PSYCH 1XX3 TEST PAPER 2026/2027 QUESTIONS AND
SOLUTIONS RATED A+
✔✔Myelin sheath - ✔✔jums across saltatory indicutions
✔✔Nodes of Ranvier - ✔✔important bc electrical signal can be weakened through
myelin sheath, signal can be strengthened again
✔✔Sending a signal - ✔✔Neurons encode signals through frequency, not size
Encoded by frequency of AP
strong signal leads to many sequential AP
Communication between neurons at the synapse
✔✔Synapse - ✔✔Indirect connection
Neurotransmitters in presynaptic neuron
Neurotransmitters vesicle moves towards cell membrane of presynaptic neyron
Neurotransmitter vesicle fuses to cell wall, releasing neurotransmitter molecules into cell
fluid
Glutamate, GABA, seratonin, dopamine
✔✔Synaptic cleft - ✔✔Neurotransmitters float freely in the cleft
Free neurotransmitters bind to postsynaptic receptors
Bind to specific receptors
✔✔Excitatory Postsynaptic Potential (EPSP) - ✔✔Excite the post-synaptic neuron
towards action potential threshold
Sodium channels open, allowing some pos changed Na ions to flow into post synaptic
cell
This depolarizes the cell, moving away from -70mv and closer to -50mv threshold to fire
A number of EPSPS must occur to reach -50mv threshold
temporal summation> Can occur one after the other
Spatial Summation>multiple EPSPs generated simutaneously from different presynaptic
neurons
✔✔Inhibitory Postsynaptic Potential (IPSP) - ✔✔Cl channels on cell membrane open,
allowing negatively charged Cl- to enter inside the cell
Neuron is hyperpolarized as resting potential is now even further away from the
threshold
✔✔ventricular zone - ✔✔lined with founder cells
✔✔Neurogenesis steps - ✔✔Begins as neural plate, folding into tube, eventually
becoming CNS (18 days +)
Cells migrate outward from ventricular zone
,Day 28-42 cell division is symmetrical as the division of each founder cell leads to 2
identical founder cells
Day 42-125 "asymmetrical" One founder cell> becomes one glial cell or one becomes
neuron cell
✔✔Neuron Migration - ✔✔begins almost immediately after first neurons are born at day
42, continues for 6 weeks after last neuron is born
Neurons almost always produce glial cells
EXP: radial glial cells
Fibres that extend outward from ventricular zone, like scaffolding
End at the outer layer of the cortex
Use these cells to migrate from ventricular zone to cortex
Deepest layers of the brain developed first
After reaching destination, neuron differentiates
Differentiation is sensitive to input a neuron receives from its connections to other
neurons
✔✔Neuron development - ✔✔Input from other cells effects this
Need certain neural input
Need to mature by growing dendrites, axons, synapses
Need neurotrophic factors from other neurons to stay alive
Compete for neurotrophic factor
Other neurons pruned away
Neural connections also pruned
Synapses begin to decline after prime, this increases processing efficiency
✔✔Rene Descartes - ✔✔"Dualist"
Body was like a machine, the mind was a separate and non-physical
Seat of the soul was in pineal gland
✔✔Central Nervous System - ✔✔Brain/spinal cord, encased in bone
Brain in skull, spine in vertebral column
✔✔Peripheral Nervous System - ✔✔collection of nerves + peripheral ganglia
✔✔Efferent nerve fibres - ✔✔Fibers that carry info outward from CNS to the periphery
of the body
✔✔Afferent nerve fibres - ✔✔Fibers that carry info inward to CNS from the periphery of
the body
✔✔PNS- Somatic - ✔✔receives info from sensory organs and controls the voluntary
movements of muscles
Brings us info we are consciously aware of
Allows us to preform actions under conscious control
,✔✔PNS- Automatic - ✔✔Controls involuntary movements outside our conscious control
Regulates smooth muscles, cardiac muscles, glands
Causes certain orgrans to contract
✔✔ANS- Sympathetic - ✔✔Preparing body for emergencies (fight/flight)
Increases heartrate, dilation of pupils
Dilation of the internal structure of lungs
Inhibition if digestion and contraction of the bladder/rectum
✔✔ANS-Parasympathetic - ✔✔Slowing of the heart
Lowering of blood pressure
Contraction of pupils
Increase in activity in gastrointestinal tract
Secretion of digestive juices
Conserve/increase the bodys energy sources
✔✔Dendrite - ✔✔Branched projections that conduct nerve impulses received from other
cells to the cell body, usually very short
Covered in tiny spires, where connections from the axons are made at a junction known
as synapse
Bring together impulses occuring across the many thousand of synapses to their final
destination of the cell body
✔✔The cell body - ✔✔Many of the specialized proteins/enzymes that participate in the
