Anatomy and Physiology BIO 243 Chapter 15

Voluntary motor control - Corticospinal tract

controls skeletal muscles of the body

Voluntary motor control - Corticobulbar tract

controls skeletal muscles of the head and face

Decussation

most motor fibers cross to the opposite side in the medulla oblongata

Lower motor neuron (LMN) damage

flaccid paralysis, muscle atrophy

Upper motor neuron (UMN) damage

spastic paralysis, exaggerated reflexes

Proprioception

detected by muscle spindles, Golgi tendon organs

Pain & temperature

carried by spinothalamic tracts

Fine touch & vibration

carried by dorsal column-medial lemniscus pathway

Sensory perception

depends on specific cortical area where CNS interprets signals

Central adaptation

CNS filters repetitive stimuli to prevent overload

Type A fibers

fast, myelinated

Type C fibers

slow, unmyelinated

Thermoreceptors

detect temperature (except some mechanical/stretch stimuli)

Needle injection

activates nociceptors

Phantom limb syndrome

somatosensory pathway still active

Sensory perception

requires at least one synapse

Anterior white column

carries impulses related to equilibrium and balance

Spinocerebellar tracts

carry proprioceptive information to cerebellum

Pain reflex

travels along spinothalamic tract to CNS

Brain damage in specific pathways

loss of corresponding sensory/motor function