Clinical Oriented Anatomy of the Brain

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Block C5 - Aging and Elderly


Anatomy
Office:Anatomy Building.
Lab:Rear of Anatomy Building.
Work-plan:None.
Pre-test:5 questions, short-answer.
Post-test:None.
Lab Report:None.
Substantia nigra in Parkinson's disease
Basal ganglia
Broca's and Wernicke's areas
Auditory pathway
Role of thalamus in visual pathway
Visual pathway lesions

Concepts[edit]

Extrapyramidal System[edit]

Indirect activation pathway.

Functions:

  1. Regulation and integration of voluntary motor activity.
  2. Regulation and maintenence of the muscle tone.
  3. Regulation and maintenence of emotional and associative movements.

Disturbances in the extrapyramidal system can lead to various problems including Parkinson's disease. Beyond this, it is not necessary to learn more about the extrapyramidal system until Block 3.5 - Neurosensory Complaints. Read more about the extrapyramidal system.

Neurological Deficits[edit]

Agnosia
Loss of ability to interpret sensory stimuli.
Astereognosis
Loss of ability to identify objects by touch.
Anosmia
Loss of the sense of smell.
Anesthesia
Total or partial loss of sensation.
Agraphia
Loss of ability to write.
Apraxia
Loss of ability to perform coordinated movement.
Ataxia
Uncoordinated movement due to muscle control problem.
Dyspraxia
Impairment in control of motor system.
Aphasia
Loss of ability to articulate or comprehend ideas.
Alexia
Loss of ability to read.
Dyslexia
Loss of ability to comprehend or recognize words.
Anterograde Amnesia
Loss of memory of events that happened before mental trauma.
Retrograde Amnesia
Loss of memory of events that happened after the mental trauma.
Dementia
Severe mental or emotional deterioration.

Eye Syndromes[edit]

Horner's Syndrome[edit]

  • Nerves from brain (hypothalamus) to eyes/face are damaged.
  • Due to stroke, tumor, or spinal cord injury.
  • Usually just one side of face (unilateral).
  • Drooping eyelid (ptosis), small pupil (miosis), and decreased sweating on one side of the face.
  • Parasymphathetic: NIII. Symphathetic: Plexus caroticus.

Argyl Robertson's Pupil[edit]

  • Bilateral.
  • Small pupils that constrict when focusing on near objects but don't constrict in bright light.
  • Ciliary ganglion damage in the peripheral pathways.

Adie's Tonic Pupil[edit]

  • Dilated, partly reactive pupil.
  • Due to damage in the ciliary ganglion behind the eye.

Eye Physiology[edit]

  • The lateral rectus muscle is the only muscle (for movement of the eye) innervated by the abducens nerve. (The other is retractor bulbi muscle, but that is not important here.)
  • The superior oblique muscle is the only muscle innervated by the trochlear nerve.

Reflexes[edit]

Caloric Reflex Test[edit]

The idea is to squirt either cold or warm water into the ear of a patient and see what happens to their eyes. They will either quickly look left or quickly look right, depending on whether the water is cold or warm.

COWS: Cold water, Opposite side. Warm water, Same side.

Absence of movement can suggest vestibular weakness or nerve damage in the brain steam (poor prognosis).

Optokinetic reflex[edit]

The head remains stationary and the eyes track an object. For example, if a hot girl walks into the lecture room, some students may track her walking in with their eyes without moving their heads.

Vestibulo-ocular reflex[edit]

The head is moving and the eyes compensate by moving in the opposite direction. (Remember, vestibular system is used for balance using the movement of the head).

Questions[edit]

Batch 2011 Pretest[edit]

  1. A lesion in this area causes: Hemianopsia contralateral.
  2. Aphasia motoric.
  3. A lesion in this area causes: Parkinson's disease.
  4. Globus pallidus interna.

See Also[edit]