Neuro - Ch16 - Sensory System

Front 1

Conscious/unconscious awareness of external/internal stimuli.

Back 1

Sensation

Front 2

Conscious awareness & interpretation of a sensation.

Back 2

Perception

Front 3

What are the 3 main structures involved in sensations?

Back 3

Sensory receptors, sensory nerves, primary sensory area (cortex)

Front 4

Each unique type of sensation.

Back 4

Sensory modality

Front 5

What are the 2 classes of sensory modalities?

Back 5

General senses, special senses

Front 6

___ senses include somatic (touch, temp, pain, proprioception) & visceral senses (conditions w/in internal organs).

Back 6

General

Front 7

___ senses include smell, taste, vision, hearing, equilibrium.

Back 7

Special

Front 8

Sensory receptors respond to (one/multiple) type(s) of stimuli.

Back 8

One

Front 9

What are 4 events that occur within a sensation?

Back 9

Stimulation of sensory receptor, transduction of stimulus into a graded potential, generation of nerve impulse when it reaches threshold, integration of sensory input by CNS.

Front 10

What are the 3 classes of sensory receptors?

Back 10

Free nerve endings, encapsulated nerve endings, separate sensory cells.

Front 11

Class of sensory receptor - bare dendrites. Pain, temp, tickle, itch, light touch.

Back 11

Free nerve endings

Front 12

Class of sensory receptor - dendrites enclosed in connective tissue capsule. Pressure, vibration, deep touch.

Back 12

Encapsulated nerve endings

Front 13

Class of sensory receptor - specialized cells that respond to stimuli. Vision, taste, hearing, balance.

Back 13

Separate cells that synapse w/ 1st order neurons

Front 14

Free/encapsulated nerve endings & olfactory receptors produce ___ potentials that produce action potentials. When large enough, it generates nerve impulse in a 1st order neuon.

Back 14

Generator potential

Front 15

Graded potentials produced by vision, hearing, equilibrium, taste receptors are called ___ potentials. They release neurotransmitter to 1st order neurons to produce postsynaptic potential which may trigger nerve impulse.

Back 15

Receptor potential

Front 16

Type of receptor that detects pressure/stretch/deformation. Touch, pressure, vibration, hearing, proprioception, equilibrium, BP.

Back 16

Mechanoreceptor

Front 17

Type of receptor that detects temperature.

Back 17

Thermoreceptor

Front 18

Type of receptor that detects pain from damage to tissue. Free nerve ending found in almost every body tissue except ___.

Back 18

Nociceptor. Brain.

Front 19

Type of receptor that detects light.

Back 19

Photoreceptor

Front 20

Type of receptor that detects chemicals for taste, smell, & body fluid changes.

Back 20

Chemoreceptor

Front 21

Type of receptor that detects osmotic pressure of body fluids.

Back 21

Osmoreceptor

Front 22

Type of receptor near body surface & receives external stimuli. Hearing, vision, smell, taste, touch, pressure, pain, vibration, temp.

Back 22

Exteroceptor

Front 23

Type of receptor found in BV, viscera, mm, etc that monitors internal environment. Not consciously felt except pain, pressure.

Back 23

Interoceptor (visceroceptor)

Front 24

Type of receptor found in mm, tendon, joint, internal ear. Sense body position, mm length/tension, jt movt.

Back 24

Proprioceptor

Front 25

Characteristic of sensory receptors where there is decreased sensitivity/responsiveness to prolonged stimuli.

Back 25

Adaptation

Front 26

(Rapid/slow) adapting receptors are specialized for detecting changes, ie smell, pressure, touch.

Back 26

Rapidly adapting

Front 27

(Rapid/slow) adapting receptors continue to send impulses as long as stimulus persists, ie pain, body position, blood composition.

Back 27

Slowly adapting

Front 28

Somatic sensations that arise from skin surface are called ___ sensations. Modalities: tactile, thermal, pain, proprioceptive.

Back 28

Cutaneous

Front 29

___ sensations are touch, pressure, vibration, itch, tickle.

Back 29

Tactile

Front 30

Rapidly adapting receptor for discriminative touch, vibration. Dendrites enclosed in dermal papillae of hairless skin.