metabolism of the cell are synthesized from the DNA templates coined in the nucleus
The axon exits through the cell body from an elongated portion called the "axon hellock"
✔✔The axon - ✔✔Terminal boutons are where connection to the dendrites are made
Surrounded by Myelin Sheath
>Insulate/speed up conduction of the AP
"White matter" of brain composed mostly of myelinated axons
✔✔Neuron subtypes - ✔✔Sensory
Receptor
Effector
Interneurons
> Multipolar, bipolar, unipolar
✔✔Sensory neurons - ✔✔Info from the environment (sound light taste touch)
Connect to receptor
✔✔Receptor cells - ✔✔Responsible for converting or transducing the physical stimuli
from the outside world into nerve impulses
Connect to sensory
, ✔✔Effector neurons - ✔✔Motor neurons activate the muscles of the body, controlling
movement
✔✔Interneurons > Multipolar - ✔✔Comprised of multiple dendrites extending from the
cell body and only a single axon
✔✔Interneurons >Bipolar - ✔✔Only has single dendrite exiting one side of the cell body
with a single axon exiting the other
*Usually sensory neurons that dendrites terminate at receptor cells*
✔✔Interneurons >Unipolar - ✔✔Only has single dendrite leaving the cell body which
eventually branches in 2 directions, one leading to the dendrites and the other along an
axon
✔✔Diffusion - ✔✔constant bumping/jolting of these molecules causes them to move
from area of high conc to low conc
✔✔Electrostatic Pressure - ✔✔When salt is dissolved in water it splits into their 2 ion
compositions
Splits into Na+ Cl-
Repulsion of 2 ions causes pressure
+ repel +/ - repel -/ + attract -
✔✔Balance of forces - ✔✔ESP doesnt play much of a role bc equal number of +/-
charges
Force of diffusion acts alone, causing equal number of +/- to move into 2nd
compartment
If immobile organic cations (a+) were in first compartment, this would cause Cl- anions
to be attracted by electrostatic pressure
Na+ cations would be repeled, Nat+ would move into other chamber, Cl- would stay
Causes larger conc of Na+ in one chamber, Cl- in another
The force of diffusion would cause Na+ to move back into chamber with A+ cations
2 forces balance out
Small voltage potential between 2 compartments
✔✔Depolarization - ✔✔Membrane potential becomes less negative, reduction of
polarization
✔✔Dorsal - ✔✔Top
✔✔Rostral - ✔✔front
✔✔Lateral - ✔✔side
SOLUTIONS RATED A+
✔✔Myelin sheath - ✔✔jums across saltatory indicutions
✔✔Nodes of Ranvier - ✔✔important bc electrical signal can be weakened through
myelin sheath, signal can be strengthened again
✔✔Sending a signal - ✔✔Neurons encode signals through frequency, not size
Encoded by frequency of AP
strong signal leads to many sequential AP
Communication between neurons at the synapse
✔✔Synapse - ✔✔Indirect connection
Neurotransmitters in presynaptic neuron
Neurotransmitters vesicle moves towards cell membrane of presynaptic neyron
Neurotransmitter vesicle fuses to cell wall, releasing neurotransmitter molecules into cell
fluid
Glutamate, GABA, seratonin, dopamine
✔✔Synaptic cleft - ✔✔Neurotransmitters float freely in the cleft
Free neurotransmitters bind to postsynaptic receptors
Bind to specific receptors
✔✔Excitatory Postsynaptic Potential (EPSP) - ✔✔Excite the post-synaptic neuron
towards action potential threshold
Sodium channels open, allowing some pos changed Na ions to flow into post synaptic
cell
This depolarizes the cell, moving away from -70mv and closer to -50mv threshold to fire
A number of EPSPS must occur to reach -50mv threshold
temporal summation> Can occur one after the other
Spatial Summation>multiple EPSPs generated simutaneously from different presynaptic
neurons
✔✔Inhibitory Postsynaptic Potential (IPSP) - ✔✔Cl channels on cell membrane open,
allowing negatively charged Cl- to enter inside the cell
Neuron is hyperpolarized as resting potential is now even further away from the
threshold
✔✔ventricular zone - ✔✔lined with founder cells
✔✔Neurogenesis steps - ✔✔Begins as neural plate, folding into tube, eventually
becoming CNS (18 days +)
Cells migrate outward from ventricular zone
,Day 28-42 cell division is symmetrical as the division of each founder cell leads to 2
identical founder cells
Day 42-125 "asymmetrical" One founder cell> becomes one glial cell or one becomes
neuron cell
✔✔Neuron Migration - ✔✔begins almost immediately after first neurons are born at day
42, continues for 6 weeks after last neuron is born
Neurons almost always produce glial cells
EXP: radial glial cells
Fibres that extend outward from ventricular zone, like scaffolding
End at the outer layer of the cortex
Use these cells to migrate from ventricular zone to cortex
