Chapter 34: Neurons and Nervous Systems Flashcards
neurons
nerve cells
glia
glial cells
cell body [of a neuron]
the nucleus and most organelles
where the typical cell ish stuff is found
dendrites
likes tree branches
trees
bring info from other sources to the cell body, like the branches bring the products of photosynthesis to the trunk [but not really]
excitable
neurons create and send electrical signals, which makes them excitable
T or F: Neurons are excitable
true
axon
a tail like projection that can be freakishly long, like almost as long as you are tall long.
telephone lines of the nervous systems
generate the action potentials, which will travel down the axon
nerve
a bundle of axons that come from tons of neurons
axon terminal
a bump like thing at the end of the axon that is super duper close to the target cell, forming a synapse
synapse
tiny gap across which two neurons communicate, either electrically or chemically [neurotransmitters]
presynaptic neuron
neuron that sends the signal
postsynaptic neuron
neuron that receives the signal
Astrocytes
Glia that surround the smallest, most permeable blood vessels that help prevent toxic chemicals from entering
Neuroplasticity
Synapse modification
Glia play a role in that
Glia
Don’t generate action potentials
Can release neurotransmitters
Support developing neurons during embryonic development
Maintain extra cellular environment and provide energy substrates
Assist in neuronal repair
Blood-brain barrier
Prevents toxic chemicals and ether soluble/large molecules from reaching the brain
Microglia
Provide the brain with immune with defenses
Act as macrophages and mediators of immune responses
Oligodendrocytes
Glia in brain and spinal cord
Their membranes insulate axons
Schwann cells
A type of glia
Insulate axons outside the brain and spinal cord with their membranes
Myelin
A lipid rich no conductive sheath formed by the multilayered wrap of glial membranes
White matter
Parts of the nervous system consisting of misty myelinated axons
Gray matter
Areas of the nervous system that are rich in cell bodies
Multiple sclerosis
Demyelinating disease
Autoimmune disease in which antibodies attack proteins in the myelin
Neural networks
Information processing systems that neurons are organized into
Afferent neurons
Carry sensory info to nervous system
Sensory cells
Convert sensory stimuli into action potentials
Efferent neurons
Carry command to physiological and behavioral effectors like muscles and glands
Motor neurons
Type of effector neuron that carry commands to muscles
Interneurons
Integrate and store information and communicate between afferent and efferent
Ganglia
Clusters of neurons
Membrane potential
The difference in electrical potential across plasma membranes
Action potentials
Nerve impulses
large, sudden, and transient changes in membrane potential that travel alone axons and prompt the release of chemical signals at the axon terminals
Voltage
a measure of the difference in electrical charge between two points
potential energy
opposite charges will move together if given a chance
Is this an example of voltage difference?
Negative and positive poles of a battery are connected by a wire and an electric current flows through them [because of the possible voltage difference]
Yes
Membrane potential
a voltage across the cell membrane, caused by differing concentrations of ions on the outside and inside of the cell
Resting Potential
the membrane potential in an inactive neuron
What is the typical resting potential in a cell?
between -60 and -70 millivolts
True or false: The inside of the cell is electrically negative compared with the outside
True
True or False: Action Potential causes the inside of the cell to become more positive
True
sodium-potassium pump
aka sodium-potassium ATPase
Sends Na+ out of the cell because it has no need for excessive amounts of positivity and brings in smaller amounts of K+
True or False: K+ and Na+ are the predominant ions in the extracellular fluid
false: Na+ and Cl- are the predominant ions in the extracellular fluid, K+ is more prevalent inside of the cell
If Na+ could follow its concentration gradient, it would move __________ of the cell?
inside, K+ would leave
True or false: concentration gradients generate resting potential
true
True or false: concentration gradients can change resting potential
true
Would you notice a voltage difference between electrodes placed in two places outside of a resting neuron?
nope, the difference lies between outside and inside of the cell
What is the voltage difference between the outside and inside of neurons caused by?
leak currents
Leak currents
occur because there are open channels which embrace the spirit of heyyyy let’s be inclusive and let everyone in/out you do you ion
K+ leakage
one of the leakiest
K+ diffuses outside of the membrane until the negative charge of the cell pulls it back
Electrochemical gradient
combination of the concentration gradient of the ion and the overall electric gradient of the cell
Equilibrium potential
of ions
no net movement
ex. K+ with an electrochemical gradient of 0 in a neuron
Voltage-gated channels
open or close in response to local changes in voltage across membrane
Chemically gated channels
open or close in response to certain molecules
Mechanically gated channels
open or close based on the mechanical force applied to the cell membrane
depolarized
ex. when neuron becomes more positive due to the influx of sodium ions
hyperpoalrized
neuron becomes more negative due to the influx of potassium ions
graded membrane potentials
small, local changes in membrane potential that vary in magnitude
integrate inputs in a cell
look at sum of all of the depolarizing and hyper polarizing
spreads quickly but decays as it spreads like water through leaky hose
True or False: graded membrane potentials can carry a signal all the way down an axon
false, only action potentials do this
axon hillock
region of the cell body at the base of the axon
high concentration of Na+ gates
must let in enough Na+ in order to reach the threshold for the neuron to fire
refractory period
Na+ gated channels can not open again
prevent signal form going backwards
all-or-nothing
DESCRIBES ACTION POTENTIALS oops caps lock
either firing or isn’t, no different rates
Why all-or-nothing?
