Chapter 3 Flashcards
What are neurons?
building blocks of the nervous system
nerve cells specialized for communication
100 billion at birth
make connections with other neurons
What are glial cells?
supporting neurons (keeping them in place)
manufacture or transport nutrients
form the myelin sheath
absorb toxins and waste materials
protects the brain from toxins via blood-barrier
during development, glial cells guide neurons to their proper place in the brain
modulating communication between neurons
What is the resting neuron?
neurons communicate through changes in charge between the interior and exterior of the axon
membrane potential difference when resting is -70 mV
membrane is semi-permeable
What happens when a neuron is “in action”?
action potential: a sudden reversal in the neuron’s membrane voltage, the shift from an negative interior to a positive interior is depolarization
all-or-none, always the same strength, uniform
originates near cell body, moves along axon to terminal
What happens after the action potential in a neuron?
absolute refractory period: brief interval when a neuron cannot fire another AP
occurs after each AP
the neuron needs to reset
What are the steps of an action potential?
- Resting
- Sodium channels open and sodium rushes in
- Sodium channels snap shut and potassium channels open to let potassium out
- Sodium-potassium pump return everything back to normal (3 Na+ for 2 K+)
What are graded potentials?
caused by excitatory/inhibitory postsynaptic potentials (EPSP/IPSP)
sum u to cause an action potential or not
depends on the charge entering the cell
can bring the cell closer (EPSP) or further (IPSP) from the threshold to fire an action potential
What is myelin?
glial cells insulate axons to increase the speed of signal transmission, along with efficiency
insulates axons in CNS
nodes of ranvier allow AP to jump which increases speed
What are neurotransmitters?
chemicals that carry messages across the synapse
What are the steps that neurotransmitters go through in the synapse?
- NT are synthesized
- NT are stored into vesicles
- NT released into the synapse
- NT bind to receptor sites on dendrite of post synaptic cell, location that uniquely recognizes the NT
- Removal of NT from the synapse
What is the function of the neurotransmitter glutamate?
excitatory
many functions including learning/memory
What is the function of the neurotransmitter GABA?
inhibitory
many functions including anxiety/motor control
What is the function of the neurotransmitter acetylcholine?
excitatory
muscular movement and memory
What is the function of the neurotransmitter norepinephrine?
both excitatory and inhibitory
learning, memory, wakefulness, eating
What is the function of the neurotransmitter serotonin?
inhibitory
mood, sleep, eating/arousal
What is the function of the neurotransmitter dopamine?
both excitatory and inhibitory
voluntary movement, emotional arousal, learning, motivation, pleasure
What is the function of the neurotransmitter endorphin?
inhibitory
numbs pain
What are agonists?
enhance neuron’s ability to synthesize, store, or release NT
mimic the action of a NT (bind to receptor site)
inhibits reuptake
What are antagonists?
reduce neuron’ ability to synthesize, store or release NT
prevent NT from binding to receptor site by blocking it
What are sensory neurons?
carry messages from sense to spinal cord and brain
What are motor neurons?
transmits output impulses from the brain and spinal cord to muscles/organs
What are interneurons?
link the input and output functions
What is the peripheral nervous system?
nerves that extend outside the central nervous system
contains the somatic nervous system
What is the somatic nervous system?
sensory and motor neurons
voluntary muscle activation
What is the autonomic nervous system?
controls glands and smooth muscles that form the heart, blood vessels, and stomach/intestine lining
What is the sympathetic nervous system?
activation/arousal function
fight or flight
affects multiple organs
What is the parasympathetic nervous system?
slows body processes
What is the central nervous system?
body to brain (sensory nerves)
brain to body (motor nerves)
interneurons (local, role in reflexes)
What are the steps of the reflex arc?
- Skin receptors
- Sensory neurons
- Interneuron
- Motor neurons
- Muscle
What is the hindbrain?
contains the brain stem, medulla oblongata, pons, and cerebellum
What is the medulla oblongata?
heart rate, respiration, etc (vital functions)
all sensory and motor neurons pass through here
What is the pons?
bridge between higher and lower levels of nervous system
regulate sleep, involved in dreaming
What is the cerebellum?
muscular movement coordination (balance)
learning and memory
What is the midbrain?
sensory portion: relay centers for visual/auditory systems
motor portion: controls eye movements
reticular formation: alerts higher brain areas of messages, then blocks or allows them to pass
What is the forebrain?
aka the cerebrum
2 hemispheres (left and right)
contains the thalamus, basal ganglia, hypothalamus, limbic system
What is the thalamus?
many nuclei
sensory processing/relay station
visual, auditory, balance/equilibrium pass through thalamus
also filters information
What is the basal ganglia?
surrounds the thalamus
at least five distinct nuclei
voluntary motor control
damage = parkinson’s disease
What is the hypothalamus?
regulates/maintains internal states
controls many basic biological drives
connection to endocrine system, controls hormone secretions
What is the limbic system?
coordinates behaviors to satisfy motivational/emotional urges from hypothalamus
involved in memory
What is the hippocampus?
part of the limbic system
forming and retrieving memories
What is the amygdala?
emotion response patterns
fear/aggression
may help avoidance of risky decisions
What are the lobes of the brain?
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe
What is the function of the frontal lobe?
speech and skeletal motor functions
What is the function of the parietal lobe?
body sensations
What is the function of the occipital lobe?
vision
What is the function of the temporal lobe?
auditory
What is the motor cortex?
controls 600+ muscles used in voluntary movements
left hemisphere controls right and vice versa
more cortical space for areas with finer motor control
Dr. Penfield was the first to investigate this area
What is the sensory cortex?
receives sensory input that gives sensations of heat, touch, cold, balance, kinesthesis
left hemisphere controls right and vice versa
What is the Broca’s Area?
speech production
ability to produce words
if damaged: slowed speech, key words only, trouble finding correct word
What is the Wernicke’s Area?
speech comprehension
producing speech that makes sense
if damaged: meaning impaired, difficulty understanding written or spoken speech
What is the association cortex?
critically involved in highest level of metal functions
if damaged: disruption/loss of speech, understanding, thinking, and problem solving
What is the prefrontal cortex?
executive functions: goal setting, judgement, strategic planning, impulse control
serial killers = reduced activity
What are some ways we have an insight into brain function?
patients with brain damage
electrical stimulation/recording
neuroimaging
What is a Computerized Axial Tomography (CT) scan?
uses highly focused beam of X-rays to take pictures of narrow slices of the brain
provides structural details
yields insights between location of brain damage and behavioral manifestation
What is Magnetic Resonance Imaging (MRI)?
structural imaging
makes out details 1/10th of those CT can resolve
images are created based on how atoms in brain respond to magnetic pulses
What is a Functional MRI (fMRI)?
functional imaging
measures changes in blood oxygen level
measuring oxygen flow should indicate where in the brain activity is occurring
high spatial resolution
poorer temporal resolution (4-6 second delay)
sensitive to head motion
What is a Positron Emission Tomography (PET)?
functional imaging
measures changes in brain activity (metabolism, blood flow, neurotransmitter activity)
measures consumption of glucose-like molecules
radioactive glucose injected into bloodstream, travels to brain, measure the radioactivity
What is hemispheric lateralization?
two hemispheres of the brain are connected by the corpus callosum
lateralization: some functions are localized to one hemisphere
left: language (Broca’s and Werniche’s areas)
right: spatial relations
What is neural plasticity?
the ability of neurons to change in structure and function
