BP Test 1
Changing a single amino acid in a protein can affect: Secondary Structure Tertiary Structure Quaternary Structure All of the above
All the above
Aristotle
Aristotle believed that the heart was the seat of cognitive function- brain functioned more like a radiator (due to the fluid-filled ventricles they observed) - 350 BCE
Nodes of Ranvier are: A. The connection between an axon and a dendrite B. Where the cell body joins the axon C. The region where action potential firing is decided D. Gaps between myelin sheaths, that contain voltage-gated sodium channels E. Areas of voltage-gated sodium channel localization following demyelination
D. Gaps between myelin sheaths, that contain voltage-gated sodium channels
Which equation most precisely describes the ion concentration gradients set up by the Na+/K+ pumps in neuronal membranes A Vm = EK B ENa > 0 > EK C ENa = 61.5 x log([Na+]OUT/Na+]IN) D INa = Vm x gNa
ENa > 0 > EK
Nernst Equation
Ek = (61.5mV) log (10) [K]out/[K]in
The Nernst equation predicts the voltage that develops when a semipermeable membrane separates different concentrations of ions. The measured value of the resting membrane potential varies slightly from the predicted value of EK because of ___ the cell. A Entry of Na+ into the cell B Leakage of Na+ out of the cell C Entry of K+ into the cell D Entry of Ca2+ into the cell
Entry of Na+ into the cell
A given neurotransmitter can be either inhibitory or excitatory, depending on the receptors expressed by the post-synaptic cell. TRUE FALSE
True
Cranial Trephination
brain surgery performed ritualistically and with simple implements (early as 6,500 BCE and as late as 18th Century)
membrane capacitance
charge required to activate the AP
Hebb's postulate
coordinated activity of presynaptic and postsynaptic neuron strengthens the synapse
Myelination results in such membrane properties
increased mebrane resistance decreaded membrane capacitance
internal resistance
stuff inside the cell
Neuron Theory
-Stated That: •The nervous system is cellular, each cell has a nucleus and is surrounded by it's own membrane -Neurons are clearly seen to develop as individual cells during embryonic development -Small lesions in the nervous system causes localized degeneration as if parts of cells have been damaged.
Ca2+ influx through NMDA increases AMPA receptor currents in two ways:
1. Maximization of existing AMPA-Rs 2. New AMPA-Rs inserted into postsynaptic membrane
Cell Theory
1838: Cell Theory -Proposed by Matthias Schleiden and Theodor Schwann -States that: •All life forms are made from one or more cells. •Cells only arise from pre-existing cells. •The cell is the smallest form of life.
Reticular Theory
1880's: Reticular Theory -Proposed by Camillo Golgi -Stated that: •The nervous system is a syncytium: a network of living material having multiple nuclei and cytoplasmic
Golgi Staining
1900's: Neuron Theory -Santiago Ramón y Cajal used a staining technique developed by Camillo Golgi to visualize neurons. •Silver nitrate stain, only affects 5% of cells
How do we study nervous systems??
3 Types of Analysis: Genetic # Genes Generation time # neurons Structural Lesion Studies Brain Mapping Functional Functional Brain Imaging Electrophysiological recordings: monitor the electrical properties of a neuron or groups of neurons Live animal
Multiple sclerosis can cause all of the following EXCEPT: A. Death of Schwann cells by excitotoxicity B. Breakage of the blood brain barrier C. Loss of saltatory conduction D. Lesions in the brain and spinal cord E. Visual impairments
A. Death of Schwann cells by excitotoxicity
Inactivation of voltage-gated sodium channels is critical because: A. It interrupts the rising phase of the action potential, allowing the membrane potential to return to rest. B. It prevents the propagation of the action potential back toward the cell body. C. It triggers the influx of K+ channels which repolarize the membrane. D. Both (B) and (C) E. Both (A) and (B) F. None of the above is due to the inactivation of voltage-gated Na+ channels
A. It interrupts the rising phase of the action potential, allowing the membrane potential to return to rest. B. It prevents the propagation of the action potential back toward the cell body.
