The Nervous System Flashcards
What is the functional unit of the nervous system?
The neuron
T or F
All cranial nerves are located within the skull
T
T or F
Ganglia are part of the CNS
F
They are part of the PNS
Nerves that come from the spine are called…
spinal nerves
Nerves that come from the brain are called…
cranial nerves
The central nervous system processes sensory information and coordinates an appropriate response through the …
PNS
The PNS can be divided into what two divisions?
The afferent and efferent divisions
T or F
The afferent division of the PNS is responsible for sending signals out of the CNS
F
The afferent division brings signals to the CNS
Which nervous systems act out motor commands from the CNS?
The somatic nervous system and the automatic nervous system
The CNS is composed of what two major anatomical parts?
the brain and spinal cord
List the 4 types of neurons
Anaxonic
Bipolar
Unipolar
Multipolar
What is unique about anaxonic neurons in comparison to other types?
Anaxonic neurons have no obvious axon
Where can anaxonic neurons be found?
In the brain and retina
Which type of neuron am I?
I am small with many dendrites
Anaxonic
What distinguishes bipolar neurons from other types of neurons?
They have one axon and one dendrite extending from the cell body
Where can bipolar neurons be found?
In the special senses
What distinguishes unipolar neurons from other types?
They have two axons and the cell body is to the side
Most sensory neurons are … neurons
unipolar
T or F
In a unipolar axon, the dendrites and axons are a single fused process.
T
What type of neuron are motor neurons (in terms of structure)?
Multipolar neurons
T or F
Multipolar neurons have three or more dendrites and one axon.
F
two or more dendrites
Interneurons link … and … neurons
sensory
motor
T or F
There are more neurons than glia in the body
F
There can be up to ten times more glia than neurons
T or F
Glia and neuroglia are interchangeable terms
T
T or F
There are different glia in the CNS and PNS
T
Neurons are supported by …
glia
What type of glial cells are the most abundant in the CNS?
Astrocytes
T or F
Anaxonic neurons are rare and don’t usually have action potentials
T
T or F
Anaxonic neurons never have an axon
F
They can but they are indistinguishable from the dendrites
Astrocytes maintain the … and help to support and provide …
BBB
structure
T or F
Each oligodendrocyte can myelinate one axon
F
One oligodendrocyte can myelinate lots of axons
Oligodendrocytes conduct action potentials by producing …
myelin
T or F
Schwann cells can support unmyelinated axons but they cannot help speed up their action potentials
T
What type of glial cell lines cavities containing cerebrospinal fluid?
ependymal cells
What is the function of ependymal cells?
To produce and circulate cerebrospinal fluid
What is the least common CNS glia?
microglia
T or F
Oligodendrocytes are phagocytic cells
F
microglia are
T or F
Satellite cells perform similar functions to astrocytes
T
What type of CNS glia is part of the immune system?
microglia
What type of PNS glia surround cell bodies in ganglia?
Satellite cells
What is the function of satellite cells?
To regulate exchange with intestinal fluid
What two types of glia are part of the PNS?
Satellite cells and Schwann cells
Bundles of axons in the CNS are called … whereas bundles of axons in the PNS are called …
tracts
nerves
Clusters of neuronal cell bodies in the CNS are called … whereas clusters of neuronal cell bodies in the PNS are called …
nuclei
ganglia
Nerves contain … and … fibres
sensory
motor
T or F
Nerves have 5 connective tissue layers
F
3
List the connective tissue layers that nerves have in order of most external to least
Epineurium
Perineurium
Endoneurium
Which connective tissue layer that surrounds nerves is responsible for making a fibrous outer sheath?
epineurium
Which connective tissue layer that surrounds nerves is responsible for separating axon bundles into fascicles?
perineurium
Which connective tissue layer that surrounds nerves is responsible for wrapping around individual axons?
endoneurium
Axons from nerves join cell bodies in …
ganglia
Ganglia are surrounded by …
epineurium
T or F
Ganglia can contain cell bodies from both afferent and efferent neurons
T
Where does white matter get its colour from?
