W2 brainstem Flashcards
Brainstem: Structures
- Contains areas crucial to the maintenance
of life - Sits superior to the spinal cord and inferior to the cerebrum
- Contains 10 cranial nerve nuclei
- Can be divided into 3 sections: medulla, pons, midbrain
Brainstem: Structures
Ventral and Sagittal view
- Crus cerebri
- Middle cerebellar peduncle
- Pyramids of the medulla
Brainstem: Structures
Dorsal view:
- Superior colliculi: Vision
- Inferior colliculi: Auditory
- Cerebellar peduncles
- Superior * Middle * Inferior
- Floor of the 4th ventricle
- Fasciculus cuneatus & gracilis
Olfactory number, affrent or effrent? and connection to CNS & function
I
affrent
cerebellum
smell (can help w taste too)
optic number, affrent or effrent? and connection to CNS & function
II
afferent
cerebrum
vision & pupilillary light reflex
oculomotr number, affrent or effrent? and connection to CNS & function
III
efferent
midbrain
Movement of eyeball & elevation of upper eyelid
Parasympathetic for pupillary constriction and accommodation
trochlear number, affrent or effrent? and connection to CNS & function
Iv
efferent
midbrain
movement of eyeball for complex movements (superior oblique
muscle)
trigeminal number, affrent or effrent? and connection to CNS & function
V
both
pons
Trigeminal has 3 branches:
* Ophthalmic (CN V1) - Sensory
* Maxillary (CN V2) - Sensory
* Mandibular (CN V3) - Mixed
* Ipsilateral muscles of mastication
general sensation for face for all trigeminal
abduccens number, affrent or effrent? and connection to CNS & function
VI
efferent
pons
movement of eyeball to abduct the eyeball (lateral rectus) ABDUCTION
facial number, affrent or effrent? and connection to CNS & function
VII
both
pons
afferent fibers to the anterior 2/3rd of the tongue
(taste- sweet and sour).
* Afferent from posterior ear canal
Efferent fibers for the ipsilateral muscles of face
(expression and lip movement) and one of the
small middle ear muscles that helps in the auditory protective reflex
Parasympathetic efferent fibers to the
glands (e.g. tears & saliva)
vestibulocochlear number, affrent or effrent? and connection to CNS & function
VIII
afferent
pons
* Afferent head movement via
* Semicircular canals
* Utricle & Saccule
(aid balance)
* Afferent for Hearing via Cochlea
glossopharengeal number, affrent or effrent? and connection to CNS & function (afferent, autonomic, parasymp, efferent)
IX
both
medulla
(taste) for posterior 1/3rd of
the tongue
* General afferent (touch, pressure, pain) for
pharynx & posterior tongue
* Autonomic afferents from the carotid sinus and carotid body convey blood pressure
and chemical signals from the carotid artery.
* Parasympathetic efferent fibers to the parotid saliva gland
* Efferent fibers to stylopharyngeus that helps elevate the pharynx in swallowing
vagus number, affrent or effrent? and connection to CNS & function (afferent, autonomic, parasymp, efferent)
X
both
medulla
* General afferent from the pharynx,
larynx and external ear
* Efferent to pharyngeal muscles
(swallowing) and larynx (voice)
* Autonomic afferent from the pharynx,
larynx, thorax and abdomen
* Parasympathetic efferent to pharynx,
Larynx, thorax and abdomen
accessory number, affrent or effrent? and connection to CNS & function
XI
efferent
medulla
* Efferent to the trapezius and
sternocleidomastoid muscles.
hypoglossal number, affrent or effrent? and connection to CNS & function
XII
efferent
medulla
* General somatic efferent to the
ipsilateral muscles of the tongue
(intrinsic and majority of extrinsic)
acronym to remember order of CN
On Occasion Our Trusty Truck Acts Funny Very Good Vehicle Any How
acroynm to remember function of CN
Some Say Marry Money But My Brother Says Big Brains Matter More
Spinal Cord: Structures
- Central nervous system protected by Bone
(skull and vertebral column) and Meninges - Meninges:
- Dura mater
- Arachnoid
- Pia mater
- Blood supply
Spinal Cord: Structures
* Dorsal (posterior) horn
site of termination of
many afferent neurons via root
Spinal Cord: Structures Ventral (anterior) horn:
contains lower motor neurons (efferent) via root
Spinal Cord: Structures * Later horn:
Processes autonomic information
(only at T1–L2 spinal segments)
Spinal Cord: Structures
* Dorsal (posterior) ROOT: A
Afferent fibers with cell bodies located in dorsal root ganglia
Spinal Cord: Structures Ventral (anterior) root
Efferent fibers with cell bodies lying within the spinal grey matter.
