Word count (no titles/figures)= 772
Q.1
Reaction:
Reactions, unlike reflexes, are voluntary and involve complex cortical processing. The stimulus is
registered and processed by sensory detectors (e.g. retina registering an incoming ball). Then it is
interpreted and processed by the brain. This information then is used to send a signal to the
responding effector muscles (e.g. catch ball). These pathways are comprised of neurons that
conduct electrical signals. Faster reaction time implies this process occurs faster. This could be due
to the elixir increasing conduction velocity of the neurons, either by:
1. Acting on receptors of Schwann cells to increase production of myelin. The myelin sheath of
a neuron insulates the axon and allows voltage gated sodium/potassium channels to be
clustered at the nodes of Ranvier, thus increasing myelination allowing a faster electrical
conduction.
2. Increasing axon diameter by stimulating the cytoskeleton to remodel. Larger axons allow for
less internal electrical resistance of ion flow, meaning that action potentials can occur faster
down the axon.
Endurance:
The ability to maintain muscle contraction over prolonged periods pertains to fatiguability. Muscle
cells have a limited ability to contract which vary depending on their muscle fibre type. If the rat was
able to have higher endurance, this could be due to the elixir causing a transition of fast twitch fibres
(least fatigue-resistant) to slow twitch fibres (most fatigue-resistant). Slow twitch fibres have greater
oxidative capacities and vascularisation compared to fast twitch, containing more myoglobulin and
mitochondria.
Strength
Strength relates to the number of fibres recruited and the tension developed by each fibre. Upon
stimulation of the cell, calcium from the sarcoplasmic reticulum is released which binds to troponin
to expose actin binding sites, allowing cross bridges between actin and myosin. The contraction
ceases once calcium is no longer enabling this process by its presence. If the elixir inhibited SERCA
pumps which facilitate calcium reuptake into the sarcoplasmic reticulum, then maximum cross
bridge would be prolonged and hence more muscle cells in a tetanic contraction. This allows for
maximal force more instantaneously.
Q.2
Dosage of Magic Elixir induces faster reaction speeds in rats by increasing neuronal conduction
velocity due to increased Schwann cell myelination.
Q.3
a) Isolated neuronal cells preparation. This preparation refers to neurons being isolated from the rat
body and examined in a physiological buffer solution. The elixir will be added to the buffer and the
effects will be studied on Schwann cells surrounding the axon.
b) Previous literature establishes increased myelination corresponds to faster conduction velocity,
and previous research observed reaction speed increase with the elixir dosage. Therefore, a more
precise cellular examination is required to determine the mechanism. This preparation requires cells
Q.1
Reaction:
Reactions, unlike reflexes, are voluntary and involve complex cortical processing. The stimulus is
registered and processed by sensory detectors (e.g. retina registering an incoming ball). Then it is
interpreted and processed by the brain. This information then is used to send a signal to the
responding effector muscles (e.g. catch ball). These pathways are comprised of neurons that
conduct electrical signals. Faster reaction time implies this process occurs faster. This could be due
to the elixir increasing conduction velocity of the neurons, either by:
1. Acting on receptors of Schwann cells to increase production of myelin. The myelin sheath of
a neuron insulates the axon and allows voltage gated sodium/potassium channels to be
clustered at the nodes of Ranvier, thus increasing myelination allowing a faster electrical
conduction.
2. Increasing axon diameter by stimulating the cytoskeleton to remodel. Larger axons allow for
less internal electrical resistance of ion flow, meaning that action potentials can occur faster
down the axon.
Endurance:
The ability to maintain muscle contraction over prolonged periods pertains to fatiguability. Muscle
cells have a limited ability to contract which vary depending on their muscle fibre type. If the rat was
able to have higher endurance, this could be due to the elixir causing a transition of fast twitch fibres
(least fatigue-resistant) to slow twitch fibres (most fatigue-resistant). Slow twitch fibres have greater
oxidative capacities and vascularisation compared to fast twitch, containing more myoglobulin and
mitochondria.
Strength
Strength relates to the number of fibres recruited and the tension developed by each fibre. Upon
stimulation of the cell, calcium from the sarcoplasmic reticulum is released which binds to troponin
to expose actin binding sites, allowing cross bridges between actin and myosin. The contraction
ceases once calcium is no longer enabling this process by its presence. If the elixir inhibited SERCA
pumps which facilitate calcium reuptake into the sarcoplasmic reticulum, then maximum cross
bridge would be prolonged and hence more muscle cells in a tetanic contraction. This allows for
maximal force more instantaneously.
Q.2
Dosage of Magic Elixir induces faster reaction speeds in rats by increasing neuronal conduction
velocity due to increased Schwann cell myelination.
Q.3
a) Isolated neuronal cells preparation. This preparation refers to neurons being isolated from the rat
body and examined in a physiological buffer solution. The elixir will be added to the buffer and the
effects will be studied on Schwann cells surrounding the axon.
b) Previous literature establishes increased myelination corresponds to faster conduction velocity,
and previous research observed reaction speed increase with the elixir dosage. Therefore, a more
precise cellular examination is required to determine the mechanism. This preparation requires cells
