ANATOMY- neurons and nerves Flashcards
(46 cards)
what makes up the CNS?
-brain
-spinal cord
what makes up the PNS?
-all other nerve tissue not within CNS
-12CNs and 31 spinal nerves
(CNS= spinal cord and brain)
what do spinal nerves connect to?
-spinal nerves connect with the spinal cord
what do cranial nerves connect with?
-cranial nerves connect with the brain
basic unit of the nervous system?
-the neuron
where are the collection of nerve cell bodies in the CNS called?
-the nucleus
Cns= nuCleus
where are the collection of nerve cell bodies in the PNS located?
-in the ganglion
what are the two main types of neurons?
-motor neurons (multipolar)
-sensory neurons (Unipolar/ pseudounipolar)
what are the main type of neurons in the CNS and describe it
-Multipolar neurons
-they have 2 or more dendrites
-they are motor neurons
-they are efferent so their impulses move from the brain towards the body wall, body cavity or organ
what are the main type of neurons in the PNS and describe it
-unipolar/ pseudounipolar
-they have a double process
-these are sensory neurons
-they are afferent so their impulses move towards the brain
what are nerves?
-collections of axons surrounded by connective tissue and blood vessels
what are the 2 modalities of nerves?
- single modality (one of somatic motor, somatic sensory, special sensory, sympathetic, parasympathetic, or visceral afferent)
- mixed modality (somatic motor, somatic sensory and sympathetic all together in one nerve
what modality do ‘tracts’ tend to consist of?
-tracts tends to consist of single modality
single modality: one of the somatic motor, somatic sensory, special sensory, sympathetic, parasympathetic, or visceral afferent
name the spinal nerves
31 pairs
8 cervical: C1- C8
12 thoracic: T1-T12
5 lumbar: L1- L5
5 sacral: S1- S5
1 coccygeal: Co1
where are spinal nerves found?
only found in the intervertebral foramina
what do the spinal nerves connect with?
-they connect with structures of the soma via rami
-the spinal cord segment of the same number via roots and rootlets
What are A-G
A= right anterior/ventral rootlet
B= right anterior/ventral root
C= right posterior/dorsal rootlet
D= right posterior/dorsal root
E= posterior rami (smaller and connects to posterior wall)
F= anterior rami (larger and connects to anterolateral body wall)
G= spinal nerve
Where do motor axons in the spinal nerves pass?
-pass from anterior horn of spinal cord
-from anterior horn to anterior rootlets
-anterior rootlets to anterior root
-anterior root to spinal nerve
anterior horn > anterior rootlets > anterior root > spinal nerve
Where do sensory axons in the spinal nerves pass?
-all sensory axons pass from the spinal nerve
-from spinal nerve into the posterior root
-from the posterior root into the posterior rootlets
-from the posterior rootlets into the posterior horn of the spinal cord
spinal nerve > posterior root > posterior rootlets > posterior horn of the spinal cord
what do general sensory nerves supply?
-all structures
what do somatic motor nerves supply?
skeletal muscle
what do sympathetic nerves supply?
-the skin and the smooth muscle of arterioles
how is a dermatome innervated?
-area of skin supplied with sensory innervation from a single spinal nerve
-also supplies sensory innervation to deeper structures
-innervation of skin by adjacent spinal nerves shows overlap
how is a myotome innervated?
-the skeletal muscles supplied with motor innervation from a single spinal nerve
-may be deep to dermatome of same spinal nerve, but not always
