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145 terms

15: spine

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Sensory information from all parts of the body is routed to the:
Somatosensory cortex
What type of receptors monicor specific conditions in the body or the external environment?
Sensory receptors
The receptors, sensory neurons and sensory pathways constitute the ________ division of the nervous system.
Afferent
_________ __________ connect our internal and external environments with the nervous system.
Sensory Receptors
The conscious awareness of a senstaion is called a:
Perception
What are the 5 special senses:
Olfaction (smell), Vision (sight) Gustation (taste), equilibrium (balance), and hearing.
What is transduction?
A sensory receptor detects and arriving stimulus and translates it into an action potential to be conducted to the CNS
Each receptor has a characteristic sensitivity. This is called:
Receptor Specificity
Free Nerve Endings are:
Branching tips of the dendrites of sensory neurons
Sensory Coding:
The translation of complex sensory information into meaningful patterns of action potentials.
Effector of the SNS:
Skeletal Muscle
Effector of the ANS:
Smooth Muscle, Cardiac Muscle and Glands
Motor Pathway of the SNS:
Pre-central Gyrus - Upper Motor Neuron - Spinal Cord - Innervate Skeletal Muscle
A ganglion is:
a collection of cell bodies outside the CNS
Motor Pathway of the ANS:
Pre-central Gyrus - Ganglion - 1st pre-ganglionic neuron - 2nd pre-ganglionic neuron
Sensory information that arrrives at the CNS is routed according to the ____ and _____ of the stimulus.
Location; Nature
the link between peripheral receptor and cortical neuron is called a.
labeled line
Each labele line consists of acons carrying information about one _______.
Modality or type of stimulus.
The translation of complex sensory information into meaningful patterns of action petentials is called:
Sensory Coding
What type of sensory neurons are always active?
Tonic receptors
What type of sensory neurons are normally inactive but become active for a short time whenever a change occurs in the conditions they are monitoring?
Phasic receptors
Phasic receptors provide information about the _______ and ___________ of a stimulus.
Intensity; rate of change
Adaptation is:
reduction in sensitivity in the presence of a constant stimulus.
Peripheral adaptation occurs when:
the level of receptro activity changes.
Temperature receptors are:
Phasic receptors
Phasic receptors are also called:
Fast-adapting receptors.
tonic receptos are also called:
slow-adapting receptors
Central Adaptation occurs:
along sensory pathways inside the CNS
Central adaptation generally involves the _______ of nuclei along a sensory pathway.
Inhibition
peripheral adaptation reduces:
the amount of information that reaches the CNS
Most of the incoming sensory information is processed in centers along the spinal cord or brain stem at the _________ level.
Subconscious
What are the 3 types of receptors for the general senses?
Exteroceptors, proprioceptors, and interoceptors
Exteroceptors provice information about the:
External environment
Proprioceptors report the positions of
Skeletal muscles and joints
Interoceptors monitor:
Visceral organs and functions
Nocicceptors are excited by:
pain
thermoreceptors are excited by:
temperature
mechanoreceptors are excited by:
physical distortion
chemoreceptors are excited by:
chemical concentration changes
The difference between a Somatic receptor and a visceral receptor is its:
Location, NOT stucture
Pain receptors are ____ ____ ____ with large receptive fields.
free nerve endings
It is difficult to determine the exact ____ of a painful sensation.
source
nociceptors may be sensitive to:
1) extremes of temperature, 2) machanical damage, 3) dissolved chemicals
What two type of axons carry pain sensations:
Type A and C
Myelinated Type A fibers carry sensations of:
fast pain or prickling pain
Slower type C fibers carry sensations of
slow pain or burning and aching pain
Pain Receptors are ____ receptors.
tonic
Painful sensations cease only after the:
tissue damage has ended
Ceentral adaptation may reduce the ____ of the pain while pain receptors remain stimulated.
perception
Endorphins and enkephalins are neuromodulators whose release inhibits activity along ____ ____ in the brain.
pain pathways
Endorphins and Enkephalins are found in the:
Limbic system, hypothalamus and reticular formation
Thermoreceptors are ____ _____ _____ located in the dermis, in skeletal muscles in the liver and in the hypothalamus.
Free nerve endings
Which are more numerous, cold or warm receptors?
Cold, three or four times more.
Temperature sensations are sent to the ____, ____, and to a lesser extent the ____.
retucular formation, thalamus, primary sensory cortex
Thermoreceptors are _____ receptors.
Phasic
Mechanoreceptors are sensitive to stimuli that distort their _____ _____.
plasma membranes
What are the 3 classes of mechanoreceptors:
Tactile, Baroreceptors, proprioceptors
Tactile receptors provide the closely related sensations of:
touch, pressure, and vibration
Baroreceptors detect pressure changes in:
the walls of the blood vessles and portions of the digestive, reproductive and urinary tracts
Proprioceptors monitor the positions of:
joints and muscles
Fine touch and pressure receptors provide details information about a ____ of stimulation.
