BPK 207 Final Actual Exam Questions and CORRECT Answers
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Course
BPK 207
Institution
BPK 207
BPK 207 Final Actual Exam Questions
and CORRECT Answers
Brain/CNS Organization - CORRECT ANSWER- -Spinal cord
-Brainstem = hindbrain (cerebellum, pons, medulla, reticular formation) and midbrain
(tectum --> superior and inferior colliculi, tegmentum --> red nucleus, substantia nigra
-D...
BPK 207 Final Actual Exam Questions
and CORRECT Answers
Brain/CNS Organization - CORRECT ANSWER✔✔- -Spinal cord
-Brainstem = hindbrain (cerebellum, pons, medulla, reticular formation) and midbrain
(tectum --> superior and inferior colliculi, tegmentum --> red nucleus, substantia nigra
-Diencephalon = thalamus and hypothalamus
-Forebrain = basal ganglia, limbic system (amygdala, hippocampus, cingulate cortex), and
cerebral cortex
Organization of movement - CORRECT ANSWER✔✔- -Movement is a collaborative effort
among regions in CNS
-Cortical, subcortical, brainstem and spinal regions all send reciprocal connections to one
another
-Each region contributes in its own way
Spinal Cord Organization (Macro) - CORRECT ANSWER✔✔- -31 spinal nerves protected
by vertebral column
-Divided into sacral, thoracic, lumbar and cervical spinal nerves
-Cervical nerves control upper limb muscles
-Thoracic nerves control muscles of trunk/chest (including abdominal)
-Lumbar nerves control lower limb and back muscles
-Sacral nerves control bowel and bladder muscles
Spinal Cord Organization - Cross Section - CORRECT ANSWER✔✔- -Grey matter (cell
bodies of neurons) = centre
-White matter (myelinated/unmyelinated axons making up ascending/descending tracts) =
outside
Spinal Cord Function - CORRECT ANSWER✔✔- -4 types of neurons in spinal cord allow
for coordinated movements
-*Local interneurons* = axons are confined to same or adjacent spinal segment
-*Propriospinal neurons* = axons reach distant spinal segments
,-*Projection neurons* = axons ascend to higher brain centres
-*Motor neurons* = axons exit the nervous system to innervate muscles
Spinal Motor Neuron Organization - CORRECT ANSWER✔✔- -Cell bodies of motor
neurons are clustered together in motor neuron pools (or motor nuclei)
--> form longitudinal columns extending over 1-4 spinal segments
-Motor nuclei innervating proximal muscles lie more medially; innervating distal muscles =
more laterally within spinal cord
Motor neurons and muscles - CORRECT ANSWER✔✔- -Typical muscle controlled by ~100
large motor neurons
-Each muscle fibre innervated by a single motor neuron, usually near midpoint
-Motor neuron plus all the muscle fibres it innervates = motor unit
-Single neuron innervates multiple muscle fibres, but a given muscle fibre is innervated by
only one motor neuron
-Commands signal muscles to contract and produce movement
Motor units - CORRECT ANSWER✔✔- -Can be fast or slow twitch
-Slow-twitch fibres tend to be recruited before fast-twitch --> first fibres recruited are more
resistant to fatigue
-Size of motor units is related to need for refined movement --> more refined movement =
fewer fibres per motor unit
-Number of motor units recruited is proportional to power needed to generate movement
Motor unit size and contractile force - CORRECT ANSWER✔✔- -Larger motor units
contain more muscle fibres --> generate more force/tension when activated
-Tension can also be increased by recruiting multiple motor units
-Muscles involved in fine movement have small motor units
-Large muscles have many motor units --> some are quite large
Size Principle of Motor Unit Recruitment - CORRECT ANSWER✔✔- -Smaller motor units
have smaller motor neurons
--> lower activation threshold --> activated at lower frequency of stimulation from CNS
,-As frequency of stimulation from CNS increases, AP frequency and tension in activated
motor units increases; larger motor units reach threshold and contribute to total muscle
tension
-Total muscle tension reflects sum of motor unit activation in a motor neuron pool
Increasing muscle force - CORRECT ANSWER✔✔- -Muscle force can be increased by
activating more motor neurons (recruits more fibres) or by increasing frequency of action
potentials in the muscle fibre (eventually produces tetanus)
Nerve-Muscle Synapse - CORRECT ANSWER✔✔- -Axon of motor neuron innervates
muscle at specialized region of muscle membrane - motor end plate
-Axon loses myelin sheath and divides into branches to form multiple extensions - synaptic
boutons --> Neurotransmitter (ACh) is released from these regions
-Boutons are positioned over junctional folds (deep depressions in the surface of post-
synaptic muscle membrane that contains ACh receptors)
Motor Neuron Signal Transfer - CORRECT ANSWER✔✔- -Depolarization of axon causes
Ca2+ to enter synaptic boutons --> causes ACh release
-Membrane at end-plate depolarizes due to ACh binding to receptors --> generates end-plate
potential
-Change activates voltage-gated Na+ channels in junctional folds --> converts potential to an
action potential that propagates along muscle fibre --> causes contraction
Importance of muscle - CORRECT ANSWER✔✔- -Almost half of body mass = muscle -->
can be largest consumer of energy; generates heat (can influence body temperature
regulation)
-Has mechanical function --> necessary for movement
-Receptors in muscles sense proprioception and regulate muscle forces through reflex arcs
-Can fatigue --> disrupts movement
Spinal Reflexes - CORRECT ANSWER✔✔- -Triggered by activation of sensory receptors
-Many reflexes are highly adaptable and control movements in a purposeful manner
-Produce coordinated patterns of muscle contraction
-Neuronal networks in spinal cord integrate responses
, Neuronal Signalling in the Spinal Cord - CORRECT ANSWER✔✔- -Neurons form specific
signalling networks that mediate specific behaviours (e.g. stretch reflex)
-Accomplished through two types of connections --> divergence (e.g. sensory receptor
neurons) and convergence (e.g. motor neurons)
Stretch Reflex - CORRECT ANSWER✔✔- -Activated in response to sudden unexpected
muscle stretch --> serves to keep limb in a specific position
-Spindle --> Ia afferent fibre --> Ia inhibitory interneuron/alpha motor neurons --> inhibitory
neuron inhibits antagonist, motor neurons stimulate homonymous muscle and synergist
Withdrawal (flexion) Reflex and Crossed-extension Reflex - CORRECT ANSWER✔✔- -
Painful stimulus activates nociceptor
-Primary sensory neuron enters spinal cord and diverges
-One collateral activates ascending pathways for sensation (pain) and postural adjustment
(shift in CoG)
-Withdrawal reflex pulls foot away from painful stimulus (flexors contract, extensors
inhibited on foot that experiences pain)
-Crossed extensor reflex supports body as weight shifts away from painful stimulus (flexors
inhibited, extensors contract on opposite foot)
Postural Reflexes - CORRECT ANSWER✔✔- -When stance is perturbed (e.g. from external
force), certain muscles are activated
-Postural reflexes rely on muscle synergies
Adaptability of Spinal Reflexes - CORRECT ANSWER✔✔- -Reflex responses are often
complex and can be changed depending on the task
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