positive feedback loop for Na+ gated channels
`self-regenerating
spread by local current to neighbors
describe axon potentials
all-or-nothing self-regenerating
True or False: Action potentials travel along all axons at the same speed
False
True or False: Action potentials fire faster with long diameter
true
myelination
glia wrap themselves around axons
nodes of Ranvier
unmyelinated gaps
saltatory conduction
action potentials jump from node to node
chemical synapse
most common type
neurotransmitters are released from presynaptic cell and bind to receptors in postsynaptic cell, causing a change
Synaptic Cleft
space between presynaptic and postsynaptic cell
Electrical Synapses
join cytoplasms of pre and post synaptic cells through GAP Junctions
Gap Junctions
made up of proteins that create channels
ions flow through these allowing a passive spread of action potential
Pro: fast transmission
Con: don’t allow for complicated integration from many different sources
connexins
proteins that make up gap junctions
neuromuscular junctions
synapses between motor neurons and skeletal muscles
bouton
end of axon terminal that contains vesicles full of neurotransmitters
ACh
neurotransmitter used by vertebrate neuromuscular synapses
Which voltage gate opens first at neuromuscular junctions?
Ca2+, the ion flows into the axon terminal where it causes ACh vesicles to fuse with the presynaptic membrane
motor end plate
depression formed by the postsynaptic membrane of a neuromuscular junction, when ACh binds to this, Na+ and K+ flow through, making inside more positive and causing depolarization
excitatory
causes depolarization
inhibitory
causes hyperpolarization
Summation
integrating the influences of many different inputs
Spatial Summation
Adds up the simultaneous influences of synapses at different sites on a cell
Temporal Summation
adds up potentials generated at the same site in a rapid sequence
How can neurotransmitter action be terminated?
Enzymes destroy it
diffuse away
get taken up by cell membranes
True or false: Every neurotransmitter can have multiple receptor sites
True
ex. ACh has nicotinic receptors and muscarinic receptors
Muscarinic receptors
ACh, tend to be inhibitory
Nicotinic receptors
ACh, tend to be excitatory
Where do neurotransmitters come from?
cell body
Ionotropic Receptors
Ion channels
quick, short-lived responses
Metabotropic Receptors
Not ion channels, cause signaling cascades
slower and longer lived
Central Nervous System (CNS)
brain and spinal cord
Peripheral Nervous System (PNS)
neurons not in brain and spinal cord
Autonomic Nervous System (ANS)
output of CNS that control involuntary function
ex. heartbeat, sweat
Sympathetic Division
Part of ANS
fight or flight
Parasympathetic Division
part of ANS
rest and digest
parachute
Preganglionic Neuron
cell body in CNS that begins autonomic pathways
Nonadrenergic Neurons
release norepinephrine
sympathetic
Cholinergic Neurons
release acetylcholine
Parasympathetic
Pacemaker
part of heart that generates beat
receives input from both para and symp
they produce opp effects
Gray Matter
Rich in cell bodies
White Matter
rich in myelinated axons
spinal reflexes
information doesn’t go to the brain, spinal cord just gives a simple reaction
monosynaptic reflexes
involve two neurons and one synapse
ex. knee jerk reaction
simplest of spinal reflexes
Antagonistic pairs of muscles
Flexors and extensors
Brainstem
pons, medulla, and midbrain
reticular system
network of brainstem neurons
diencephalon
central region of the brain
thalamus and hypothalamus— maintains homeostasis
telencephalon
Surrounds diencephalon
limbic system
limbic system
instinctive reactions
pleasure, pain, fear, emotion, memory
Amygdala
Emotion
fear and fear memories
Hippocampus
memory
Cerebrum
outer part of telencephalon
Muscle spindles
Modified muscle fibers in the quadriceps that form stretch receptors that are inner cared by the neuron
Cerebrum
Dominant part of mammalian brain
Two hemispheres
Left and right cerebral hemispheres
Make up cerebrum
Cover outer parts of brain with the exception of cerebellum
Cerebral cortex
Outermost layer of cerebral cortex
Convolutions
Ridges that the cerebral cortex is folded into to maximize surface area
Association cortex
Areas of the cerebral cortex that are involved in higher order information processing
Hard to define specific function because responsible for integration of information from many different senses and memory
Temporal lobe
Processes auditory info
Also visual processing
Association areas recognize, identify, and name objects
Agnosias
Disorders caused by damage to the temporal love
Aware of object but can’t identify
Frontal lobe
Association areas involved with feeling and planning contribute to personality
Primary motor cortex
In frontal lobe
Neurons in this region control muscles in specific parts of the body
Parietal lobe
Association area attends to complex stimuli
Visual info to 3D
Primary somatosensory cortex
In parietal lobe
Receives touch and pressure information
Occipital lobe
Receives and processes visual info
Association areas make sense of visual world and translate visuals into language
Ex. Woman with damage can’t see motion, just still images
Lateralization
Occurs mainly in one half of the brain
Ex. Language
T or F: language abilities are localized in the left hemisphere
True
Aphasia
Deficit in ability to use or understand words
Often from damage to left hemisphere
Broca’s area
In frontal lobe
A language area
Essential for PRODUCTION of language
Patients with damage to this area can still understand speech
Wernicke’s area
Located in temporal lobe
A language area
Essential to UNDERSTANDING language
Patients with damage to this area can produce fluent sounding gibberish
Learning
Modification of behavior by experience
Memory
Ability of nervous system to retain what it has learned and experienced
Long-term potentiation (LTP)
High frequency electrical stimulation is neuronal circuits makes them
More sensitive to later stimulation
Associative learning
Two unrelated stimuli linked to same response
Conditioned reflex
Example of associative learning
Pavlov
Ex. Dog salivation experiment
Observational learning
More complex
Watch another person exhibit behavior
Form and store a memory of that
Copy/use info
Declarative memory
I know that….
