QUIZ 4 Flashcards
1
Q
cranial nerves
A
- peripheral nerves of the brain
- 12 paired cranial nerves
- directly comes off the brain (not spinal cord)
- numbered by emergence (forebrain to hindbrain) (rostral to caudal)
2
Q
numbered cranial nerves
A
1 olfactory 2 optic 3 oculomotor 4 trochlear 5 trigeminal 6 abducent 7 facial 8 vestibulocochlear 9 glosophyaryngeal 10 vagus 11 accessory 12 hypoglossal
3
Q
purely special somatic sensory nerves cranial nerves
A
- olfactory (1)
- optic (2)
- vestibulocochlear (8)
4
Q
motor cranial nerves
A
- oculomotor (3)(parasympathetic)
- trochlear (4)
- abducent (6)
- accessory (11)
- hypoglossal (12)
5
Q
mixed cranial nerves
A
- trigeminal (5)
- facial (7) (parasympathetic)
- glossophyaryngeal (9)(parasympathetic)
- vagus (10) (parasympathetic)
6
Q
oculomotor nerve
A
-movement of the eye
7
Q
cranial nerve pathway
A
starts in brain -> ganglion -> synapse with new neuron -> postganglion -> target organ
8
Q
anterior cranial fossa
A
- frontal
- ethmoid
- sphenoid
9
Q
middle cranial fossa
A
- sphenoid
- parietal
- temporal
10
Q
posterior cranial
A
- holding cerebellum
- occipital
11
Q
cranial foramina
A
- cribriform plate -> olfactory
- optic canal -> optic
- superior orbital fissure -> ophthamic, trochlear, oculomotor, abducens
- foramen rotundum- maxillary
- foramen ovale- mandibular
- internal acoustic meatus- facial, vestibulocochlear
- jugular foramen- glosopharyngeal, vagus, accessory
- hypoglossal canal- hypoglossal
12
Q
trigeminal
A
- mandibular
- mylohyoid
- lingual
13
Q
olfactory nerve (1)
A
- special somatic sensory
- goes through cribriform plate of the ethmoid bone (top of nasal cavity)
- many of them
- synapse of the olfactory bulb
- post synapse -> olfactory tract to cerebral cortex
- anterior cranial fossa
- olfactory bulb is inferior to the frontal lobe
- bipolar neurons
- skip the thalamus* (unlike other somatic sensory)
- go directly to the temporal lobe and limbic system
14
Q
dog olfactory bulb
A
- much larger
- rely more on smell
15
Q
optic nerve (2)
A
- special somatic sensory
- transmit signals from retina
- enters the skull through the optic canal of the sphenoid
- round foramina (medial superior)
- comes in form the front to the back
- chiasm- neurons meet
- nerve becomes a tract in CNS
- light will come in through eye -> hit retina (rod and cones) -> transmission -> optic nerve -> optic chiasm
- visual field of left eye hits the right side of the retina (right occipital cortex) vice versa
- thick -> many neurons
16
Q
lateral geniculate body is a nucleus that relays optic sensory information from the eye towards the visual cortex of the cerebrum. given what you know about brain region function where is the lateral geniculate body found
A
- thalamus
- diencephalon that is receiving somatic sensory signals from most somatic sensory information (not olfactory) -> then sent to cerebrum (occipital lobe)
17
Q
vestibulocochlear nerve
A
- special somatic sensory of balance and hearing
- two branches: vestibular branch and cochlear branch
- vestibular branch:
- balance (knowing where your body is in space)
- 3 semicircular canals -> help you orient your body
- transmits signals from semicircular canals -> through internal auditory canal -> goes out to the brain stem
- cochlear branch:
- comes from cochlea
- cochlea- snail shaped, hearing, vibrations
- auditory auricles- pick up vibrations through hairs
- go to thalamus -> cerebrbum
18
Q
peripheral nerves
A
- come out from the brain
- numbers from anterior to posterior
19
Q
visceral efferent
A
- motor
- pre and post ganglion
20
Q
accessory nerve (CN XI)
A
- somatic motor
- two roots:
- cranial root- medulla oblongata
- *spinal root- spinal cord C1-C5 -> enters via foramen magnum
- two branches:
- cranial branch- accessory (runs next to) to vagus
- spinal branch- innervates trapezius and sternocleidomastoid -> exits via jugular foramen
21
Q
hypoglossal nerve (CN XII)
A
- somatic motor
- innervates the tongue
- intrinsic tongue
