Neurology anatomy Flashcards
(110 cards)
1
Q
What is neuron?
A
- individual cell
- elongated
- excitable tissue
- detect and transmit messages as nerve impulses from one part of the body to another (dendrite receive information/ axon transmits information)
2
Q
neuron vs nerve
A
nerve:
- bundle of neuronal axon in the PNS
- no cell body
neuron:
- individual cell with a cell body
- found in both CNS and PNS
_ in CNS, a bundle of axon called a tract
3
Q
What is nerve?
A
- A nerve is a visible collection of neuronal fibers held tgt by connective tissue (only in PNS)
4
Q
Autonomic system include which 2 categories?
A
Sympathetic nervous system: activated in critical situations
Parasympathetic: activated at rest
5
Q
What does a single system comprise of?
A
CNS: brain to spinal cord
PNS: sensory and autonomic nervous system
6
Q
what are the three layers of meninges?
A
- dura matter
- tough outer layer
- in the cranium adhered yo periosteum
- in the spinal cord
- bilamina- periosteal layer and meningeal layer (venous sinus) - arachnoid matter
- blood vessels and CSF
- arachnoid trabeculi
- subarachnoid space
- cisterna magna (clinical site to collect CSF) - Pia matter
- adhered to surface of the neuraxis
7
Q
How many ventricles in central nervous system?
A
4 ventricles:
- lateral ventricles (L & R)
- third ventricles
- fourth ventricles
8
Q
What is choroid plexus?
A
- produce CSF (formed by ultrafiltration of blood plasma and epithelial cell secretions)
- vascular invaginations of pia mater into the ventricles (3rd and 4th ventricles: roof/ lateral ventricle: floor)
9
Q
Describe cerebrospinal fluid (CSF).
A
- clear, colourless fluid
- composition: protein, glucose, chloride and sometimes lymphocytes
- found in ventricles of brain/ subarachnoid space/ central canal of spinal cord
- pressure is kept constant by drainage: venules subarachnoid space/ venous sinuses of the brain/ lymphatic vessels of the spinal nerve roots.
10
Q
what is the function of CSF?
A
- cushions and protects the CNS
- provides buoyant support for the brain
- nourishes CNS
- removes metabolites from CNS
- pathway for pineal secretions to reach the pituitary gland.
11
Q
How many pairs of cranial nerves in peripheral nervous system?
A
12 pairs of cranial nerves
12
Q
list the 4 peripheral receptors.
A
- exteroceptors (temp, touch)
- interoceptors
- proprioceptors (muscle stretch, tension, position, joint movement)
- nocioceptors (Pain)
13
Q
List the 12 cranial nerves
A
CN I Olfactory nerves
CN II Optic nerves
CN III Oculomotor nerve
CN IV Trochlear nerve
CN V Trigeminal
CN VI Abducent nerve
CN VII Facial nerve
CN VIII Vestibulocochlear nerve
CN IX Glossopharyngeal nerve
CN X Vagus nerve
CN XI Accessory nerve
CN XII Hypoglossal nerver
14
Q
state the of afferent (sensory) pathway of peripheral nervous system.
A
- sensory information travels from the sensory receptors to CNS
- ascend in peripheral fibers to spinal cord, then spinal tracts to brain
- pathway can be (i) somatic: interacting with external environment or (ii) visceral: relating to internal environment.
- integration of sensory information occurs in the CNS (e.g. parietal lobe in the cerebral cortex has the somatosensory center: the primary receptive area for touch and proprioception
15
Q
state the efferent (motor) pathway of peripheral nervous system.
A
- information travels from the CNS motor cortex/ cerebellum to efferent organs
- descending in upper motor neuron (UMN) in CNS to Lower motor neurons (LMN) in the PNS via peripheral nerves
- these pathways can be: (i) somatic: to skeletal muscle (voluntary) or (ii) visceral: to cardiac muscle, glands (involuntary)
- the efferent organ performs the reaction or response to the stimulus
16
Q
where is the location of sympathetic nervous system?
A
thoracolumbar region
17
Q
where is the location of craniosacral region?
A
craniosacral region
18
Q
example of parasympathetic.
A
- constricts pulpil
- vasodilation
- stimulates salivation
- constricts bronchi
- inhibits heart
- stimulate gallbladder
- stimulate digestive activity
- contracts bladder
19
Q
What can senses be subdivided in?
A
- somatic sense
- skin (pain, touch, temp), muscle, tendon and joint
- general somatic afferent fiber - visceral sense
- glands, viscera, blood vessels
- general visceral afferent fibers - special sense
- vision, hearing, smell and taste
- special somatic afferent fibers (vision, hearing, balance)
- special visceral afferent fibers (taste and smell)
20
Q
describe the pathway of spinothalamic tract.