Digoxin is a neurotoxin found in the foxglove plant. Digoxin disrupts the function of the Na+/K+ ATPase (sodium/potassium pump), such that it causes an increase in the intracellular concentration of Na+. What would you expect to happen to the resting membrane potential of neurons in an individual who has been exposed to digoxin? A. The resting membrane potential would become more depolarized (i.e. more positive) B. The resting membrane potential would be unaffected C. The resting membrane potential would become more hyperpolarized (i.e. more negative) D. You cannot predict changes in the resting membrane potential from the information given
A. The resting membrane potential would become more depolarized (i.e. more positive)
Which of the following are factors that influence the speed of action potential propagation? Select all that apply to receive credit. A. The size of the axon B. The number of dendrites on a neuron C. Voltage-gated ion channel kinetics D. Initial depolarization reaching threshold E. The degree of myelination
A. The size of the axon C. Voltage-gated ion channel kinetics E. The degree of myelination
Sodium channels found at the Nodes of Ranvier have: A. Voltage gates B. Inactivation gates C. Delay mechanism (i.e. they are slow to open) D. both (A) and (B) E. both (B) and (C)
A. Voltage gates B. Inactivation gates
Trephination (trepanning) is: A. drilling a hole in the skull to treat disease or injury B. part of the mummification process C. the surgical removal of a small part of the brain D. a noninvasive way to scan and study the brain
A. drilling a hole in the skull to treat disease or injury
3 Major Components of the Cytoskeleton
Actin Filaments (Microfilaments) Intermediate Filaments (Neurofilaments) Microtubules Polarized filaments made of α and β tubulin (tubular shape)
All of the following are functions of the plasma membrane EXCEPT: A Barrier to maintain intracellular environment B Support for cellular structure and organelle movement C Signaling between cells and the environment D Gatekeeper for selective permeability
B Support for cellular structure and organelle movement
Which of the following is supported by phrenology? A The brain functions as a whole. B There is some localization of function in the brain. C Visual processing occurs in several lobes of the brain. DThere is more than one brain area that is responsible for aggression.
B There is some localization of function in the brain.
Neurons contain two types of processes: axons and dendrites. What is the major difference between the two? A. Dendrites travel long distances while axons are typically short. B. Dendrites are specialized to receive incoming signals from other neurons while axons carry the output of the neuron C. A cell body gives rise to a single dendrite and multiple axons D. Axons are often highly branched for integration of lots of information while dendrites have few (or no) branches.
B. Dendrites are specialized to receive incoming signals from other neurons while axons carry the output of the neuron
In neurons, the extracellular concentration of Ca2+ >> the internal concentration of Ca2+. If a neuron contains only open Ca2+ channels at rest, the resting membrane potential for the neuron will be _____________ (hint: assume Na+, K+, and Cl- cannot cross the plasma membrane in these cells). A. Not quite equal to the equilibrium potential for Ca2+ or K+ B. Equal to the equilibrium potential for Ca2+ (ECa) C. You cannot tell what the resting membrane potential would be from the information given. D. Between the equilibrium potentials for Na+ and K+, but closer to EK, like we observe in a typical neuron. E. Equal to the equilibrium potential for K+ (EK)
B. Equal to the equilibrium potential for Ca2+ (ECa)
The notion of dualism as proposed by Descartes stated that: A. Science and the church are one and the same B. Humans have a non-material soul and a material body that are not the same C. Humans have a non-material soul and a material body that are one and the same D. The mind and brain are one and the same
B. Humans have a non-material soul and a material body that
The work visualizing the brain done by Santiago Ramon y Cajal supported A. that the brain has fluid-filled ventricles which, means that its primary function is to cool the blood, like a radiator. B. The Neuron Theory/Doctrine C. the nervous system acting as a syncytium D. The idea that increased brain size causes animals to have more complex behaviors E. Phrenology
B. The Neuron Theory/Doctrine
The rabies virus infects neurons through retrograde transport, the virus enters at the synaptic terminal and then gets transported to the cell body to gain access to the nucleus. A treatment for rabies virus could block this process by inhibiting: A. translation B. dynein C. kinesin D. ribosomes E. glycoslyation