- extrinsic tongue:
- hyoglossus
- genioglossus
- styloglossus
- NOT palatoglossus
- does NOT contribute to the ansa cervicalis
- C1 spinal nerve simply runs along it for a bit
- goes from the medulla oblongata through a very thin foramen -> hypoglossal canal
22
Q
trochlear nerve (CN IV)
A
- only has somatic motor
- only innervates one muscle:
- superior oblique muscle
- movement of the eye
- attaches at the orbit (back) and goes through a pulley-like sling called the trochlea
- ligaments attached to lateral superior side
- passed from inside of the skull to the eye orbit through the superior orbital fissure of sphenoid
23
Q
superior orbital fissure of sphenoid
A
- where the trochlear nerve passes through to go from inside skull to eye orbit
- space between the lesser wings (superior cranial fossa) and greater wings (middle cranial fossa)
- abducens nerve goes through here too
- trochlear
- oculomotor
- opthalmic
24
Q
abducens nerve (CN VI)
A
- somatic motor
- innervated lateral rectus muscle
- abducts the eye
- from back to lateral side
- pull from the lateral side of the eye -> abducts laterally
- goes through the superior orbital fissure of the sphenoid
25
oculomotor nerve (CN III)
- visceral efferent: parasympathetic (involuntary)
- somatic motor (voluntary)
- ciliary ganglion
- somatic motor muscle that it innervates:
- levator palpebrae superioris (opens eyelid)
- superior oblique
- superior rectus
- inferior rectus
- medial rectus
- lateral rectus
- inferior oblique (medial, rotation)
- Parasympathetic muscles it innervates (involuntary):
- ciliary muscle (shapes lens -> oval to round shape)
- synapse at the ciliary ganglion
- constrictor pupillae (constricts pupil depending on light)
26
oculomotor palsy
- oculomotor palsy -> weak muscle function for muslces innervated by the oculomotor (in the eye)
- lateral palpebrae superioris- weakened -> ptosis of eyelid (drooping)
- parasympathetic issues would involve weakening of the pupillary constriction (constrictor pupillae)
- lack of direct and consensual pupillary reflexes (light)
- when you shine light in one eye you expect pupil reflex in both eyes -> this wont happen if there is oculomotor palsy
- lack of accommodation reflex (close vision) -> speed at which your lens can change shape (influenced by ciliary muscle)
- long distance to short distance
- lens shape modification (ciliary muscle)
27
abducens palsy
- limited ocular movement
- abduction of eye is lacking
- somatic motor only
- only one eye can abduct
- both can adduct
- lazy eye
28
trigeminal nerve (CN V)
-3 branches: ophthalmic (superior orbital fissure), maxillary (foramen rotundum), mandibular (foramen ovale)
-provides general somatic innervation to face, dura, jaws, and tongue
-motor innervation to mastication muscles
-travels along postganglionic neurons (parasympathetic)
-
29
trigeminal nerve (CN V): somatic face
```
Sensory:
-eyeball (ophthalmic ->pain)
-skin of nose (ophthalmic)
-skin of forehead (ophthalmic)
-maxillary teeth (maxillary -> pain)
-skin of cheeks (maxillary)
-mandibular teeth (V3)
-skin of lower jaw (V3)
-oral mucosa (V3)
-tongue anterior 2/3 (not taste -> its touch) (V3)
Motor:
-masticatory muscles (V3)
```
30
foramen rotundum
-round shape
31
trigeminal nerve: ophthalmic division (CN V1)
- Somatic Sensory:
- eyeball
- skin of nose
- skin of forehead
- enters through superior orbital fissure
- exits from orbit through supraorbital notch (forehead)
32
trigeminal nerve: maxillary division (CN V2)
- Somatic Sensory
- maxillary teeth
- skin of cheeks
- foramen rotundum
- exits from maxilla from the infraorbital foramen (below orbit)
33
trigeminal nerve: mandibular division (CN V3)
- Somatic Sensory:
- mandibular teeth
- skin of lower jaw
- oral mucosa
- tongue anterior 2/3 (not taste)
- Somatic Motor:
- masticatory muscles (temporalis, masseter, pyerygoids)
- leaves skull through foramen ovale
- goes into mandible through mandibular foramen
- exits through the mental foramen (chin)
34
masseter