Source
Crude touch and pressure receptors provide poor localization because they have ____ receptive fields.
large
What are the 6 types of tactile receptos in the skin:
1) Free nerve endings, 2) root hair plexus, 3) Tactile discs, 4) Tactile corpuscles (meissner), 5) Lamellated corpuscles (pacinian), 6) Ruffini corpuscles
Wherever hairs are located, the nerve endings of the root hair plexus monitor:
distortions and movements across the body surface
Tactile Discs or Merkel discs are extremely sensitive ____ _____ and pressure receptors.
fine touch
Tactile corpuscles or Meisner corpuscles are fairly ____ structures and are most abundant in:
Large; eyelids, lips, nipples, external genitalia
Lamellated Corpuscles or pacinian corpuslces are senstivie to ____ _____.
Deep pressure
Ruffini Corpuscles are senstivie to _____ and ______ of the skin.
pressure; distortion
Ruffini Corpuscles are located in the:
reticular (deep) dermis
Baroreceptors monitor ____ ____ in the walls of major vessels.
Blood pressure
Baroreceptors in the lungs monitor the degree of lung ____.
expansion
What are the three major groups of proprioceptors:
Muscle spindles, golgi tendon organs, receptors in joint capsules
Muscle spindles monitor skeletal muscle ____ and trigger ____ ____.
length, stretch reflexes
Golgi Tendon organs located at the junction between a _____ _____ and it's ____.
skeletal muscle; tendon
Golgi tendon organs are stimulated by:
tension in the tendon
Golgi tendon organs monitor the external tension developed during _____ _____.
Muscle contraction
Joint capsules are richly innervated by free nerve endings that detect ____, ____, and movement at the ____.
pressure, tension, joint
Your sense of body position results from integration of information from:
Joint capsules, Muscle spindles, golgi tendon organs and receptors of the inner ear
Most proprioceptive information is processed at ____ levels.
subconscious
Specialized Chemoreceptive neurons can detect small changes in the _____ of specific chemicals or compounds.
concentration
Cehmoreceptors do NOT send information to the ____ ____ ____, so we are not consciously aware of the sensations they provide.
Primary Sensory Cortex
What is reciprocal innervation:
One muscle contracts and the other relaxes
What are the 3 major Somatic Sensory Pathways?
1) Posterior column pathway, 2) spinothalamic pathway, 3) spinocerebellar pathway
The Posterior Column Pathway carries sensation of:
fine touch, pressure, vibration and proprioception
The Posterior column pathway begins and ends:
begins: peripheral receptor; ends: sensory cortex of the cerebral hemispheres
Decussation is:
The crossing of an axon from one side to the other.
The Ventral nuclei of the thalamus sorts arriving sensory information according to:
1) the nature of the stimulus, 2) the region of the body involved
Posterior column pathway carries sensations to the:
Thalamus and then to the Cerebral Hemisphere
the Processing of information in the Thalamus determines whether you perceive a given sensation as:
fine touch or pressure/vibration
The spinothalamic pathway provides conscious sensations of:
crude touch, pressure, pain, and temperature
In the Spinothalamic pathway, the sensory axons of the first-order synapse on second-order neurons within the:
Posterior Gray Horns
The axons of the spinothalamic interneurons cross to the opposite side of the spinal cord _____ ascending.
before
Anterior spinothalamic tracts carry:
crude touch and pressure sensations
Lateral spinothalamic tracts carry:
pin and temperature sensations
Spinothalamic tracts end at the third-order neurons in the ventral nucleus group of the:
Thalamus and then the Primary sensory cortex
The spinocerebellar patheway sends information about the position of ____ ____, ____ and ____ to the Cerebellum.
Skeletal muscles; tendons; joints
The information of the spinocerebella pathway does not reach our:
awareness
Spinocerebellar axons of first-order sensory neurons synapse on interneurons in the:
Dorsal Gray horns of the spinal cord
Visceral Sensory pathways carry visceral sensory information to the ____ ____, a large nucleus in the medulla oblongata.
Solitary nucleus
Viceral Sensory information is carried by which cranial nerves:
V, VII, IX and X
The spinal nerves T1-L2 carry visceral sensory information provided by receptos in organs located btween the ____ and the ____ ____.
Diaphragm, pelvic cavity
The dorsal roots of the spinal nerves S2-S4 carry visceral sensory information from organs in the:
inferior portion of the large intestine
Visceral Sensory information ascends within the ______ pathway.
