Cell Body
largest component of neuron; coordinates information processing tasks and keeps the cell alive
Neurons
cells in the nervous system that communicate with one another to perform information-processing tasks
Dendrites
receive information from other neurons and relay it to the cell body
Axon
transmits information to other neurons, muscles, and glands; each neuron has one
Myelin Sheath
insulating layer of fatty material; composed of glial cells
Glial Cells
support cells found in the nervous system; perform various tasks
Synapse
the junction or region between the axon of one neuron and the dendrites or cell body of another
Sensory (Afferent) Neurons
receive information from the outside world and convey this information to the brain via the spinal cord
Motor (Efferent) Neurons
carry signals from the spinal cord to the muscles to produce movement
Interneurons
connect sensory neurons, motor neurons, or other interneurons
Resting Potential
the difference in electric charge between the inside and outside of a neuron's cell membrane; creates environment for possible electrical impulse
Action Potential
an electric signal that is conducted along the length of a neuron's axon to the synapse; only occurs when threshold is reached; ALL or NONE
Refractory Period
the time following an action potential during which a new action potential cannot be initiated
Nodes of Ranvier
gaps between myelinated sections of axon; charge jumps between them in saltatory conduction
Terminal Buttons
knoblike structures that branch out from an axon; filled with vesicles containing neurotransmitters
Neurotransmitters
chemicals that transmit information across a synapse to a receiving neuron's dendrites
Receptors
parts of cell membrane on dendrites that receive neurotransmitters and either initiate or prevent a new electrical signal
Acetylcholine (ACh)
-vairous functions including voluntary motor control
-found in brain neurons and synapses of muscles and body organs
-contributes to regulation of attention, learning, sleeping, dreaming, and memory
-linked with Alzheimer's
Dopamine
-regulates motor behavior, motivation, pleasure, and emotional arousal
-plays role in drug addiction
-linked to schizophrenia, Parkinson's
Glutamate
-major excitatory neurotransmitter involved in information transmission throughout the brain
-too much can result in overstimulation, cause seizures
Norepinephrine
-influences mood and arousal
-states of heightened awareness
-mood disorders
Serotonin
-regulation of sleep and wakefulness, eating, and aggressive behavior
Endorphins
-act in pain pathways and emotional centers of the brain
-dulls pain, elevates mood
GABA (gamma-amniobutyric acid)
-primary inhibitory neurotransmitter
-stop firing of neurons
-too little can result in neuron over activation
Agonists
drugs that increase the action of a neurotransmitter; by binding to a receptor, it activates neurotransmitter
Antagonists
drugs that block the function of a neurotransmitter
Nervous System
interacting network of neurons that conveys electrochemical information throughout the body
Central Nervous System (CNS)
-brain + spinal cord
-receives sensory information from external world
-processes and coordinates information
-send commands to muscular and skeletal systems for action
Peripheral Nervous System (PNS)
-connects the central nervous system to the body's organs and muscles
-divided into somatic and autonomic systems
Somatic Nervous System
-set of nerves that conveys information into and out of the CNS
-consciously controlled, used to perceive, think coordinate behavior
-grab the book, kick the ball
Autonomic Nervous System (ANS)
-set of nerves that carry involuntary and automatic commands that control blood vessels, body organs, and glands
-regulates bodily systems outside of conscious control
-divided into sympathetic and parasympathetic
Sympathetic Nervous System
-set of nerves that prepares the body for action in threatening situations (pupil dilation, heart rate, sweat glands, suppresses immune responses, bowel function, and pain response)
Parasympathetic Nervous System:
-helps body return to normal resting state
-does the opposite functions of sympathetic system to return to normal state (constricts pupils, etc.)
