-
1st order neurons
-Cell body lies in the dorsal root ganglion
-
2nd order neuron
-Cell body is in the spinal cord or medulla oblongata
-
3rd order neuron
- Cell body is in the thalamus
-
Adiadochokinesia
Inability to perform rapidly alternating movements
-
Astereognosis
Loss of the ability to distinguish between objects through touch and manipulation
-
Asynergia
Loss of coordination in performing motor acts
-
Ataxia
Loss of proper coordination between muscles
-
Dysmetria
Inability to judge distance & stop movement at chosen spot
-
Ascending Tracts Chart (see chart week 3)
- Fasciculus Gracilis
- Fasciculus Cuneatus
- Anterior Spinothalamic
- Lateral Spinothalamic
- Anterior Spinocerebellar
- Posterior Spinocerebellar
-
Descending Tracts Chart (see chart week 4)
- Anterior Corticospinal
- Lateral Corticospinal
- Lateral Reticulospinal (medullary)
- Medial Reticulospinal (pontine)
- Rubrospinal
-
Difference between Upper & Lower Motor Neurons
- Upper Motor Neuron-
- Form descending tracts
- Lower Motor Neuron-
- Directly innervate skeletal muscle
-
Pyramidal Signs
Clinical signs of damage to the upper motor neuron functions of the corticospinal tract only
-
Upper Motor Neuron Syndromes (5)
- §Pyramidal Weakness
- §No wasting of muscles
- §Spasticity
- §Hyperreflexia
- §Positive Babinski reflex
-
Lower Motor Neuron Syndromes (6)
- §Weakness (paresis)
- §Paralysis (plegia)
- §Atrophy
- §Hypotonia
- §Hyporeflexia or Areflexia
- §Visible spontaneous contractions of motor units
-
Because of the crossing of the principal motor pathways in the lower brain stems, lesions in the cerebral hemispheresand higher brain stem cause paralysis of the...
Spinal cord lesions lead to paralysis of the limbs on the...
§ limbs opposite (contralateral) to the side of the lesion
§limbs on the same side as (ipsilateral to) the lesion
-
Cerebellum
External Structures
§Two lateral (right/left) hemispheres partially separated by a layer of the dura mater called
falx cerebelli
-
Cerebellum
§Structure that connects the hemispheres at the midline
Vermis
-
Cerebellum
Functions
- •Operates at unconscious level
- •Controls the maintenance of equilibrium
- •Influences posture and muscle tone
- •Coordinates movement
-
Dermatome
A skin area innervated by the sensory fibers of a single nerve root
-
Myotome
A group of muscles primarily innervated by the motor fibers of a single nerve root
-
Cranial Nerves
- I Olfactory S
- II Optic S
- III Oculomotor M
- IV Trochlear M
- VI Trigeminal B
- VI Abducens M
- VII Facial B
- VIII Vestibulocochlear S
- IX Glossopharyngeal B
- X Vagus B
- XI Accessory M
- XII Hypoglossal M
-
Cranial Nerve- Function? S-M-B?
I - Olfactory
Sensory – Smell
-
Cranial Nerve- Function? S-M-B?
II - Optic
Sensory – Vision
-
Cranial Nerve- Function? S-M-B?
III - Oculomotor
Motor – Muscles that raise eyelids, move eyes, adjust amount of light entering the eye & focus lenses
-
Cranial Nerve- Function? S-M-B?
IV - Trochlear
Motor – Muscles that move one eye
-
Cranial Nerve- Function? S-M-B?
V - Trigeminal
- Ophthalmic
- Maxillary
- Mandibular
Sensory – Impulses from the surface of the eyes, tear glands, scalp, forehead & upper eyelids
Sensory – Impulses from upper teeth, upper gum, upper lip, lining of the palate and skin of face
Sensory – Impulses from scalp, skin of jaw, lower teeth, lower gum & lower lip
Motor - Muscles of mastication and muscles in the floor of the mouth
-
Cranial Nerve- Function? S-M-B?
VI - Abducens
Motor – Muscles that move one eye
-
Cranial Nerve- Function? S-M-B?
VII - Facial
Sensory – Impulses associated with taste receptors of the anterior of the tongue
Motor – Impulses to muscles of facial expression, tear glands & salivary glands
-
Cranial Nerve- Function? S-M-B?
VIII - Vestibulocochlear
- Vestibular
- Cochlear
- Sensory – Impulses associated with equilibrium
- Sensory – Impulses associated with hearing
-
Cranial Nerve- Function? S-M-B?
IX - Glossopharyngeal
Sensory – Impulses from the pharynx, tonsils, posterior tongue and carotid arteries
Motor – Impulses to salivary glands and to muscles of pharynx for swallowing
-
Cranial Nerve- Function? S-M-B?
X - Vagus
Sensory – Impulses from pharynx, larynx, esophagus & viscera of thorax & abdomen
- Motor – Somatic motor impulses to muscles associated with speech and swallowing
- – Autonomic motor impulses to viscera of the thorax & abdomen
-
Cranial Nerve- Function? S-M-B?
XI - Accessory
- Cranial
- Spinal
- Motor – Impulses to muscles of the soft palate, pharynx and larynx
- Motor – Impulses to muscles of the neck and back; some proprioception input
-
Cranial Nerve- Function? S-M-B?
