Ch. 2 - Nervous System Flashcards
How many poles does the brain have?
3
frontal, temporal, occipital pole
The sympathetic nervous system is responsible for _______ and the parasympathetic nervous system is responsible for _______.
fight or flight
rest and digest
What is the largest area of the brain?
telencephalon
What divides the left and right hemisphere of the telencephalon?
sagital fissure/sulcus
What separates the telencephalon from the cerebellum?
horizontal fissure
What separates the temporal lobe of the telencephalon from the upper part of the cerebrum?
lateral fissure
What are the 4 lobes of the telencephalon?
frontal, parietal, occipital, temporal lobe
What is the outer covering of the telencephalon called?
cortex
The fold of the cortex are called…
gyri (bumps) and sulci (valleys)
The precentral gyrus is the ____ cortex.
motor (movement is initiated here)
The postcentral gyrus is the _____ cortex.
sensory
Where is the diencephalon located?
the centre of the base of the cerebrum
What are the 4 components of the diencephalon?
thalamus, hypothalamus, subthalamus, epithalamus
The thalamus is a large nucleus located on both sides of the _________.
third ventricle
What senses go through the thalamus?
every sense BUT smell
What is situated below the thalamus and connected to the pituitary gland?
hypothalamus
The _______ is located below the thalamus.
subthalamus
The _______ is a small nucleus located behind the thalamus.
epithalamus
What does the grey matter of the cerebrum contain?
cell bodies of the neurons
The grey matter is confined to the ________ and the ________.
cortex, basal ganglia
The _________ are deep nuclei and mostly related to motor function.
basal ganglia
What are the different basal ganglia?
lentiform nucleus, caudate nucleus, amygdala
The thalamus and the internal capsule are made up of ________.
white matter (fibres, axons)
What are the three types of white matter fibres?
association, commissural, and projection fibres
What are the association fibres responsible for?
communication within one hemisphere
-stay in the same half
What are the commissural fibres responsible for?
communication between the hemispheres
-one half to the other half
What are the three sets of the commissural fibres?
anterior commissure, posterior commissure and the corpus callosum
The __________ connects the hemispheres and has lots of fibres.
corpus callosum
What are the projection fibres responsible for?
communication between different levels of the nervous system (not confined to the cerebrum)
-one level to another
Most cranial nerves enter/leave through which structure?
brain stem
What are the two large fibre bundles of the midbrain?
anteriorly the cerebral peduncles (tracks) and posteriorly the superior/inferior colliculi (little bumps)
Which cranial nerves are attached at the junction of the midbrain and the pons
CN III (oculomotor) and CN IV (trochlear)
Which structure bridges the cerebellar hemispheres?
pons
Which cranial nerves emerge from the anterior surface of the pons
CN V (trigeminal)
What is located behind the pons?
fourth ventricle and cerebellum
What is the medulla oblongata continuous with?
spinal cord
On the anterior surface of the medulla oblongata are the ______ medially and the _____ laterally
pyramids, olives
What is the cerebellum responsible for?
coordination
What is the cerebellum connected to the brain stem via?
large middle cerebellar peduncles
The spinal cord extends in the vertebral canal from the _______ down to _______.
foramen magnum to L1/2
How many sets of spinal nerves emerge from the spinal cord and leave through the intervertebral foramina?
32
The spinal cord tapers at the _______________.
conus medullaris
What attaches the conus medullaris to the sacrum?
filum terminale (thread like)
The nerves that exit below L2 form which structure?
cauda equina
What are the thickenings of the spinal cord called?
cervical and lumbar enlargements
The anterior horns in the spinal cord are responsible for what?
motor function
The posterior horns in the spinal cord are responsible for what?
sensory function
The intermediate horn for the sympathetic nervous system is between…
T1 and L2
The white matter is arranged into which three columns?
posterior, lateral and anterior funiculi
The ventricles are continuous with the narrow central canal of the _________.
spinal cord
The anterior horn of the lateral ventricles is located in which lobe?
frontal lobe
The posterior horn of the lateral ventricles is located in which lobe?
