Midterm 1 Review

Question 1

how brain brings information in

Answer 1

transducers

Question 2

Brain sends out info using:

Answer 2

muscles

Question 3

Organization

Answer 3

Function (whats the job within the brain) <–> structure(where is it in the brain)

Question 4

Dividing up the nervous system.

Answer 4

nervous system

->Central Nervous System
—>Spinal cord
—>Brain

->Peripheral nervous system
—>Somatic nervous system
—>autonomic nervous system

Question 5

Neuron

Answer 5

(From up to down):

Neuron Part. ||. Zone

Dendrites (branches) ||. Input
Soma, axon hillock (head area) ||. Integration
Axon ||. conduction
Axon terminals || output
presynamptic terminals

Question 6

Neurodevelopment

Answer 6

1. Neurogenesis
2. Cell migration
3. Cell differentiation
4. Synaptogenesis
5. Neuronal Cell death
6. Synapse rearrangement

Question 7

Neurogenesis

Answer 7

occurs in ventricular zone

neurons don’t divide, but cell division in ventricular zone gives rise to neurons and glia.

Question 8

Cell migration

Answer 8

guided by radial glial cells

mostly done prenatally in primates

Neurons destined for
same brain nucleus
aggregate

movement aided by cell adhesion molecules

Question 9

cell differentiation

Answer 9

undifferentiated cells are stem cells.

Genes guide
expression of neural
characteristics.

Neurons sprout axons
and dendrites

Question 10

synaptogenesis

Answer 10

Axons and dendrites
grow to meet synaptic
targets

Growth cones on the
ends of dendrites and
axons

Chemical gradients
guide the process

Upon reaching target,
growth come becomes
synaptic terminal

Question 11

Neuronal cell death

Answer 11

Neurons are initially
overproduced
20-80% of neurons die
early (differs by brain
region)

Competition for
synaptic targets;
competition for trophic
factors; programmed
cell death

Question 12

Synapse rearrangement

Answer 12

Synaptic pruning is the
removal of overabundant
synapses

Reorganization of synaptic
patterns occurs in the brain
from back to front.

Good synaptic contacts
remain, others are
removed

Neurons that fire
together, wire together

Question 13

plasticity

Answer 13

During plasticity, synapses can
strengthen (potentiate) or weaken
(depress)

Question 14

long vs short term habituation

Answer 14

Short-term habituation occurs because
the synapse connecting the sensory to
motor neuron becomes weaker

Long-term habituation occurs because
some of the synapses connecting the
sensory to motor neuron are pruned away

Question 15

Neuron communication

Answer 15

Information flows
within a neuron via
electrical signals

Information flows
between neurons via
chemical signals

The synapse is where the axion terminals of the presynaptic neuron meets the dendrites of the postsynaptic neuron

Question 16

Forces that act to equilibrate ions

Answer 16

Diffusion: the spread of
molecules from areas of high
concentration to low
concentration, called a
gradient

Electrostatic pressure: the
propensity of ions to move
toward areas with the
opposite charge

If these were the only forces
at work, there would be no
voltage.

Question 17

Mechanisms for maintaining a
voltage across a neuron’s membrane

Answer 17

Selective permeability:
The lipid bilayer that
separates the extracellular
from intracellular space
allows some substances
to pass through, but not
others

Active ion transport:
specialized pumps within
the lipid bilayer that pump
ions in and out of the cell

Question 18

Action Potential

Answer 18

Injecting positive current causes a neuron to
depolarize — become less polarized

When enough current is injected to depolarize
the neuron past a threshold, an action potential
is produced

When a presynaptic neuron “fires” an action
potential, it causes a postsynaptic potential in
the postsynaptic neuron

Excitatory neurons cause excitatory
postsynaptic potentials (EPSPs)
when they fire

Inhibitory neurons cause inhibitory
postsynaptic potentials (IPSPs)
when they fire

Neurons can sum their presynaptic inputs,
leading to an action potential (spatial vs temporal)

Question 19

Synapses

Answer 19

briefly translate electrical action
potentials into chemical signals, then back into electrical signals

Synaptic vesicles are like small
bags filled with neurotransmitters, just
waiting in the presynaptic terminal for
an action potential to arrive.
When an AP arrives at the synapse, it
activates voltage-gated calcium
(Ca2+) channels, which allow
calcium levels to increase in the
presynaptic terminal.
Increased Ca2+ causes vesicles to
fuse with the membrane of the
presynaptic terminal, releasing
neurotransmitter into the synaptic
cleft.m

Question 20

main inhibitory transmitter of the brain

Answer 20

GABA

Question 21

main excitatory transmitter of the brain

Answer 21

glutamate

Question 22

transmitter used by neurons to activate the muscles

Answer 22

acetylcholine