myelin
Where does grey matter get its colour from?
cell bodies
T or F
Grey matter contains tracts whilst white matter contains nuclei
F
vice versa
T or F
Like white matter, grey matter contains axons, but they are unmyelinated
T
T or F
Graded potentials are local and die out whilst action potentials travel along axons
T
T or F
The spinal cord is a major reflex centre
T
… allow sensory neurons to enter the spinal cord.
posterior rootlets
… allow motor neurons to exit the spinal cord.
anterior rootlets
T or F
Paired spinal nerves emerge from the
spinal cord
T
T or F
The spinal cord is shorter than the vertebral column
T
What is the cauda equina “horses tail”?
Roots of spinal nerves extending inferior to
the spinal cord
List the 4 spinal cord and vertebral regions from highest to lowest
cervical
thoracic
lumbar
sacral
The spinal cord is encased by the …
vertebral canal
What are the spaces between vertebrae called?
intervertebral foramen
What are the meninges?
three layers of membranes that cover and protect your brain and spinal cord
The roots of spinal nerves emerge from the …
intervertebral foramen
Between each vertebra is an … which provides a gelatinous cushioning to the spinal cord.
intervertebral disk
The cervical, thoracic, lumbar and sacral segments of the spinal corded are divided by the …
sympathetic ganglion chain
What 3 layers make up the meninges
The dura, arachnoid and pia mater
Which layer of the meninges is an outer fibrous sheath?
Dura mater
Which layer of the meninges is an Inner membrane bound to
spinal cord?
Pia mater
Which layer of the meninges provides support to blood
vessels of the spinal cord?
Pia mater
The epidural space is between the … mater and …
dura
vertebrae
The epidural space contains …, … and …
loose connective tissue, blood vessels & adipose tissue
Epidurals administered during childbirth are placed in the … or … spinal region
lumbar or sacral
The subarachnoid space is between … mater and … mater
arachnoid
pia
T or F
The subarachnoid space does not contain cerebral spinal fluid
F
When local anesthesia is administered in the spine it is injected into the … space
subarachnoid
Grey matter of the spinal cord is organised into …
horns
Grey matter of the spinal cord is organised into what three horns?
Dorsal (posterior) horn
Ventral (anterior) horn
Lateral horn
Cell bodies of interneurons receiving sensory info are present in which horn of the spinal cord?
The dorsal
Cell bodies of somatic motor neurons are present in which horn of the spinal cord?
The ventral
Cell bodies of autonomic motor neurons are present in which horn of the spinal cord?
Lateral
… in the spinal cord allows communication within the CNS
white matter
Neurons enter & exit the spinal cord through …
roots
List the 3 types of spinal roots
Dorsal root
Dorsal root ganglia
Ventral root
Which root of the spinal cord deals with Motor (efferent) axons?
ventral root
Which root of the spinal cord deals with sensory neuron cell bodies?
dorsal root ganglia
Which root of the spinal cord deals with sensory (afferent neurons)?
dorsal root
T or F
Spinal roots contain
both sensory and motor neurons
F
Spinal roots contain
either sensory neurons
or motor neurons
Each dorsal and ventral root fuses to form a …
spinal nerve
There are … pairs of spinal nerves
31
a spinal nerve is … - … cm long
1-2
T or F
Spinal nerves contain both sensory and motor axons
T
The ulner nerve is a … nerve
peripheral
short spinal nerves
branch into … and may
converge into a nerve …
rami
plexus
T or F
In order for something to be considered a “reflex” it must produce a standardised response with little variability
T
T or F
Reflexes can only be processed in the spinal cord
F
Brain and spinal cord
Reflexes can be … or …
mono or polysynaptic
monosynaptic reflexes have one synapse between … and … neuron
afferent
efferent
polysynaptic reflexes have more than one synapse aka they involve …
interneurons
The “wiring” for a reflex is
called a …
reflex arc
Reflex arcs consist of what 5 things?
