Spinal cord and sensory part of nervous system

Descripción

Based on PUM physiology presentations and own notes
Soheila Amri
Test por Soheila Amri, actualizado hace más de 1 año
Soheila Amri
Creado por Soheila Amri hace más de 2 años
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Resumen del Recurso

Pregunta 1

Pregunta
Functions of sensory systems; choose WRONG
Respuesta
  • Monitor the internal and external environment
  • Transmits signals from CNS to periphery
  • Control of movement
  • Transmits peripheral signal to CNS for processing
  • Regulation of internal organs

Pregunta 2

Pregunta
Which of these are sensory input under general (somatic) sensation?
Respuesta
  • Touch
  • Pain
  • Vision
  • Hearing

Pregunta 3

Pregunta
Which of these are sensory input under general (somatic) sensation?
Respuesta
  • Smell
  • Thermal sensation
  • Proprioception
  • Taste

Pregunta 4

Pregunta
Which of these are NOT sensory input under special sensation?
Respuesta
  • Vision
  • Hearing
  • Taste
  • Pain
  • Smell

Pregunta 5

Pregunta
What is true about the senses?
Respuesta
  • General senses have receptors distributed over a large part of the body
  • General senses have receptors within specific organs
  • General senses located in skin, muscle and joints are somatic (touch, pain, temp, etc..)
  • General senses located in internal organs are visceral (pain and pressure)
  • Balance is not a special sense

Pregunta 6

Pregunta
Stages of sensation; choose proper order
Respuesta
  • Stimulation, Perception, Transduction, Transmission
  • Stimulation, Transmission, Perception, Transduction
  • Stimulation, Transduction, Transmission, Perception
  • Stimulation, Transmission, Transduction, Perception

Pregunta 7

Pregunta
Receptor types choose correct
Respuesta
  • Somatic and olfactory senses reception is through secondary sensory neurons
  • General secondary receptors release neurotransmitter that bind to a neuron that transmits info to brain
  • Special secondary receptors release neurotransmitter that bind to a neuron that transmits info to brain
  • In taste, hearing, sight and balance it is through specialized epithelial receptor cells - secondary receptor.

Pregunta 8

Pregunta
Choose correct match of location and receptor
Respuesta
  • Exteroreceptors - associated with skin
  • Proprioceptors - associated with joints, tendons, muscle, vestibular system
  • Visceroreceptors - associated with organs
  • Exteroreceptors - associated with organs

Pregunta 9

Pregunta
Choose correct receptor with the type of activation.
Respuesta
  • Nociceptors - respond to changes in temperature
  • Thermoreceptors - extreme mechanical, chemical, or thermal stimuli. Pain sensation
  • Mechanoreceptors: compression, bending, stretching of cells. Touch, pressure, proprioception, hearing, and balance sensation
  • Chemoreceptors - chemicals become attached to receptors on their membranes. Smell and taste sensation
  • Photoreceptors - respond to light. Vision

Pregunta 10

Pregunta
Division of sensation; choose WRONG
Respuesta
  • PROPRIOCEPTION – profound
  • EKSTEROCEPTION – superficial
  • INTEROCEPTION – special
  • TELECEPTION – visceral

Pregunta 11

Pregunta
Which of these are not an attribute of stimulus
Respuesta
  • Modality (type of sensation; touch, pain)
  • Location
  • Intensity
  • Timing - When stimuli starts
  • Reflex

Pregunta 12

Pregunta
Division of sensations; according to the head
Respuesta
  • EPICRITIC SENSATION – identification, localisation, characteristic, strength of stimulus possible
  • PROTOPATHIC SENSATION – identification, localisation, characteristic, strength of stimulus possible
  • PROTOPATHIC SENSATION – impossible precise identification of stimulus; often connected with impairing factors - crude touch, pain, extreme temperature
  • EPICRITIC SENSATION – impossible precise identification of stimulus; often connected with impairing factors - crude touch, pain, extreme temperature

Pregunta 13

Pregunta
Modalities of stimulus;
Respuesta
  • Modality is encoded by a single pathway.
  • Each pathway encodes one specific sense
  • Each type of sensation (touch, sound, light, etc.) is called modality of sensation
  • Different modality of sensation is transmitted by a specific nerve fiber and determined by where the nerve fiber terminates in the brain

Pregunta 14

Pregunta
Location of stimulus; choose correct
Respuesta
  • Receptors fires action potential only when stimulus impinges on the receptive field.
  • Fine resolution requires large receptive fields
  • Coarse resolution requires fewer receptive fields to cover the same body surface area
  • Receptive field in skin differ in size and response to touch

Pregunta 15

Pregunta
Location of stimulus; coarse and fine resolution. Choose correct.
Respuesta
  • Coarse resolution; Certain regions of the body, such as arms & legs, have such very large receptive fields.
  • Coarse resolution; Two stimuli separated by as much as 40 mm will be perceived as a single point
  • Coarse resolution; Sensitive regions of the body with small secondary receptive fields include the fingertips.
  • Coarse resolution; Two stimuli separated by as little as 2 mm will activate separate pathways and will be perceived as distinct stimuli
  • Meissner occupy small receptive fields
  • Paccini occupy large receptive fields