occipital lobe
The inferior horn of the lateral ventricles is located in which lobe?
temporal lobe
The body of the lateral ventricles is located in which lobe?
parietal lobe
What are the choroid plexuses filled with?
cerebrospinal fluid (CSF)
What connects the lateral ventricles with the third ventricle?
foramina of monro
What joins the third and fourth ventricle?
aqueduct of sylvius
In the lateral recesses of the fourth ventricle are the ________.
foramina of luschka
What is located at the inferior angle of the fourth ventricle?
foramen of magendie
The CSF travels from the ventricles to the _________ via the foramen of luschka+magendie
subarachnoid space
The CNS is encased in three layers of specialized connective tissue; they are…
dura mater, arachnoid mater, pia mater
The dura mater is located…
outside of the brain and spinal cord
The dura mater invaginates into the sagital fissure to form the _________.
falx cerebri
The dura mater invaginates into the horizontal fissure to form the _________.
tentorium cerebelli
What is the name of the fat-filled space between the skull and the vertebral column
epidural space
What is the name of the layer that is thin and filmy that contains the blood vessels
arachnoid layer
The CSF circulates in the __________.
subarachnoid space
What connects the arachnoid and pia mater?
denticulate ligaments
Which layer is attached to the superficial cortex and the outer surface of the spinal cord?
pia mater
The functions of the CSF are…
metabolic and protective
The CSF circulates all around the CNS in the subarachnoid space, providing a _______.
shock absorptive function
The arachnoid mater penetrates through the dura into which structure?
superior sagital sinus
What are the large openings of the subarachnoid space called?
cisterns
What is the name of the opening that is created when the spinal cord terminates at L1/2 and the dura and arachnoid mater extend into the sacrum
lumbar cistern (spinal tap or lumbar puncture performed here)
The brain receives blood from which two sources?
carotid and vertebral arteries
The vertebral arteries connect to form the ________.
basilar artery
The basilar artery splits into the two _________.
posterior cerebral arteries
The single _______ joins the two anterior cerebral arteries.
anterior communicating artery
The paired ________ joins the middle and posterior cerebral arteries.
posterior communicating artery
The communicating arteries form the _______ around the pituitary gland.
circle of willis
The anterior/posterior cerebral arteries supply which surface of the brain?
sagital
The anterior/posterior cerebral arteries supply the _______ of the outer cortex.
periphery
The ______ comes through the lateral fissure and supplies the centre of the brain.
middle cerebral artery
The cerebellum is supplied by which arteries?
superior and inferior cerebellar arteries
The spinal cord gets blood from where?
vertebral arteries at the superior end and from the aorta lower down
The veins of the brain empty into the _______ sinuses which drain into the _______ vein.
dural venous sinuses, internal jugular vein
What is the somatic peripheral nervous system responsible for?
voluntary motor control and general sensation information
The somatic peripheral nervous system consists of ___ paris of spinal nerves and ___ pairs of cranial nerves
31/32 spinal nerves, 12 cranial nerves
The dorsal root of the nerve…
receives sensory information
The ventral root of of the nerve…
sends motor information
Why are the sacral nerves unique?
split into rami before exiting the foramina
The cell bodies of the the motor nerves are located where?
anterior horn; axons run into the ventral root
The cell bodies of the sensory nerves are found in the …
dorsal root ganglia
The spinal nerves are classified ________ according to their spinal levels
alphanumerically
C1-C8
cervical nerves; exit above the corresponding vertebrae
T1-T12
thoracic nerves; exit below the corresponding vertebrae
L1-L5
lumbar nerves; exit below the corresponding vertebrae
S1-S5
sacral nerves; exit below corresponding vertebrae
The autonomic peripheral nervous system…
provides involuntary motor control and visceral sensory perception
The dorsal columns are made up of the _______ and are responsible for…
fasciculus gracilis+cuneatus, carry out all major sensory information that the brain needs
Define ipsilateral.
fibres that stay on the same side
all fibres eventually cross over
Define contralateral
fibres that cross over
Which senses are carried out in the dorsal columns?
