Neuroscience QUIZ Flashcards
- What are the parts of the neuron? Where are they located on a neuron? What do they do?
-Dendrites: receive chemical neurotransmitters
-Soma (cell body)
–>nucleus: DNA genetic material of the cell
-Axon-Hillock: where soma meets axon; is where action potential begins
-Axon: Signal is now called action potential (electrical); carries electrical current to terminals
–>Myelin Sheath: an insulator material that helps to prevent the signal from degrading
–>Nodes of Ranvier: areas of the axon that are exposed between gaps in the myelin; allow the electrical signal traveling down the axon to refresh its strength and carry on to the end of the axon
-Telodendria: Are the end branches of an axon
-Axon Terminals (Synaptic Buttons): releases neurotransmitters
Sensory Neurons: carry info from the sensory receptors in or on the body to the spinal cord
Interneurons (association neurons): Include associate sensory and motor activity withing the CNS
Motor Neurons: Send signals from the brain and spinal cord to muscles
- The roles of the primary neurotransmitters discussed in class (e.g., What would happen if we had too much of one? Too little?)
Neurotransmitter: Chemical released by a neuron onto a target with an EXCITATORY or INHIBITORY effect
-Outside the CNS = Hormone
Acetylcholine (ACh): Activates skeletal muscles in the somatic nervous system (SNS) and may excite or inhibit internal organs in the autonomic nervous system (ANS)
Epinephrine (EP) (Adrenaline): A chemical messenger that acts as a hormone to mobilize the body for fight or flight during times of stress and as a neurotransmitter in the CNS
Norepinephrine (NE) (Noradrenaline): Neurotransmitter foud in the brain and the parasympathetic division of the autonomic nervous system; accelerates heart rate in mammals.
–Decreased NE activity is associated with both hyperactivity and attention-deficit/hyperactivity disorder (ADHD)
Dopamine (DA): Release causes repetition of behaviors, thought to be the neurotransmitter system most affected by addictive drugs and behavioral addictions
–Loss of DA is related to muscle rigidity and dyskinesia in Parkinson’s disease
–Increase in DA may be related to schizophrenia
Serotonin: (an amine transmitter) Plays a role in regulating mood and aggression, appetite and arousal, respiration, and pain perception
Glutamate (Glu): Amino acid neurotransmitter; typically opens Na+ and Ca 2+ channels and therefore EXCITES neurons
Gamma-aminobutyric acid (GABA): Amino acid neurotransmitter; typically opens Cl- channels and therefore INHIBITS neurons.
- What is an action potential? How is it propagated? Where is it propagated? How do axon diameter and myelination affect conduction speed?
Action Potential: The graded potentials (EPSPs and IPSPs); dendrite and cell body are spatially and temporally summed together.
–If their summed voltage at the initial segment surpasses the threshold, and action potential is generated
–It then propagates down the length of the axon.
- What is a membrane potential? How is it maintained?
Membrane Potential: This is the difference in electrical charge between the inside and outside of a neuron.
–Plasma Membrane: It separates the inside of the cell from the outside environment
–Ions: Are atoms that have either lost or gained electrons and thus have a positive or negative charge
One way it is maintained is: Na-K pump
–Sodium-Potassium Pump: This is a transport
protein that uses energy to constantly pump
three sodium ions (3 Na) out of the cell while
pumping two potassium ions (2 K+) into the
cell
——-> Because there are more positive ions being pumped out than in, it helps keep the membrane potential negative
–Resting Potential: Electrical charge across
the cell membrane in the absence of
stimulation
-The inside of the membrane at rest is -70mV
relative to the extracellular side
-A store of negative energy in the
intracellular side relative to the extracellular
side
-Three features contribute to the cell membrane’s resting charge:
1. Because the membrane is relatively impermeable to large molecules, the negatively charged proteins remain inside the cell.
- Ungated potassium and chloride channels allow potassium and chloride ions to pass freely, but gates on sodium channels keep out positively charged sodium ions.
- Na+–K+ pumps extrude Na+ from the intracellular fluid and inject K+.
- What are depolarization and hyperpolarization? Which ions are generally responsible for these? How are these related to the terms EPSP and IPSP?
Depolarization: Decrease in electrical charge across a membrane (more POSITIVE)
-Usually due to INWARD flow
Hyperpolarization: Increase in electrical charge across a membrane (more NEGATIVE)
-Usually due to the inward flow of CHLORIDE IONS or outward flow of POTASSIUM IONS of SODIUM
Ions responsible:
1. Potassium (K+): . For the membrane to become hyperpolarized, its extracellular side must become more positive, which can be accomplished with an outward movement, or efflux, of potassium ions.
–But if potassium channels are ordinarily
open, how can the efflux of potassium ions
increase? Apparently, even though
potassium channels are open, some
resistance to the outward flow of potassium
ions remains. Reducing this resistance
enables hyperpolarization.
- Chloride (CI−): Even though chloride ions can pass through the membrane, more ions remain on the outside than on the inside, so an influx of chloride ions due to decreased resistance to Cl− flow can result in brief increases of Cl− inside the cell.
–Because the Nernst potential for Cl− is 64
mV and near the resting membrane
potential, increased Cl− conductance has the
effect of stabilizing (or “clamping”) the
membrane voltage, effectively preventing
large depolarizations.