B. dynein
A patient diagnosed with Multiple Sclerosis exhibits weakness, stiffness and painful spasms in their legs which only seems to get worse. It is likely that they have lesions in the ______________. This suggests that they have _________________ MS. A. cerebellum; relapsing/remitting B. spinal cord; primary progressive C. cerebellum; secondary progressive D. thalamus; primary progressive E. cerebellum; primary progressive F. spinal cord; secondary progressive G. spinal cord; relapsing/remitting
B. spinal cord; primary progressive
AMPA receptors
Bind Glutamate -> More channels open = Large Influx of Na+ -> Strong depolarization = Big EPSP
NMDA receptors
Binding glutamate + Strong Depolarization Channel Opens = Influx of Na+ and Ca2+
Neurons have a mutation that impairs the cell's ability to make ATP. Which of the following would be the most affected? A. Diffusion B. Facilitated Diffusion C. Active Transport D. Anterograde transport
C. Active Transport D. Anterograde transport
Which is NOT true of the Na+/K+ ATPase (sodium/potassium pump)? A. It pumps ion against their concentration gradients B. It pumps sodium out of neurons and potassium in C. It pumps potassium out of neurons and sodium in D. It consumes ATP E. It is necessary for the resting membrane potential
C. It pumps potassium out of neurons and sodium in
The _______ describes the membrane potential when a permeable ion is at electrochemical equilibrium. The measured value of the resting membrane potential varies slightly from this predicted value for K+ because the cell is somewhat permeable to _______ at rest. A. Goldman equation; Na+ B. Ohm's Law; Cl- C. Nernst equation; Na+ D. Nernst equation; negatively charged proteins
C. Nernst equation; Na+
What role does the cytoskeleton play in neurons? A. maintaining neuron shape B. movement or migration of axons C. trafficking of cargoes to and from the cell body D. components of the cytoskeleton are responsible for all of the above functions E. the cytoskeleton components perform none of the above functions
D. components of the cytoskeleton are responsible for all of the above functions
Franz Gall observed that animals with larger brains tended to manifest more complex behaviors. It has been shown that ________________ is the best predictor of an animal to exhibit higher order behavior. A. increased amounts or circulating estrogen B. increased size of the hippocampus C. increased brain to body weight ratio D. increased size of the cortex E. total brain weight
D. increased size of the cortex
What happens to Vm if we add (+) ions to the cell?
Depolarization
Negative Feedback Loop
Depolarization -> K+ channels OPEN -> K+ efflux -> REPOLARIZATION
Positive Feedback Loop
Depolarization -> Na+ channels OPEN -> Na+ influx -> Depolarization ->
Changing a single amino acid in a protein will only affect its primary structure, and likely have no impact on its function. True False
False A change in a single amino acid in a protein will create a new primary structure, but this can also have impacts on the secondary, tertiary and quaternary structures of the protein. A single amino acid change and impact every aspect of the protein causing alterations in shape as well as function
Large molecules and ions cannot freely diffuse across the plasma membrane. True False
False Large molecules and ions cannot freely diffuse across the membrane. The interior of the plasma membrane is hydrophobic which keeps out ions and large molecules cannot squeeze through. Molecules in both these classes need help moving into and out of the cell through processes like active or passive transport and exo- or endocytosis.
Hippocrates
Hippocrates made a number of "correct observations" about brain illness and deemed the brain the seat of intelligence and sensation
What happens to Vm if we add (-) ions to the cell?
Hyperpolarization
Ohm's Law
I = g x V I= current g= conductance V= voltage V = I x R can be used to figure out Current, Voltage or Resistance.
Law of Dynamic Polarization
Information always flows from presynaptic to postsynaptic with regard to a specific synapse
Long Term Potentiation (LTP)
Long Lasting Increase in EPSP
At the peak of the action potential, the axonal membrane approaches the equilibrium potential for A K+ B Na+ C Cl- D All of the above
Na+
Sensitization
Noxious stimulus (tail shock) -> then touch siphon -> enhanced gill withdrawal response synaptic facilitation (increase in neurotransmitter release)
Equipotentiality
One part of the brain is not more important than the other •Karl Lashley - conducted similar ablation studies and concluded that some functions were not localized. •Impairment was related to the amount of tissue removed rather than its location. •His conclusion was that brain tissue had an equal potential for the mediation of brain functions.
