through sensory receptors

throughout the body, such as in the skin, eyes, nose, ears, and tongue, and pass it on toward the brain and spinal cord to initiate a response.

Sensory neurons are also known as?

Afferent neurons

Motor neurons

Transmit signals from the brain to our muscles and other

organs.

Motor neurons are also known as?

Efferent neurons

Interneurons

Relay neurons, or connectors, allow for information to pass between neurons.

Soma

The body of a nerve cell

Dendrites

Tree-like protrusions extending from the cell body

Terminal branches

Branched endings of an axon that transmit messages to other neurons

Terminal buttons

Small knobs at the end of axons that secrete chemicals called neurotransmitters

Vesicles

Small membrane sacs that specialize in moving products into, out of, and within a cell

Neurotransmitters

Chemicals that transmit information from one neuron to another

Central nervous system (CNS)

Consists of the brain and spinal cord, acting as the body's main command center for processing information and coordinating responses

Myelin

An insulating, fatty layer that wraps around nerve fibers (axons) in the brain, spinal cord, and other nerves.

Peripheral nervous system

Glial cells form a myelin sheath

around the axons.

Neurilemma

The thin sheath around a nerve axon (including myelin where this is present).

Synapses

Neurons do not typically touch one another. They communicate chemically across very small gaps

Electrochemical communication

Neurotransmitters from the terminal buttons of one cell are released into the synapses between that cell and other cells

Neural firing

Neural conduction is the process by which information travels through a neuron.

Resting potential

The inside of the neuron contains more potassium and chloride ions than the outside, and the outside

contains more sodium ions than the inside. Because this imbalance creates a possibility of a voltage change.

Depolarization

The process during the action potential when sodium is rushing into the cell causing the interior to become more positive.

Action potential

The brief positive charge creates an electrical impulse

Threshold

The point at which it fires, usually about -55 mv.

All-or-none principle

Cells either fire (if the electrical charge inside the cell reaches a threshold) or they don't fire, and when an action potential does occur in a cell, it always occurs with the same charge.

Receptors

Specialized cells or protein molecules that detect and respond to specific stimuli

Reuptake

The originating neuron reabsorbs the chemicals in a process

Functions of Neurotransmitters

Regulate, maintain, and adjust your mood, memory, actions, and survival.

Some neurotransitters are classifed as?

Excitatory neurotransmitters

Inhibitory neurotransmitters

These inhibit (prevent) the next neurons from firing.

Acetylcholine (ACh)

Was the first neurotransmitter discovered. It is active in both the peripheral and central nervous systems.

Serotonin

One of the most important neurotransmitters is serotonin, which is connected to mood, emotion, appetite, sleep, and sexual desire.

Dopamine

Sometimes called the pleasure chemical of the brain, dopamine is released into the pleasure centers of the brain, specifically the nucleus accumbens, which is a part of the mesolimbic or "reward" pathway.

Epinephrine

It is in the endocrine system, which is associated with energy; in the sympathetic nervous system, it is associated with response to high-emotion situations, such as emergencies.

Adrenaline

A hormone released into the bloodstream in response to physical or mental stress

Norepinephrine

It is active in the sympathetic nervous system's response to danger.

Fight-or-flight response

Occurs when people encounter something dangerous or even life-threatening and respond physiologically in a way that prepares them to fight or flee.

GABA

Stands for gamma-aminobutyric acid

Gamma-aminobutyric acid

The primary inhibitory neurotransmitter that slows things down, calming the central nervous system.

Glutamate

The major excitatory neurotransmitter, is the opposite of GABA.

Long-term potentiation (LTP)

A pattern of neural firing that strengthens synaptic

connections over time.

Endorphins

Relieve pain and stress. Which are released by the

pituitary gland, is often called the brain's natural aspirin.

Agonists

Activate the receptors for certain neurotransmitters and ultimately make the effects of the neurotransmitter

stronger.

Antagonists

They are chemicals that inhibit or oppose the actions of neurotransmitters.

Neuroplasticity

Is the ability of the brain to create new neurons, form

new neural connections, and recruit neurons from other parts of the brain to perform functions once performed by the damaged neurons.

Behavioral genetics

Focuses on discovering how genes and experiences

interact and lead to specific behaviors and mental abilities.

Genome

A genome is the entirety of that individual's hereditary information.

Genotype

Refers to the person's specific genetic blueprint, which is determined by the total pattern of chromosomes inherited from each parent.

Phenotype

The actual characteristics a person develops, taken together

DNA (deoxyribonucleic acid)

A complex molecule containing the genetic information that makes up the chromosomes and contains the building blocks of life

Genes

They are segments of DNA that contain instructions to make proteins, the building blocks of life.

Sensitive period

Time in life (sometimes called a critical period) is when the organism has a period of increased sensitivity to environmental influence.

Konrad Lorenz's

Study of imprinting in ducks and geese.

Reciprocal determinism

By interacting with the world around us, we have a role in changing the environment in which we live.

Heritability

It is a measure of the degree to which our traits are inherited.

Charles Darwin

Demonstrated that the basic principle of natural selection is that, given a range of possible inherited trait variations, those traits that lead to increased reproduction and survival of the species are most likely to be passed down to generations that follow.

Adaptation

The process by which an organism or species becomes better suited for life in its environment

Evolutionary psychology

It is the study of the evolution of mind and behavior based on principles of natural selection.

Genetic mutations.

With every generation, random errors in gene replication lead to changes in a species.

Epigenetics

An individual could change gene expression to adapt to the environment without having to wait generations for a trait to become active through the DNA.