Sodium (Na+): Depolarization can be produced if normally closed sodium channel gates open to allow an influx of sodium ions.
EPSP: Excitatory Postsynaptic Potential
–Brief DEPOLARIZATION of a neuron
membrane in response to stimulation
–Depolarized neurons are more likely to
produce an action potential
–Associated with the opening of sodium
channels; allows influx of Na+
IPSP: Inhibitory Postsynaptic Potential
–Brief HYPERPOLARIZATION of a neuron
membrane in response to stimulation
–Hyperpolarized neurons are less likely to
produce an action potential
–Associated with the opening of potassium
channels (allows an efflux of K+) or with the
opening of chloride channels (allows an
influx of Cl-)
- What does the term “lateralized” mean? Which functions within the brain may often be lateralized?
Process whereby functions become localized primarily on one side of the brain
-Analysis of speech takes place largely in the
left hemisphere.
-Analysis of musical sounds takes place
largely in the right hemisphere.
- Know the roles of the specific parts of the brain discussed in class (ex: hypothalamus, thalamus, amygdala, medulla, cerebellum, prefrontal cortex, orbitofrontal cortex, insular cortex, Wernicke’s area, Broca’s area, Heschel’s gyrus, hippocampus, PAG, etc.)
Spinal Cord: Controls most body movements
-can act independently of the brain
Brainstem: Begins where spinal cord enters the skull
-Receives AFFERENT nerves coming from
senses and sends EFFERENT nerves out to
control movements
-Is responsible for most-life sustaining
behavior
-Structures:
—>Hindbrain: Is evolutionary the oldest part
of the brain
-Controls various motor functions ranging
from breathing to balance to fine
movements
—>Midbrain: Structures here are critical for
producing orienting movements, species-
specific behaviors, and pain perception
—>Diencephalon: The between brain, which
integrates sensory and motor information
on its way to the cerebral cortex; two
principal parts are the hypothalamus and
thalamus
-Hypothalamus: Diencephalon structure that contains many nuclei associated with temperature regulation, eating, drinking, and sexual behavior -Thalamus: Diencephalon structure through which information from all sensory systems is organized, integrated, and projected into the appropriate region of the neocortex
—>Cerebellum:
Forebrain: The major internal and external forebrain structures integrate sensation, motivation, emotion, and memory to enable such advanced cognitive functions as thinking, planning, and using language.
-Structures:
—>Neocortex (cerebral cortex): Regulates various mental activities
—>Basal Ganglia: Control of voluntary movement
—>Limbic System: Regulates emotions and behaviors that store and require memory
—>Neocortext (“New bark”):
-Six layers of gray matter
-Constructs and responds to a perceptual world
—>Allocortex:
-Evolutionarily older
-Three or four layers of gray matter
-Controls motivational states
-Include the hippocampus, part of the amygdala, the cingulate cortex, several structures that make up the olfactory system, and other related areas:
- Amygdala: Anxiety and fear
- Cingulate cortex: Emotion formation and processing, learning, memory, linking behavior to motivation
- Olfactory system: Olfactory bulbs and receptors, pyriform cortex in front of brain, vomeronasal organ (VNO)
- Limbic system: Disagreement about structure; obsolete
PAG: (Periaqueductal Gray): Electrical stimulation of the PAG suppresses pain
-PAG neurons project to the spinal cord where they inhibit pain pathway neurons
Wernicke’s Area: Cotex of the LEFT planum forms a speech zone (contains sound images of words) (comprehension of speech)
Broca’s Area: Anterior speech area in the LEFT hemisphere that functions with the motor cortex to produce the movements needed for speaking (production of speech)
Heschl’s Gyrus: Cortex of the larger right hemisphere has a special role in analyzing music.
Orbitofrontal Cortex: Important region of the brain involved in the processing of rewards and punishments.
-It receives and integrates inputs from all the
sensory modalities: taste, smell,
somatosensory, auditory and visual, as well
as visceral sensory and visceral motor
information.
Insular Cortex: A portion of the cerebral cortex located deep within the lateral sulcus in each hemisphere of the mammalian brain. -It is believed to be involved in consciousness,
emotion, and the regulation of the body’s
homeostasis
- What are the divisions of the nervous system and their roles?
Nervous System
1. Central Nervous System (CNS): Mediates behavior
-Brain
-Spinal Cord
2. Peripheral Nervous System (PNS):
-Somatic Nervous System: Transmits sensation, produces movement
–Cranial nerves
–Spinal nerves
-Autonomic Nervous System: Blanaces internal function
–Sympathetic Division: Arousing
–Parasympathetic Division: Calming
-Enteric Nervous System: Controls the gut
- What are the 4 lobes of the brain? What are the primary functions found within each of the lobes?
Cerebral Cortex:
Frontal (executive function)
Parietal (sensory integration)
Temporal (auditory, taste, smell, memory)
Occipital (visual)
- What do the terms “afferent” and “efferent” mean? How do these terms relate to the Bell-Magendie Law?
Afferent (Arriving): Info comes INTO CNS
Efferent (Exiting): Info LEAVES the CNS
Bell-Magendie Law: Afferean neurons enter the spinal cord dorsal (from the back) whereas efferent neurons issue from the spinal cord ventrally (from the front)
