Term
| What does the PNS include? |
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Definition
nervous structures outside the brain and spinal cord=
-cranial nerves and spinal nerves |
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Term
| What are the functional components of PNS? |
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Definition
Motor: categorized as somatic or visceral
Sensory inputs: classified as general or special |
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Term
What are somatic motor neurons of PNS?
Visceral? |
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Definition
somatic-go to skeletal muscle
visceral- autonomic NS |
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Term
| Spinal Nerves have -- pairs? Containing? How are they named? |
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Definition
31 pairs containing thousands of nerve fibers and connect to the spinal cord
Named according to point leave from spinal cord. |
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Term
| Pairs per section of spinal region: |
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Definition
8 pairs of cervical (C1-C8)
12 pairs of thoracic nerves (T1-T12)
5 pairs of Sacral (S1-S5)
1 pair of coccygeal nerves (co1) |
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Term
| Spinal cord is --, spinal nerves leave at -- |
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Definition
segmented
leave at regular intervals between vertebrae |
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Term
| How do Spinal nerves connect to the spinal cord? |
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Definition
| By the dorsal and ventral root |
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Term
| Roots are composed of-- which are arranged-- |
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Definition
| Rootlets- arranged continuously along spinal cord |
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Term
Dorsal root contains --
Cell bodies are located -- |
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Definition
sensory fibers
in the dorsal root ganglion |
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Term
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Definition
| motor fibers arising from anterior (ventral) gray column |
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Term
| What do the spinal roots branch into? |
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Definition
| Dorsal ramus and ventral ramus |
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Term
Dorsal and ventral rami contain--
Dorsal rami innervates--
Ventral rami innervate- |
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Definition
both sensory and motor neurons
A horizontal strip of muscle and skin on back
Anterior torax and abdomen in a simple segmented pattern, gives off lateral and anterior cutaneuous branches |
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Term
| What is a dermatome, what innervates it? |
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Definition
| An area of skin innervated by cutaneous branches of a single spinal nerve |
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Term
| What nerves supply the upper limb? |
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Definition
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Term
anterior surface of the lower limb-
posterior surface of the lower limb- |
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Definition
lumbar nerves
sacral nerves |
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Term
| Functions of Peripheral sensory receptors- |
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Definition
| Structures that pick up sensory stiumuli from inside and outside body and initiate signals in sensory axons |
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Term
| Types of Peripheral sensory receptors- |
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Definition
Exteroceptors
Interoceptors (visceroceptors)
Proprioceptors |
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Term
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Definition
Sensitive to stimuli arising from outside body
Located at or near body surfaces
Include receptors for touch, pressure, pain, and temp |
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Term
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Definition
Receive stimuli from internal viscera
Monitor a variety of stimuli |
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Term
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Definition
Monitor degree of stretch
Located in musculoskeletal organs |
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Term
| How do sensory receptors in PNS exist as? |
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Definition
Nerve endings of sensory neurons
Receptor cells- specialized epithelial cell or small neurons; synapse with sensory neurons
-usually associated with special senses |
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Term
| How are receptors as nerve endings divided? |
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Definition
2 groups:
-free nerve endings
-encapsulated nerve endings |
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Term
| What do receptors as nerve endings of sensory neurons monitor? |
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Definition
| touch pain pressure vibration stretch temperature and proprioception |
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Term
| Where are free nerve endings present? Respond to: |
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Definition
abundant in epithelia and underlying connective tissue
Respond to pain and temperature- widely distrubuted throughout body |
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Term
| What is a specialized type of free nerve ending? |
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Definition
| hair follicle receptors- wrap around hair follicles, light touch. |
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Term
Encapsulated Nerve Endings Consist of:
enclosed in:
Examples: |
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Definition
consists of one or more ends of sensory neurons
Enclosed in connective tissue *
Ex: Meissner's corpuscle and Pacinian Corpuscle |
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Term
| What are Meissner's corpuscles |
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Definition
spiraling nerve ending surrounded by schwann cells
occur in the dermal papillae (skin)
Discriminative touch
occur in sensitive, hairless areas of skin |
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Term
| What are Pacinian Corpuscles? |
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Definition
Single nerve ending surrounded by layers of flattened Schwann cells (onion-like)
Occur in the deep dermis and hypodermis
Sensitive to deep pressure/vibration |
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Term
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Definition
Monitor stretch in locomotory organs
-muscle
-tendons
-joints
Three types |
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Term
| What are the tree types of proprioceptors? |
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Definition
Muscle spindles
Golgi tendon organs
join receptors |
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Term
| What do muscle spindles do? |
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Definition
measure the changing length of muscle
-imbedded in perimysium between muscle fascicles
consist of intrafusal fibers *(specialized skeletal muscle cells that can still contract)
-Sensory nerve endings wrap around intrafusal fibers
-Muscle stretch causes intrafusla fibers to stretch= detected by nerve endings
Part of reflexes |
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Term
| What do Golgi tendon organs do? |
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Definition
located near the muscle-tendon junction
-monitor tension w/in tendons
-prevent over contraction of muscle |
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Term
| What do joint receptors do? |
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Definition
mostly synovial joints
-sensory nerve endings w/in joint capsules
monitor joint position |
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Term
| Somatic motor neuron's cell bodies in ventral gray matter of spinal cord exit- |
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Definition
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Term
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Definition
| a motor neuron and all the muscle cells it innervates |
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Term
| How does a motor unit innervate? |
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Definition
| 1 MN innervates many skeletal muscle cells, but each muscle cell is only innervated by one motor neuron |
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Term
| What is a neuromuscuscular junction? How many per muscle cell? |
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Definition
synapse between a motor neuron and a muscle fiber
One neuromuscular juntion per muscle cell |
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Term
| What is a motor end plate? |
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Definition
| Axon terminal plus specialized region of muscle cell membrane |
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Term
What is a nerve plexuses?
Ventral rami (except --) : |
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Definition
a network of nerves
t2-12 exceptions
branch and join w/one another
form nerve plexuses in cervical, brachial, lumbar, and sacral regions
Primarily serve the limbs
Fibers form ventral rami crisscross. |
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