The CNS - spinal cord Flashcards
How long is the spinal cord?
45cm (depends on height of individual)
How many segments are in the spinal cord?
31
What are the sections of the spinal and how many segments are there in each section?
(from top of spine to the base)
- Cervical - 8
- Thoracic - 12
- Lumbar - 5
- Sacral – 5
- Coccygeal – 1
How do we differ between each segment?
each section has a pair of nerves that comes out on either side
What are meninges?
3 protective layers of membranes that surround and protect the brain and spinal cord
What are the 3 meninges?
- Dura mater
- Arachnoid mater
- Pia mater
What are the features of the spinal cord
- Roots
- Ganglion
- Central canal
What is the grey matter of the spinal cord?
- Dorsal or posterior roots – sensory
- Anterior or ventral - motor
Where are somatic and visceral sensation from?
somatic = skeleton
visceral = internal organs
Describe the steps of a reflex
1) arrival of stimulus & activation of receptor
2) activation of a sensory neuron
3) information processing in CNS
4) activation of a motor neuron
5) response by effector
What 4 ways are reflexes classified by?
- development
- response
- complexity of circuit
- processing site
What are the types of development reflexes?
- innate (genetically determined)
- acquired (learned)
What are the types of response reflexes?
- somatic (control skeletal muscle contractions)
- visceral (control actions of smooth & cardiac muscles, glands)
What are the types of complexity of circuit reflexes?
- monosynaptic (one synapse)
- polysynaptic (multiple synapses)
What are the types of processing site reflexes?
- spinal reflexes (processing in spinal cord)
- cranial (processing in brain)