- muscle of mastication
- zygomatic arch of the cheek bone to the mandible
- innervated by the trigeminal mandibular division (V3)
35
temporalis
- between the skull and the zygomatic arch of the cheek bone to the mandible
- muscle of mastication
- innervated by the trigeminal mandibular division (V3)
- contract on sides of head when you clench your teeth
36
pterygoids
- muscle of mastication
- innervated by the trigeminal mandibular division (V3)
- from back of palate to the mandible
37
facial nerve (CN VII)
- exits through the internal acoustic meatus
- somatic sensory taste
- general somatic auricle (floppy bit around the ear)
- somatic motor facial expressions muscles
- parasympathetic innervation of the lacrimal gland (tear gland) and submandibular, sublingual glands (salivary)
- three branches: greater petrosal (parasympathetic to lacrimal gland), chorda tympani (parasympathetic to salivary glands: special sensory taste), and facial nerve (somatic motor to facial expression)
- Special Sensory:
- taste (anterior 2/3 of tongue)
- Somatic Motor:
- facial expression muscles
- Parasympathetic: lacrimal gland
- salivary glands (submandibular, sublingual)
38
facial nerve: greater petrosal (CN VII)
- solely parasympathetic to lacrimal gland
- in internal acoustic meatus
- greater petrosal branch branches out after the facial nerve enters the temporal bone through the internal acoustic meatus
- greater petrosal branch exits via the hiatus of facial canal
- goes back towards the orbit through the foramen lacerum
- preganglionic neurons will synapse at the pterygopalatine ganglion
- postganglion parasympathetic neurons travel along the branches of trigeminal maxillary nerve (V2)
- postganglionic parasympathetic innervation goes to the lacrimal glands
39
facial nerve: chorda tympani (CN VII)
- parasympathetic to salivary glands: special sensory taste
- goes through the petrotympanic fissure
- goes through the internal acoustic meatus
- chorda tympani branch goes through the petrotympanic fissure at the temporal bone
- merges with trigeminal mandibular (V3)
- receives taste from the anterior 2/3 from the tongue
- provides parasympathetic innervation to salivary glands
- parasympathetic preganglion will synapse at the submandibular ganglion
- postganglionic neurons will travel to submandibular and sublingual glands
40
facial nerve: facial nerve (CN VII)
- third branch
- (somatic motor to facial expression
- passes through the stylomastoid foramen
- goes through the internal acoustic meatus
- leaving the temporal goes through the stylomastoid foramen
- branches again into 5 branches -> go in different directions to innervate different somatic motor facial expression muscles
41
lacrimal gland
- found lateral superior to each eyeball
- produces tear fluid
- lubricates the eye
- moves from the lateral superior across the eyeball towards the lacrimal duct -> goes into the nasal duct
- innervation by the greater petrosal branch of the facial nerve
42
where is the sublingual gland found
-deep to tongue
43
salivary glands
- submandibular gland (CN VII)- under mandible
- sublingual gland (CN VII)- deep to tongue
- parotid gland (CN IX -> tympanic)
- parasympathetic innervation to the submandibular and sublingual glands
44
facial paralysis (bells palsy)
- common cause: inflammation of facial nerve at stylomastoid foramen
- loss of muscle tone
- lower orbicularis oculi falls away from eye
- weakening of orbicularis oris
- dry cornea
- saliva dribbling
- food accumulation during chewing
45
glossopharyngeal nerve (CN IX)
-jugular foramen
-two branches tympanic (foramen ovale) and glossopharyngeal (jugular foramen)
-special somatic sensory taste
-general somatic for oropharynx
-general visceral afferent- carotid body and sinus
-somatic motor efferent stylopharyngeus
-parasympathetic to otic ganlgion
Somatic Sensory:
-pharynx
-posterior 1/3 of tongue (touch)
Special Sensory:
-taste (posterior 1/3 of tongue)
Visceral Sensory (afferent):
-carotid body- blood chemoreceptor
