Neurology Flashcards
what are the 2 types of neurons in the PNS?
sensory and motor
what are the 2 types of nerves in the PNS?
spinal and cranial
how many pairs of cranial nerves are there?
12
what is the name of the 10th cranial nerve (n.X)?
vagus nerve
how many pairs of spinal nerves are there?
30+
what do neurons with their cell bodies inside the CNS develop from?
the neural tube
where are the cell bodies of somatic motor neurons?
inside the CNS
where are the cell bodies of preganglionic autonomic neurons?
inside the CNS
what do neurons with cell bodies in ganglia outside the CNS develop from?
neural crest
where are the cell bodies of postganglionic neurons?
in ganglia outside the CNS
where are the cell bodies of sensory neurons?
in ganglia outside the CNS
what induces each spinal nerve to grow
an embryonic somite
what are muscles innervated by?
nerve(s) to their myotome(s) of origin
what are plexi?
tangles of nerves
why do adjacent spinal nerves often form plexi after leaving the vertebral column?
overlap between skin and muscle regions
how many cervical nerves are there?
7+1
at which vertebrae do the spinal nerves end?
Cd 4/5/6/7
where does the C1 motor nerve exit?
lateral foramen of the atlas
what do the nerves pass through in the vertebra in general?
the intervertebral notch
where do the cranial/cervical nerves emerge in relation to the same numbered vertebra?
cranial
where do the non C nerves arrange relative to the same numbered vertebra?
caudal
how many T nerves are there? (dog)
13
how many lumbar nerves are there? (dog)
7
how many sacral nerves are there? (dog)
3
how many caudal nerves are there?
4-7
what is the grey matter in vertebrae composed of?
cell bodies
what is the white matter in vertebrae composed of?
axons
what innervates hypaxial muscles, limbs, body wall (hypomere)
ventral ramus
what does ventral ramus innervate?
hypaxial muscles, limbs, body wall (hypomere)
what does dorsal ramus innervate?
epaxial muscles (epimere)
what innervates epaxial muscles (epimere)?
dorsal ramus
what do C1-5 innervate?
segmental skin and spinal muscles, some innervate some of cranial truncobrachial junction muscles
what does C1 not have?
sensory fibres, dorsal root
what is the sensory region innervated by C2?
skin of caudal head/medial ear
what do C5,6,7 form?
phrenic nerve to diaphragm
what hypaxial rami form the brachial plexus?
C6-T2
how many nerves are in the forelimb?
around 12
where is the brachial plexus? (dog)
deep to the scapula
what cord innervates the elements of the limb girdle?
girdle cord
what are the components of the girdle cord?
cleidobrachial, subscapular, suprascapular
what does the sub-scapular nerve innervate?
subscapularis
what does the suprascapular nerve innervate?
supraspinatus and infraspinatus
what does the cleidobrachial nerve innervate?
brachiocephalicus
what are the components of the cranial cord?
cranial superficial pectoral nerve, musculocutaneous nerve
what does the cranial superficial pectoral nerve innervate?
superficial pectoral
what does the musculocutaneous nerve innervate?
elbow flexors
what are the components of the lateral cord?
thoracodorsal nerve, axillary nerve, radial nerve
what does the thoracodorsal nerve innervate?
latissimus dorsi
what does the axillary nerve innervate?
shoulder flexors
what are the components of the caudal cord?
caudal (deep) pectoral nerve, median nerve, ulnar nerve
what are the 4 nerve chords from the brachial plexus?
girdle, cranial, caudal, lateral
what does the radial cord innervate?
elbow muscles, carpus muscles, digit extensors
what does the median cord innervate?
carpus, digit flexors
what does the ulnar cord innervate?
FCU, DDFuln, manus muscles
what are the four long nerves from the brachial plexus?
musculocutaneous, ulnar, radial, median
what does the musculocutaneous nerve innervate?
elbow flexors, medial skin
what does the radial nerve innervate?
elbow, carpus, digit extensors; cranial and dorsal skin
what does the ulnar nerve innervate?
carpus and digit flexors, caudal and digit V skin
what does the median nerve innervate?
carpus and digit flexors, palmar skin
where is the ulnar nerve located in the manus?
deep to muscles
where is the median nerve located in the muscles?
superficial layer to skin
what forms the carpal canal?
carpal flexor retinaculum
what is sweeney?
damage to suprascapular nerve causing suprascapular paralysis leading to rapid atrophy of supraspinatus and infraspinatus
what do n.T3-T12 innervate?
spinal segments and intercostal spaces
what do n.T3-T12 run caudal to?
each rib
what do n.T13-L3 provide sensory innervation to?
the flank
which hypaxial rami mingle as the lumbosacral plexus?
