Psycholgy chapter 3 Erm Help

What are the three basic types of neurons

Sensory neurons, motor neurons, interneurons

Sensory neurons

detect information from the physical world and pass it to the brain

Motor neurons

Direct muscles to contract or relax to produce movement

Interneurons

Facilitate communication between sensory and motor neurons

Structure of a neuron

1. dendrites, 2. cell body (soma), 3. Axon, 4. terminal buttons, 5. Synapse

Dendrites

Receive signals from other neurons.

Cell Body (Soma)

Integrates incoming signals.

Axon

Conducts electrical signals (action potentials) away from the cell body.

Terminal Buttons

Release neurotransmitters into the synapse.

Synapse

The gap between neurons where chemical communication occurs.

What are the key electrical steps in an action potential?

Resting potential, depolarization, threshold reaches, Repolarization, relative refractory periods

Resting Potential

Neuron is polarized (~ -70mV).

Depolarization

Excitatory signals open Na⁺ channels, making the inside more positive.

Threshold Reached

Triggers the all-or-none action potential.

Repolarization

K⁺ channels open, K⁺ exits, restoring negative charge inside.

Refractory Periods

Brief period after firing when it is harder to fire again.

Relative Refractory Period

brief period of time following action potential when a neuron’s membrane potential is more negative, making it harder to fire again

What happens chemically when neurons communicate?

Action potential reaches the terminal buttons.

Vesicles release neurotransmitters into the synapse.

Neurotransmitters bind to specific receptors on the postsynaptic neuron.

Signal is terminated via reuptake, enzyme deactivation, or autoreception.

Agonists

ENHANCE neurotransmitter action (e.g., mimic it, block reuptake, increase production). Example: Heroin mimics endorphins; SSRIs block serotonin reuptake.

Antagonists

INHIBIT neurotransmitter action (e.g., block receptors, break down neurotransmitter, decrease production).

What are the two main divisions of the nervous system?

Central nervous system (CNS) and peripheral nervous system

Central Nervous System (CNS)

Brain and spinal cord.

Peripheral Nervous System (PNS)

All other nerve cells in the body, including somatic and autonomic systems.

What are the four lobes of the cerebral cortex and their primary functions?

Occipital Lobes, Parietal Lobes, Temporal Lobes, Frontal Lobes

Occipital Lobes

Vision (primary visual cortex).

Parietal Lobes

Touch, attention, spatial awareness (primary somatosensory cortex).

Temporal Lobes

Hearing, memory, object/face perception (primary auditory cortex).

Frontal Lobes

Movement, decision-making, social behavior, personality (prefrontal & primary motor cortex).

Why is the prefrontal cortex important

Prefrontal Cortex: Critical for attention, working memory, decision-making, social behavior, and personality.

Prefrontal Cortex

Critical for attention, working memory, decision-making, social behavior, and personality

what did Phineas Gage's case demonstrate?

After frontal lobe damage, he underwent major personality changes (became impulsive, irritable), demonstrating the frontal lobe's role in personality and executive function.

What is the corpus callosum

A massive bridge of axons connecting the brain's two hemispheres, allowing information exchange.

what does split-brain research tell us?

Studies of patients with a severed corpus callosum show that each hemisphere can function independently and has specialized functions (e.g., language often in left hemisphere, spatial tasks in right).

Neuron Structure

Composed of dendrites (receive signals), cell body/soma (integrates signals), axon (conducts action potential), terminal buttons (release neurotransmitters), and synapse (gap for chemical communication). The myelin sheath (glial cells) insulates some axons for faster signal transmission; gaps are Nodes of Ranvier.

Action Potential

An all-or-none electrical signal that passes along the axon when excitatory signals depolarize the neuron to its threshold. Involves depolarization (Na⁺ in), repolarization (K⁺ out), and refractory periods (absolute and relative).

Excitatory vs. Inhibitory Signals

Excitatory signals depolarize the cell membrane, increasing the likelihood of firing. Inhibitory signals hyperpolarize the cell membrane, decreasing the likelihood of firing.

Excitatory signals

depolarize the cell membrane, increasing the likelihood of firing.

inhibitory Signals

hyperpolarize the cell membrane, decreasing the likelihood of firing.

Neurotransmitters

Chemical substances that transmit signals between neurons at the synapse. Examples: Dopamine (reward, movement), GABA (inhibits action potentials), Glutamate (enhances action potentials).

Agonist Mechanisms

Enhance neurotransmitter action by increasing production (e.g., L-DOPA), blocking reuptake (e.g., SSRIs), or mimicking the neurotransmitter (e.g., heroin mimics endorphins).

Antagonist Mechanisms

Inhibit neurotransmitter action by decreasing production, facilitating destruction, or blocking postsynaptic receptors.

Prefrontal Cortex

Frontmost part of frontal lobes; critical for attention, working memory, decision-making, social behavior, and personality (demonstrated by Phineas Gage case).

Hippocampus

Subcortical structure associated with the formation of memories.

Amygdala

Subcortical structure vital for associating stimuli with emotional responses and processing emotional information.

Thalamus

Gateway to the brain; receives almost all incoming sensory information before it reaches the cortex.

Central Nervous System (CNS)

Composed of the brain and spinal cord.

Peripheral Nervous System (PNS)

All nerve cells outside the CNS; includes somatic and autonomic nervous systems.

Somatic Nervous System

Transmits sensory and motor signals between CNS and skin, muscles, and joints.

Autonomic Nervous System (ANS)

Transmits sensory and motor signals between CNS and glands/organs. Divisions: Sympathetic (prepares body for action) and Parasympathetic (returns body to resting state).

Endocrine System

Communication system using hormones released into the bloodstream to influence tissues. Key gland: Pituitary gland (controls other endocrine glands)

Plasticity

The brain's property allowing it to change as a result of experience or injury. Decreases with age but continues throughout life.

Neurogenesis

The production of new neurons; influenced by environment and occurs throughout life.

Insula

Part of cerebral cortex deep in lateral fissure; important for taste (primary gustatory cortex), pain, perception of bodily states, and empathy.

Basal Ganglia

Subcortical system important for planning and production of movement; includes nucleus accumbens.

Brain Stem

Extension of spinal cord; controls survival functions (heart rate, breathing, etc.). Includes medulla, pons, midbrain, and reticular formation (alertness, sleep).

Cerebellum

Large structure at back of brain stem; essential for coordinated movement, balance, motor learning, and motor memory.

Split-Brain Research

Study of patients with severed corpus callosum; shows hemispheric specialization (e.g., left hemisphere for language, right for spatial tasks) and the left hemisphere's role as the "interpreter."

Corpus Callosum

Massive bridge of axons connecting the two cerebral hemispheres, allowing information flow. Severed in split-brain surgery.

Sympathetic Division (ANS)

Prepares the body for action ("fight or flight").

Parasympathetic Division (ANS)

Returns the body to a resting state ("rest and digest")