-carotid sinus- blood pressure
Somatic Motor:
-stylopharyngeus (muscle on either side of pharynx -> elevate pharynx and larynx)
Parasympathetic:
-parotid gland (salivary -> tympanic)
46
carotid body
- on the carotid artery
- blood chemoreceptor -> senses changes in CO2 and O2 levels -> can alter heart rate
- innervated by glossopharyngeal (CN IX)
- visceral sensory (afferent)
47
carotid sinus
- pressure based
- around the circumference of the artery
- innervated by glossopharyngeal (CN IX)
- visceral sensory (afferent)
48
glossopharyngeal nerve: tympanic branch (CN IX)
- very small
- only for the parasympathetic for the parotid salivary gland
- foramen ovale
- preganglionic neurons synapse with the otic ganglion
- postganglionic neurons will go to the parotid gland
49
glossopharyngeal nerve: glossopharyngeal gland (CN IX)
-transmits everything but the parotid salivary gland
-jugular foramen
-Somatic Sensory:
-pharynx
-posterior 1/3 of tongue (touch)
Special Sensory:
-taste (posterior 1/3 of tongue)
Visceral Sensory (afferent):
-carotid body- blood chemoreceptor
-carotid sinus- blood pressure
Somatic Motor:
-stylopharyngeus (muscle on either side of pharynx -> elevate pharynx and larynx)
50
vagus nerve (CN X)
-goes through jugular foramen
-special somatic sensory for taste (in epiglottis)
-general somatic auricle
-general visceral afferent- larynx abdomen
-somatic motor efferent- pharynx, larynx
-**parasympathetic innervation of thorax and abdomen
Somatic Sensory:
-external auditory meatus
Special Sensory:
-taste (epiglottis)
Visceral Sensory:
-tracheobronchial tree
-viscera (abdomen + thorax)
Somatic Motor
-pharyngeal constrictors larynx
Parasympathetic
-heart
-abdominal organs
51
spinal nerves
- peripheral nerves of the spinal cord
| - mean of which the brain, CNS, and spinal cord communicate with the outside
52
spinal cord
- CNS
- neural tube invaginates in the back and curls up -> forms a tube with a canal in the middle -> ventricles of the brain and the central canal of the spinal cord
- incorporates cells from neural crest
- mass of tissue develops on the ventral and dorsal sides of the neural canal -> becomes central canal of the spinal cord
- neural canal becomes smaller as it develop -> becomes the central canal
- white matter develop
53
nuclei of grey matter of the spinal cord
- Ventral region- upper, nerves exiting -> motor
- Dorsal region- lower, nerves entering -> sensory
- interneurons synapse with motor neurons or move up to the brain -> process information
54
roots
- sensory and motor roots
- 31 pairs of anterior and posterior roots each up and down the spinal cord
- form spinal nerves
- dorsal- sensory, entering
- ventral- motor, exiting
- join together and form spinal nerve
55
gray matter of the spinal cord
- Dorsal contains:
- somatic sensory nuclei
- visceral sensory nuclei
- afferent nuclei
- Ventral contains:
- autonomic efferent nuclei
- motor nuclei
- somatic motor nuclei
-nuclei involve cell bodies and axons that are unmyelinated in the grey matter
56
white matter of the spinal cord
- sensory and motor tracts (nerves in CNS)
- myelinated
- Sensory ascending tracts in the dorsal and lateral regions
- Motor descending tracts in the lateral and ventral regions -> involved in autonomic
57
structure of the spinal cord
- similar along the length of the cord
- H shaped horn of grey matter that occupies the center
- white matter surrounds on the outside
- shape of horns change as you move from cervical, thoracic, lumbar, sacral
- basic structure is still the same
58
vertebral column in relationship to vertebral canal
- spinal cord is shorter in an adult than the vertebral canal/column
- spinal cord begins as the same length but as you grow the vertebrae growths in length at a greater rate
- spinal nerves that came out of the spinal column gets pulled down as the sacrum extends down -> so the spinal nerves continue down lower than the spinal cord
- vertebral column/canal- C1-S5
- spinal cord- C1-L1/L2