XII - Hypoglossal
Motor – Impulses to muscles that move the tongue
-
Meninges Function
Protects brain & spinal cord
-
Epidural Space
Space between the dura mater and the periosteum of the bone (skull)
-
Subdural Space (potential space)
- Space between the dura mater (meningeal layer and arachnoid)
- Filled with thin film of fluid (may fill w/blood as with hemorrhage)
-
Subarachnoid Space
Space between the arachnoid mater and the pia mater
-
Cranial Meninges
- Dura mater
- Arachnoid Mater
- Arachnoid Granulations (villi)
- Pia Mater
-
Cranial Meninges
Dura mater
- Tough, outermost membrane-
- Splits into 2 layers forming channels called the dural sinuses
- Periosteal Layer – outermost layer
- Meningeal Layer – innermost layer
-
Cranial Meninges
Arachnoid Mater
- Thin, web-like membrane that is located between the dura & pia mater
-
Cranial Meninges
Arachnoid Granulations (villi)
- Small, mushroom shaped protrusions (finger-like projections) of arachnoid-
- Located in the dural sinuses -
- Re-absorb CSF into the venous system
-
Cranial Meninges
Pia Mater
- Very thin, inner layer that clings or attaches to brain surface-
- Dips into grooves & contours
-
Spinal Meninges
- Dura Mater
- Arachnoid
- Pia
- Filum Terminale
-
Spinal Meninges
Dura Mater
- Composed of only one meningeal layer
-
Spinal Meninges
Arachnoid
- Continuous with the cranial arachnoid
-
Spinal Meninges
Pia
- Closely conforms to the spinal cord
-
Spinal Meninges
Filum Terminale
– Pia mater gathers into a very thin, non-nervous filament at the conus medullaris
-
Cranial Meninges – Dura Mater
Falx cerebri
Dura mater dips or folds down into the median longitudinal fissure between (separates) the right & left cerebral hemispheres
-
Cranial Meninges – Dura Mater
Tentorium cerebelli
Tentorium cerebelli Dura also dips or folds down into the space between the cerebellum and the overlying occipital lobes forming a tent-like covering over the cerebellum (separates occipital lobes of the cerebrum from the cerebellum)
-
Cranial Meninges – Dura Mater
Falx cerebelli
Dura mater dips between (separates) the two cerebellar hemispheres
-
Meninges of the Spinal Cord
Filum Terminale
§ Spinal Pia mater gathers into a very thin, non-nervous filament at the conus medullaris
§ Extends for approximately 20cm
§ Attached to the periosteum of the first coccygeal vertebra§ Helps anchor and stabilize the spinal cord
-
Meninges of the Spinal Cord
Pia Mater
Dentate Ligaments
- §Dentate Ligaments
- §Toothlike extensions
- §Located on each side of the entire spinal cord
- §Attached to the arachnoid and dura
- §Serve to anchor and stabilize the spinal cord
-
Lateral Ventricles
- Pair of C-shaped structures with “horns”-
- The C-shape allows the ventricles to reach into all lobes of the cerebrum
-
Interventricular Foramen
-Connects the lateral and third ventricles
-
Third Ventricle
Floor of the third ventricle is formed by the hypothalamus-Walls are formed by right/left thalamus
-
Cerebral Aqueduct
Connects the third & fourth ventricle
-
Fourth Ventricle
- - Extends laterally into each cerebellar hemispheres forming recesses
- - Fourth ventricle narrows inferiorly and becomes the central canal of the spinal cord
-
Cerebrospinal Fluid ( CSF)
Clear lymph-like fluid that is produced by the choroid plexus located in the lateral, third & fourth ventricles
- Fills the entire subarachnoid space which surrounds the brain and spinal cord
-
- Protective cushioning for brain & spinal cord
-
Circle of Willis (Cerebral Arterial Circle)
- - Right & Left Internal Carotid Arteries
- - Right & Left Vertebral Arteries
-
Right & Left Internal Carotid Arteries
-Bifurcate into the
- -Anterior cerebral arteries
- -Middle cerebral arteries
-
Anterior Communicating Artery
Connects the Right & Left Anterior Cerebral Arteries
-
Middle cerebral arteries
- Give rise to the...
striate arteries
-
Striate arteries
- -Frequent site of CVAs
- -Known as “arteries of stroke”
-
Posterior Communicating Arteries
- Connects the middle cerebral and posterior cerebral arteries
-
Right and Left Vertebral Arteries - Gives rise to:
- Anterior Spinal & Posterior Spinal arteries
- Posterior Inferior Cerebellar arteries Basilar artery
- -Joins together to form Basilar artery
-
Basilar Artery
Bifurcates into the..
Posterior Cerebral Arteries
-
Anterior Spinal artery (1)
Posterior Spinal arteries (2)
- - Three longitudinal vessels run the length of the spinal cord-
- Insufficient to supply the cord below cervical levels
-
Radicular arteries
Serial reinforcement or Supplemental arteries for the spinal cord
-
Superior sagittal sinus
-Receives blood primarily from the superior cerebral veins and superior anastomotic vein
-
Inferior sagittal sinus
-Receives flow of veins from the medial aspect of the hemisphere
-
Straight Sinus
- The Great Cerebral vein runs into the Straight Sinus
-
Confluence of the Sinuses
Convergence of the Superior Sagittal and Straight Sinuses
-
Transverse Sinus
- Blood flows laterally from the confluence and also receives blood from the cavernous sinus
- -Continuous with the Sigmoid sinus
-
Sigmoid Sinus
- - Continues from the transverse sinus
- - Joins the Internal Jugular vein at the level of the jugular foramen
-
Diseases / Disorders per handout
see handouts
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