Chapter 15- Sensory Pathways & SNS Flashcards
(97 cards)
0
Q
Perception
A
The conscious awareness of a sensation
1
Q
Sensation: __________ information
A
Arriving
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Q
Special senses
A
- Olfaction
- Vision
- Gustation
- Hearing
- Equilibrium
3
Q
General senses: Sensitivity to
A
- Temp
- Pain
- Touch
- Pressure
- Vibration
- Proprioception
4
Q
Proprioception
A
Awareness of body position (bones, joints, muscles)
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Q
Transduction
A
Translation of a sensation into an action potential that can be conducted to the CNS
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Q
Receptor potential
A
When a stimulus changes the transmembrane potential of a receptor cell
7
Q
Receptor potential can either be ________?
A
Graded depolarization or graded hyperpolarization
8
Q
Generator potential (definition):
A
A depolarizing potential in the sensory neuron
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Q
Where do action potentials develop?
A
In the axon of a sensory neuron
10
Q
Receptor specificity
A
Each receptor has a characteristic sensitivity
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Q
Receptor specificity (example):
A
Tongue receptors respond to taste
12
Q
Receptive field
A
Specific area monitored by receptor cell
13
Q
The ________ a receptive field the ________ your ability to localize a stimulus
A
Larger; Less
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Q
Tonic receptors
A
AKA slow-adapting receptors; ALWAYS active
15
Q
Tonic receptors (example):
A
Nociceptors (pain)
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Phasic receptors
A
- AKA fast-adapting receptors; Normally INACTIVE, becomes active for short time when change occurs
- Provides info about intensity and rate of change of a stimulus
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Q
Phasic receptors (example):
A
Thermoreceptors (cold+warm)
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Q
afferent (sensory; up and in)
A
brings information from the body’s periphery TOWARD THE BRAIN
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Q
Efferent (motor; down and out)
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they bring the responses FROM THE BRAIN to the muscles and the glands
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Q
Labeled line
A
Link btw peripheral receptor and cortical neuron
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Q
Cortical
A
From the cortex
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Q
Each labeled line consists of ________?
A
Axons carrying info about one modality (type of stimulus); CNS interprets the modality entirely on the basis of the labeled line over which it arrives
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Q
Labeled line (example):
A
When you rub your eyes, you usually see flashes of light; stimulus is mechanical (pressure)
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The inventory of the active labeled line _______
Indicates the type of stimulus.
| Where it arrives within the sensory cortex determines its perceived location
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Adaptation (definition):
A reduction in sensitivity in the presence of a constant stimulus
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Peripheral adaptation
Occurs when the level of receptor activity changes; reduces the amount of info that reaches the CNS
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Central adaptation occurs _______?
Along sensory pathways of the CNS
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Central adaptation usually involves ________?
Inhibition of nuclei along a sensory pathway
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Central adaptation (example):
Becoming used to a newly exposed smell
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Nociceptors (general sense)
* Pain
| * free nerve ending w/ large receptive fields
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Nociceptors: commonly found in ________?
* Superficial skin
* joint capsules
* walls of blood vessels
* periostea of bones
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Nociceptors; sensitive to _______?
* extremes of temp
* mechanical damage
* dissolved chemical
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Types of axons
Type A and Type C fibers
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Type A
Carry sensations of FAST pain
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Type A (example):
Injection site or deep cut
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Type C
Carry sensation of SLOW pain
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Type C (example):
Burning or aching pain
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Thermoreceptors
* Temp and phasic receptors
| * free nerve endings
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Free nerve endings (FNE)
Afferent; relay info from the body to brain
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Thermoreceptors (location):
* The dermis
* skeletal muscles
* liver
* hypothalamus
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Thermoreceptors; ______ receptors are ______ times more numerous than ______ receptors
Cold
3 or 4
Warm
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Mechanoreceptors
* Sensitive to stimuli that distort their cell membranes
| * Respond to distortion of the membrane
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Mechanoreceptors (3 Classes):
* Tactile receptors
* Baroreceptors
* Proprioceptors
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Tactile receptors
Provides sensations of touch, pressure, and vibration
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Tactile receptors (examples):
* Root of hair plexus
| * Tactile discs
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Baroreceptors
Detect pressure changes in the walls of blood vessels and in portions of the digestive, reproductive, & urinary tracts
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Proprioceptor
* Monitors position of joints, the tension in tendons, and ligaments and the state of muscular contraction
* Doesn't adapt to constant stimulation
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Proprioceptors (3 major groups):
* Muscle Spindles
* Golgi Tendon Organs
* Receptors in Joint Capsules
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Muscle spindles
Monitor skeletal muscle length and trigger stretch reflexes
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Golgi Tendon Organs
Monitor external tension developed during muscle contraction; stimulated by tension in tendon
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Receptors in Joint Capsules
Joint capsules are innervated by FNE that detect pressure, tension, and movement at the joint
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Chemoreceptors (chemicals)
* Specialized nerve cells
| * can detect small changes in the concentration of specific chemicals or compounds (H+, monitor CO2 levels)
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Chemoreceptors (location):
Brain stem centers of the brain, carotid bodies, and aortic bodies
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Somatic Sensory Pathways
Carry info FROM the skin and muscles of the body wall, head, neck, and limbs
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First order neuron
Sensory neuron that delivers sensations to the CNS
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First order neuron (location):
Cell body located in DORSAL ROOT GANGLION or a CRANIAL NERVE GANGLION
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Second order neuron (location):
Interneuron located in the SPINAL CORD or BRAIN STEM
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2nd order neuron synapse on 3rd in ________?