Spinal Reflexes
simple pathways in the nervous system that rapidly generate muscle contractions
Hindbrain
-medulla, cerebellum, pons
-area of the brain that coordinates information coming into and out of the spinal cord
-controls basic functions of life (respiration, alertness, motor skills)
Medulla
-regulates automatic functioning
-extension of spinal cord into skull that coordinates heart rate, circulation, respiration
Reticular Formation
-cluster of neurons inside medulla
-regulates sleep, wakefulness, levels of arousal
-muscle reflexes, pain perception
Cerebellum
-large structure that controls fine motor skills
-"little brain"
-orchestrates sequences of movements
-balance, coordination
Pons
-regulates sleeping, waking and dreaming
-structure that relays information from the cerebellum to the rest of the brain
-"bridge
Midbrain
consists of tectum, tegmentum
Tectum
-orients an organism in the environment
-receives stimulus from eyes, ears, skin a coordinates movement in the direction of the stimulus
Tegmentum
-involved in movement and arousal
-also helps to orient organism toward sensory stimuli
Forebrain
consists of: cerebral cortex, subcortical structures (thalamus, hypothalamus, pituitary gland, amygdala, hippocampus), corpus callosum
Cerebral Cortex
outermost layer of the brain, visible to naked eye, divided into hemispheres
Subcortical Structures
area of the forebrain housed under the cerebral cortex near the very center of the brain
Thalamus
-relays and filters information from the sense and transmits information to the cerebral cortex
-all major senses except smell
-filters, gives weights to certain inputs
-closes certain pathways during sleep
Hypothalamus
-regulates body temperature, hunger, thirst, and sexual behavior
-tiny, but oversees wide range of basic behaviors
-Four Fs: feeding, fighting, fleeing, mating
Pituitary Gland
-stress, digestive activities, reproductive processes
-"master gland" of the body's hormone-producing system, uses hormones to direct functions of many other glands in the body
-hypothalamus �> pituitary gland �> other glands
Limbic System
-loosely defined
-hypothalamus, amygdala, hippocampus
-group of forebrain structures involved in motivation, emotion, learning, and memory
-where subcortical structures meet cerebral cortex
Hippocampus
-creates new memories and integrates them into a network of knowledge so that they can be stored indefinitely in other parts of the cerebral cortex
-new, short term memory
Amygdala
-plays central role in emotional processes, formation of emotional memories
-tip of each horn of the hippocampus
-associates feelings with events
Basal Ganglia
-set of subcortical structures that directs intentional movements
-receive input from cerebral cortex, send outputs to motor centers in the brain stem
Corpus Callosum
connects large areas of the cerebral cortex on each side of the brain and supports communication of information across the hemispheres
Occipital Lobe
-processes visual information
-receptors in eyes to thalamus to occipital lobe, processed in occipital cortex
Parietal Lobe
-processes information about touch
-in front of occipital lobe
-contains somatosensory cortex
Somatosensory Cortex
-skin areas on the contralateral surface of the body
-body areas that are more sensitive have a larger part of the somatosensory cortex devoted to them
-part of parietal lobe
Motor Cortex
-in front of somatosensory cortex
-corresponds to different body parts
-initiates voluntary movements and sends messages to the basal ganglia, cerebellum, and spinal cord
-part of parietal lobe
Temporal Lobe
-responsible for hearing and language
-lower right side of each hemisphere
-receives information through primary auditory cortex
-secondary units process information
Frontal Lobe
-specialized areas for movement, abstract thinking, planning, memory, anticipation, and judgement
-contains motor cortex
-manipulation of thought
Association Areas
-composed of neurons that help provide sense and meaning to information registered in the cortex
-interprets information gathered from highly specialized neurons in the cortex
-less specialized neurons, more flexible
Plasticity
-adaptability of sensory cortices
-sensory cortices are not fixed, adaptable to changes in sensory inputs
-functions that were assigned to certain areas of the brain may be capable of being reassigned to other areas of the brain to accommodate changing in
Wernicke's Area
-speech and language comprehension
-left hemisphere
Broca's area
involved in speech production
-left hemisphere
Mirror Neurons
-neurons which are activated by performing an action or by seeing another perform the same action
-may play a role in developing new motor skills
-empathy and language
-dysfunction linked to autistic spectrum disorders
Hormones
-manufactured in endocrine system and released into blood stream
-some hormones may be classified as neurotransmitters depending on how it is "operationalized"
-melatonin: regulates biological rhythm
-adrenal hormones: involved in emotions and stress
Lesion Method
damage or remove section of the brain and observe the effects
Computerized Axial Tomography Scan (CT)
-x-images the brain to show tissue density
-used to locate tumors and fissures
Positron Emission Tomography Scan (PET)
-harmless radioactive substance is injected into bloodstream
-brain is scanned by radiation detectors to see changes in blood flow through the brain
Functional Magnetic Resonance Imaging (fMRI)
-provides structural and functional view of the brain
-detects twisting of hemoglobin molecules in the blood as they are exposed to magnetic pulses
-oxygenated hemoglobin concentrates in the active areas of the brain
Electroencephalograph (EEG)
-device used to record electrical activity in the brain
-used in testing function for different levels of consciousness and different tasks
Magnetic Resonance Imagining (MRI)
-provides structural view of the brain
-applies brief but powerful magnetic pulses to the head to record how these pulses are absorbed through the brain
Area V1
part of the occipital love that contains the primary visual cortex
Functional Pathways from Occipital Cortex (2)
-ventral "above stream" (what is it?)
-dorsal "below stream" (where is it?)
Area A1
portion of the temporal lobe that contains the primary auditory cortex
Olfactory Receptor Neurons (ORNs)
receptor cells that initiate the sense of smell
Olfactory Bulb
-brain structure located above the nasal cavity beneath the frontal lobes
-vast number of ORN types to distinguish between odorants
Pheromones
-biochemical odorants emitted by other members of the species that can affect the animal's behavior or physiology
-reproductive, relationship roles
-related to sexual orientation