discriminatory (fine) touch, joint position (proprioception), vibration
Which senses are carried out in the anterolateral columns?
non-discriminatory (crude) touch, pain, temperature
The fibres of the dorsal columns run from…
below T6
The fibres of the lower limb travel in the ________.
fasciculus gracilis
The fibres of the upper limb (above T6) travel in the __________.
fasciculus cuneatus
The fibres of the dorsal column synapse on the secondary neurons in the lower medulla in the _____________.
nucleus gracilis and nucleus cuneatus
Where do the axons in the dorsal columns crossover and become contralateral?
nucleus gracilis
Where do the axons of the dorsal columns synapse for the second time?
thalamus
Where does the dorsal column pathway end?
postcentral gyrus in the sensory cortex
The axons of the anterolateral column synapse in the…
dorsal horn
The anterolateral pathway goes into the brain stem and attaches to the ______.
medial leminscus
The anterolateral column axons synapse a second time in the ______ and travel to the _______.
thalamus, postcentral gyrus
The descending motor pathways are responsible for…
initiate movement in the muscles
Which is the most direct motor pathway?
corticospinal tract
Where do most of the fibres crossover to form the lateral corticospinal tract?
lower medulla
The fibres that remain ipsilateral form the ….
anterior corticospinal tract
All corticospinal fibres terminate in the ______ and synapse with the ________.
anterior horn, large anterior horn neurons
Which tracts make up the extra pyramidal system?
rubrospinal, vestibulospinal, reticulospinal tracts
The olfactory nerves (CN I) synapse in the ______.
olfactory bulb
What is the rhinencephalon?
part of the brain where the 2nd neuron is synapsed
Which nerves come from the retina and pass back through the optic canal?
optic nerve (CN II)
Where do the two optic nerves meet/cross?
optic chiasm
What happens if you lose the optic chiasm
tunnel vision, no peripheral
Which nerves emerge from the brain stem?
CN III, IV, VI
Which muscles do the oculomotor nerves (CNIII) supply?
superior rectus, inferior rectus, medial rectus, inferior oblique, levator palpebrae superioris
The trochlear nerves (CN IV) supply which muscle?
superior oblique
The abducens nerves (CN VI) supply this muscle.
lateral rectus
The extraocular nerves (CN III, IV, VI) exit through what?
superior orbital fissure
Which nerve directly arises from the pons?
trigeminal nerve (CN V)
Where does the opthalamic component of the trigeminal nerve (CN V1) exit?
superior orbital fissure
Where does the maxillary component of the trigeminal nerve (CN V2) exit?
foramen rotundum
Where does the madnibular component of the trigeminal nerve (CN V3) exit?
foramen ovale
What are each of the components of the trigeminal nerve for?
opthalmic - forehead
maxillary - cheek
mandibular - jaw
Which cranial nerve passes through the internal acoustic meatus?
facial nerve (CN VII)
How does the facial nerve exit the skull?
stylomastoid foramen
The facial nerve provides parasympathetic supply to which glands?
submandibular, sublingual, lacrimal
Which nerve exits the brain stem lateral to CN VII and enters the internal acoustic meatus?
vestibulococlear nerve (CN VIII)
Which nerve brings sensory information regarding sound and position back from the internal ear?
vestibulococlear nerve (CN VIII)
What is the glossopharyngeal nerve (CN IX) attached to?
medulla below the exit of CN VIII
CN IX provides __________ to the parotid glands, __________ to the stylopharnygeus muscle, and ________ to the posterior 1/3 of the tongue.
parasympathetic innervation, motor innervation, sensory innervation
Which nerve is the great parasympathetic nerve of the thorax and abdomen?
vagus nerve (CN V)
Where does CN X exit?
jugular foramen
Which cranial nerves exit the spinal cord at the upper cervical levels (neck)
spinal accessory (CN XI)
Which nerve arises from the rootlets that exit between the pyramid and olive of the medulla?
hypoglossal (CNXII)
What is CN XII responsible for?
extrinsic and intrinsic muscles of the tongue
Which nervous system is considered the unconscious motor component of the visceral nervous system?
autonomic nervous system
What does the autonomic nervous system innervate?
smooth muscle of the viscers, glands and blood vessels
Sympathetic nerves arise from …
T1-L2
Parasympathetic nerves originate from which cranial nerves?
