PHGY 215 Module 2,5,6 Practice
Questions with Accurate Solutions 2026
Edition.
nervous system - Answer - Made up from the central nervous system and the peripheral
nervous system (Made up from the somatic nervous system)
The central nervous system (CNS) allows you to perform many complex functions such as... -
Answer 1) subconscious neuronal regulation of your internal environment
2) emotions
3) voluntary movement
4) perception
5) higher cognitive functions such as learning and memory
CNS and PNS work together - Answer Afferent division of the PNS carries sensory information
from the periphery to the CNS where is is processed. The CNS can then send necessary
instructions back to the periphery through the efferent division.
Neuronal cells of the nervous system - Answer 1. Afferent neurons
2. Interneurons
3. Efferent Neurons
Afferent neurons - Answer Majority of these line in the PNS. They send information to the
CNS, the peripheral ending has a sensory receptor.
In response to appropriate stumble, the receptor generates an action potential that is
transmitted down the adherent fibre to the nerve cell body. This action potential is then
transmitted down the shorter central axon which terminates n other neurone within the spinal
cord. The cell body does not have dendrites
,Interneurons - Answer most numerous class of neutrons (99% in the body). The lie completely
within the CNS. They are connector neurone that lie between the afferent neurons and the
efferent neurons.
Play a role in creating neural circuit for integrating responses to peripheral information. Also
play a role in higher brain functions (learning and decision making)
efferent neurons - Answer cell bodies lie within the CNS where they receive converging
presynaptic snouts when theres inputs initiate an action potential, it travels down the efferent
fibre to the effector organ. The efferent fibre lies mainly outside the CNS
glial cells - Answer are non-neuronal cells that do not initiate nor propagate action potentials.
They use chemical signals to communicate between glial cells and neurons.
They form the connective tissue of the brain and their primary role is supportive in that they
maintain homeostatic control of the extracellular environment around the neurons
they have been shown to modulate some neuronal activities and play a role in learning and
memory
Are the most numerous cells of the CNS (90%) but due to their size and number they only
account for 50% of the total brain volume
Protection of the CNS: Bone- the skull and vertebrae - Answer The cranium (skull) completely
surrounds the brain while the spine completely surrounds the spinal cord. These provide hard
physical barriers as protection agains damage
Protection of the CNS: the protective membranes (Meninges) #1: Dura Mater - Answer
Outermost membrane is a tough double membrane that lies next to the bone. The two layers
are always in direct in contact but in certain regions thy may be separated to create blood-filled
spaces called the dural sinuses (large ones called venous sinuses)
Venous blood draining from the brain empties into these sinuses to be returned to the heart.
Cerebral spinal fluid can also drain into dural sinuses
protective membranes: Arachnoid Mater - Answer Middle meninges is more delicate and hilly
vascularized
,The area of dural sinuses projections of the arachnoid matter called arachnoid granulation vili
penetrate through the dural and extend into the sinuses. This allows the transfer of
cerebrospinal fluid from the subarachnoid space to cross the villi to the blood of the sinuses.
protective membranes: Cerebrospinal Fluid - Answer protects the brain acting like a shock-
absorber. The density of the CSF is similar to that of the brain tissue itself which allows the brain
to be suspended within it. The fluid is located between the arachnoid mater and the pia matter.
CSF is essential for the transfer of materials between the blood and neural tissues. The brains
intestinal fluid surrounds and supplies the neurons and glial cells.
CFS or bloodstream are not indirect contact with intracellular fluid, they influence its
composition. The CSF has a stronger influence that the blood stream, and is highly regulated
Choroid plexus are highly vascularized masses of pia matter that dip into pockets of ependymal
cells and create the CFS. A chord plexus can be found in each of the 4 ventricles. The entire
volume of the CSF is between 125-150 mL and is replaced more than 3 times a day
CSF flows through the ventricles. Within the 4 ventricle, CSF can enter the subarachnoid space
to flow between the meningeal layers and over the entire brain. It also flows into the central
canal of the spinal cord. CSF is reabsorbed from the subarachnoid space through the arachnoid
villi to enter the venous blood
protective membranes: The blood brain barrier (BBB) - Answer Endothelial cells of the brain
capillaries are joined together by tight junctions to prevent materials from passing between the
cells.