59
spinal nerves
- cervical- 8
- thoracic- 12
- lumbar- 5
- sacral- 5
- coccygeal- 1
- total= 31
60
vertebral column
- cervical- 7
- thoracic- 12
- lumbar- 5
- sacral- 5
- coccygeal- 3
- total= 32
61
segmental body plan
- dermatome- area of skin supplied by one spinal nerve (sensory)
- myotome- muscles supplied by one spinal nerve (sensory & motor)
- cervical, lumbar, thoracic, sacral spinal nerves innervate the whole body
- face is innervated by trigeminal cranial nerve
62
parts of spinal nerve
- 2 roots
- trunk (nerve itself)
- 2 branches (ventral and dorsal ramus)
- dorsal and ventral root combines and form spinal nerve which branches off into ventral and dorsal ramus
- bc the ventral and dorsal combine the spinal nerve is mixed (sensory and motor)
63
dorsal ramus
- smaller than ventral ramus bc the dorsal ramus supplies epaxial muscles (deep muscles of the back)
- mixed (sensory and motor axons)
- epaxial muscles are supplied with sensory and motor
64
ventral ramus
- bigger than dorsal ramus
- supplies hypaxial muscles (everything but the deep muscles of the back)
- mixed (sensory and motor axons)
- hypaxial muscles are supplied with sensory and motor
65
white and gray rami communicans
-involve the autonomic nervous system
66
dorsal root ganglion
- sensory
- cell body
- outside the CNS
- dorsal
67
conus medullaris and cauda equina
- spinal cord has slight cervical expansion
- narrows down in the thorax
- lumbar expansion that comes at an end at L1/L2 -> conus medullaris
- spinal nerves continue to be pulled down
- spinal nerves that run by themselves (without spinal cord) -> is the cauda equina
- cauda equina runs until dural sac
68
dural sac
- pia mater, arachnoid mater and dura mater continue down
- pulled down into the vertebral canal down to the level of S2
- surrounds spinal cord and continues down and surrounds cauda equina down to level of S2
- becomes a string/cord -> filum terminale
69
filum terminale
- string/cord that runs down to the bottom of the sacrum
- pulls the dural sac down
- pia mater
70
meninges
- pia mater- intimitely applies to spinal cord and brain
- subarachnoid space- CSF- separates pia and arachnoid
- arachnoid mater- superficial to the pia
- dura mater- most superficial
- forms a ring around the nerve rootlets -> nerve rootlets run in the subarachnoid space
71
subarachnoid space
- nerve rootlets run here
- CSF here
- separates the pia and arachnoid mater
- can be sampled for CSF below the level of L2 -> bc you dont been to worry about damaging the spinal cord
- also can do anesthesia below L2 in the epidural space
- at the level of L4 the iliac blades appear -> gives an idea where to puncture
72
monosynaptic reflex arc
- synapse of the primary sensory neuron with the primary motor neuron
- direct communication of the sensory and motor neuron
- ex. patellar tendon stretch
- taps the patellar tendon with mallet
- sends signal to quadricep femoris muscle (effector organ) -> extension of leg
73
polysynaptic reflex
- involved 3 neurons with interneuron (between the sensory and primary motor neuron)
- receptor (senses things like temperature)
- reflex is mitigated by interneuron
- motor neuron sends signal to effector organ
- biceps brachii contracts and moves away from hot temperature
- interneurons run up and down the spinal cord up into the brain to let you know the senses and what to do
74
plexuses of the spinal nerves
- braiding together of the spinal nerves
- spinal nerves of diff levels come together to innervate target organs
- cervical
- brachial
- lumbosacral or lumbar and sacral plexus
- braid together so that no signal nerve as having axons only from one spinal nerve outlet
75
cervical plexus
- derived by nerves from C1, C2, C3, C4
- forms a loop around the internal jugular vein (ansa cervicalis) -> C1,C2,C2
- phrenic nerve comes out below the cervical plexus -> C3, C4, C5
- phrenic nerves runs into the thorax to innervates the abdominal diaphragm