Spinothalamic
The Somatic Nervous System (SNS) controls the contractions of
Skeletal Muscles
The output of the SNS is under:
Voluntary control
The Somatic Motor pathways always involve at least two motor neurons:
an upper motor neuron and a lower motor neuron
An Upper motor neuron's cell body lies in a
CNS processing center
A Lower motor neuron's cell body lies in a
nucleus of the brain stem or spinal cord
SNS - the upper motor neuron synapses on the lower motor neuron, which in turn innervates a single motor unit in a:
Skeletal muscle
Activation of the lower motor neuron triggers a ____ in the innervated muscle.
Contraction
Destruction of or damage to a lower motor neuron eliminates ____ and ____ control over the innervated motor unit.
Voluntary; reflex
What are the 3 integrated motor pathways of the SNS?
Corticopsinal pathway, medial pathway and lateral pathway
The corticospinal pathway provides voluntary control over:
Skeletal muscles
The corticospinal pathway begins at the:
Primary motor cortex (pre-central gyrus)
axons in the corticobulbar tracts synapse on lower motor neurons in the motor nuclei of which cranial nerves?
III, IV, V, VI, VII, IX, XI and XII
Corticotubular tracts provide conscious control over skeletal muscles tah tmove the:
eye, jaw, and face
The Corticospinal tracts synapse on lower motor neurosn in the:
anterior gray horns of the spinal cord
Corticospinal tracts are visible along the ventral surface of the medulla oblongata as a pair of thick bands called the:
pyramids
The components of the medial pathway help control gross movement sof the:
trunk and proximal limb muscles
the components of the lateral pathway help control the:
distal limb muscles that perform more precise movements
The axons of the upper motor neurons in the medial and lateral pathways synapse on the same lower motor neurons innervated by the:
Corticospinal pathway
What are the 3 tracts of the medial pathway:
Vestibulospinal, Tectospinal, Reticulospinal
vestibulospinal Tract: Vestibular nuclei receive information over the Vestibulocochlear nerve (VIII) and monitor the position and movement of the ____.
Head
Tectospinal Tract: Axons in the tectospinal tracts direct reflexive changes in the position of the head, neck and upper limbs in response to:
bright lights, sudden movements, or loud noises
Reticulospinal Tracts: The reticular formation receives input from almost every ____ and ____ pathway.
Ascending; Descending
The lateral pathway of the SNS is primarily concerned with the control of ____ ____ and the more precise movements of the ____ parts of the limbs.
muscle tone; distal
the upper motor neurons of the lateral pathway lie within the red nuclei of the:
mesencephalon
Axons of the Lateral pathway descend intot the spinal cord in the:
rubrospinal tracts
The Basal Nuclei provide the background patterns of movement involved in:
Voluntary motor activities
Basal nuclei do not exert direct control over:
lower motor neurons
The basal nuclei establish patterns of movement via two majorb pathways. One groupof axons synapses on ____ neurons, and the second group of axons synapses in the ____ ____.
Thalamic; reticular formation
Sensations of fine touch, pressure, vibration and proprioception are carried in the:
Posterior Column pathway
"The Posterior Column pathway ; transmits information from mechanoreceptors and proprioceptors to the ____ and then to the primary sensory cortex of the ____ ____."
Thalamus; Cerebral Hemispheres
Sensations of Crude touch, pressure, pain and temperature are carried by the:
Anterolateral (spinothalamic) pathway
"The anterolateral (spinothalamic) pathway transmits information from thermoreceptors and Nociceptors to the ____ and then to the primary sensory cortex of ____ ____."
Thalamus; Cerebral Hemispheres
Sensations about position of skeletal muscles, joints and tendons are carried to the ____ via the _____ pathway.
Cerebellum; Spinocerebellar
True/False: Information transmitted along the Spinocerebellar pathway does NOT reach our conscious awareness.
True
Somatic sensory pathways are pathways that transmit information from peripheral ____ receptors to the ____.
Somatosensory; CNS
The primary Sensory cortex of the cerebrum is the site of:
Conscious perception of sensation
Sensory pathway route:
1) Somatic receptor, 2) 1st order neuron, 2) CNS, 3) 2nd order neuron, 4) Thalamus, 5) 3rd order neuron, 6) Primary sensory cortex of the cerebrum
What does the first order neuron do:
Carries sensations from the somatic receptors to the CNS
What does the 2nd order neuron do:
Carries the signal from the CNS to the Thalamus.
What does the 3rd order neuron do:
Carries the signal from the Thalamus to the primary sensory cortex of the cerebrum
Where is the cell body of the 1st order neuron located:
Dorsal root ganglion
Where is the cell body of the 2nd order neuron located:
Interneuron in the brain or spinal cord