Nervous System Flashcards
What are the 2 functions of the nervous system?
Receive and process info (stimuli) from the environment
Coordinate and carry out an appropriate action to respond to those stimuli.
Explain the difference between CNS and PNS.
CNS: brain and spinal cord, controls the PNS
PNS: all nerves outside CNS
Explain the difference between the somatic and autonomic (visceral) NS.
Somatic: stimuli largely external (touch, vibration) and internal (joint pain). responses voluntary (motor control over skeletal muscles)
Visceral: stimuli primarily internal (body temp, heart rate). Response involuntary (control over smooth muscle, visceral organs and their functions)
The ______ is the basic cellular unit of the NS.
Neuron
Neurons communicate through ___________ and information travels _______.
Chain-like connections, unidirectionally.
Name and describe the 5 components of a neuron.
Dendrite: receives short info
Cell body: processes info
Myelin: insulation - increases speed of electrical impulses
Axon: relays info as electricity, can be long
Synapse: passes info onto other nerves or effector organ chemically
Name and explain the difference between the 2 types of neurons.
Motor/efferent: unidirectional
Dendrites –> cell body –> axon –> PNS (target organ)
Pseudo-unipolar: sensory/afferent
Sensory receptors –> branched axon –> CNS
What is the posterior root ganglion?
group of cell bodies for the sensory neurons
What is the ventral horn?
Group of cell bodies for the motor neurons.
Name and describe the parts of the spinal nerve (6).
- Rootlets: axon bundles from sensory neurons (post.) and motor neurons (ant.) closest to spinal cord.
- Roots: convergence of rootlets. posterior root contains cell.
- Spinal nerve: convergence of roots, emerges from vertebral column
- Rami: first split of spinal nerve into
- Posterior ramus: to intrinsic back muscles and associated skin
- Anterior ramus: to everything else
How are skeletal muscle fibers stimulated to contract?
By the somatic NS via motor neurons.
Name the superior vertebrae and their quantity.
Thoracic (12), Lumbar (5), Sacral (5), coccygeal
Name the inferior vertebrae and their quantity.
cervical nerves (8)
Which vertebrae is the exception?
Spinal C8
Name the 6 elements of the inside of the spinal cord.
Central canal, posterior and anterior horn, lateral horn, gray matter, white matter.
Out of the gray and white matter, which one is myelinated and which isn’t?
White is myelinated, gray isn’t.
Name the 4 elements of the outside of the spinal cord.
Posterior median sulcus, postero-lateral sulcus, anterolateral sulcus, anterior media fissure.
What is the cervical enlargement called and where is it?
Brachial plexus, C5-T1
What is the lumbar enlargement called and where is it?
Lumbosacral plexus (L1-S4)
What is the end of the spinal cord called?
Conus medullaris
What is the cauda equina?
Axons of inferior spinal nerves.
Where does the spinal cord end at birth vs as an adult?
Birth: L3
Adult: L1/L2
Name in order from outermost to innermost, the meninges of the spinal cord.
Extradural/epidural space
Dura mater
Subdural space
Arachnoid mater
Subarachnoid space
Pia mater
What is dura mater?
Connective tissue that envelops spinal cord.
Where does CSF circulate?
Subarachnoid space.
What derives from the pia mater?
Filum terminale.
Where is the denticulate ligament located?
Between C3-C4, runs from arachnoid to dura.
How many pairs of spinal nerves are there?
31
What is a dermatome?
area/region of skin innervated by a single spinal nerve