Memory of events/facts:people
Conscious recall and description
Procedural memory
Perform a task
Ride a bike
Immediate memory
RIGHT NOW almost photographic but lasts about 2 seconds
Short-term memory
Not as much info as immediate, but longer lasting
Long-term memory
Lasts the longest amount of time
True or False: sleepwalking occurs during REM sleep
False
true or false: the body is paralyzed during REM sleep
True
REM sleep
Stands for rapid eye movement
Body is paralyzed
Vivid dreams
Brain activity most similar to an awake brain
Non-REM sleep
Stages 1-4 of sleep
Majority of sleep is non REM (in adults)
Insular cortex (insula)
Part of forebrain
Integrates info from all over the body to create a sensation of how the body feels
Muscle spindles
Modified muscle fibers in the quadriceps that form stretch receptors that are inner cared by the neuron
Cerebrum
Dominant part of mammalian brain
Two hemispheres
Left and right cerebral hemispheres
Make up cerebrum
Cover outer parts of brain with the exception of cerebellum
Cerebral cortex
Outermost layer of cerebral cortex
Convolutions
Ridges that the cerebral cortex is folded into to maximize surface area
Association cortex
Areas of the cerebral cortex that are involved in higher order information processing
Hard to define specific function because responsible for integration of information from many different senses and memory
Temporal lobe
Processes auditory info
Also visual processing
Association areas recognize, identify, and name objects
Agnosias
Disorders caused by damage to the temporal love
Aware of object but can’t identify
Frontal lobe
Association areas involved with feeling and planning contribute to personality
Primary motor cortex
In frontal lobe
Neurons in this region control muscles in specific parts of the body
Parietal lobe
Association area attends to complex stimuli
Visual info to 3D
Primary somatosensory cortex
In parietal lobe
Receives touch and pressure information
Occipital lobe
Receives and processes visual info
Association areas make sense of visual world and translate visuals into language
Ex. Woman with damage can’t see motion, just still images
Lateralization
Occurs mainly in one half of the brain
Ex. Language
T or F: language abilities are localized in the left hemisphere
True
Aphasia
Deficit in ability to use or understand words
Often from damage to left hemisphere
Broca’s area
In frontal lobe
A language area
Essential for PRODUCTION of language
Patients with damage to this area can still understand speech
Wernicke’s area
Located in temporal lobe
A language area
Essential to UNDERSTANDING language
Patients with damage to this area can produce fluent sounding gibberish
Learning
Modification of behavior by experience
Memory
Ability of nervous system to retain what it has learned and experienced
Long-term potentiation (LTP)
High frequency electrical stimulation is neuronal circuits makes them
More sensitive to later stimulation
Associative learning
Two unrelated stimuli linked to same response
Conditioned reflex
Example of associative learning
Pavlov
Ex. Dog salivation experiment
Observational learning
More complex
Watch another person exhibit behavior
Form and store a memory of that
Copy/use info
Declarative memory
I know that….
Memory of events/facts:people
Conscious recall and description
Procedural memory
Perform a task
Ride a bike
Immediate memory
RIGHT NOW almost photographic but lasts about 2 seconds
Short-term memory
Not as much info as immediate, but longer lasting
Long-term memory
Lasts the longest amount of time
True or False: sleepwalking occurs during REM sleep
False
true or false: the body is paralyzed during REM sleep
True
REM sleep
Stands for rapid eye movement
Body is paralyzed
Vivid dreams
Brain activity most similar to an awake brain
Non-REM sleep
Stages 1-4 of sleep
Majority of sleep is non REM (in adults)
Insular cortex (insula)
Part of forebrain
Integrates info from all over the body to create a sensation of how the body feels
