Exam 1 (Motor) Flashcards
4 Main Functions of CSF?
1) Reduces traction on nerves and blood vessels by floating the brain and sc
2) Cushioning effect
3) Removes metabolites from CNS
4) provides stable ionic environment for CNS
Layers Head from outside to inside
- skull
- dura mater (meningeal layer)
- Arachnoid space (meningeal layer)
- Sub-arachnoid space
- Pia mater
- Cerebral cortex
BBB Components
- Astrocytic Process (creates tight junctions)
- Capillary Cell Membrane
CSF Circulation
Produced in choroid plexus and lateral 4th ventricle, then to arachnoid space via arachnoid villa, then superior sagittal sinus, then to venous system
What does the central sulcus divide?
Pre and Post cntral gyrus
What does the lateral sulcus divide?
Parietal and frontal lobes from temporal lobe
What is the body’s central stress response system?
Hypothalmic-pituitary adrenal axis (HPA axis)
Limbic System Componenets
Hippocampus, amygdala, thalamus, hypothalamus, frontal cortical areas
Hippocampus
-Librarian of the brain/ memory center
- CONSCIOUS memory about emotion
Amygdala
-Threat detector
- UNCONSCIOUS emotional memory
Pre-frontal cortex (PFC)
emotional regulation and inhibitory control
Limbic System function
Process sensory info and prepare the body to act
List the lateral descending pathway tracts
- Corticospinal
- Lat. Corticospinal
- Corticobulbar
- Rubrospinal
Lateral Descending Pathway Functions (General)
- voluntary movement
- distal muscles
- flexors
- more fine motor skills oriented
Lateral Corticospinal tract Function
- distal muscles
- fine motor movements
Corticobulbar Tract Function
- muscles of head and face
- movements of tongue (speech)
CN 7 (Facial) innervation to face
- upper face is bilateral
- lower face is contralateral (opp. side)
Lateral Pathway Tracts origin/termination
1) Corticospinal/Lat. Corticospinal:
- origin: cerebral cortex
- termination: grey matter of sc (synapse on alpha motor neurons or intenuerons)
2) Corticobulbar:
-origin: cortex
-termination- nuclei of CN 5, 7, and 12
3) Rubrospinal:
-origin: red nucleus in brainstem
-terminates: grey matter in sc (internuerons)
Rubrospinal Tract Function
- maintain muscle tone in flexors of UE
- contralateral control of flexors in UE
- distal control
- NO INVOLVEMENT IN LE
Medial Pathway Tracts Functions
1) Anterior Corticospinal:
- axial and proximal limb control
2) Vestibulospinal:
- maintains upright position
- posture and balance
- reflex adjustment of head (medial division)
3)Reticulospinal:
- integrated vestibular, sensory info. with commands from cortex
- bilateral control
- extensors of proximal muscles
- reflexes (origin allows for homeostasis bc medulla inhibits reflexes while pontine facilitates reflexes)
4) Tectospinal:
- reflex control of head and neck movements to visual and auditory stimuli
Parkinsons
Hypokinetic, hypertonic
Pyramidal vs. Extrapyramidal Signs and Symptoms
1) Pyramidal (ex: stroke):
- Clasp knife effect (spasticity)
- hypertonicity in UE flexors and LE extensors (flexor synergy)
- Increased DTR/ positive Babinski sign
- dystonia (involuntary mvmnt that is non-rhythmic)
-paralysis of voluntary movements
2) Extrapyramidal (ex: Parkinsons):
- cogwheel rigidity
- hypertonicity in flexors of limb and trunk (bilateral)
- involuntary mvmnt presents as tremor (rhythmic)
- negative babinski sign
Motor Neuron Pool (MNP) vs. Motor Unit
MNP: cell bodies of motor neurons that innervate ONE specific muscle and the associated spinal level (ex: biceps at C5-C6)
* 1 MNP contains MANY motor units*
Motor Unit: a motor neuron, its axon, and the muscle fibers it innervates
Lesions to Lat. Corticospinal Tract
- In Brainstem: affect opposite side (side it will cross over to)
- In SC: affect same side (bc it has already crossed)
Lesion to Corticobulbar Tract
Impact CN 5, 7, and 12