CMB2007 PNS EXAM QUESTIONS AND VERIFIED
DETAILED ANSWERS
what is the peripheral nervous system? -Answer all the neurones carrying information to
affinity neurons or from effector neurons to the CNS
state and explain the 3 structural parts of a neuron -Answer Axon-carries information
away from the cell body
Cell body, soma-contains the nucleus and all the organelles
Dendrites-carry information to the cell body
Describe the process whereby electrical activity is transmitted between neurons. -
Answer Electrical activity in an axon: action potential
Electrical activity that this represents is transmitted between neurons at the synapse
When the action potential reaches the synapse chemical messengers or
neurotransmitters are released from vesicles in the pre-synaptic bouton.
These cross the synaptic cleft and bind to receptors on the post-synaptic membrane,
initiating a depolarisation or hyperpolarisation in the dendritic membrane of the
post-synaptic neuron
how is the spinal cord protected? - Answer The spinal cord is protected by the
vertebrae, it runs through a canal created by tunnels in each vertebra - vertebral canal
anatomic position - The body erect; feet flat, facing forward; eyes facing forward; arms
to the side, palms facing forward with thumbs pointing outward.
vertebral canal - The vertebral canal is the vertical passageway formed by each
vertebrae
When the vertebrae are stacked on top of each other to form the spine these foramen
form the vertebral canal that runs the whole length of the vertebral column.
, This canal contains the spinal cord and provides it with some protection.
explain the cross sectional anatomy of the spinal cord - Answer The outer section of the
spinal cord is comprised of white matter; it is composed of axons of neurons that form
ascending or descending pathways.
The inner section is comprised of grey matter. This is where the cell bodies of neurons
are located and is where synapses occur between these cell bodies, their dendrites and
the axons of other neurons.
Nerves from the body enter through the dorsal roots of the spinal cord and nerves exit
the spinal cord through the ventral root (ventral horn).
what is the somatic nervous system responsible for? - Answer Responsible for
conscious control of our bodies and the corresponding feedback
Somatic sensory nerves (afferent) detect pain, temperature, touch and proprioception
(where the body is in space)
Somatic efferent nerves are motor skeletal muscles
what is different about somatic neurons? -Answer Somatic neurons do not synapse once
they have left the CNS, they project directly to their target cell via a single neuron
describe the 2 types of somatic nerves -Answer Spinal nerves that arise from the spinal
cord
Cranial nerves that arise directly from the brain
at what vertebra does the spinal root leave the spinal cord - Answer A spinal root leaves
the spinal cord below each vertebra (T1, T2 etc) except in the cervical region where
they exit superior to the vertebrae and lucky C7 has one above (C7 nerve) and one
below (C8 nerve).
This produces 31 spinal roots. There is an additional root from the coccyx
DETAILED ANSWERS
what is the peripheral nervous system? -Answer all the neurones carrying information to
affinity neurons or from effector neurons to the CNS
state and explain the 3 structural parts of a neuron -Answer Axon-carries information
away from the cell body
Cell body, soma-contains the nucleus and all the organelles
Dendrites-carry information to the cell body
Describe the process whereby electrical activity is transmitted between neurons. -
Answer Electrical activity in an axon: action potential
Electrical activity that this represents is transmitted between neurons at the synapse
When the action potential reaches the synapse chemical messengers or
neurotransmitters are released from vesicles in the pre-synaptic bouton.
These cross the synaptic cleft and bind to receptors on the post-synaptic membrane,
initiating a depolarisation or hyperpolarisation in the dendritic membrane of the
post-synaptic neuron
how is the spinal cord protected? - Answer The spinal cord is protected by the
vertebrae, it runs through a canal created by tunnels in each vertebra - vertebral canal
anatomic position - The body erect; feet flat, facing forward; eyes facing forward; arms
to the side, palms facing forward with thumbs pointing outward.
vertebral canal - The vertebral canal is the vertical passageway formed by each
vertebrae
When the vertebrae are stacked on top of each other to form the spine these foramen
form the vertebral canal that runs the whole length of the vertebral column.
, This canal contains the spinal cord and provides it with some protection.
explain the cross sectional anatomy of the spinal cord - Answer The outer section of the
spinal cord is comprised of white matter; it is composed of axons of neurons that form
ascending or descending pathways.
The inner section is comprised of grey matter. This is where the cell bodies of neurons
are located and is where synapses occur between these cell bodies, their dendrites and
the axons of other neurons.
Nerves from the body enter through the dorsal roots of the spinal cord and nerves exit
the spinal cord through the ventral root (ventral horn).
what is the somatic nervous system responsible for? - Answer Responsible for
conscious control of our bodies and the corresponding feedback
Somatic sensory nerves (afferent) detect pain, temperature, touch and proprioception
(where the body is in space)
Somatic efferent nerves are motor skeletal muscles
what is different about somatic neurons? -Answer Somatic neurons do not synapse once
they have left the CNS, they project directly to their target cell via a single neuron
describe the 2 types of somatic nerves -Answer Spinal nerves that arise from the spinal
cord
Cranial nerves that arise directly from the brain
at what vertebra does the spinal root leave the spinal cord - Answer A spinal root leaves
the spinal cord below each vertebra (T1, T2 etc) except in the cervical region where
they exit superior to the vertebrae and lucky C7 has one above (C7 nerve) and one
below (C8 nerve).
This produces 31 spinal roots. There is an additional root from the coccyx
