Lab 2- Brain And Cranial Nerves Flashcards
Dura Mater
Most superficial.
periosteal layer and Meningeal layer
How is it different than spinal Dura Mater?
There are two layers around the Dura Mater
What is contained between the inner and outer layers of the Dura Mater?
Large collecting veins (sinuses)
What are venous sinuses?
Large collecting veins
What vessels to do the Venous sinuses drain into
Internal jugular veins
Dural folds
Where meninges fold into brain
Falx Cerebri
Projects between cerebral hemispheres and longitudinal fissure
Name 2 dural sinuses located in this fold
Superior sagittal sinus
Inferior sagittal sinus
Tentorium cerebelli
Separates cerebrum from the cerebellum hemisphere
Name the dural sinus located in this fold (tentorium cerebelli)
Transverse sinus
Falx cerebelli
Divides cerebellar hemispheres
Arachnoid Mater
Middle meningi layer
What is between the arachnoid Mater and Pia mater (in the subarachnoid space)
CSF (cerebral spinal fluid)
Pia Mater
Deepest layers
Attaches to brain by astrocytes
What attaches the pia mater to the brain surface?
Astrocytes
What is contained in the Pia Mater
Blood vessels
What are the major functions of the Medeulla oblongata?
Cardiac center
Vasomotor center
Respiratory center
Reflex center
What is meant by decussation of pyramids?
Crossover point for the major motor tract.
Left cortex controls motor activity of right side of body.
What are the major functions of the pons?
•Pneumotáxic and apneustic areas
-modify activity of respiratory rhythmicity center in medulla oblongata
What are the major functions of the midbrain?
Auditory and visual reflexes
What is the function of the superior colliculi?
Visual reflexes
What is the function of the inferior colliculi?
Auditory reflex
What is the function of the thalamus?
Directs all sensory info and sends to correct part of the brain
What are the major functions of the hypothalamus?
Hunger center
Thirst center
Regulates temperature
What is the function of them mammillary bodies?
Olfactory reflexes
What connects the pituitary gland to the hypothalamus?
Infundibulum
What are the major functions of the cerebellum?
Coordination of movement
Adjustment of postural muscles
Sense of equilibrium
How is the arrangement of white and gray matter different than in the spinal cord?
Spinal cord – gray matter is surrounded by white matter.
What is the function of the basal nuclei?
Sub conscious control of skeletal muscle
Frontal lobes
i. Precentral gyrus
Motor
Speech (usually left lobe)
Personality
Parietal lobes
i. Postcentral gyrus
Sensation (except smell)
Language
Occipital lobe
Vision
Temporal lobes
Hearing
Smell
Language
What are cranial nerves?
Connected to brain primarily at the brainstem
Are cranial nerves part of the peripheral or central nervous system?
Peripheral
What is meant by somatic motor?
Skeletal muscle
What is meant by parasympathetic motor?
Smooth
Cardiac
Glands
1 (I): olfactory nerve (most rostral)
S
Function: sensory, providing sense of smell
Test: Being able to smell and identify things
Symptoms: anosmia– Impaired sense of smell
2 (II): optic nerve
A
Function: sensory, providing vision
Tests: Visual acuity test, Visual field test, funduscopic exam
Symptoms: loss of vision or blindness and visual field, peripheral or central.
What crosses at the optic chiasm?
Fibers from medial half of each retina cross to opposite side of brain
3 (III): oculomotor nerve
M
Function: motor- Voluntary eye movement
Test: check pupil size, shape, equality.
Pupillary reflex
Check for symmetric eye movements
Symptoms: drooping eyelid, dilated pupil, double vision, difficulty focusing, and inability to move In certain directions.
4 (IV): trochlear nerve
M
Function: somatomotor- voluntary Eye movements (superior oblique)
Test: check for symmetric eye movements- patient holds head in a neutral position and follows an object held by examiner
Symptoms: vertical diploplia (double vision) and inability to rotate Eye inferolaterally
6 (VI): abducens nerve
B
Functions: somatomotor, voluntary Eye movements (lateral rectus)
Test: check for symmetric Eye movements
Symptoms: inability to rotate Eye laterally and at rest, Eye rotates medially because of unopposed action of the medial rectus muscle. Cannot move eyeball laterally beyond midpoint.
Describe the pupillary reflex
Shine light in each eye and check for pupil constriction.
What does consensual pupillary constriction mean?
When you shine a light in one eye, both eyes should still constrict.
The afferent portion of the pupillary reflex involves cranial nerve __________.
Optic (2)
The efferent portion of the pupillary reflects involves cranial nerve ______.
Oculomotor (3)
5 (V): trigeminal nerve branches
M
- Ophthalmic
- Maxillary
- Mandibular
Function:
- somatic motor (V3) to muscles of mastication.
- sensory (V1-V3) to face and cornea.
Test: Touch a wisp of cotton on the cornea and they should blank.
Symptoms: Produces loss of sensation, impaired chewing, and loss of corneal reflex.
-tic douloureux: severe, stabbing pain to one side of face.
7 (VII): facial nerve branches
B
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
Function:
- Somatomotor to muscles of facial expression.
- parasympathetic (motor) to lacrimal and salivary glands.
- special sensory taste to anterior 2/3 of tongue.
Test:
- test anterior 2/3 of tongue with substances like salt and vinegar.
- test response to tear glands to ammonia fumes.
- test motor functions by asking the subject to raise eyebrows, furrow brow, smile, etc…
Symptoms: Bells palsy
8 (VIII): Vestibulocochlear nerve
S
Function:
- receptors in vestibular apparatus
- sense of balance and equilibrium
Test: Romberg test
Symptoms: Vertigo, nausea, loss of balance, and nystagmus
What does the Romberg test evaluate?
Balance
Describe how to perform the Rhomberg test.
- patient stands with arms at side, feet together.
- examiner stands close to prevent falls.
- normal equals maintaining position for 20 seconds with minimal swaying.
Describe how to interpret the Romberg test.
Any loss of balance is a failed test.
9 (IX): glossopharyngeal nerve
B
Function:
- somatomotor to muscle of pharynx
- parasympathetic (motor) to salivary glands
- provides control over swallowing, salvation, gagging, sensations from posterior 1/3 of tongue.
Test:
-gag reflex: Touch each side of throat with tongue depressor.
Symptoms: loss of bitter and sour taste, impaired swallowing, loss of gag reflex.
10 (X): vagus nerve
B
Function:
•Somatomotor to muscles of pharynx and larynx.
•parasympathetic (motor) fibers of heart and other viscera.
-Controls secretion of digestive fluids
-Controls cardiac muscle and smooth muscle of viscera.
• sensory to pharynx and larynx
Test: vagus function- patient says “ahh” examiner observes for pallet elevation and symmetry.
Symptoms: difficulty swallowing, hoarseness or loss of voice, fatal if both are severed.
11 (XI): accessory nerve
M
Function:
•spinal portion
- somatomotor to trapezius and Sternocleidomastoid.
Test:
- shrug shoulders against resistance
- turn head against resistance
Symptoms: impaired head, neck and shoulder movement, head turned towards injured side
12 (XII): hypoglossal nerve
M
Function:
•somatomotor to tongue-tongue movements of speech, food manipulation and swallowing.
Test: ask patient to stick tongue out.
Symptoms: inability to produce tongue if both are damaged or deviation towards the injured side and Ispilateral atrophy if one side is damaged.