The THALAMUS if awareness is reached
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Ganglion
Group of cell bodies that lie OUTSIDE the CNS
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Nuclei
Group of cell bodies INSIDE the CNS
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Soma
Cell bodies
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Decussation
Crossing over
| *somewhere along its length, axon of 2nd order neuron crosses over the opposite side of CNS
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Third order neuron
It's axon ascends and synapses on neurons of the primary sensory cortex located on the post central gyrus
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Somatic sensory (major pathways):
* Posterior Column Pathway
* Spinothalamic Pathway
* Spinocerebellum Parhway
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Posterior Column Pathway
Carries sensations of fine touch, pressure, vibration, and Proprioception
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Fine AKA
Highly localized
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Spinothalamic Pathway
Provides conscious sensations of crude touch, pressure, pain, and temp
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Crude AKA
Poorly localized
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Spinothalamic Pathway (2 tracts):
* Anterior Spinothalamic Tract
| * Lateral Spinothalamic Tracts
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Anterior Spinothalamic Tract
Carry crude touch and pressure sensations
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Lateral Spinothalamic Tract
Carry pain and temp sensations
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Spinocerebellum Pathway
* Carries sensation of Proprioception
| * Doesn't reach our consciousness
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Visceral Sensory Pathways (internal/Afferent)
Carry info collected by interoceptors that monitor visceral tissues and organs primarily within thoracic and abdominopelvic body cavities
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Interoceptors include:
* Noceceptors
* Thermoreceptors
* Tactile
* Baroreceptors
* Chemoreceptors
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Where is most visceral sensory info delivered to?
Solitary nucleus
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Solitary nucleus
A large nucleus in the medulla oblongata
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We remain unaware of these sensations because
Visceral sensory info doesn't reach the primary sensory cortex
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What cranial nerves carry visceral sensory info?
5, 7, 9, 10
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Where do cranial nerves carry visceral sensory info from?
* Mouth
* Palate
* Pharynx
* Larynx
* Trachea
* Esophagus
* Associated glands and vessels
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The dorsal roots of spinal nerves _______ carry visceral sensory info provided by receptors in organs located btw the _______ and _______ cavity
* T1-T12
* Diaphragm
* Pelvic
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Order of neurons- most info ends where?
Medulla oblongata
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Somatic motor pathways (voluntary/efferent)
Controls the contractions of skeletal muscles
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Upper motor neuron (SMP)
Cell body lies a CNS processing center
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Where does the upper motor neuron synapse?
On the lower motor neuron
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Lower motor neuron (SMP)
Cell body lies in a nucleus of the brain stem or spinal cord
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What does a lower motor neuron innervate?
A single motor unit in a skeletal muscle (this signals contraction)
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Motor unit
A lower motor neuron and all of the muscle fibers it innervates
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Only the _______ of the lower motor neuron extends outside of the _______
Axon; CNS
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What happens to a lower motor neuron if it were damaged?
It eliminates voluntary and reflex control over the innervated motor unit
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Somatic motor (major pathways):
* Corticospinal Pathway
* Medial Pathway
* Lateral Pathway
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Corticospinal Pathway (SMP)
Provides voluntary control over skeletal muscles
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Medial Pathway (SMP)
Control of muscle tone and gross movements of neck, trunk, and proximal limb muscles
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Lateral Pathway (SMP)
Control of muscle tone and more precise movements of the distal part of the limbs
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What are the basal nuclei and cerebellum responsible for?
Coordination and feedback control over muscle contractions
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What does the basal nuclei provide?
Background patterns of movement involved in voluntary motor activities
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What does the cerebellum monitor?
* Proprioceptive sensations
* Visual info
* Vestibular (balance) sensations