- cutaneous sensory nerves from C2, C3, C4 are the lesser occipital, greater auricular, transverse cervical, and supraclavicular
- ansa cervicalis- innervates the hyoid muscles -> omohyoid, sternohyoid, sternothyroid, thyrohyoid
76
brachial plexus
- involves the ventral rami of the nerves C5-T1
- 3 trunks
- emerge from the vertebral column and run out between the muscles of the neck -> scalenus anterior and scalenus medius
- run alongside the subclavian artery
- under the clavicle they braid around on both sides to surround the final branch of the subclavian artery which becomes the axillary artery
- ventral rami of C5 and C6 join together -> form the superior trunk
- suprascapular nerve comes off the superior trunk
- ventral rami of C8 and T1 join together -> form inferior trunk
- C7 is left alone -> middle trunk
- trunks begin to braid:
- superior trunk sends axons down to middle trunk and middle trunk sends axons up to superior trunk -> forms lateral and posterior cords
- inferior trunk sends axons up to middle trunk -> posterior cord (has axons from superior, middle and inferior trunks)
- inferior trunk is left alone -> medial cord
- cord begin to branch:
- lateral cord -> lateral pectoral nerve, musculocutaneous nerve
- posterior cord -> subscapular, radial, axillary
- medial cord -> medial pectoral nerve, ulnar nerve
- axons from the lateral and medial cord join and give off the median nerve
77
lumbar plexus
- L2-L4
| - produces obturator and femoral nerves
78
sacral plexus
- produces superior gluteal nerve, quadriceps femoral nerve, inferior gluteal nerve, obturator internus and sciatic nerve (fibular and tibial nerves)
- S1-S3
79
brachial plexus injury
- can be injured during parturition (birth)
- pulling on head during birth
- results in shoulder dystocia (brachial plexus is stretched)
- results in plasy -> erb-duchenne palsy
80
ventral nerves of the brachial plexus
- musculocutaneous -> goes to bicep brachii and brachialis and corico brachialis
- median
- ulnar
81
dorsal nerves of brachial plexus
- axillary
- radial
- suprascapular
- subscapular
82
lumbosacral plexus
- two plexuses joined by a trunk (between L4 and L5)
- L2-L4- lumbar plexus
- lumbosacral trunk- L4-L5
- lumbosacral trunk joins the lumbar plexus to S1-S3
83
dorsal and ventral nerves of lumbar plexus
- dorsal: femoral nerve
| - ventral: obturator
84
dorsal and ventral nerves of the lumbar plexus
- ventral- tibial (greater sciatic foramen)
| - dorsal- fibular (greater sciatic foramen)
85
autonomic nervous system
- efferent visceral compartment
| - divide into sympathetic and parasympathetic
86
difference between somatic motor and visceral efferent (autonomic)
- type of control
- type of effector organ that they innervation
- number of neurons from CNS to effector organ
- type of neurotransmitter
87
somatic vs autonomic: type of control
- somatic- voluntary (conscious)
- autonomic- involuntary (unconscious)
- you can control the autonomic by some extent through meditation (raise heart beat)
88
somatic vs autonomic: type of effector organ that it innervations
- somatic- skeletal muscle
| - autonomic (visceral efferent)- smooth, cardiac glandular
89
somatic vs autonomic: number of neurons from CNS to effector organ
- somatic- only one neuron (myelinated) runs out of the CNS from the spinal cord directly to synapse on the effector organ
- autonomic- two -> preganglionic (myelinated) and postganglionic (unmyelinated)
90
sympathetic innervation of the adrenal medulla
- special case
- first neuron is myelinated (preganglionic)
- synapse at the ganglion -> the ganglion is the adrenal medulla -> releases ACh
- postganglionic within the adrenal medulla are very short and secrete neurotransmitters (epinephrine) directly in the adrenal medulla
- secretion is picked up by capillaries and circulates in the blood
- adrenal medulla is a sympathetic ganglion
91
sympathetic system
- preganglionic neuron short
- postganglionic neuron long
- ganglion closer to CNS
- fright, flight, fight
- preganglionic secretes ACh