L4-S2
what are the 4 main nerves of the hindlimb?
genitofemoral nerve, fibular and tibial nerves, obturator nerve
where does the genitofemoral nerve pass through?
inguinal canal
what is the sciatic trunk/nerve?
2 nerves, 1 dorsal and 1 ventral, that run together
what does the femoral dorsal nerve innervate?
hip flexors and stifle extensors
what does the obturator nerve innervate?
medial thigh muscles
what does the sciatic trunk innervate?
gluteals and hams
what does the sciatic trunk separate into?
fibular and tibial nerves
what does the fibular nerve innervate?
hock flexors and digital extensors
what does the tibial nerve innervate?
hock extensors and digital flexors
where are the cell bodies of sensory nerves?
within dorsal root ganglion
where are the cell bodies of motor neurons?
within grey matter
where do the motor and sensory nerve join in the spinal cord?
at the exit of the vertebral column (foramen)
what is the hypomere?
the lateral plate of mesoderm that develops into the walls of the body cavities
what might the diaphragm be evolved from?
a subscapular muscle
what is the important nerve for weightbearing in the forelimb?
radial nerve
what innervates the lateral aspect of the paw?
ulnar nerve
what path does the radial nerve take?
starts medial and caudal and spirals around humerus to become lateral and cranial
+ cards for which hypaxial rami each nerve comes from?
what muscle does the femoral nerve run through?
iliopsoas
what nerve is important for weightbearing in the hindlimb?
femoral nerve
where do the tibial and fibular nerves separate?
just distal to stifle
which remains caudal, the tibial or fibular nerve?
the tibial nerve
which moves to be cranial, the tibial or fibular nerve?
the fibular nerve
which nerve is most prone to injury in the hindlimb?
obturator nerve
paralysis of what nerve is a cause of ‘downer cow syndrome’ in cows giving birth?
obturator nerve
which nerves innervate segmental muscles of the tail?
S3-Cd4-7
what do S3-Cd4-7 innervate?
segmental muscles of the tail
what are the extrinsic muscles of the tail?
medial, lateral, dorsal and ventral sacrocaudalis
what do the signs of spinal cord injury depend on?
severity of damage (affecting progressively deeper regions of cord) and cranio-caudal location along cord
what spinal nerves contribute to the girdle cord?
C6,7 and a little from 8
what spinal nerves contribute to the cranial cord?
C7/8, little from 6
what spinal nerves contribute to the lateral cord?
C7/8 and T1
what spinal nerves contribute to the caudal cord?
C8/T1/T2
where are the origins of parasympathetic nerves?
craniosacral- can’t come from C1 to L7
where are the origins of sympathetic nerves?
thoracolumbar- none in cranial nerves
where do parasympathetic nerves have their ganglia?
near to the organ of effect
where do sympathetic nerves have their ganglia?
close to the CNS, distant from organ of effect
where are the cell bodies of motor neurons?
in the grey matter ventral horn
where do sensory neurones have to enter the spinal cord?
dorsally
where do motor neurons have to exit the spinal cord?
ventrally
what does the autonomic nervous system control?
digestion, respiration, perspiration, metabolism, maintaining blood pressure, reproduction
what is the sympathetic nervous system responsible for?
fight or flight
what is the parasympathetic nervous system responsible for?
rest and digest
how many neurons are there between the CNS and target organ in the ANS?
2
where are the cell bodies of 1st order neurons?
in the CNS
what does the 1st order neurons develop from?
neural tube
where are the cell bodies of the 2nd order neurons (parasympathetic)?
close to the target organ
what do 2nd order neurons develop from?
neural crest
which are well myelinated, 1st or 2nd order neurons?
1st order
what colour are well-myelinated neurons?
white
what colour are less well-mylelinated neurons?
grey
which has long post ganglionic fibres, sympathetic or non-sympathetic?
sympathetic
which has more post-ganglionic fibres from each pre-ganglionic fibre, sympathetic or parasympathetic??
sympathetic
what do sympathetic nerves mainly release?
noradrenaline and co-transmitter Y-NPY
what do parasympathetic nerves release?
acetylcholine and co-transmitter VIP)
what does neuropeptide Y (NPY) do?
augment the vasoconstrictor effects of noradrenaline and
what does vasoactive intestinal peptide (VIP) do?
stimulate the secretion of water and electrolytes, dilates intestinal smooth muscles and peripheral blood vessels, inhibits gastrin-stimulated gastric acid secretion
what receptors do sympathetic nerves act on?
adrenoreceptors
what receptors do parasympathetic nerves act on?
muscarinic receptors
what is the distribution of sympathetic innervation?
cardiac and all smooth muscle
what is the distribution of parasympathetic innervation?
cardiac and smooth muscle of the viscera only
what is the position of the cell bodies of the 1st order sympathetic neurons?
thoracolumbar (T1-L3/4)
what is the position of the cell bodies of the 1st order parasympathetic neurons?
craniosacral
which cranial nerves have parasympathetic fibres?