Back 30

Meissner's corpuscle (corpuscle of touch)

Front 31

Type of rapidly adapting receptor w/ free nerve endings found around hair follicles that detect hair movt.

Back 31

Hair root plexus

Front 32

Type of slow adapting receptor w/ flattened dendrites touching merkel cells of stratum basale. Discriminative touch.

Back 32

Merkel disc

Front 33

Encapsulated slow adapting receptor found deep in dermis, ligs, tendons, hands, soles. Most sensitive to stretching. Heavy/continuous touch, pressure.

Back 33

Ruffini corpuscle

Front 34

Sustained sensation felt over a larger area than touch & occurs w/ deformation of deeper tissues.

Back 34

Pressure

Front 35

Onion-like CT capsule enclosing a dendrite. Rapidly adapting & found in dermis/subQ layer & widely distributed (viscera, jts, mm, etc). Senses pressure/high-frequency vibration. Respond to acceleration/deceleration of jts.

Back 35

Pacinian corpuscle

Front 36

Itch sensation is caused by stimulation of free nerve endings by certain ___, ie bradykinin often b/c of local inflammatory response.

Back 36

Chemicals

Front 37

Condition where pts w/ amputated limb still experience sensations as if limb were still there. May be caused by sensory nerves or part of brain that used to carry/integrate info for amputated limb.

Back 37

Phantom limb sensation

Front 38

Cold receptor is found in ___ layer & respond to temps b/w 50-105º F.

Back 38

Stratum basale

Front 39

Warm receptors found in ___ respond to temps b/w 90-118º F.

Back 39

Dermis

Front 40

Pain is produced below ___º & over ___º F.

Back 40

50-118º F

Front 41

What can activate nociceptors?

Back 41

Thermal, mechanical, chemical stimuli. Excessive distension, mm spasm, inadequate blood flow.

Front 42

Tissue injury releases what chemicals?

Back 42

K+, kinins, prostaglandins

Front 43

Type of pain that occurs rapidly after stimuli (0.1 sec). Sharp pain like needle puncture/cut. Not felt in deeper tissues.

Back 43

Fast pain (acute)

Front 44

Type of pain that begins more slowly & increases in intensity. Aching, throbbing, burning. Found in both superficial & deeper tissues.

Back 44

Slow pain (chronic)

Front 45

Pain that can be superficial if arising from skin or deep if from skeletal mm, jts, tendons.

Back 45

Somatic pain

Front 46

Pain felt in/under skin overlying stimulated organ. Localized damage may not be painful but diffuse visceral manipulation severe.

Back 46

Visceral pain

Front 47

Phenomena where pain is felt in surface area far from stimulated organ.

Back 47

Referred pain

Front 48

Where is referred pain for heart attack felt & what spinal cord segment?

Back 48

Skin along left arm & segment T1-T5

Front 49

2 drugs that block formation of prostaglandins that stimulate nociceptors.

Back 49

Aspirin, ibuprofen

Front 50

Anesthetic that blocks conduction of nerve impulses along pain fibers.

Back 50

Novocaine

Front 51

Narcotic-opiate that lessens the perception of pain in brain.

Back 51

Morphine

Front 52

Ability to assess weight of an object.

Back 52

Weight discrimination

Front 53

Sensory info for proprioception is sent to where?

Back 53

Cerebellum, cerebral cortex

Front 54

What are 3 types of proprioceptors?

Back 54

Mm spindles, tendon organs, jt kinesthetic receptors

Front 55

Muscle spindles are (slow/fast) adapting.

Back 55

Slow

Front 56

Specialized mm fiber that is wrapped w/ mm spindle.

Back 56

Intrafusal mm fiber

Front 57

What are the only mm that lack mm spindles?

Back 57

Mm of middle ear

Front 58

Which mm have more mm spindles?

Back 58

Those that control fine movt

Front 59

What do mm spindles detect? How do they react?

Back 59

Mm length/stretch. Contract to prevent overstretching.

Front 60

Neurons found at both ends of intrafusal fibers & adjust tension in mm spindle to variations in mm length.

Back 60

Gamma motor neurons

Front 61

Ordinary skeletal mm fibers are called ___ fibers supplied by ___ neurons.

