the spinal cord. protection vertebrae spinal meninges three layers of connective tissue – dura...
TRANSCRIPT
The Spinal Cord
Protection
VertebraeSpinal meninges• Three layers of connective tissue– Dura mater– Arachnoid mater– Pia mater
• Continuous with cranial meningesCerebrospinal fluid (CSF)
Spinal Meninges
• Epidural space: between vertebrae and dura mater
• Dura mater- tough, dense connective tissue• Arachnoid mater: resembles spider’s web– Extends into subarachnoid space
• Subarachnoid space –CSF circulates in this space
• Pia mater: thin, delicate layer –Adheres to surface of spinal cord (and
brain)–Contains blood vessels
Spinal Meninges
Spinal Meninges
Structure of the Spinal Cord
Structure of the Spinal Cord
Spinal Nerves
Nerves attached to spinal cord by 2 roots• Dorsal root: made of axons of sensory neurons– Dorsal root ganglion: swelling containing cell
bodies of sensory neurons• Ventral root: composed of axons of motor
neurons– Both somatic motor and autonomic motor
Spinal Cord Functions
Pathways for nerve impulses within tracts• Ascending (sensory)• Descending (motor)Reflexes: fast, involuntary sequences of actions
in response to stimuli• Can be simple (withdrawal) or complex
(learned sequence such as driving car)
The Reflex Arc
1. Sensory receptor: responds to stimulus2. Sensory neuron: through dorsal root ganglion
and root posterior horn 3. Integrating center: single synapse between
sensory and motor neurons4. Motor neuron: from anterior horn ventral
root spinal nerve 5. Effector: muscle or gland responds
The Reflex Arc