III, VII, IX, X
what is the name of cranial nerve III?
occular motor nerve
what is the name of cranial nerve VII?
facial nerve
what is the name of cranial nerve IX?
glossopharyngeal nerve
what is the name of cranial nerve X?
vagus nerve
where do 1st and 2nd order neurons synapse in sympathetic nervous system?
in discrete ganglia
where do 1st and 2nd order neurons synapse in parasympathetic nervous system?
often independently on or near target organ
what is the most important nerve in the parasympathetic nervous system?
vagus nerve
approximately how many of the parasympathetic nerves in body are stimulated by vagus nerve?
75%
where do sympathetic neurons originate in the spinal cord?
the intermediate/lateral horn of spinal cord
what is the somatic afferent axon part of?
the sensory peripheral system
what is the visceral afferent axon not part of?
the ANS
what does the sympathetic chain run alongside?
the spinal cord
what are the 3 options for the 1st order neuron in the sympathetic chain?
can synapse immediately, travel up or down chain before synapsing, or pass straight through chain to synapse in outlying prevertebral ganglion
what are the 3 sympathetic ganglia cranially in the neck?
the cervicothoracic/stellate ganglion, cranial cervical ganglion and middle cervical ganglion
which spinal nerves supply the cervicothoracic ganglion?
C7-T3
which spinal nerves supply the cranial cervical ganglion?
C1-C3
which spinal nerves supply the middle cervical ganglion?
C4-6
where is the cranial cervical ganglion found?
at base of skull
where do the left and right sympathetic chains merge?
at L7 in impar ganglion
what are the 3 main ganglia outlying from the sympathetic chain?
coeliac, cranial mesenteric, caudal mesenteric
where are the coeliac, cranial mesenteric and caudal mesenteric ganglia found?
at the roots of their named arteries
what connects the coeliac, cranial mesenteric and caudal mesenteric nerves with the sympathetic chain?
the splanchnic nerve
what is the greater splanchnic nerve derived from?
T11-T12
what is the lesser splanchnic nerve derived from?
T11-L1
what vertebrae is the lumbar nerve derived from?
L3-5
what are the 2nd order sympathetic nerves supplying the thoracic viscera called?
cardiosympathetic nerves
what artery supplies the foregut?
coeliac artery
what artery supplies the midgut?
cranial mesenteric artery
what artery supplies the hindgut?
caudal mesenteric artery
where do the first order neurons in the sympathetic supply to the foregut synapse?
coeliac ganglion
where do the first order neurons in the sympathetic supply to the midgut synapse?
cranial mesenteric ganglion
where do the first order neurons in the sympathetic supply to the hindgut synapse?
caudal mesenteric ganglion
what do the lumbar splanchnics synapse with in the caudal mesenteric ganglion to supply the pelvic viscera?
hypogastric nerve
what do sympathetic fibres from T1-L3 target?
organs in skin (arrector pili, sweat gland and blood vessel smooth muscle)
what protects the sympathetic nerves that supply the blood vessels and skin of the neck?
transverse foramen
where is the adrenal medulla positioned?
cranial/dorsal to kidney with outer cortex surrounding central medulla
what replaces the second order neurons in the adrenal medulla?
chromaffin cells
what cells release adrenaline into the blood?
chromaffin cells
which cranial nerves provide parasympathetic supply to the head?
III, VII, IX
what supplies the heart with parasympathetic innervation?
cardiovagal nerves
where do the right and left vagal nerves separate and fuse?
along the oesophagus near aorta
what allows nerves to pass from the thoracic to the abdominal cavity?
hiati in the diaphragm
what provides parasympathetic supply to the lesser curvature of the stomach, liver and ventral pancreas?
ventral vagus
what provides parasympathetic supply to the greater curvature of the stomach, then continues to the remainder of the foregut as plexus on the coeliac artery?
dorsal vagus
what supplies the midgut with parasympathetic innervation as plexus on cranial mesenteric artery?
dorsal vagus
what supplies parasympathetic innervation to the pelvic viscera?
pelvic nerves from S1 and 2
what are the target organs of the parasympathetic pelvic nerves?
rectum, ureter, bladder, urethra, genitalia
what supplies parasympathetic innervation to the hindgut viscera?
pelvic nerves from S1 and S2 that travel to pelvic plexus then either pass along gut wall or join with hypogastric nerve
what is Horner’s syndrome?
common clinical syndrome resulting from loss of sympathetic innervation to head (eye)
