Hubs191 final exam latest updated 2025
Centeral nervous system - -made up of the brain and the spinal cord
Peripheral nervous system - -made up of the peripheral nerves and ganglia
Neurons - -specialised in structure and function for transmission of information
Morphological types of neurons - -multipolar, bipolar, unipolar, anaxonic
Glia cells - -support, nourish and protect neurons
Dendrites - -receive input and send info to the cell body
Cell body - -contains nucleus and organelles, contains lots of rer to make proteins
Axon hillock - -location where inputs are summated before actin potential
Axon - -carries electrical impulses, can be myelinated or unmyelinated
Axon terminal - -end of axon and where the neurotransmitter is released
Nucleus - -group of cell bodies
Tract - -bundle of axons
Grey matter - -group of cell bodies or soma in the cerebral cortex or the spinal cord
White matter - -bundle of axons in the cerebral cortex or the spinal cord
Ganglion - -group of cell bodies
Nerve - -bundle of axons
Input zones - -recieves chemical signal from other neurons (dendricytes and cell body)
Summation zone - -sums up input (axon hillock)
Conduction zone - -carry electrical signals (between brain to/from spinal cord or from
periphery sensory receptors to/from effector cells )
Output zone - -make contact with input zone of other neurons (or effectors) and release
the neurotransmitter
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Glia - -make up the majority of the brain. 5 morphological types
Astrocytes - -supply nutrients to neurons by covering capillaries, bind together to
minimise damage as a response to injury
Microglia - -immune cells in cns, engulf organisms and clean up debris and
malfunctioning cells
Ependymal cells - -line fluid filled spaces and have cilia that circulate cerebral spinal
fluid (in the brain and in the spinal cord)
Oligodendrocytes - -support nerve fibres and ensheath them with myelin
Schwann cells - -located in the peripheral nervous system. Support the nerve fibres and
ensheath them with myelin.
Myelin sheath - -lipid (fat) wrapped around the axon which increases the velocity of
conduction
Somatic - -aware of and have control over
Somatic afferent - -sensory infromation that we are aware of
Somatic efferent - -voluntary muscle control
Autonomic - -not aware of and no control over
Autonomic efferent - -involuntary muscle control
Autonomic afferent - -sensory information that we are unaware of.
Somatic efferent nervous system - -upper motor neuron: cell body in brain, axon in the
spinal cord. Lower motor neuron, cell body in spinal cord, axon in spinal nerve.
Acetylcholine is neurotransmitter used to signal
Autonomic efferent nervous system - -neuron #2 has cell body in the cns, axon is in the
pns. This neuron is myelinated and synapse with unmyelinated neuron #3 occurs in the
autonomic ganglion. Neuron #3 had cell body in pns and axon in pns to effector where it
synapses on.
Synapse in autonomic efferent ns - -at autonomic ganglion this is acetylcholine, but at
the effector this is acetylcholine or norepinephrine
Sympathetic autonomic nervous system - -uses norepinephrine in synapse, prepares
body for stress responses.
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Sympathetic autonomic nervous system effects - -increases heart rate, pupil dilation
and sweat. Decreases gastric motility and saturation. Constricts blood vessels.
Structure of sympathetic autonomic nervous system - -myelinated axon #2 is shorter,
unmyelinated axon is longer. Sympathetic ganglion is closer to the cns.
Parasympathetic nervous system - -synapse only uses acetylcholine. Prepares the body
for restful situations
Parasympathetic nervous system effects - -decreases heart rate and pupil size,
increases gastric motility and salivation
Parasympathetic structure - -myelinated axon #2 is longer, unmyelinated axon #3 is
shorter, parasympathetic ganglion is further away from the cns
Chemical signal to electrical signal - -neurotransmitter binds to the binding site, causing
the channel to change shape and open. This allows ions to flow in or out , allowing ions
to flow in and out. Voltage begins to change and if it changes to -60mv an action
potential will occur.
Voltage gated channels - -these open when the chanels sense a large change in
voltage. Depolarized to threshold voltage (-60mv) there are two gates so three states in
which the channels can be in.
Mechanically gated ion channels - -stimulus is deformation of the membrane. When
membrane returns to its original shape, the channels will close.
Dendrites and cell body channels - -chemically gated neuron channels (na+ and k+)
Axon hillock and axon channels - -voltage gated ca 2+ channels open
Rmp - -intracellular space is more negatively charged than extracellular fluid. (ics high
k+, low na+. Ecf high na+, low k+)
Local potentials - -change in voltage in a specific area of a cell. Two forms are
excitatory and inhibitory
Excitatory presynaptic neurons - -excitatory presynaptic neurons release excitatory
neurons which bind to chemically gated na+ channels. This causes the release of na+
into the post synaptic cell causing depolarization
Inhibitory presynaptic neurons - -inhibitory presynaptic neurons release inhibitory
neuron that binds to chemically gated cl- or k+ channels, this causes k+ or cl- to be
released into the postsynaptic cell causing it to become hyperpolarized (more negative)
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