– Receptor
– Sensory neuron
– Integration centre
– Motor neuron
– Effector
What do stretch reflexs detect?
Detects changes in muscle length (muscle stretch) and
causes contraction of the same muscle
T or F
Stretch reflexs are polysynaptic
F
mono
What type of reflex is the patellar reflex?
A stretch reflex
… are the sensory
receptors for the stretch reflex
Muscle spindles
… monitor position of
skeletal muscles & joints
Proprioceptors
Muscle … detect changes in muscle length
spindles
T or F
extrafusal muscle
fibres are regular contractile skeletal
muscle
T
T or F
Stretching muscle spindle
decreases the firing of the
sensory neurons
F
increases
T or F
Compressing a muscle spindle decreases firing of the sensory neuron
T
Stimulation of sensory neurons causes stimulation of … neurons and the
contraction of … muscle fibres
alpha motor
extrafusal
Is the withdrawl reflex and example of a monosynaptic or polysynaptic reflex?
Poly
(Regarding the withdrawal reflex)
… interneuron stimulates motor neuron to biceps
… interneuron inhibits motor neuron to triceps
Excitatory
Inhibitory
T or F
During the withdrawal reflex the biceps contract while triceps relax
T
What is reciprocal inhibition?
a general phenomenon in which the stretch of one muscle inhibits the activity of the opposing muscle.
Is the crossed extensor reflex contralateral or ipsilateral?
Contralateral reflex rather than ipsilateral
What is a contralateral reflex?
Motor response on opposite side to stimulus
What is an ipsilateral reflex?
Motor response on same side as stimulus (eg.
Stretch & withdrawal reflexes)
Stretch and withdrawal reflexs are examples of … reflexes
ipsilateral
The … reflex occurs with the withdrawal reflex
crossed extensor
T or F
In fish the brain and spinal cord are of equal weight
T
Is the human brain or spinal cord heavier?
The human brain is heavier than the human spinal cord
The human brain weights about … kgs
1.5
T or F
Cranial meninges are NOT continuous with spinal meninges
F
They are continuous
Match the cranial meninges name to characteristic
- Dura mater
- Arachnoid mater
- Pia mater
a. Subarachnoid space contains CSF
b. No epidural space (bound to skull)
c. Sticks to surface of brain
1a, 2b and 3c
Which mater layer of the cranial meninges contains two layers with blood filled space in between? And what is this called?
Dura mater
The dural sinus
Cerebrospinal fluid … and … the brain and spinal cord
cushions
nourishes
Cerebrospinal fluid is produced in the … of the …
choroid plexuses of the ventricles
The … ventricles of the brain are continuous with the central canal of the spinal cord
4
Fluid leaks out of choroid plexus … to form CSF
capillaries
CSF composition is maintained by … cells
ependymal
CSF circulates through the … of the spinal cord and the … of the brain
central canal
ventricles
T or F
CSF escapes through ventricle openings into the subarachnoid
space
T
CSF enters venous blood through …
arachnoid villi
Arachnoid tissue projects into …
dural sinuses
The blood brain barrier is formed by tightly adhered … cells
capillary
… signal capillary cells to tighten
Astrocytes
T or F
Molecules must pass through capillary cells to access the brain
T
The elevated ridges of the brain are called …
Gyri
The shallow depressions of the brain are called … and the deep depressions …
sulci
fissures
The grey matter surrounding the cerebrum is known as the …
cerebral cortex
The inner core of grey matter is called the …
basal nuclei
The cerebrum is split into … hemispheres and is connected by the …
two
corpus callosum
The diencephalon is composed of the … and …
thalamus
hypothalamus
The brain stem is composed of what three parts?
The midbrain, pons and medulla oblongata
What are the 4 major regions of the brain?
The cerebrum, diencephalon, cerebellum and brain stem
The cerebral cortex can be divided into what 4 lobes based on structural features?
