CNS
Brain and Spinal Cord
PNS
Cranial nerves and spinal Nerves
How many pairs of nerves in the cranial nerves?
12
Do all cranial nerves have afferent and efferent nerves?
No, some do not have efferent nerves
How many pairs of nerves in the spinal nerves?
31
Do all spinal nerves have afferent and efferent nerves?
Yes
Where are Afferents in Spinal Nerves located and what do they do
Located in Dorsal Root. Bring info to the CNS from PNS
Where are Efferents in Spinal Nerves located and what do they do
Located in Ventral Root. Bring info to PNS from CNS
What kind of cell bodies to the afferents have in the Spinal Nerves
Unipolar cell bodies and found outside CNS
What kind of cell bodies do efferents have in spinal nerves
Multipolar cell bodies and found inside CNS
What are the two branches of the PNS
Somatic and Autonomic
What is Somatic Nervous system and what do Afferents and Efferents do?
- Conscious perceptions
- All afferents are sensory
- Efferents connect CNS directly to Skeletal muscle (only one synapse)
What is Autonomic Nervous System and what do Afferents and Efferents do?
- Not consciously perceived
- Afferents send info from organs to CNS
- Efferent connect CNS to smooth muscle (forms 2 synapses)
What are the two types of tissue in the brain and spinal cord
Gray matter and white matter
What is gray matter
- cell bodies, dendrite and axons of unmyelinated neurons (take up stain)
- Processing Center
What is White matter
- Myelinated axons located in gray matter (no able to take up stain)
- Wiring
Where is gray matter found?
- Forms “H” shape in spinal cord. Surrounded by white matter
- Exterior of brain and clumps within white matter in interior of brain
Two layers of support for the CNS
- Outer bony layer
2. Membrane layer - Meninges