Back 61

Extrafusal. Alpha motor.

Front 62

Where are golgi tendon organs found?

Back 62

Junction of tendon & mm

Front 63

What do golgi tendon organs detect? How do they react?

Back 63

Tension/contraction. Relaxes mm to prevent excessive tension.

Front 64

What 2 receptors are found in jts?

Back 64

Ruffini & pacinian corpuscles

Front 65

Where do somatic sensory pathways relay info in the brain? At the same time, axon collaterals of these neurons send signals where?

Back 65

Primary somatosensory area in cerebral cortex. Cerebellum, reticular formation of brain stem.

Front 66

Somatic sensory neuron that conducts impulses from somatic receptors to brain/spinal cord, ie cranial/spinal nn.

Back 66

1st order neuron

Front 67

Somatic sensory neuron that conducts impulses from brain stem/spinal cord to thalamus. Decussates to opposite side of brain.

Back 67

2nd order neuron

Front 68

Somatic sensory neuron that conducts impulses from thalamus to primary somatosensory cortex (postcentral gyrus of parietal lobe).

Back 68

3rd order neuron

Front 69

Regions in CNS where neurons synapse & are part of sensory/motor pathway called ___.

Back 69

Relay stations

Front 70

Pathway to cortex for conscious proprioception & tactile sensations. Neurons part of posterior columns - consist of gracile/cuneate fasciculus. Fine touch, stereognosis, proprioception, vibratory sensations.

Back 70

Posterior column-medial lemniscus pathway

Front 71

In posterior column-medial lemniscus pathway, signals travel up spinal cord in ___. Cross over in ___ to become ___ ending in ___. These fibers reach ___.

Back 71

In posterior column-medial lemniscus pathway, signals travel up spinal cord in POSTERIOR COLUMN. Cross over in MEDULLA to become MEDIAL LEMNISCUS PATHWAY ending in THALAMUS. These fibers reach CORTEX.

Front 72

Pathway that carries pain, temp, tickle, itch, crude touch, pressure.

Back 72

Anterolateral or spinothalamic pathway

Front 73

What 2 tracts are involved in spinothalamic pathway?

Back 73

Lateral spinothalamic (pain temp), anterior tract (tickle, itch, crude touch, pressure).

Front 74

In spinothalamic pathway, 1st order neurons connect ___ w/ synapses in ___. 2nd order sensory neurons in ___ matter of spinal cord send fibers to other side of spinal cord & up ___ matter to synapse w/ ___. 3rd order in thalamus projects to ___.

Back 74

In spinothalamic pathway, 1st order neurons connect RECEPTOR CELLS w/ synapses in SPINAL CORD. 2nd order sensory neurons in GRAY matter of spinal cord send fibers to other side of spinal cord & up WHITE matter to synapse in THALAMUS. 3rd order in thalamus projects to CEREBRAL CORTEX-PRIMARY SENSORY AREA.

Front 75

Relative sizes of cortical areas are proportional to what 2 things? How can they be modified?

Back 75

# of sensory receptors, sensitivity of each body part. Modified w/ learning.

Front 76

Where is the primary somatosensory area?

Back 76

Postcentral gyrus of parietal lobe

Front 77

What 2 tracts are the major routes for proprioceptive impulses reaching the cerebellum?

Back 77

Anterior & posterior spinocerebellar tracts

Front 78

Impulses to cerebellum detect what?

Back 78

Posture, balance, coordination of skilled movts

Front 79

Condition that causes progressive degeneration of posterior spinal cord. Caused by bacterium treponema pallidum. Loss of somatic sensations. Proprioceptive impulses fail to reach cerebellum. Gait uncoordinated/jerky.

Back 79

Syphilis

Front 80

Upper motor neurons extend from ___ to ___ or ___. Lower motor neurons extend from ___ or ___ to ___ (also called ___ b/c many regulatory mechanisms converge here).

Back 80

Cortex, brain stem, spinal cord. Brain stem, spinal cord, cortex. Final common pathway.

Front 81

What is the primary function of the cerebellum?

Back 81

Corrects/refines voluntary mm contraction & posture based on sensory info from body about actual movts. Senses equilibrium (posture/balance).

