ANS and spine Flashcards
Meninges
Protective coverings for the spinal cord
Layers of meninges
Dura mater
Arachnoid mater
Pia mater
Dura mater
Surrounds the spinal cord, each segment forms the epineurium
Outer layer of meninges that is dense collagenous tissue
Arachnoid mater
Middle layer of meninges
Arachnoid space
Deep to arachnoid mater, contains web like projections and CSF
Pia mater
Loose CT that is connected to the spinal cord and forms dentate ligaments and filum terminale
Epineurium
Surrounds the entire nerve projection
Dentate ligament
Runs along the spinal cord and stabilizes
Filum terminale
Fibrous band that extends from conus medullaris and connects to the coccyx, stabilizes the spinal cord
Vertebral levels of the spinal cord
C-7
T-12
L-5
S-5
Where does the spinal cord end
L1/L2
Why is there a vertebrosegmental discrepancy between spinal cord and vertebral column
Vertebral column grew faster than the spinal cord during development
Spinal cord levels of the spine
C-8
T-12
L-5
S-5
Cervical vertebra and spinal cord level discrepancy
Occipital bone is technically C1, and the C1 spinal nerve exits below that
So the spinal nerves leaving the cervical spine exit above the associated vertebral segment
Vertebrosegmental discrepancies in Cervical
Nerve exits above associated vertebra
Nerve exits horizontally
Vertebrosegmental discrepancies in thoracic
Nerve exits below the associated vertebra
In upper T nerve exits horizontally to assoc. vertebrae
Lower T, nerve is descending more vertically to get to associated vertebrae
Vertebrosegmental discrepancies in lumbar
Spinal nerve goes down vertically to reach the associated vertebrae
Vertebrosegmental discrepancies in sacral
Since in the cauda equina, all spinal nerves come from L1-L2 and descend to associated vertebrae
Gray matter
Synapses of cell bodies
Parts of the gray matter
Ventral horn
Lateral horn
Dorsal horn
Ventral horn
Somatic motor neuron cell body
Lateral horn
Visceral motor neuron
Found in T1-L2
Dorsal horn
Receive sensory info (somatic and visceral)
Why is there swelling in the cervical and lumbar vertebral regions
More synapsing (cell bodies) in the parts of the spine where the limbs are
White matter
Axons surrounded by myelin sheath
Sending and receiving signals
Amount of white matter matter as you go from sacral to cervical
Increases, more neurons entering in to go to the brain
Dorsal column tract
Between posterior horns (dorsal horns)
Ascending ipsilateral sensory, fine touch, vibration, proprioception
Anterolateral tract
Ascending contralateral tract for pain and temperature
Corticospinal tract
Located between lateral horn and dorsal horn
Descending ipsilateral tract contain motor neurons
Cervical spine looks like
High amount of white matter
Wide and flat
Increase ventral horn enlargement for arm and hand motor
Thoracic spine looks like
Small ventral horns
Lateral horn
Lumbar spine looks like
Increase in size of ventral horn for lower limbs synapsing
Round shape
Sacral spine looks like
Large ventral horn
Small amount of white matter
Ventral root
Efferent motor from spine to body
Dorsal root
Afferent sensory from body to spine
Myotome
Group of muscles that are innervated by a single spinal nerve root
Ventral root that innervates section of muscles
Dermatome
Region of skin that sends sensory information to single spinal nerve root (1 dorsal root to 1 area of skin)
Intervertebral space
Where the dorsal and ventral roots form spinal nerve trunk
Dorsal rami
Skin and muscles of back
Sensory and motor
C5 dermatome and myotome
Lateral elbow
Shoulder adbuction
Ventral ramus
Body wall and limbs
Motor and sensory
C6 dermatome and myotome
Tip of thumb
Elbow flexion
C7 dermatome and myotome
Tip of middle finger
Elbow and wrist extension
C8 dermatome and myotome
Tip of pinky
Finger and wrist flexion
T1 dermatome and myotome
Medial elbow
Finger add/abduction
T4 dermatome and myotome
Nipples
T10 dermatome and myotome
Bellybutton
L1 dermatome and myotome
Inguinal ligament
L2 dermatome and myotome
Hip flexion
L4 dermatome and myotome
Medial ankle
Knee extension
L5 dermatome and myotome
Top of foot
Dorsiflexion
S1 dermatome and myotome
Lateral ankle
Plantar flexion
S2 dermatome and myotome
Popliteal fossa
S4-5 dermatome and myotome
Perianal and anal sphincter
Autonomic nervous system
Component of the peripheral nervous system that regulates involuntary physiological processes like HR, BP, R, digestion
3 components of the ANS
Sympathetic
Parasympathetic
Enteric
Origination of sympathetics and relation to symp chain
T1-L2
White ramus for exciting spinal cord and entering symp chain to send signals above and below
Gray ramus for exciting chain
At levels above or below this section there is only a grey ramus because no innervation leaving the spinal cord
Parasympathetics location
Medulla
S2-4
2 neuron pathway sympathetics
Preganglionic - sympathetic ganglion (chain or pre-aortic) - postganglionic - target organ
2 neuron pathway parasympathetic
Preganglionic - intramural ganglion - postganglionic - target organ
Notocord
Becomes intervertebral discs
Neural crest cells
Become dorsal root ganglia
Sympathetic chain ganglia
Pre-aortic ganglia
Intramural ganglia
Sympathetics to abdominal cavity
Bypass the sympathetic chain ganglia and instead synapse in the pre-aortic ganglia
Sympathetics to heart and lungs
Synapse in the sympathetic chain and then go out to the heart and lungs as cardiopulmonary splanchnic nerve
Where medulla parasympathetics innervate
Eyes
Salivary glands
Heart
Bronchial tree
Foregut
Midgut
Where sacral parasympathetics innervate
Hindgut
Pelvic perineum (penis/clitoris)
Where does the preganglionic neuron synapse in the sympathetic chain
On the level where the postganglionic neuron exits the sympathetic chain
Visceral sensation
Organs sending info to your brain
Visceral sensory neurons
Conduct impulses from organs, glands, to CNS and are parallel to their visceral motor counterparts (except they enter dorsal root)
Can caused referred pain
Referred pain
Occurs when sensory info comes to the spinal cord from one location (appendix) but is interpreted by the CNS as coming from another location (skin) which is innervated by the same spinal cord level