Repolarization of the action potential is due to: A Opening of voltage-gated sodium channels B Opening of voltage-gated potassium channels C The Na+/K+ ATPase Pump D The inactivation of voltage-gated sodium channels
Opening of voltage-gated potassium channels
Goldman Equation
P = g in picture Goldman Equation Solves for the membrane potential given conductance and equilibrium potential
Operant conditioning
Punishment and/or Reinforcement strengthen or weaken behavior.
Tetrodotoxin
Sodium channel blocker
A neuron at rest is stimulated to fire an action potential, in an experiment , you decide add Dendrotoxin (K+ channel blocker) to see how this would affect the membrane potential (Vm) during the action potential. Your results show: A The action potential doesn't fire. B The action potential fires, and the neuronal membrane returns its resting state over the normal time course C The action potential fires, and the membrane remains depolarized for an extended period of time (does not readily return to rest) D The action potential fires, but the Vm does not reach it's peak potential.
The action potential fires, and the membrane remains depolarized for an extended period of time (does not readily return to rest)
Which of the following is NOT a main factor that influences the speed of action potential propagation? A The size of the axon B The degree of myelination C The kinetics of the voltage-gated ion channels D The number of dendrites on the neuron
The number of dendrites on the neuron
Glycosylation
allows proteins to be targeted to different vesicles in the Golgi apparatus
White Matter
axons
What are two membrane properties that are altered by myelin? a. Internal resistance (ri) and membrane capacitance (cm) b. Membrane resistance (rm) and internal resistance (ri) c. Area and conductance (g) d. Membrane resistance (rm) and membrane capacitance (cm)
d. Membrane resistance (rm) and membrane capacitance (cm)
Big axon results in such membrane properties
decreased internal resitance increased conduction velocity
Conduction velocity
distance / time
Declarative Learning & Memory
facts & events consciously recalled "easy come - easy go" use it or you lose it
Multiple Sclerosis
is an chronic inflammatory demyelinating disease of the central nervous system Areas affected by MS -Brain -Spinal cord -Optic nerves
Posterior hippocampus
is larger in experienced taxi drivers Mental map of London is stored in the posterior hippocampi
Molecules that CANNOT get into the cell
large molecules or ions
membrane resistance
leakiness of the membrane
Membrane properties of "naked" axons
low membrane resitance high membrane capacitance high internal resistance
The Patch Clamp Method
measures ions moving through individual ion channels
Conduction velocity depends on 3 axon properties
membrane resistance = leakiness of the membrane membrane capacitance = charge required to activate the AP internal resistance = stuff inside the cell
Non-associative:
permanent change in the strength of response to a single stimulus (often due to repeated exposure to the same stimulus)
Blue eyes or brown hair are examples of ___________.
phenotypes
Associative:
predictive relationship, association between two stimuli or stimuli and a behavior is learned -Classical conditioning: Innate response is expressed in response to a neutral stimulus -Operant conditioning: Learning to predict future events based on experience (negative or positive)
Somatic motor neurons
stimulate skeletal muscles' contraction
Anterior hippocampus
region is larger in non-taxi drivers
Autonomic motor neurons
regulate activity of smooth muscles, cardiac muscles, and glands
Implicit/Procedural Learning & Memory
skills & behaviors performed without conscious recall require practice - but not easily forgotten
Molecules that can get into the cell
small, non-polar(hydrophobic), neutral molecules
Gray Matter
somas and ganglia
Habituation
the same stimuli causes weaker and weaker responses after repeated occasions
retrograde
to the cell body
anterograde
to the synapse
kinesin
transports vesicles anterograde (to the synapse) require ATP
dynein
transports vesicles retrograde (to the cell body) require ATP
René Descartes (1633)
•Attempted to explain the behavior of humans and animals by comparing them to a machine -Brain is a machine and is involved in fluid mechanics (fluid from the brain inflates the muscles) •Dualism: Separation of Mind and Body -Mind was a spiritual essence, non-material soul -Body was the material machine •The connection of mind and body is the pineal gland
Hippocampal Place Cells
•Different cells encode different places in the overall spatial field •The shape and size of firing fields can be quite different from one cell to the another