Front 82

What is the fn of basal ganglia?

Back 82

Establish mm tone, starts/stops, corrects movt (semivoluntary automatic), inhibits unwanted movt, influences cortical fn including sensory, limbic, cognitive, linguistic fns.

Front 83

Condition of damage to lower motor neurons. No voluntary movt on same side of damage, no reflex actions, mm limp/flaccid, decreased mm tone.

Back 83

Flaccid paralysis

Front 84

Condition of damage to upper motor neurons. Paralysis on opposite side from injury, increased mm tone, exaggerated reflexes.

Back 84

Spastic paralysis

Front 85

How is input to lower motor neurons different in a direct vs indirect pathway?

Back 85

Direct - input directly from cortex. Indirect - input from motor centers in brain stem.

Front 86

What 3 cortex areas contribute to descending motor pathways? Where are they located?

Back 86

Primary motor area - precentral gyrus, frontal lobe. Premotor area - frontal lobe. Somatosensory area - postcentral gyrus, parietal lobe. (p519 AP)

Front 87

Corticle area devoted to mm is proportial to the # of ___.

Back 87

Motor units

Front 88

Direct motor pathways consist of what 3 pathways?

Back 88

Anterior/lateral corticospinal, corticobulbar pathway

Front 89

Most upper motor neurons decussate in ___.

Back 89

Medulla

Front 90

Lateral corticospinal tract - upper motor neurons originate from ___ & travel through ___, then 90% decussate in ___. Form ___ column & synapse in ___ gray horn of spinal cord.

Back 90

Upper motor neurons originate from CORTEX & travel through CEREBRAL PEDUNCLES, then 90% decussate in MEDULLA. Form LATERAL WHITE column & synapse in ANTERIOR gray horn of spinal cord.

Front 91

Anterior corticospinal tract - upper motor neurons originate from ___ & travel through ___, then 10% continue in ___ column & synapse in ___ gray horn of spinal cord.

Back 91

Upper motor neurons originate from CORTEX & travel through CEREBRAL PEDUNCLES, then 10% continue in ANTERIOR WHITE column & synapse in ANTERIOR gray horn of spinal cord.

Front 92

What is the fn of the lateral vs anterior corticospinal tract?

Back 92

Lateral - skilled movts distal limbs (hands, feet). Anterior - neck/trunk mm.

Front 93

Corticobulbar tract - upper motor neurons originate from ___ & travel through ___, then end at motor nuclei of cranial nn except which 3?

Back 93

Corticobulbar tract - upper motor neurons originate from CORTEX & travel through CEREBRAL PEDUNCLES, then end at motor nuclei of all cranial nn except OLFACTORY, OPTIC, VESTIBULOCOCHLEAR.

Front 94

What is the fn of the corticobulbar tract?

Back 94

Head mm movt - eyes, tongue, chewing, expression, speech, neck.

Front 95

Amyotrophic lateral sclerosis causes progressive mm weakness. No cure, several cause theories, drugs treat symptoms. Death 2-5 years. It attacks what 3 areas of the CNS?

Back 95

Motor areas of cortex, axons upper motor neurons, cell bodies lower motor neurons.

Front 96

What are the 5 tracts that form the indirect motor pathways (extrapyramidal)? Where do they receive input? What is each fn?

Back 96

Rubrospinal - red nucleus of midbrain (hand movt), tectospinal - sup colliculi of midbrain (body movt reflex to auditory/visual stimuli), vestibulospinal - vestibular nucleus of medulla (balance/posture), medial/lateral reticulospinal tracts - reticular formation (mm tone, posture).

Front 97

What is the circuit of the basal ganglia w/ cortex & thalamus?

Back 97

Cortex, basal ganglia, thalamus, cortex

Front 98

What results from damage to basal ganglia?

Back 98

Uncontrollable, abnormal body movt, mm rigidity, tremors, cognition, behavior.

Front 99

What is the primary function of the cerebellum?

Back 99

Corrects/refines voluntary mm contraction & posture based on sensory info from body about actual movts. Senses equilibrium (posture/balance). Active in learning & rapid, highly skilled movts.