Occipital, temporal, parietal & frontal lobes
The insular cortex is folded within the …
lateral sulcus
Match the lobes of the cerebral cortex with their characteristics:
- Occipital lobe
- Temporal lobe
- Frontal lobe
- Parietal lobe
a. Primary motor cortex
b. Primary somatosensory cortex
c. Visual cortex
d. Auditory and olfactory cortex
1c, 2d, 3a and 4b
Which lobe of the cerebral cortex am I?
Perception of the general senses (e.g. temperature, pain, touch, pressure, vibration and proprioception). Tells us awareness, location & intensity.
Parietal lobe
The primary somatosensory cortex is divided into regions that receive sensory info
from …
different parts of the body
The … (little man)
represents the
sensitivity of each body
region.
sensory homunculus
Which lobe of the cerebral cortex am I?
Voluntary control over skeletal muscle
* Fine tuned by lower brain centres
* Receives instruction from the premotor cortex
Frontal lobe
T or F
Primary motor cortex activates motor neurons but does not initiate
motor activity
T
T or F
Like the somatosensory cortex the primary motor cortex is also organised by regions of the body
T
T or F
The motor homunculus
looks the same as the sensory homunculus
F
The motor homunculus
looks different to the
sensory homunculus
Does the motor or sensory homunculus devote more space to the hand?
The motor
Which cortex of the brain am I?
* Planning and problem solving
* Directing attention
* Decision making
* Creativity
* Personality traits
The prefrontal cortex
T or F
The limbic system is the part of the brain involved in our behavioural and emotional responses.
T
What am I?
Clusters of grey matter embedded in white matter of the
cerebrum
Basal nuclei
Which part of the brain Controls motor activity by fine-tuning motor commands of
upper motor neurons?
Basal nuclei
Which part of the brain is responsible for subconscious control of motor activity?
– skeletal muscle tone
– provide pattern and rhythm for movement – eg movement of arms and
legs during walking
Basal nuclei
Which part of the brain is the coordinator and predictor of movement (refines movements that are already planned, and helps to maintain balance & posture)
The cerebellum
All sensory information (except smell) synapses at the …
thalamus
Which part of the brain am I?
Homeostatic control (Body temp; urine output; food intake)
– Endocrine role (hormone secretion; control of endocrine glands)
– Emotional & behavioural drives
– Control of autonomic function
Hypothalamus
Which part of the brain am I?
Motor information from the
cerebellum and basal nuclei travel
through the thalamus to the cortex
– Plays an important role in consciousness
Thalamus
What are some functions of the brain stem?
Highway between spinal cord and higher brain structures
– Autonomic control centres for cardiovascular & respiratory systems
– Controls awakening and levels of alertness
– Attachment of most cranial nerves
– Subconscious control of skeletal muscle
movement
T or F
The medulla oblongata, pons & midbrain are all part of the brainstem
T
There are … pairs of cranial nerves
12
What is the motor nervous system controlling glands, cardiac muscle, smooth muscle & adipose tissue.
The autonomic nervous system
The … nervous system control blood pressure, body temperature and water balance
autonomic
The target organs of the ANS are in the … and … cavities
thoracic and abdominopelvic
cavities
T or F
The divisions of the ANS innervate different organs
F
What are the divisions of the ANS?
– Sympathetic
– Parasympathetic
T or F
Each division of the ANS has some level of activity
even at rest
T
Basal rate of activity is called …
Autonomic tone
…. allows the ANS to both increase or decrease activity
Autonomic tone
T or F
Blood vessels are only innervated by the
sympathetic NS
T
Blood vessels can constrict or dilate by
varying the rate of … in … neurons
APs
sympathetic
The ANS has a … motor neuron chain
two
Somatic nervous system has … motor neuron.
one
ANS has two motor neurons that synapse at an … in the PNS.
autonomic ganglion
Cell bodies of preganglionic neurons are in the … of the spinal cord
lateral horn
Preganglionic fibres leave the … of the spinal cord
ventral roots
T or F
Preganglionic fibres are (mostly) long. Postganglionic fibres are (mostly) short.