- postganglionic secrete norepinephrine
- outflow from the CNS from the spinal cord (T1-L2)
92
parasympathetic system
- preganglionic neuron long
- postganglionic neuron short
- ganglion closer to target organ (sometimes even in the wall of the target organ)
- rest and digest
- preganglionic secretes ACh
- postganglionic secrete ACh
- outflow cranially (4 cranial nerves) and caudal/sacral (S2,S3,S4)
93
sympathetic outflow
- outflow from the CNS from the spinal cord (T1-L2)
- the fibers that flow out run to a paraverteberal ganglion (ganglion next to vetebrae)
- from the lateral horn -> runs out through the ventral root -> spinal nerve -> ventral ramus -> jumps onto a sympathetic ganglion through white ramus communicans
- exits out sympathetic ganglion through the gray ramus communicans
- white ramus communicans (lateral) -> myelinated and thicker
- gray ramus communicans (medial) -> unmyelinated
- sympathetic trunk connects the ganglion together -> forms a chain
94
sympathetic chain
- paravertebral ganglia are connected by sympathetic trunk -> creates the sympathetic chain
- 3 cervical ganglia- inferior, middle, superior cervical ganglia -> no outflow bc they arnt connect to a spinal nerve to CNS
- 14 thoracolumbar ganglia- they do have outflow
- 5-6 lumbosacral ganglia- no direct outflow from a spinal nerve
95
innervation of sympathetic nervous system
- innervation of the body wall (sebaceous glands, erector pili)
- innervation of thoracic organ (lungs and heart)
- innervation of abdominopelvic organ (stomach, small/large intestine, liver, kidney, spleen, pancreas)
- innervation of adrenal medulla (special case)
- innervation of head (and other structures up and down chain)
96
sympathetic innervation of the body wall
- outflow from T1-L2
- presynaptic fibers run to ventral root -> spinal nerve -> ventral ramus
- then through white ramus communicans -> the paravertebral ganglion
- synapse at sympathetic paravertebral ganglion
- postsynaptic fibers run to spinal nerve via gray ramus communicans
- goes back into the ventral ramus to go to the body wall
- ex. erector pili, sebaceous glands
97
sympathetic innervation of the thoracic organ
- outflow from T1-T4
- presynaptic fibers run out of spinal cord through ventral root -> spinal nerve -> ventral ramus
- run to paravertebral ganglion (via white ramus)
- synapse at sympathetic paravertebral ganglion
- postsynaptic fibers run directly to target organ via sympathetic organ nerve (not gray ramus communicans)
98
sympathetic innervation of the abdominopelvic organ
- outflow from T5-L2
- presynaptic fibers run out of spinal cord through ventral root -> spinal nerve -> ventral ramus
- to paravertebral ganglion (via white ramus)
- DO NOT synapse in sympathetic paravertebral ganglion (just go through it -> still myelinated)
- run to a collateral ganglion via splanchnic nerve
- synapse in collateral (pre-aortic or pre-vertebral) ganglion (now it is unmyelinated)
- collateral includes: celiac, superior mesenteric, inferior mesenteric
- postganglionic fibers to target organ
- 2 ganglion but only one synapse
99
collateral abdominal ganglia
- there are 3
- T5-T9 -> celiac ganglion (stomach, liver, gallbladder, spleen, pancreas, kidney)
- T9-T12 -> superior mesenteric ganglion (small intestine and first part of large intestine)
- T12-L2 -> inferior mesenteric ganglion (lateral part of large intestine, rectum, pelvic organs)
- distribute the postganglionic fibers to the abdominal contents (foregut, midgut, hindgut)
100
sympathetic innervation of adrenal medulla
- outflow from T5-T9
- presynaptic fibers run out of spinal cord through ventral root -> spinal nerve -> ventral ramus
- run to paravertebral ganglion (via white ramus)
- DO NOT synapse in sympathetic paravertebral ganglion
- run out to celiac ganglion via the splanchnic nerve
- DO NOT synapse in celiac ganglion
- run through celiac ganglion to adrenal medulla
- synapse in adrenal medulla
- postganglionic release norepinephrine in the adrenal medulla