Exchange of materials between the blood and the brain must pass through the endothelial cells
and is highly regulated. It is important that sudden changes in blood plasma composition will
not influence the composition of the brains intracellular fluid and affect neuronal function
Is a multicomponent neuromuscular unit, allowing the barriers premeability to be regulated by
a variety of cell types. This is beneficial because the BBB must not only protect the cells of the
brain from toxins, but also be able to respond to the dynamic metabolism of neurons, glial cells
and the extracellular matrix. The permeability of the barrier needs to be highly regulated. A
complex neurovascular unit is required so that each comment of the brain can provide
necessary input.
The spinal cord - Answer Long tube of neurons and supports cells which extends from the
brainstem through a hole in the skull to the lumber region fo the vertebral column. It acts as a
highway for the flow of information between the brain and the body. Can also independently
control reflexes
, Is encapsulated by the meaninges creating an extracellular environemnt
Cross section of the spinal cord: grey matter - Answer Consists of nerve cell bodies, short
interneurons and glial cells. contains a central canal which is filled with CSF. each half of the grey
matter can be divided into regions called horns
Dorsal Horn - Answer cell bodies of interneurons on which afferent neurons terminate
lateral horn - Answer cell bodies of autonomic efferent nerve fibers
ventral horn - Answer cell bodies of somatic efferent neurons
Cross section of the spinal cord: White matter - Answer Consists of bundles of nerve fibres or
axons. Each bundle is connected to a specific region of the brain to transmit information from
the brain to the periphery (descending tracks of efferent neurons) or from the periphery to the
brain (ascending tracks of afferent neurons)
Afferent and Efferent connections - Answer Vental horn contains cell bodies for the efferent
motor neurons and the lateral horn contains cell bodies for the atomic efferent fibres.
The cell bodies for the afferent nerves are located outside of the spinal cord in regions called
dorsal root ganglia
Ganglia are collections of neuron cell bodies that receive information form the periphery and
relay it to the interneurons of the dorsal horn within the spinal cord grey matter
The dorsal root ganglia are connected to the spinal cord by two different pathways, the dorsal
root containing the adherent input and the ventral root containing the efferent outpost. The
efferent cell bodies are located within the cord
The afferent and efferent cells from nerves which connect the CNS to the rest of the body via
PNS
Structure of a Nerve - Answer - A nerve is a bundle of peripheral afferent and efferent axons
covered in connective tissues that are following the same pathway
there axons are not communicating with each other. Nerves do not contain the cell bodies of
the neurons. theres are found within the CNS or in ganglia in the pNS
Questions with Accurate Solutions 2026
Edition.
nervous system - Answer - Made up from the central nervous system and the peripheral
nervous system (Made up from the somatic nervous system)
The central nervous system (CNS) allows you to perform many complex functions such as... -
Answer 1) subconscious neuronal regulation of your internal environment
2) emotions
3) voluntary movement
4) perception
5) higher cognitive functions such as learning and memory
CNS and PNS work together - Answer Afferent division of the PNS carries sensory information
from the periphery to the CNS where is is processed. The CNS can then send necessary
instructions back to the periphery through the efferent division.
Neuronal cells of the nervous system - Answer 1. Afferent neurons
2. Interneurons
3. Efferent Neurons
Afferent neurons - Answer Majority of these line in the PNS. They send information to the
CNS, the peripheral ending has a sensory receptor.
In response to appropriate stumble, the receptor generates an action potential that is
transmitted down the adherent fibre to the nerve cell body. This action potential is then
transmitted down the shorter central axon which terminates n other neurone within the spinal
cord. The cell body does not have dendrites
,Interneurons - Answer most numerous class of neutrons (99% in the body). The lie completely
within the CNS. They are connector neurone that lie between the afferent neurons and the
efferent neurons.
Play a role in creating neural circuit for integrating responses to peripheral information. Also
play a role in higher brain functions (learning and decision making)
efferent neurons - Answer cell bodies lie within the CNS where they receive converging
presynaptic snouts when theres inputs initiate an action potential, it travels down the efferent
fibre to the effector organ. The efferent fibre lies mainly outside the CNS
glial cells - Answer are non-neuronal cells that do not initiate nor propagate action potentials.
They use chemical signals to communicate between glial cells and neurons.
They form the connective tissue of the brain and their primary role is supportive in that they
maintain homeostatic control of the extracellular environment around the neurons
they have been shown to modulate some neuronal activities and play a role in learning and
memory
Are the most numerous cells of the CNS (90%) but due to their size and number they only
account for 50% of the total brain volume
Protection of the CNS: Bone- the skull and vertebrae - Answer The cranium (skull) completely
surrounds the brain while the spine completely surrounds the spinal cord. These provide hard
physical barriers as protection agains damage
Protection of the CNS: the protective membranes (Meninges) #1: Dura Mater - Answer
Outermost membrane is a tough double membrane that lies next to the bone. The two layers
are always in direct in contact but in certain regions thy may be separated to create blood-filled
spaces called the dural sinuses (large ones called venous sinuses)
Venous blood draining from the brain empties into these sinuses to be returned to the heart.