F
vice versa
Sympathetic preganglionic neurons synapse with neurons in what three groups of ganglia?
sympathetic chain ganglia, collateral ganglia and the adrenal medullae
The cell bodies of preganglionic neurons are in the … and … of the spinal cord
brain stem and sacral segment
Preganglionic fibres travel through the … or … nerves
cranial nerves or pelvic
The vagus nerve (cranial nerve X) provides …% of all parasympathetic outflow
75%
T or F
All ANS preganglionic fibres release acetylcholine
T
T or F
No sympathetic postganglionic fibres release Ach
F
Some do
Most sympathetic postganglionic fibres release …
norepinephrine
Fibres releasing Ach are called … fibres.
Fibres releasing norepinephrine are called … fibres
cholinergic
adrenergic
What are the two types of cholinergic receptors?
Nicotinic and muscarinic
T or F
Nicotinic receptors are GPCRs
F
Muscarinic receptors are
T or F
Muscarinic receptors are cation channels
F
Nicotinic receptors are
… receptors bind epinephrine and norepinephrine with differing affinities
Adrenergic
T or F
Adrenergic receptors are GPCRs
T
Adrenergic receptors are found on … target organs
sympathetic
Each division of the ANS can be stimulated locally through … reflexes
visceral
Localised reflex of the parasympathetic or sympathetic NS?
Swallowing reflex
Pupil size changes
Swallowing reflex = Para
Pupil size change = symp
The … Ns can respond by
mass discharge
sympathetic
Why does the sympathetic NS have a generalised response (mass discharge)?
– Amplified by hormonal response (adrenal medullae)
– Preganglionic neurons diverge to form synapses with many different
ganglionic neurons
Mass discharge can be activated by … or …
mental or physical stress
T or F
Sensory receptors are most sensitive to one type of stimulus
T
Stimulus energy (eg. Pressure, temp. etc) must be converted to … to be perceived
electrical energy
Each stimulus type causes stimulation of the cortex
through a different …
labelled line
Stimulus intensity is determined by which two things?
- Frequency of action potentials
– Strong stimulus = more frequent action
potentials - Number of receptors activated
– Strong stimulus = more receptors activated
The location of a stimulus is determined by stimulation of a …
receptive field
Sensory information about touch, pressure, vibration, pain and
temperature will go to the …
primary somatosensory cortex
T or F
All receptors adapt to constant stimulation
F
Most
What are the main differences between tonic and phasic receptors?
Tonic receptors
– Adapt slowly (or not at all)
– Constant response to stimuli
– Eg. Pain receptors
* Phasic receptors
– Adapt quickly
– Responds to changes in stimuli
– Pressure receptors
What are the three types of mechanoreceptors?
- Tactile receptors (touch, pressure & vibration)
– Baroreceptors (pressure eg. Blood vessels)
– Proprioceptors (position of joints & muscles)
…receptors provide info about touch, pressure & vibration
Mechano
What are the 6 types of tactile receptors in the skin?
Free nerve endings
Root hair plexus
Tactile discs
Tactile (Meissner’s) corpuscles
Lamellated (Pacinian) corpuscles
Ruffini corpuscles
Pain is detected by …
nociceptors
Pain is associated with emotional and behavioral responses due to nociceptors activation of the … and … systems
hypothalamus
limbic
Fast pain is transmitted over … fibres whilst slow pain is transmitted over … fibres
A-delta fibres (myelinated axons)
C fibres (unmyelinated axons)
T or F
Fast pain is poorly localised and slow pain is easily localised
F
vice versa
What are the two types of thermoreceptors?
warmth & cold
Temperature extremes are detected by …
nociceptors
Perception of hot or cold
depends on the … &
… of receptor
stimulation
combination
intensity
T or F
Thermoreceptors are fast adapting phasic receptors
T
T or F
Each muscle fibre has two neuromuscular junctions
F
Each muscle fibre only has one neuromuscular junction
