Spinal Cord Flashcards
All sensory and motor connections between the brain and the rest of the body (except the cranial nerves) travel through the _____
Spinal cord
Some nervous activity does not involve the brain but is completely contained by neurons within and branching out of the spinal cord
Reflexes
The spinal cord passes through the ____ of the vertebrae
Vertebral foramen
Pairs of ____ exit at each level of the spinal cord
Spinal nerves
Regions are named by _____
Where spinal nerves exit (roughly correlates with the regions of the spine)
Pairs of nerves in reach region: Cervical Thoracic Lumbar Sacral Coccygeal
C-8 pairs T-12 pairs L-5 pairs S-5 pairs C-1 pair
Spinal cord functions where sensory information ascends and motor commands descent
Conduction
Spindal cord function of processing information from diverse sources
Neural integration
Spinal cord functions where central pattern generators (neural networks) coordinate simple repetitive movements
Locomotion
Spinal cord function involving involuntary stereotyped reponses to stimuli
Reflexes
The spinal cord end at _____
the L1 vertebrae
After the L1 vertebra a group of axons continue down the vertebral column-called ______ that innervates ____ and _____
Cauda equina (horse’s tail)
Pelvic viscera
lower limbs
Spinal cord meninges (continuous with brain meninges), superficial to deep
Vertebra Epidural space Dura mater Subdural space Arachnoid mater Suarachnoid space Pia mater CN tissue (brain or spinal cord)
Spinal meninges with:
Tough outer layer
Epidural space
Dense irregular connective tissue
Dural mater=dural sheath around cord
Spinal meninges:
Middle layer
Subarachnoid space with cerebral spinal fluid (CSF)
Simple squamous epithelium
Arachnoid layer
Spinal meninges:
Delicate, inner layer
1-2 layer of squamous cells
Pia mater
In the brain, grey matter is ____ to white matter
superficial
In the brain, grey matter is superficial to white matter except for ____ that lie deep to white matter
nuclei
In the spinal cord white is _____ to grey
superficial
Grey matter:
Contains ____myelin
___ posterior (dorsal horns) containing ____
___ anterior (ventral horns)
___ lateral horns within _____ and _____ regions
Little
Two, interneurons
Two
Two, thoracic, lumbar
White matter: \_\_\_\_ axons \_\_\_ pairs of columns in the spinal cord containing tracts 1 2 3
Myelinated Three 1. Posterior (dorsal) 2. Lateral 3. Anterior (ventral)
In grey matter-Axons of sensory (afferent) neurons and cell bodies of interneurons
Posterior horns
In grey matter-somas of autonomic motor neurons and somatic motor neurons
Lateral neurons
Lateral horns are found in the ___ and ____ regions only
Thoracic, lumbar
In grey matter-cell bodies of somatic (efferent) motor neurons
Anterior horns
Dorsal horns are always ____, ventral horns are ____ and ____
Pointed
Fatter, rounded
Cable-like bundles of axons wrapped by connective tissue in the PNS
Cable-like bundles of axons wrapped by connective tissue in the CNS
Nerves
Tracts
Nerve:
_____wraps one axon (loose connective tissue)
____wraps a fasicle of axons (epithelial tissue)
_____wraps entire nerve (dense irregular connective tissue)
Endoneurium
Perineurium
Epineurium
______ carry sensory info to brain, wheras _____ carry motor info from brain
Ascending tracts
Descending tracts
The first neuron is called the ____
The second neuron is called the ____
The third neuron is called the ____
First order neuron
Second order neuron
Third order neuron
Sensory (afferent) pathways carry sensations from the ____ to the _____
Periphery
Brain
Sensory (afferent) pathways typically involve __ neurons
3
Sensory (afferent) pathways passes through the ____
Thalamus
What neurons receive input in the skin and conducts signal to peripheral ganglion to the brainstem
First order neurons
What neurons signals from the brainstem to the thalmus
Second order neurons
What neurons conduct signal from the thalmus to the primary somatosensory cortex
Third order neurons
The motor pathways have how many neurons
2 neurons: upper and lower
Crossing from left to right and vice versa (i.e. left hemisphere of the brain receives sensory information from the right side of the body)
Decussation
Out covering of a nerve
Epineurium
Nerve is bundles of axons called ____, surrounded by _____
Fascicles
Perineurium
Each axon of a nerve fasicle is covered by ____
Endoneurium
Clusters of cell bodies found outside the brain and spinal cord
Ganglia
Clusters of cell bodies within the CNS
Nuclei
Soma of the sensory (afferent) neurons are found in _____
The posterior root ganglion
Nerves arise from the spinal cord as small bundles of axons called ____
Rootlets
Rootlets join together to form bigger ____ of spinal nerve
Roots
Distally, spinal nerve splits into two branches called:
Rami:
Posterior ramus
Anterior ramus
Innervates errector spinae muscles and posterior integument
Posterior ramus
Splits into multiple other branches that innervates everything else
Anterior ramus
Sometimes another ramus can branch off the spinal nerve called a _____-contain axons of the automic NS
Communicating rami
Proximal spinal nerve branches:
Distal spinal nerve branches:
Posterior root (posterior root ganglion), anterior root Posterior ramus, anterior ramus
In the thorax, the anterior ramus becomes the ____
Intercostal nerve
The anterior ramus and the posterior ramus join to become the ______
Spinal nerve
The spinal nerve is a mix of ____and ___ fibers
Afferent and efferent
Plexus
Braid
Sometimes the anterior rami of spinal nerves branch and merge to form a ______
Plexus
Large nerves split off from the plexus to innervate muscles:
Cervical plexus
Brachial plexus
Lumbar plexus
Sacral plexus
Properties of a reflex
Requires stimulation
Quick
Involuntary
Sterotyped
Visceral reflex is for
Glands, cardiac muscle and smooth muscle
Visceral reflex is controlled by the
Autonomic nervous system
Somatic reflex is for
Skeletal muscles
Somatic reflex is controlled by the
Somatic nervous system
Pupil dilation, defication, vomiting is
Visceral reflex=autonomic nervous system
Knee-jerk reaction
Somatic reflex=somatic nervous system
The knee jerk reflex is an example of a ____ reflex
Monosynaptic reflex
Reflexes that include interneurons int he CNS are called ____reflexes
Polysynatic reflexes
Reflex Arc
- Somatic receptors
- Afferent nerve muscles
- Integrating center
- Efferent nerve fibers
- Skeletal muscles
