LIFESCI 2CC3 Midterm 1

retrieval practice

the repeated retrieval of an item of information from memory

- self testing or taking practice tests

distributed practice

spacing the study of material to be remembered by including breaks between study periods

What are the two most effective study strategies?

- Retrieval practice

- Distributed practice

Interleaved practice

Implementing a schedule of practice that mixes different kinds of problems, or a schedule of study that mixes different kinds of material, within a single study session

Elaborative interrogation

Generating an explanation for why an explicitly stated fact or concept is true

Self-explanation

Explaining how new information is related to known information, or explaining steps taken during problem solving

What is the hierarchy of the nervous system from highest to lowest?

1. Systems

2. Circuits

3. Cells

4. Genes

In which direction to afferent neurons go?

Conducting towards or inward

In which direction to efferent neurons go?

Conducting away or outwards

What role to interneurons play?

What were the differing opinions of Golgi and Cajal

Golgi concluded that neuron processes form a continuous web, whereas Cajal later found that neurons are discrete and autonomous cells.

What are the two major cell types in the nervous system?

Neurons and Glia cells

What is the function of neurons?

Electrical signaling and intercellular communication

What is the function of glia cells?

Supportive function, and recently found to have the ability to signal with neurons

- Outnumber neurons 1:3

Draw and Label a neuron

- Dendrites

- Cell Body

- Nucleus

- Axon Hillock

- Myelin

- Axon

- Nodes of Ranvier

- Presynaptic terminal

- Synaptic cleft

Where do projection nuerons get their name?

Because they travel long distances

- Transmits information afferently

What is the myotatic reflex?

Also known as the "knee-jerk" response

- external stimuli is picked up by sensory neurons

- Interneurons in the CNS (grey matter) relay sensory information into motor information

What is included in the CNS?

brain and spinal cord

What is included in the PNS?

cranial and spinal nerves

- sensory receptors, ganglia, and nerves

- motor axons and cells

In amyotrophic lateral sclerosis (ALS), the neurons that innervate the skeletal muscles die, resulting in impaired voluntary movement. ALS is a disease of which system?

Somatic motor system

What is the difference between visceral and somatic?

Somatic neurons transfer information from the skin of muscles to the CNS, whereas visceral neurons transfer information from organs to the CNS

Autonomic motor division

neurons innervate smooth muscle cells, cardiac muscle cells, and glands; produce involuntary actions

Associational systems

Neural cell circuits that are not part of the relatively defined sensory (input) and motor (output) systems; they mediate the most complex and least well defined brain functions.

Label a diagram of the brain and body with superior, rostral, anterior, dorsal, ventral, caudal, posterior, and inferior

Brain: Superior = above, inferior = below, anterior = front, posterior = behind, dorsal = top, rostral = front, caudal = back, ventral = bottom

Body: Superior = above, inferior = below, anterior = front, posterior = behind, dorsal = back, rostral = top, caudal = bottom, ventral = front

Draw a diagram of a a coronal, sagittal, and horizontal plane

- Coronal is a vertical plane that goes from one side to the other

- Sagittal is a vertical plane that goes from the back to the front (or vice versa)

- Horizontal is a horizontal plane

Difference between lateral and medial

Later is towards the side whereas medial is towards the middle

What is included in the forebrain?

Cerebrum (cerebral hemispheres) and diancephalon

What is included in the hindbrain?

Cerabellum, brainstem

What is included in the brainstem?

midbrain, pons, medulla oblongata

Gyri vs sulci

Gyri (Folds) and sulci (grooves)

What is the sulci that divides the frontal lobe and the parietal lobe?

Central sulcus

What are the 4 main lobes in the brain? and where are they?

1. Frontal lobe is most rostral

2. Parietal lobe is caudal to the frontal lobe

3. Temporal lobe is ventral to the frontal and parietal lobe

4. Occipital lobe is caudal to the parietal and temporal lobe.

Where is white matter and grey matter found in the brain vs the spinal cord?

In the brain, white matter is found medially, while grey matter is found laterally. In the spinal cord, white matter is found laterally, and grey matter is found medially

What cells myelinate axons in the CNS vs PNS

Schawnn cells myelinate axons in the PNS, while Oligodendrocyte cells myelinate axons in the CNS

Where does white matter get its name from?

It is white because of the myelinated sheath around the axons (allows for faster conductance), grey matter only contains cell bodies and dendrites

What is the cerebral cortex?

A thin layer of neural tissue (grey matter) that covers the entire cerebrum

How many cranial nerves are there, and what is their function?

12, they're responsible for sensory and motor control of the head neck, and shoulders

Draw a segment of spinal cord, labeling the vertebra, grey matter, white matter, dorsal root ganglion, spinal nerve(s), sympathetic chain ganglia, ventral/dorsal horn, dorsal/ventral root, dorsal/ventral/lateral column

In which part of the spinal cord does information move efferently?

Ventral

In which part of the spinal cord does information move afferently?

Dorsal

What is the structure that separates the left and right hemispheres of the brain?