Cerebral spinal fluid can also drain into dural sinuses
protective membranes: Arachnoid Mater - Answer Middle meninges is more delicate and hilly
vascularized
,The area of dural sinuses projections of the arachnoid matter called arachnoid granulation vili
penetrate through the dural and extend into the sinuses. This allows the transfer of
cerebrospinal fluid from the subarachnoid space to cross the villi to the blood of the sinuses.
protective membranes: Cerebrospinal Fluid - Answer protects the brain acting like a shock-
absorber. The density of the CSF is similar to that of the brain tissue itself which allows the brain
to be suspended within it. The fluid is located between the arachnoid mater and the pia matter.
CSF is essential for the transfer of materials between the blood and neural tissues. The brains
intestinal fluid surrounds and supplies the neurons and glial cells.
CFS or bloodstream are not indirect contact with intracellular fluid, they influence its
composition. The CSF has a stronger influence that the blood stream, and is highly regulated
Choroid plexus are highly vascularized masses of pia matter that dip into pockets of ependymal
cells and create the CFS. A chord plexus can be found in each of the 4 ventricles. The entire
volume of the CSF is between 125-150 mL and is replaced more than 3 times a day
CSF flows through the ventricles. Within the 4 ventricle, CSF can enter the subarachnoid space
to flow between the meningeal layers and over the entire brain. It also flows into the central
canal of the spinal cord. CSF is reabsorbed from the subarachnoid space through the arachnoid
villi to enter the venous blood
protective membranes: The blood brain barrier (BBB) - Answer Endothelial cells of the brain
capillaries are joined together by tight junctions to prevent materials from passing between the
cells.
Exchange of materials between the blood and the brain must pass through the endothelial cells
and is highly regulated. It is important that sudden changes in blood plasma composition will
not influence the composition of the brains intracellular fluid and affect neuronal function
Is a multicomponent neuromuscular unit, allowing the barriers premeability to be regulated by
a variety of cell types. This is beneficial because the BBB must not only protect the cells of the
brain from toxins, but also be able to respond to the dynamic metabolism of neurons, glial cells
and the extracellular matrix. The permeability of the barrier needs to be highly regulated. A
complex neurovascular unit is required so that each comment of the brain can provide
necessary input.
The spinal cord - Answer Long tube of neurons and supports cells which extends from the
brainstem through a hole in the skull to the lumber region fo the vertebral column. It acts as a
highway for the flow of information between the brain and the body. Can also independently
control reflexes
, Is encapsulated by the meaninges creating an extracellular environemnt
Cross section of the spinal cord: grey matter - Answer Consists of nerve cell bodies, short
interneurons and glial cells. contains a central canal which is filled with CSF. each half of the grey
matter can be divided into regions called horns
Dorsal Horn - Answer cell bodies of interneurons on which afferent neurons terminate
lateral horn - Answer cell bodies of autonomic efferent nerve fibers
ventral horn - Answer cell bodies of somatic efferent neurons
Cross section of the spinal cord: White matter - Answer Consists of bundles of nerve fibres or
axons. Each bundle is connected to a specific region of the brain to transmit information from
the brain to the periphery (descending tracks of efferent neurons) or from the periphery to the
brain (ascending tracks of afferent neurons)
Afferent and Efferent connections - Answer Vental horn contains cell bodies for the efferent
motor neurons and the lateral horn contains cell bodies for the atomic efferent fibres.
The cell bodies for the afferent nerves are located outside of the spinal cord in regions called
dorsal root ganglia
Ganglia are collections of neuron cell bodies that receive information form the periphery and
relay it to the interneurons of the dorsal horn within the spinal cord grey matter
The dorsal root ganglia are connected to the spinal cord by two different pathways, the dorsal
root containing the adherent input and the ventral root containing the efferent outpost. The
efferent cell bodies are located within the cord
The afferent and efferent cells from nerves which connect the CNS to the rest of the body via
PNS
Structure of a Nerve - Answer - A nerve is a bundle of peripheral afferent and efferent axons
covered in connective tissues that are following the same pathway
there axons are not communicating with each other. Nerves do not contain the cell bodies of
the neurons. theres are found within the CNS or in ganglia in the pNS
