Cerebral perfusion, brain anatomy and reflexes Flashcards
Cerebral perfusion is primarily driven by what?
PCO2
At what oxygen pressure will O2 influence CPP?
Severe hypoxemia < 50 mmHg
What is the cerebral perfusion pressure equal to (what is the equation)?
CPP = MAP - ICP
What are the signs of Increased ICP (cushing reflex)?
- Hypertension
- Bradycardia
- Respiratory depression
- Wide pulse pressure
When does CPP not become proportional to PCO2?
When PCO2 is > 90 mmHg
What symptoms will an ACA-MCA watershed infarct cause?
Proximal upper and lower extremity weakness (“man-in-a-barrel” syndrome)
What symptoms will a PCA-MCA watershed infarct give?
Higher-order visual dysfunction
How is CSF drained?
Into cerebral veins from arachnoid granulations
A venous sinus will present with what?
- Additionally what risk factors may they have
Signs/symptoms of increased ICP
- Headache
- Seizures
- Papilloedema
- Focal neurological deficits
Risk factors are hypercoagulable states e.g:
- OCP use
- Pregnant
- Factor V Leiden
Where is the nucleus of CNXI found?
Spinal cord
What is the pineal gland responsible for?
- Melatonin secretion
- Circadian rhythms
What are the superior colliculi responsible for?
Direct eye movemtns tostimuli (noise/movements) or objects of interest
What are the inferior colliculi responsible for?
Auditory
Name the vagal nuclei
- Nucleus tractus solitarus
- Nucleus ambiguus
- Dorsal motor nucleus
What is the function of the nucleus tractus solitarus?
- Visceral sensory info (taste, baroreceptors, gut distension)
- May play a role in vomitinfg
- CN VII, IX, X
What is the function of the nucleus ambigus?
- Motor innervation of pharynx, larynx, upper esophagus (e.g swallowing, palate elevation)
- CN IX, X, XI (cranial portion)
What is the function of the dorsal motor nucleus?
Sends autonomic (parasympathetic) fibers to heart, lungs, upper GI
- CN X
What cranial nerve innervates the stylopharyngeus (elevation of pharynx/larynx)?
CN IX
What are the mastication muscles?
- Masseter
- Temporalis
- Medial pterygoid (all close the jaw)
- Lateral pterygoids (protrude the jaw)
What are the mastication muscles innervated by?
V3
What are the 9 structures a needle must pass through in a lumbar puncture?
- Skin
- Fascia and fat
- Supraspinous ligament
- Intersponous ligament
- Ligamentum flavum
- Epidural space (epidural anaesthesia occurs here)
- Dura mater
- Arachnoid mater
- Subaracnoid space (CSF collection occurs here)
When may primitive reflexes be seen in adults?
When a frontal lobe lesion occurs
Describe the Moro reflexx
Abduct/extend arms when startled, then draw together
Describe the Rooting reflex?
Movement of head toward one side if cheek or mooth is stroked (nipple seeking)
Describe the sucking reflex
Sucking response when roof of mouth is touched
Describe the palmar reflex
Curling of fingers if palm is stroked
Describe the plantar reflex
Dorsiflexion of large toe and fanning of other toes with plantar stimulation
- Babinski sign
Descrbe the Galant reflex
Stroking along one side of the spine while newborn is in ventral suspension face down) causes lateral flexion of lower body toward stimulated side
What dermatomes cover the peni;e and anal zones?
S2, 3, 4
Where is the T10 dermatome?
Umbilicus
Where is the T7 dermatome?
xiphoid process
Where is the C4 dermatome?
Low collar shirt
Where is the C2 dermatome?
Posterior half of the skull
Where is the C3 dermatome?
High turtleneck shirt
What nerves innervate the achilles reflexx?
S1, 2
What nerves innervate the Pattelar reflex?
L2, 3, 4
What nerves innervate the biceps and brachiradialis reflexes?
C5, 6
What nerves innervate the tricpes reflex?
C6, 7, 8
What nerves innervate the anal wink relfex?
S3, 4
What nerves innervate the cremasteric reflex?
L1, 2
When do the primitive reflexes disappear?
Within 1st year of life