A
getting info from the spine up to thalamas. then to the primary somatosensory cortex
21
Q
What is the 2 categories that can access the function of receptor?
A
- Acuity
- simple test of sensory nerve function
- the ability to discern two nearby objects touching the skin are truly two distinct points, not one
- determined by the density of receptors - Dermatomes
- an area of skin supplied by nerve from a single spinal root
- they overlap and usually slope ventrocaudally
- named after its spinal nerve
- clinically useful in determining site of spinal damage
22
Q
what is the 2 main pathways for conscious sensory afferent nervous system?
A
- spinothalamus pathway
- medial lemniscus pathway
23
Q
State the 2 sub-divided pathways under the spinothalamic pathway.
A
- Lateral spinothalamic pathway
- sensation of pain and temperature - Anterior spinothalamic pathway
- sensation of crude touch, pressure, tickling and itching
24
Q
State the routes of the spinothalamic pathway.
A
- First order neuron: starts at the sensory receptor
- Secondary order neuron: starts at the dorsal horn of spinal cord
- Third order neuron: starts at thalamus and terminates at cerebral cortex, contralateral hemisphere.
25
Which 2 areas do medial lemniscus pathway associated with?
Relays sensation of fine touch, proprioception, vibration and stereigenesis
1. Fasciculus cuneatus
- signals upper limb: T6>
2. Fasciculus gracilis
- signal lower limb:
26
State a medial lemniscus pathway
- First order neuron: start at sensory receptor
- second order neuron: starts at medulla
- third order neuron: starts at medulla and terminates at cerebral cortex, contralateral hemisphere.
27
What does unconscious sensory pathway transmit info for?
- muscle tone
- posture
- coordination
28
Where does unconscious sensory pathway terminate?
ipsilateral cerebellum (terminate on the same side)
29
what is the two pathway of unconscious sensory pathway in afferent sensory nervous system?
1. Dorsal spinocerebellar tract
- lower limb information L3-L8 (ipsilateral cerebellum)
- Cuneocerbellar tract T3>: upper limb information (ipsilateral cerebellum)
2. Ventral spinocerebellar tract
- Spinal interneurons (REFLEXES)
- Double cross the SC to entre on ipsilateral side cerebellum
- Involved in voluntary movement, important cerebellum has access to this information for coordination of movement.
30
How does proprioception of different areas travel to the brain?
1. Neck, trunk, limbs via:
- spinal nerve: dorsal root
- Spinal cord: dorsal and ventral funiculi
2. Head, its muscle and joint via:
- CN VII vestibulocochlear nerve
- CN V Trigeminal nerve
31
What is the pathway of conscious proprioception?
- afferent nerve fibers enters spinal cord
- ascending signal to cerebral cortex (contralateral side)
- descending signal to spinal nerve
- efferent nerve fibre
*e.g. Medial lemniscus pathway (secondary neuron decussates to the contralayeral side)
32
What is the pathway for unconscious proprioception?
- afferent nerve fibers enter spinal cord
- synapse to somatic efferent neuron (reflex arc)
- ascending signal to ipsilateral side cerebellum (requires 2 neurons)
33
What does cerebellar ataxia affect?
impacting cerebellum/ muscle coordination/ balancing
34
how does cerebellum integrate in coordination?
- input via:
(i) vestibular
(ii) visual
(iii) proprioception/ somatosensory
(iv)motor efference copy signals
- output via:
(i) thalamus
(ii) hippocampus
(iii) super colliculus
- to
(i) motor cortex
(ii) posterior parietal cortex
35
Lesion localization in cerebellum
- lesions to the vermis result in truncal ataxia
- lesions to the flocculonodular lobe results in eye movement abnormalities
- lesions to cerebellar hemisphere results in ipsilateral ataxia
36
Describe enteric nervous system (ENS)
- embedded in lining GIT
- operates independently of the brain and SC
- consists of 2 plexuses (ganglia):
(i) myenteric (Auerbach's): inner/ outer layer of muscularis externa - increase tone and peristalsis
(ii) subsacral (meissner's): submucosa- sensory nerve endings signal both layers of enteric plexus
- short reflexes: respond to digestive movement and chemical changes (release acid in the stomach)
- long reflexes: connect ENS to CNS respond to food, emotion or danger (e.g. mastication of food stimulates secretion of gastric acid)
37
What peripheral nerves are involved in micturition?
1. Pudendal nerve (somatic)
- going to urethral external muscle
2. Hypogastric nerve (sympathetic)
- detrusor muscle relax
- internal sphincter contract
3. Pelvic nerve (parasympathetic)
- detrusor muscle contract
- internal sphincter relax/ opening internal sphincter
38
what is the 2 phase of micturition?