Spinal Cord: White matter
Bilateral (mirror)
* Ascending tracts: Afferent
* Descending tracts: Efferent
Spinal Cord: Spinal nerves
- 31 Spinal nerves
- Exit vertebral canal through intervertebral foramina
- Part of the peripheral nervous system
- Contain both motor and sensory axons
- Divided into segments:
- 8 Cervical nerves
- 12 Thoracic nerves
- 5 Lumbar nerves
- 5 Sacral nerves
- 1-2 Coccyx nerves
- Ventral ramus:
Supplies muscles of back and overlying skin
- Dorsal ramus
Supplies muscles of trunk & limbs and
overlying skin
Dermatomes
Area of skin (“Dermis”) innervated by a
single spinal nerve
* Afferent
Myotomes
Group of muscles
innervated by a single spinal nerve
* Efferent
C5 myotome
Elbow flexion
C6 myotome
wrist ext
C7 myotome
elbow extension
C8 myotome
flexion of tip of middle finger
T1 myotome
finger abduction
L2 myotome
hip flexion
L3 myotome
knee extension
L4 myotome
ankle dorsiflexion
L5 myotome
great toe extension
S1 myotome
ankle planterflexion
Spinal cord injury
damage to the spinal cord that may cause temporary or permanent change to function of the cord.
SPINAL CORD INJURIES pathophysiology
- Loss of all forms of sensation
- Reduced or Inability to feel pain
- Loss of ability to move
- Partial loss of voluntary movement
- Altered or lost sensation in a dermatome at and below the level of the lesion
- Decreased or lost muscle power in a myotome at and below the level of the lesion
- Decreased or lost stretch reflex
- Altered or lost control of BP, blad
- Altered or lost sensation in a dermatome at and below the level of the lesion
- Decreased or lost muscle power in a myotome at and below the level of the lesion
- Decreased or lost stretch reflex
- Altered or lost control of BP, blad
complete spinal cord injury
Lack of sensory and motor function
incomplete spinal injury
Preservation of sensory and/or motor function
Quadriplegia
Injury of the cervical cord results in quadriplegia
C1-C3 – paralysis of the diaphragm and respiratory muscles
most common = C4-5
Paraplegia
Damage to the cord below the cervical level, sparing arm function
causes paralysis in the lower limbs
Most common level of injury T12/L1
Segmental nerve lesions causes
- Altered or lost sensation in a dermatome at that level
- Decreased or lost muscle power in a myotome at that level
- Decreased or lost stretch reflex
Vertical tract lesion is in the spinal cord vertical tracts, and result in:
Altered or lost sensation below the level of the lesion
* Motor tract signs
* Altered or lost control of BP, bladder, bowel control, and thermoregulation
Peripheral nerve lesions cause:
×Altered or lost sensation in a peripheral nerve distribution
× Decreased or lost muscle power in a peripheral nerve distribution
× Decreased or lost stretch reflex
Brown-Sequard syndrome
segmental : Ipsilateral loss of lower motor neurons and sensations
below: Ipsilateral loss of voluntary motor control, conscious proprioception and light touch. Contralateral loss of nociceptive and temperature sensation.
Central cord syndrome
- Usually occurs at the cervical level as a result of trauma
- Small lesion: Loss of nociceptive and temperature at the level of the lesion
- Larger lesion: Impair upper limb motor
Anterior cord syndrome
- Damage to anterior spinal cord
- Loss pain and temperature sensation
- Loss of motor control
- Preserved conscious proprioception and light touch
SPINAL CORD INJURIES: Shock
A temporary loss of all functions below the lesion due
* Resulting in flaccid paralysis and sensory loss
* Last about a day but can persist for up to a month
* Reflexes gradually return, progressing from flaccid paralysis to spastic paresis
* Muscle tone and tendon reflexes may take months to recover
ASIA A spinal cord injury
No sensory or motor function preserved in the sacral segments S4-5
ASIA B spinal cord injury
Preservation of sensory function in S4-S5
ASIA C spinal cord injury
Motor function preserved at the most caudal segments for
voluntary anal contraction. OR the patient meets the criteria for sensory incomplete status and
has some sparing of motor function more than three levels below the ipsilateral motor level on
either side of the body.
ASIA D spinal cord injury
Motor Incomplete. Motor incomplete status as defined above, with at least half (half or more) of key muscle functions below the single NLI having a muscle grade ≥ 3.