CN III, VII, IX ,X and sacral levels S2-4
Where do the sympathetic preganglionic neurons originate and exit?
originate: intermediate horn of the grey matter
exit: anterior ventral root
Preganglionic neurons enter the sympathetic trunk via the ________ and exit via the ________.
white ramus communicans, grey ramus communicans
Where are the sympathetic trunks located?
on each side of the vertebral column
The sympathetic ganglia run from which levels?
C1-S5
What does somatotopic mean?
top part of the body is served by the top, bottom is served by the bottom
The superior cervical ganglion represents…
C1-4
The middle cervical ganglion represents…
C5-6
The inferior cervical ganglion represents…
C7-8
The most inferior two coccygeal ganglia fuse in midline to form which structure?
ganglion impar
Where do the nerves to the skin and blood vessels of the limbs, body walls, head and neck synapse?
sympathetic trunk
What are the three ways the sympathetic nerves will synapse?
- synapse in the sympathetic trunk ganglion at the same level they exited the spinal cord
- travel superiorly to synapse at a higher-level (head, neck, upper limbs)
- travel inferiorly to synapse in the sympathetic trunk (skin, arteries of the badomen, pelvis and lower limbs)
At what level does white rami exit?
T1-L2
Where do the splanchnic nerves travel?
viscera
The preganglionic nerves of the lung and somer heart innervation synapse at …
its own level and goes directly to the appropriate plexus
The pregnaglionic nerves of the head, neck and rest of the hear synapse at…
- travel superiorly
- synapse in the trunk
The preganglionic nerves of the bladder and reproductive organs synpase at…
-descend to the inferior lumbar and sacral levels
The preganglionic neurons of the GI tract synapse at…
- pass directly through the corresponding sympathetic ganglion and emerge anteromedially
- synpase in the abdominal preaortic ganglia or the renal ganglia
Which cranial nerve carries efferent neurones for the pupil and lens muscles?
oculomotor (CN III)
Which cranial nerves serve the salivary and lacrimal glands?
facial (CN II) and glossopharyngeal (CN IX)
Which cranial nerve sends preganglionic fibers to the viscera of the thorax and abdomen as well as to the GI tract 2/3 along the length of the transverse colon?
vagus (CN X)
Where do the pelvic splanchnic nerves arise from?
S2-4
What level are the greater splanchnic nerves?
T5-9 (supplies the foregut)
What level supplies the midgut?
T10-11 (lesser splanchnic)
What level supplies the kidneys?
T12
What level supplies the hindgut?
L1-2 (lumbar splanchnics)
The sympathetic innervation of the organs above the diaphragm is from…
the upper ganglia in the sympathetic trunk C1-T4
The head and neck receive preganglionic fibres from …
T1
The thoracic organs receive innervation from …
T1-4
The pathway to the lungs is via ______ with the postganglionic fibres originating in the trunk at the same levels
T2-4
Which splanchnics are considered the thoracic splanchnic nerves?
greater, lesser, and least thoracic and lumbar splanchnics
The fibres for the abdomen originate in the…
thoracic splanchnic nerves
The lest splanchnic nerve goes to the kidney and synapses in the __________.
ganglia of the renal plexuses
The greater thoracic splanchnic nerve synapses in the ______ to innervate the foregut (stomach and first part of the duodenum).
celiac ganglion
The lesser thoracic splanchnic nerve supplies the ________ via the superior mesenteric ganglion.
midgut (remainder of the duodenum and the small and large intestine as far as 2/3 along the transverse colon)
The _________ innervate the hindgut (rest of the GI) and synapse on the inferior mesenteric ganglion.
lumbar splanchnic nerves
Where does the pelvis receive postganglionic fibres from?
lower paravertebral ganglia and small ganglia located near the target organs
What supplies the smooth muscle in the pharynx and larynx as well as all the organs in the thorax
vagus nerve
