BIOL 171 Lecture Notes - Lecture 10: Dorsal Root Ganglion, Arachnoid Mater, Dura Mater
Document Summary
Spinal cord conducts sensory impulses from body to brain conducts motor impulses from brain to body controls reflex activities. **motor tracts pyramidal (corticospinal): direct pathways precise, voluntary movements (writing, etc) extrapyramidal tracts: indirect pathways. Spinal integration integrating centres: regions in cns that relay impulses from sensory to motor neurons reflexes: fast, predictable, automatic responses to environmental changes. Sc serves as an integrating centre for spinal reflexes (promotes homeostasis) Spinal reflexes four important somatic spinal reflexes stretch (patellar) reflex monosynaptic reflex prevents over-stretching injury (hammer knee) >1 muscle group activate to lift foot crossed extensor reflex extends contralateral limb to maintain balance occurs with flexor reflex pain signals contralateral sc > contralateral extensors contract, flexors relax contralateral limb extends to support body. Physiological role of reflexes protection minimizes duration of exposure to noxious stimuli maintain posture, balance co-ordination. Clinical use of reflexes abnormal reflexes may indicate neural pathology. A. right adult reflex (toes forward) b. wrong adult reflex (toes back)
