Quiz 9/17 Flashcards
Spinal cord
means for communication from the brain to body/body to brain
surrounded by vertebral column
3 layers of meninges
- pia mater
- arachnoid
- dura mater
pia mater
inner layer of meninges
arachnoid
web-like, filled with cerebral spinal fluid
dura mater
tough, outside layer
spinal cord form (sections)
Cervical (neck)
Thoracic (chest)
Lumbar (lower back)
Sacral (pelvis)
Coccygeal (tailbone)
Information highway …
conveys motor (efferent) and sensory (afferent) information between brain/body
Spinal nerves emerge from
spinal cord, innervate parts of neck and BELOW neck
each spinal nerve has
- dorsal root ganglion
- dorsal ramus
Dorsal root ganglion
- collection neuronal cells
- signals to CNS from PNS (AFFERENT)
Dorsal ramus
part of spinal nerve after the nerve exits intervertebral foramen
(outside spinal cord, still part of nerve)
upper motor neuron
- originates in brain (CNS)
- sends signals down spinal cord
- “commands” the movement
damage to UMN
spasticity (spastic muscle)
hyperflexia (flex too much)
lower motor neuron
-originates in spinal cord (PNS)
-directly control muscles by sending signals on to muscles and glands
- “carries out” action
damage to LMN
flaccid paralysis
muscle atrophy (smaller/dried up)
decreased reflexes
spinal cord function
- relay efferent & afferent info between body/brain
- mediate reflexes through reflex arc
reflexes
- controlled at level of spinal nerves/cord
- signal goes to spinal cord & return via reflex arc
movement of reflexes
- muscle stimulated
- muscle spindles detect stretch
- info sent thru sensory neurons to dorsal root (gray matter)
- info sent to ‘interneurons’
- motor message sent via ventral root
- muscle contracts
Spinal cord injury
damage to the spinal cord, often thru traumatic causes (car accidents/falls)
can result in paresis or plegia
PARA plegia/paresis
involves the legs
QUADRI plegia/paresis
involves arms and legs
parts of the brainstem
- midbrain (most superior)
- pons (middle portion)
- medulla (lowest portion)
functions of brainstem
- regulate major life functions (heartbeat, respiration)
- mediate head & neck reflexes
- regulate alertness & wakefulness
pons
superior to medulla, inferior to midbrain, anterior to cerebellum
-inch length and bulbous
-connected to cerebellum middle cerebellar peduncle
- acts as BRIDGE relaying tracts, cerebellum, lower structures medulla and spinal cord