- 3 ganglion 1 synapse
101
sympathetic innervation of kidney
- outflow from T5-T9
- presynaptic fibers run out of spinal cord through ventral root -> spinal nerve -> ventral ramus
- run to paravertebral ganglion (via white ramus)
- DO NOT synapse in sympathetic paravertebral ganglion
- run out to celiac ganglion via the splanchnic nerve
- synapse in celiac ganglion
- postganglionic runs to the kidney
102
sympathetic innervation of head (things that are above or below the chain outflow)
- outflow from T1-L2
- travel up (or down chain)
- turn superiorly or inferiorly
- presynaptic fibers run out of spinal cord through ventral root -> spinal nerve -> ventral ramus
- run to paravertebral ganglion (via white ramus)
- travel up or down the sympathetic chain to other paravertebral ganglion
- travels up to cervical paravertebral sympathetic ganglion
- travels up or down to another thoracic paravertebral sympathetic ganglion (above outflow at T1)
- down to lumbar or sacral paravertebral sympathetic ganglion (below outflow of L2)
- smooth muscle of eye, salivary glands, sacral region
103
sympathetic innervation of things above the sympathetic chain outflow (cervical-> head)
- cervical sympathetic ganglia: superior (C1-C2), middle (C4-C6), inferior/stellate (C7)
- they dont have white ramus communicans (only grey)
- from the superior cervical ganglion -> sympathetic fibers run upwards to:
- the eye: dilator pupillae and ciliary muscle (relax)
- lacrimal (no effect on it)
- submandibular sublingual (stimulates -> mucous)
- parotid (no effect)
- the sympathetic preganglion can synapse and provide postganglion through gray ramus to body wall (sweat)
- the sympathetic preganglion can synapse and postganglion goes to organ nerve to eye, lacrimal, salivary glands
- the sympathetic preganglion can synapse and postganglion goes to sympathetic nerve to thoracic organ
- pathway:
- presynaptic fibers run out of spinal cord through ventral root -> spinal nerve -> ventral ramus
- run to paravertebral ganglion (via white ramus)
- runs up the sympathetic trunk to another paravertebral ganglion in the neck
- synapse at cervical ganglion -> 2 choices -> go to spinal nerve through grey ramus communicans (no white ramus communicans bc there is no outflow here) to the body wall OR go to organ in the head (smooth muscle of eye, salivary glands, lacrimal gland) or down to the thoracic organ
104
parasympathetic innervation by cranial nerves in the head
- CN III- oculomotor -> innervates constrictor pupillae and ciliary muscle (contrict) via ciliary ganglion
- CN VII- facial -> greater petrosal -> innervates lacrimal via pterygopalatine ganglion; chorda tympani nerve -> innervation submandibular sublingual via submandibular ganglion
- CN IX- glossopharyngeal -> innervates parotid via otic ganglion
- CN X- vagus -> no cranial ganglion
105
sympathetic innervation of things up or down to another thoracic paravertebral sympathetic ganglion
- synapse in the ganglion and run to the gray ramus to the body wall
- synapse in the ganglion and run to a target nerve to a thoracic organ
- heart and lungs
106
sympathetic innervation running down to lumbar or sacral paravertebral sympathetic ganglion (below)
-below the level of outflow
-they dont have white ramus communicans (only grey)
-synapse in ganglion to gray ramus to body wall (ex. sweat gland in lower limb)
OR
-do NOT synapse in lumbosacral paravertebral ganglion (runs through)-> emerges as splanchnic nerve and synapse in pre-aortic or presacral collateral ganglion (superior mesenteric ganglion) to the target organ
107
mass discharge
- sympathetic trunk connects paravertebral ganglia -> results in mass discharge
- once the sympathetic system is turned on the sympathetic neurons from T1-L2 are activated up and down the chain (above and below)
- everything is stimulated at the same time (hairs stand up, pupils dilated, heart rate increase, digestive rate decrease, far eye sight)
- fight or flight response