1. filling phase
2. empting phase
39
Somatic reflexes vs autonomic reflexes
Somatic reflexes:
- respond to external environment
-simple reflex
- 2 nerves and one muscle (stretch reflex/ spinal reflex)
Autonomic reflexes:
- respond to changes in the internal environment
- Brainstem reflexes: complex functions like heart rate, blood pressure
- Hypothalamic reflexes: homeostasis
40
Definition of UMN
- the neurons of the brain that control body motor activity
- cell bodies are located in the cerebellum and brain stem
- Entire UMN is confined to CNS
41
what is the function of UMN?
Tells the LMN what to do
- stimulate or inhibit LMN
- initiation of voluntary movement
- maintenance of muscle tone and support against gravity
- regulation of posture
42
Definition of LMN
- the neurons that directly innervate the muscle
- cell bodies are located in the ventral grey horn of the spinal cord
43
What is the function of LMN?
- receive input from UMN
- connects CNS with the muscle (PNS)
- spinal reflexes
44
UMN dysfunction
- Paretic (weakness) to paralysis
- Gait:
> long strided
> crossing
> scuffing
- loss of inhibition
> spacicity
> Hyperreflexia/ hypertonia/ abnormal reflexes
> abnormal posture
> extensor opisthotonos
45
LMN dsyfunction
- paretic to paralysis
- gait
> short-strided
> choppy
> Lame
- hypotonia
- hyporeflexive
- rapid muscle atrophy
46
what are the cranial nerve reflexes?
1. pupillary light
2. palpebral
3. corneal
4. nasa mucosa sensation
5. lip pinch
6. gag reflex
7. tongue reflex
47
What are the spinal nerves reflexes?
1. Tendons: myotatic
- patelle
- biceps
- triceps
2. withdrawal: flexion
- thoracic limb
- pelvic limb
3. perineal: anal
48
state the nerve(s) involve in the Pupillary light reflex.
- CN II optic nerve (S)
- CN III oculomotor nerve (M)
49
state the nerve(s) involve in the palpebral reflex.
- CN V trigeminal nerve: ophthalmic branch & maxillary branch (S)
- CN VII facial nerve (M)
50
state the nerve(s) involve in the corneal reflex.
- CNV trigeminal n (S)
- CN VII facial n (M)
- CN VI abducens n (M)
51
state the nerve(s) involve in the nasal mucosa reflex.
- CN V tigeminal: V1 ophthalmic branch & V2 maxillary branch (S)
- ventral horn cervical spinal cord (M)
52
state the nerve(s) involve in lip pinch
- CN V trigeminal n: V2 Maxillary branch (top lip) [S] & V3 Mandibular branch (bottom lip) [S, M]
- CN VII facial nerve
53
state the nerve(s) involve in gag reflex.
- CN IX pharyngeal n (S)
- CN X vagus n (M)
54
Is menace response a reflex?
No, it is a behaviour response
55
what is associated with the vision and integration of visual pathway in the menace response?
visual and integration of visual pathways with the
- cortical: higher brain perception of threat
- cerebellum: movement
56
What reaction will be done in menacing gesture near the eye?
the menacing gesture leads to a blink with or without moving the head.
CN II optic n (S)
CN VII facial (M)
57
state the nerve(s) involve in cutaneous trunci (spinal nerve reflex).
- spinal cord nerves T2 - T4 (S)
- Response: motor skin twitch cutaneous trunci m via lateral thoracic nerve
Funtion:
- localise spinal cord lesion
58
What is patella spinal nerve reflex?
- It is a myotatic reflex that responds to stretch
- Stimuli: tap the patella tendon
- Positive response stifle extension
- quadriceps muscle contraction
- surgery in patella area can diminish the reflex action (or absence)
59
state the nerve(s) involve in patella reflex (spinal nerve reflex).
- afferent/ efferent: femoral n (L4-L6)
- spinal cord: dorsolateral funiculus
60
State the perineal spinal nerve reflex.
- Pudendal nerve
- Touch or pinch the perineal region
- positive response is contraction of anal sphincter (anal wink)
- common in cat
- this reflex is conscious
61
State the clinical application of pudendal nerve.
- tail injuries associated with the sacral vertebral S1-3 are frequently seen in cats
- the lumbosacral plexus nerve roots L4-S3 supply the hindlimb, bladder, rectum and perineal region
- the bladder is innervated by the pelvic n and pudendal n from the sacral nerve roots S1-3.
