1.1-1.3 REVIEW

Neuron

A specialized cell that transmits electrical impulses and chemical signals in the nervous system.

Cell Body (Soma)

The part of the neuron that contains the nucleus and organelles, integrating signals and maintaining cell health.

Dendrites

Branch-like structures of a neuron that receive signals from other neurons and transmit them to the cell body.

Axon

A long projection of a neuron that transmits electrical impulses away from the cell body to other neurons or muscles.

Myelin Sheath

A fatty layer that insulates the axon, speeding up signal transmission; its deterioration can lead to slower communication.

Axon Terminals

The endpoints of the axon that release neurotransmitters to communicate with other neurons.

Synapse

The gap between neurons where neurotransmitters are released, facilitating communication.

Sensory Neurons (Afferent Neurons)

Neurons that transmit sensory information from receptors to the central nervous system (CNS).

Interneurons

Neurons that connect sensory and motor neurons within the CNS, processing information and coordinating responses.

Motor Neurons (Efferent Neurons)

Neurons that carry signals from the CNS to muscles and glands, facilitating movement and responses.

Neurotransmitters

Chemical messengers that transmit signals across synapses between neurons, regulating mood, cognition, and bodily functions.

Shortage Effects

A lack of neurotransmitters can lead to disorders, such as low serotonin linked to depression.

Surplus Effects

An excess of neurotransmitters may cause overstimulation, like excess dopamine contributing to schizophrenia.

Inhibitory Neurotransmitters

Chemicals that decrease neuron activity, helping to calm the nervous system (e.g., GABA).

Excitatory Neurotransmitters

Chemicals that increase neuron activity, promoting alertness and learning (e.g., glutamate).

Agonist Drugs

Substances that mimic neurotransmitters, enhancing their effects (e.g., morphine mimicking endorphins).

Antagonist Drugs

Substances that block neurotransmitter effects (e.g., naloxone blocking opioids).

Central Nervous System (CNS)

Composed of the brain and spinal cord, it processes information and coordinates activities.

Peripheral Nervous System (PNS)

Nerves outside the CNS that connect it to limbs and organs, facilitating communication.

Somatic Nervous System

A part of the PNS that controls voluntary movements and sensory information.

Autonomic Nervous System

A part of the PNS that regulates involuntary functions, divided into sympathetic and parasympathetic systems.

Natural Selection

A mechanism of evolution where individuals with advantageous traits are more likely to survive and reproduce.

Survival of the Fittest

The concept that individuals with beneficial traits are more likely to survive and pass those traits to the next generation.

Behavior Geneticist

A scientist who studies the influence of genetics and environment on behavior.

Twin Studies

Research comparing similarities between identical and fraternal twins to estimate heritability of traits.

Genetic Predisposition

The increased likelihood of developing certain traits or behaviors based on genetic makeup.

Chromosomes

Structures within cells that contain DNA, with genes influencing various traits.

Prenatal Environment

The environment in the womb that can affect fetal development and later behavior.

Heritability

A statistical estimate of the proportion of variance in a trait attributable to genetic factors within a specific population.