Flashcards in Neuro and Intracranial Dynamics Deck (111)
How does sensory info travel up the spinal cord?
Up through spinothalamic tracts through the brainstem and cerebellum to the cerebrum
How does motor info travel down the spinal cord?
Down through corticospinal tracts, through brainstem and cerebellum, down spinal cord to the effector organ
Where do the corticospinal tracts pass and what is the significance?
Cross at the level of the medulla, therefore movement on one side of the body is controlled by the other side of the brain.
What is decussation?
Cross over of descending motor tracts (corticospinal tracts) at the medulla
Which cranial nerves exit through the brainstem?
All except I and II
Do cranial nerves cross over?
No, so they are responsible for same side (ipsilateral) sensory and motor information
What is CN II responsible for and what occurs in deficits?
Deficits result in impaired visual fields
What is CN III responsible for and what occurs in deficits?
Raises eyelid, pupil constriction, eye movement
Deficits result in ptosis and pupil dilation
What is CN IX responsible for and what occurs in deficits?
Gag, swallowing, phonation
Deficits result in impaired gag and difficulty speaking
What is CN X responsible for and what occurs in deficits?
Deficits result in impaired swallowing and speech
What are the afferent / efferent portions of the pupil and corneal reflex?
CN II sees light
CN III constricts pupil
CN V detects stimulus
CN VII causes facial twitch
What is the weakest point of the skull and why is it vulnerable?
Pterion --> Junction of the skull bones
What are the divisions of the skull base?
Anterior, middle, posterior fossa
What are the 3 main areas of the brain?
What are elements of the cerebrum?
2 central hemispheres composed of pairs of:
1) Frontal lobe
2) Parietal lobe
3) Temporal lobe
4) Occipital lobe
Central hemispheres communicate through corpus collosum
What is the frontal lobe responsible for?
Contains motor cortex
High level cognitive functioning, concentration, judgment, memory, emotion, personality.
Contains Broca's area responsible for motor speech
What happens with frontal lobe deficits?
Contralateral motor impairment, behaviour and personality changes, impaired speech
What is the parietal lobe responsible for?
Contains sensory cortex
Interpret sensations, proprioception
What happens with parietal lobe deficits?
Sensation deficits, left and right confusion, neglect syndromes
What is the temporal lobe responsible for?
Integration of auditory and visual areas, contains Wernike's area responsible for understanding of speech.
Visual, auditory, olfactory perception, learning, memory
What happens with temporal lobe deficits?
Receptive aphasia if Wernike's area is damaged
What is the occipital lobe responsible for?
Visual perception, visual reflexes, smooth eye movements
What is the cerebellum?
Located in posterior fossa, controls fine movement and coordination of muscle groups, maintaining balance
What happens with cerebellar deficits?
Gait disturbances, ataxia, dysmetria (lack of coordination)
What is the reticular activating system (RAS)?
Group of nuclei throughout the brainstem, moderates wakefulness and consciousness.
Disturbances in RAS result in altered LOC, fibers fan out to all aspects of the cerebrum
What are the 3 main subdivisions of the brainstem?
What is the midbrain responsible for?
Motor function, relay system between cerebral hemispheres, subcortical structures, cerebellum, and spinal cord
What is the pons responsible for?
Respiratory patterns, controlling rate
What is the medulla responsible for?
Extends through foramen magnum and becomes spinal cord.
Site of decussation, controls respiration, vomiting, hiccupping, vasomotor function affecting blood pressure