Lateral (Sylvian) fissure

Who was "Jack the Dripper"

Dr. Jack Kevorkian helped people commit suicide by injecting them with a potassium chloride solution that would induce cardiac arrest

What are the three types of electrical signals?

1. Receptor potential: initiated by a sensory stimulus; occur in sensory neurons

2. Action potential: all-or-none; travel along axons

3. Synaptic potential: occur in postsynaptic cells as a results of synaptic communication

What is the Nernst Equation, and when would you use it?

Membrane Potential (Vm) = (58/valence) log([ion concertation outside the cell]/[ion concentration inside the cell]

- should be used when the concentrations of a single ion are known

What is the Goldman-Hodgkin-Katz equation, and when do you use it?

Membrane Potential (Vm) = 58 log({pK[K]o + pNa[Na]o + pCl[Cl]i}/{pK[K]i + pNa[Na]i + pCl[Cl]o}

- Should be used when the concentrations and permeability constants are known for multiple ions

During action potential, is sodium or potasium more permeable?

Sodium

What's the voltage at resting potential?

between -50 and -80 mV

Why is the resting potential negative?

The membrane contains "leaky" K+ channels that are open when the cell is at rest

- The membrane of the resting neuron is more permeable to potassium than any other ion

- Accumulation of more sodium ions outside the cell than potassium ions inside the cell

Why would an injection of KCl be lethal?

Changes the resting potential of a neuron to approximately 0 through a massive influx of potassium (K+)

- Without negative resting potential, neurons can no longer generate action potentials

Assume that, for a typical mammalian cell, Ek = -75mV, Ena = +45mV, and Vrest = -75mV. In what direction is the elctrochemical force on Na+ ions?

Inwards, because the movement of positive ions inwards will making the resting potential more positive; making Vrest closer to Ena

What are passive responses?

Changes in membrane potential due to a stimulus that do NOT breach the threshold and trigger an AP

- leaky channels (membrane resistance)

- flowing down the axon (axial resistance)

What are the physical and biological symptoms of Guillain-Barre syndrome?

Physical: weakness in feet and legs, may spread to upper body and arms; trouble walking; difficulty using facial muscles

Biological: immune system creates antibodies that attack peripheral glial cells (Schwann cells)

Active current flow vs. passive current flow

Active current flows is the generation of current due to an added source of current flow, whereas passive current flow doesn't entail voltage-dependent changes in membrane permeability

Why are squid axons used as a model?

Very large (up to 1mm)

- Much easier to insert wire electrodes inside axon to make electrical measurements

If a current is negative, it is_______

Inward

What are the effects of TTX on current?

Tetradotoxin (TTX) blocks Sodium (Na+) channels

- No strong early inward current due to sodium

- leaky late outward potassium current due to potassium

What are the effects of TEA on current?

Tetraethylammonium (TEA) blocks Potassium (K+) channels

- No delayed "leaky" outward current due to potassium

- Strong early inward current due to sodium

What is Ohm's Law?

V=IR

- V: change in membrane potential

- I: current across the membrane

- R: resistance of the plasma membrane

How do you calculate conductance of an ion?

conductance = Iion/(driving force)

- Iion: Ionic current that flows during an increase in membrane conductance

- driving force: membrane voltage (Vm) minus the equilibrium potential for the ion (Eion)

How do you calculate driving force?

DF = Vm - Eion

- Vm: membrane voltage

- Eion: Equilibrium potential for the ion flowing through the conductance

Define conduction velocity, and how can it be increased?

The rate of transmission of the AP

- increase axon diameter

- adding myelin sheath (saltatory conduction)

What are the four different types of patch clamp techniques?

1. Cell-attached recording: recording pipette makes a seal with the cell over a channel without breaking the membrane, measures single channel current

2. Whole cell recording: recording pipette makes a seal with the cell wall while breaking the membrane, thereby exposing the intracellular fluids, measures multi-cell current

3. Outside-out recording: recording pipette is attached to the cell wall over a channel and the gate is removed in a way it creates a bulb, measures the exterior properties of the channel

4. Inside-out recording: recording pipette is attached to the cell wall over a channel and the gate is removed in a way it creates a cavity, measures the interior properties of the channel

What are the three types of gated channels?

1. Voltage-gated

2. Heat- and stretch-gated

3. Ligand-gated (both extracellular and intracellular)

Where is the voltage sensor on the voltage-gated Na+ channel?

Segment 4

How does Lidocaine cause numbing?

Binds to the S6 alpha helix of domain 4, blocking Na+ influx, preventing an AP

Are sea anemones poisonous or venomous?

Venomous

What is the effect of scorpion poison on neurons?

Depolarization elicits a current that doesn't disappear

- takes orders of magnitude longer for the membrane potential to hyperpolarize

What is the function of the strongest known poisons?

Promote Na+ activation and prevent inactivation

What is the movement of ions in the sodium potassium pump?

3 sodium out, 2 potassium in

Define electrogenic

decrease in positive charge