- acquired reflexes
- more complex, learned motor patterns; rapid automatic responses but are learned
- anterior gray horns
- contain somatic motor nuclei
- anterior white columns
- lie b/t the anterior gray horns and the anterior median fissure- interconnected by anterior white commissure
- ascendind tract
- carry sensory info toward the brain
- brachial plexus
- innervates the pctoral girdle and upper limb- C5-T1- nerves that form this plexus orig from trunks and cords- musculocutaneous nerve, median nerve, ulnar nerve, axillary nerve, radial nerve
- cervical plexus
- consists of the ventral rami of spinal nervs C1-C5; the branches of the cerv plex innervate the muscles of the neck and extend into the thoracic cavity
- cords
- smaller branches that originate at the trunks (brachial plexus)
- cords and trunks named after_____
- their location relative to the axillary artery
- gray commissure
- posterior to and anterior tot he central canal containing axons that cross from one side of the cord to the other befor they reach a destination in the gray matter
- innate reflex examples
- w/draw from pain; chewing, suckling, tracking objects w/ eyes
- innate reflexes
- result from conncetions that form b/t neurons during development-appear in a predictable sequence; genetically or developmentally programmed
- intersegmental reflex arcs
- the most complicated spinal reflexes in which many segments interact to produce a coordinated, highly variable response
- lateral white column
- the withe matter b/t the anterior and posterior columns on each side
- latral gray horns
- only located in the thoracic and lumbar segments contain visceral motor nuclei
- Lumbar Plexus
- contains axons from ventral rami of spinal nervs T12-L14
- monosynaptic reflex
- simplest reflex arc; sensory neuron synapses directly on a motor neuron
- nerve plexus
- where the ventral rami of adjacent spinal nerves blend their fibers and produce a serios of compound nerve trunks; the ventral rami form 4 major pluxuses: cervical, brachial, lumbar, sacral
- neural circuits
- the pattern of interaction among neurons that provides clues tot the functional characteristics ofa neuronal pool: divergence, convergence, serial processing, paralellel prcessing, reverberation
- neuronal pools
- functional groups of inrerconnected neurons; can be diffuse, or localized;; diff neural circuits
- nuclei
- groups of cell bodies in the gray matter of the CNS
- peripheral neuropathies
- regional losses of sensory and motor function most often resulting from nerve trauma or compression
- phrenic nerve
- major nerve of the cervical plexus- provides nerve supply to the diaphragm
- polysynaptic reflex
- longer delay b/t stimulus and response; can produce more complicated responses b/c the interneurons can control motor neurons that activate several muscle groups simultaneously
- posterior gray horns
- contain somatic and visceral sensory mnuclei
- posterior white columns
- lie b/t the posterior gray horns and the posterior median sulcus
- postganionic fibers
- innervate smoth smucles, glands, and organs in the thoracic cavity extend directly from the ganglion to their respective effector organs- form a series of sympathetic nerves- unmyelinated and gray- known as the gray ramus
- preganglionic fibers
- distally, the first branc from the spinal nerve that carries visceral motor fibers to a sympathetic ganglion- preganglionic fibers are myelinated- called the white ramus
- reflex arc
- the wiring of a single reflex
- Reflexes
- rapid, automatic responses to specific stimuli- preserve homeostatsis by making rapid adjustments in the function of organs or organ systems
- Reflexes are classified on the basis of:
- 1. Thier development
2. The nature of the resulting motor response
3. the complexity of the neural circuit involved
4. the site of info processing - somatic reflex examples
- superficial reflexes (those triggered by stimuli at the skin or mucous membranes; stretch reflexes (triggered by the sudden elongation of a tendon; deep tendon flex
- Somatic Reflexes
- provide a mechanism for the involuntary control of the musc. system
- steps in a simple neural stretch reflex
- 1. arrival of stimulus and activation of receptor
2. The activation of a sensory neuron
3. Information processing
4. Activation of a motor neuron
5. response of a peripheral effector - tract
- contained by each column of white matter- a bundle of axons in the CNS that relatively uniform with respect to diameter, myelination, and conduction speed- all axons w/in a tract relay same kind of info in the same direction- short tracts carry info b/t segments of the spinal cord- long tracts connect the spinal cord w/ the brain
- trunks
- large bundles of axons contributed by several spinal nerves (brachial plexus)
- white matter of the spinal cord
- superficial contains large #s of myelinated and unmyelinated axons- divided into 3 regions called colums