62
what is bladder innervated by?
pelvic nerve and pudendal nerve
63
where does cranial nerve III-XII exit from?
cranial nerve III-XII exit from brainstem
64
where is the origin of CN I olfactory nerve?
cerebral hemisphere
65
Where is the entry of the CN I olfactory nerve?
cribiform plate
66
What does it innervate? And what is its function?
innervation: Nasal mucous
function: sense of smell
67
dsyfunction of olfactory nerve
anosmia
68
what is origin of CN II Optic nerve?
cerebral hemisphere
69
what is the entry of CN II Optic nerve?
optic canal
70
What does CN II Optic nerve innervate? And what is the function of it?
Function: vision
Innervation: retina (rods/cones)
71
What is the origin of CN III Oculomotor nerve?
midbrain
72
what is the composition of CN III Oculomotor nerve?
- somatic motor and parasympathetic visceral
73
where does CN III Oculomotor nerve exist?
orbital fissure
74
What does CN III Oculomotor nerve innervate? And what's the function of it?
Innervation: extraocular eye mm, ciliary mm, sphincter of iris
Function:
- somatic motor: inward, upward, downward eye movement and upper eyelid
- parasympathetic visceral: pupillary sphincter, eye accommodation
75
what are the 7 muscles associated with CN III Oculomotor nerve?
- dorsal ventral rectus mm
- lateral medial rectus mm
- dorsal ventral oblique mm
- retractor bulbi m
76
Dilation of pupil
mydriasis
77
what is it called when pupil size is uneven?
anisocoria
78
what is the origin of CN IV Trochlear nerve?
midbrain
79
where is the entry of CN IV Trochlear nerve?
superior orbital fissue
80
what is the composition of CN IV Trochlear nerve?
somatic efferent
81
what is the innervation and function of CN IV Trochlear nerve?
Innervation: dorsal oblique muscle eye
Function: downward and inward eye movement
82
dysfunction of CN IV Trochlear nerve leads to ...
loss of downeard, inner movement of eye
83
what is the origin of CN VI Abducent nerve?
pons
84
where is the entry of CN VI Abducent nerve?
superior orbital fissure
85
what is the composition of CN VI Abducent nerve?
somatic motor
86
what is the innervation and function of CN VI Abducent nerve?
innervation: lateral rectus muscle, retractor bulbi muscle of eye
function: outer and lateral movement of eye
87
dysfunction of CN VI Abducent nerve
loss of lateral eye movement
88
what is the origin of CN V Trigeminal nerve?
pons
89
what is it 3 branches of CN V Trigeminal nerve? where do they exit?
1. Ophthalmic br: dorsal orbital fissure
2. Maxillary br: foramen rotundum
3. Mandibular br: foramen ovale
90
what is the composition of CN V Trigeminal nerve?
sensory and motor
91
what does CN V Trigeminal nerve innervate ?
V1 Ophthalmic br (sensory) : eye, forehead, nasal mucosa
V2 Maxillary br (sensory) : upper jaw, cheek, nose, nasal mucosa
V3 Mandibular br (sensory + tongue somatic motor) : mandible skin (S)
92
dysfunction of CN V Trigeminal nerve
atrophy masticatory muscle, mandibular n damage > low jaw tone "drop jaw"
93
what test can be done to access different branch of trigeminal nerve?
- corneal reflex: ophthalmic n
- palpebral reflex: ophthalmic n
- nasal mucosa: maxillary n
- pinch lower lip: mandibular n
94
Where does infraorbital block desensitize?
(maxillary branch) oral mucosal and upper lip rostral to the foramen
injection site: 3rd premolar
95
what is the origin of CN VII Facial nerve?
pons and medulla
96
where is the exit of CN VII Facial nerve?
internal acoustic meatus
97
what is the composition of CN VII Facial nerve?
sensory, somatic motor
98
state an example of parasympathetic nervous system.
lacrimal tear test
99
what is the origin of CN VIII vestibulocochlear nerve?
pons and medulla
100
where does CN VIII vestibulocochlear nerve exit?
acoustic meatus
101
what is the origin of CN IX vestibulocochlear nerve?
medulla
102
where does CN IX vestibulocochlear nerve exit?
jugular foramen
103
where is the origin of CN X vagus nerve
medulla
104
where does CN X vagus nerve exist?
jugular foramen
105
what does CN X vagus nerve exist
- muscle of larynx, pharynx, oesophagus and soft palate
- parasympathetic innervation of thoracic and abdominal viscera
106
Where is the origin of CN XI Accessory nerve?
medulla oblongata
107
where is the exist of CN XI Accessory nerve?
jugular foramen
108
Where is the origin of CN XII Hypoglossal nerve?
medulla
109
Where does CN XII Hypoglossal nerve exist?
hypoglossal foramen
110