ASIA E spinal cord injury
Normal motor and sensory function.
what are the 3 protective connective tissue layers of meninges
- dura mater
- arachnoid mater
- pia mater
what are the functions of meninges
- covers and protects CNS
- protect blood vessles
- form dural venous sinuses
- house cerebrospinal fluid
dura mater
dura= tough
outer most layer
tough fibourous memebrane that is tightly adhered tov the inside of the skull
flax cerebri
seperates cerebrum
flax cerebelli
seperates cerebellum
tentorium cerebelli
seperates cerebellum and cerebrum
dural venous sinuses
number of blood- filled channels into which the cerebral veins empty to return blood from head to heart
dural sac
extends to spinal cord
arachnoid mater
arachnoid= cobweb
closely apposed and loosely attached to the dura
contains arachnoid granulations
subarachnoid space
- bw arachnoid and pia
- filled w cerebrospinal fluid
- protective role as it offers buoyancy and cushioning against sudden head movements
- arachnoid trabeculae (fine fibrous connections bw arachnoid and pia) provide support that suspends brain
pia mater
pia= delicate
innermost
extremly thin and delicate, following the contours of brain
dense rich blood supply of underlying neural tissue
ventricular system
lateral ventricle (two)
third ventricle (bw thalamus
4th ventricle ( post. to pons and medulla
cerebrospinal fluid secreted where? flows where? reabsorbed where?
secreted mostly in choroid plexus
flows through the lateral ventricles and enters the subarachnoid space
flows around spinal cord and brain
reabsorbs into venous sinuses
cerebrospinal fluid functions
clears waste, provides nutrients and buoyancy
hydrocephalus
if cerebrospinal fluid system is blocked, pressure builds in the ventricles causing hydrocephalus
hydrocephalus clinical signs in infants/ children
disproportionate large head, large anterior fontanel, poor feeding, inactivity, downward gaze of eyes
blood supply to brain functions
deliver O2 and glucose
removes waste
blood-brain barrier
circle of willis made up of
basilar artery and carotid arteries which link on the inferior surface
3 major paired cerebral arteries that arise from circle of willis are
anterior, middle and inferior cerebral arteries
anastomoses
multitude of arteries and veins serving the same tisse
collateral circulation may be adequate to maintain brain function
anterior cerebral artery innervates
cortical branches: medial carotid surfaces of the frontal and parietal lobe, prefrontal cortex
central branches:part of corpus callosum and basal ganglia, inf part of anterior internal capsule
middle cerebral artery innervates
cortical branches: nervous system that corrosponds w head upper limband thoracic areas of motor and sensory cortex, hearing areas, language areas, frontal cortex, part of basal ganglia
posterior cerebral artery innervates what reas
visual areas, subthalamic nuclei, hippocampus
what is the brainstems blood supply
vertebrobasilar sytem
what is the cerebellum blood supply
superior cerebellar arteries, anterior inferior cerebellar arteries, posterior inferior cerebellar arteries
cerebral veins drain into?
dural sinuses and eventually into the jugular veins
stroke def
sudden and unexpected damage to brain cells that causes symptoms that last for more than 24 hours in the part of the body controlled by those cells
transient ischemic attach
a breif, focal loss of brain function, w full recovery from neurological defects w/in 24 hours
completed stroke
symptoms that persists for longer than 1 day and are stable
progressive stroke
some ppl w ischemic stroke have deficits that increase intermittley over time
ischemic stroke
embolus lodges in a vessel obstructing blood flow. this deprives an area of blood flow leading to imediate onset of deficits
haemorrhagic stroke
burst, deprives the downstream vessles of the blood and extravascular blood exerts pressure on surrounding brain. this presents with worst defets w/in hours then gets better
can cuase death w the increase in instracapsule pressure
subarachnoid haemorrhage
bleeding into the subarachnoid space, causes sudden excruciating headache with a brief loss of consciousness
stroke off anterior cerebral artery
loss of fine touch in contralateral limb
contralateral gait difficulties
lack of emotionsal expressiveness and impulsiveness
inability to think of possibilites
urinary incontinence
stroke cmiddle cerebral artery
contralateral homonymous hemianopia
contralateral hemiplegia to face and upper limb motor impairment
contralateral hemisensory to face and upper limb sensory impairment
difficulty understanding spacial relationship
neglect
nonverbal communication
stroke posterior cerebral artery
difficulty w eyemovement and blindness
visual agnosia
memory loss
stroke basilar artery
complete occlusion causes death
tetraplegia
loss of sensation
coma
stroke cerebrallar artery
ataxia difficulty coordinating movement
Which of the following is the outermost meningeal layer?
dura mater
The falx cerebri is responsible for:
Separating the two cerebral hemispheres
What is the function of the subarachnoid space?
Provides buoyancy and protection to the Cerebrum
Arachnoid granulations are involved in:
CSF reabsorption
Which of the following ventricles is located between the thalami?
Third ventricle
The choroid plexus is primarily responsible for:
form cerebrospinal fluid
The middle cerebral artery supplies
Lateral surface of the cerebral cortex, including Broca’s and Wernicke’s areas