Deepest layers of the brain developed first
After reaching destination, neuron differentiates
Differentiation is sensitive to input a neuron receives from its connections to other
neurons
✔✔Neuron development - ✔✔Input from other cells effects this
Need certain neural input
Need to mature by growing dendrites, axons, synapses
Need neurotrophic factors from other neurons to stay alive
Compete for neurotrophic factor
Other neurons pruned away
Neural connections also pruned
Synapses begin to decline after prime, this increases processing efficiency
✔✔Rene Descartes - ✔✔"Dualist"
Body was like a machine, the mind was a separate and non-physical
Seat of the soul was in pineal gland
✔✔Central Nervous System - ✔✔Brain/spinal cord, encased in bone
Brain in skull, spine in vertebral column
✔✔Peripheral Nervous System - ✔✔collection of nerves + peripheral ganglia
✔✔Efferent nerve fibres - ✔✔Fibers that carry info outward from CNS to the periphery
of the body
✔✔Afferent nerve fibres - ✔✔Fibers that carry info inward to CNS from the periphery of
the body
✔✔PNS- Somatic - ✔✔receives info from sensory organs and controls the voluntary
movements of muscles
Brings us info we are consciously aware of
Allows us to preform actions under conscious control
,✔✔PNS- Automatic - ✔✔Controls involuntary movements outside our conscious control
Regulates smooth muscles, cardiac muscles, glands
Causes certain orgrans to contract
✔✔ANS- Sympathetic - ✔✔Preparing body for emergencies (fight/flight)
Increases heartrate, dilation of pupils
Dilation of the internal structure of lungs
Inhibition if digestion and contraction of the bladder/rectum
✔✔ANS-Parasympathetic - ✔✔Slowing of the heart
Lowering of blood pressure
Contraction of pupils
Increase in activity in gastrointestinal tract
Secretion of digestive juices
Conserve/increase the bodys energy sources
✔✔Dendrite - ✔✔Branched projections that conduct nerve impulses received from other
cells to the cell body, usually very short
Covered in tiny spires, where connections from the axons are made at a junction known
as synapse
Bring together impulses occuring across the many thousand of synapses to their final
destination of the cell body
✔✔The cell body - ✔✔Many of the specialized proteins/enzymes that participate in the
metabolism of the cell are synthesized from the DNA templates coined in the nucleus
The axon exits through the cell body from an elongated portion called the "axon hellock"
✔✔The axon - ✔✔Terminal boutons are where connection to the dendrites are made
Surrounded by Myelin Sheath
>Insulate/speed up conduction of the AP
"White matter" of brain composed mostly of myelinated axons
✔✔Neuron subtypes - ✔✔Sensory
Receptor
Effector
Interneurons
> Multipolar, bipolar, unipolar
✔✔Sensory neurons - ✔✔Info from the environment (sound light taste touch)
Connect to receptor
✔✔Receptor cells - ✔✔Responsible for converting or transducing the physical stimuli
from the outside world into nerve impulses
Connect to sensory
, ✔✔Effector neurons - ✔✔Motor neurons activate the muscles of the body, controlling
movement
✔✔Interneurons > Multipolar - ✔✔Comprised of multiple dendrites extending from the
cell body and only a single axon
✔✔Interneurons >Bipolar - ✔✔Only has single dendrite exiting one side of the cell body
with a single axon exiting the other
*Usually sensory neurons that dendrites terminate at receptor cells*
✔✔Interneurons >Unipolar - ✔✔Only has single dendrite leaving the cell body which
eventually branches in 2 directions, one leading to the dendrites and the other along an
axon
✔✔Diffusion - ✔✔constant bumping/jolting of these molecules causes them to move
from area of high conc to low conc
✔✔Electrostatic Pressure - ✔✔When salt is dissolved in water it splits into their 2 ion
compositions
Splits into Na+ Cl-
Repulsion of 2 ions causes pressure
+ repel +/ - repel -/ + attract -
✔✔Balance of forces - ✔✔ESP doesnt play much of a role bc equal number of +/-
charges
Force of diffusion acts alone, causing equal number of +/- to move into 2nd
compartment
If immobile organic cations (a+) were in first compartment, this would cause Cl- anions
to be attracted by electrostatic pressure
Na+ cations would be repeled, Nat+ would move into other chamber, Cl- would stay
Causes larger conc of Na+ in one chamber, Cl- in another
The force of diffusion would cause Na+ to move back into chamber with A+ cations
2 forces balance out
Small voltage potential between 2 compartments
✔✔Depolarization - ✔✔Membrane potential becomes less negative, reduction of
polarization
✔✔Dorsal - ✔✔Top
✔✔Rostral - ✔✔front
✔✔Lateral - ✔✔side