Pregunta 16

Pregunta
Location of stimulus; choose correct
Respuesta
  • Primary neuron response is improper to stimulus strength
  • lateral inhibition - adjacent relay cells are inhibited from firing by the excited relay cell
  • feed forward inhibition - primary sensory cell inhibits directly adjacent relay cells.
  • Lateral inhibition increases stimulus contrast

Pregunta 17

Pregunta
Intensity of stimulus;
Respuesta
  • Population code - more sensory receptors are activated as stimulus gets greater
  • Intensity is encoded through the firing rate of receptors
  • Duration of action potential code for underlie perception of stimulus strength
  • Frequency of the stimulus is encoded by the time course of firing

Pregunta 18

Pregunta
Timing of stimulus
Respuesta
  • Duration of the stimulus is encoded by the time course of firing
  • Phasic receptors - long-lasting stimulus will produce a prolonged repetitive discharge in the primary afferent neurons. (pain)
  • Phasic reseptors - long-lasting stimulus will produce a short-lived response in the primary afferent neurons.
  • Tonic receptors are fast-adapting

Pregunta 19

Pregunta
Which of these are NOT tonic receptors?
Respuesta
  • Baroreceptors
  • Paccinian corpuscles
  • Nociceptors
  • Poprioceptors

Pregunta 20

Pregunta
Choose correct match of somatic sensory receptors to its stimuli.
Respuesta
  • Tactile receptors (mechanoreceptors) - receptors detect position and movement
  • Thermal receptors - stimuli: heat and cold
  • Nociceptors - stimuli: painful touch, cut, extreme temperatures
  • Proprioceptive - stimuli: touch, pressure, vibration
  • Static proprioceptors - tonic discharge
  • Static proprioceptors - phasic discharge

Pregunta 21

Pregunta
Pacini's corpuscle;
Respuesta
  • Stimulus: deep cutaneous pressure; vibration
  • Located in epidermis
  • Lamellated corpuscles, single dendrite to layers of corpuscles arranged like
  • Pacini's corpuscle is a skin, sensory nerve ending
  • Slow adapting

Pregunta 22

Pregunta
Meissner's (tactile) corpuscle
Respuesta
  • Has a two-point discrimination. Ability to detect simultaneous stimulations at two points on the skin.
  • Rapidly adapting
  • Numerous and close together on thigh and chest
  • Used to determined temp of objects.

Pregunta 23

Pregunta
Merkel (tactile) disks; Choose WRONG
Respuesta
  • Axonal branches end as flattened expansions associated with epithelial cells
  • Responsible for steady-state signals (continuous touch)
  • Slowly adapting
  • Basal layers of hypodermis
  • Light touch and superficial pressure

Pregunta 24

Pregunta
Ruffini's end organ
Respuesta
  • Primarily in dermis of fingers
  • Rapidly adapting
  • Respond to continuous touch or pressure
  • Slowly adapting

Pregunta 25

Pregunta
Hair follicle receptors
Respuesta
  • Does not respond to bending of hair as occurs in light touch
  • Hair end organs
  • End organ receptor fields overlap; sensation not very localized, yet very sensitive
  • Respond to bending of hair as occurs in light touch

Pregunta 26

Pregunta
Free nerve endings; Choose WRONG
Respuesta
  • Simplest, most common sensory receptor
  • Scattered through most of body; visceroceptors are of this type.
  • Picks up warm 10-15 times more numerous than cold
  • Pain: respons to freezing cold and burning hot, cut of skin, painful touch

Pregunta 27

Pregunta
Thermal sensation - choose correct
Respuesta
  • Rapidly adapting
  • Large receptive area
  • Warm receptors: up to 30C, max excitability at 44-46C;
  • Thermal signals are transmitted in pathways same to those for pain signals
  • Cold receptors: max excitability at 24-28oC;

Pregunta 28

Pregunta
Thermal sensation - choose correct
Respuesta
  • Warm sensation - Transmission by C fibers
  • For each 10C change metabolic rates (temp) alters intracellular chemical reactions more than 2-fold.
  • Cold sensation - Transmission by C fibers
  • Cold sensation - Transmission by Aδ

Pregunta 29

Pregunta
Muscle spindle;
Respuesta
  • Provide information about tension of muscles
  • 3-10 specialized intrafusal skeletal muscle cells
  • Provide information about length of muscles
  • Involved in stretch reflex

Pregunta 30

Pregunta
Golgi tendon organ - Choose wrong
Respuesta
  • Proprioceptors associated with tendons
  • Respond to increased tension on tendon
  • Involved in invers stretch reflex
  • Provide information about length of muscles

Pregunta 31

Pregunta
Stimulus encoding - Choose correct
Respuesta
  • Lateral inhibition - Key attributes of the stimulus must be represented in the signals of the primary SN
  • Stimulus transduction - Stimulus energy is converted into electrochemical energy
  • The stimulus information must be encoded into an electrical signal of some sort. These will result in information about intensity, duration, and location.
  • Neural encoding - sensory information must be fine tuned to achieve maximal discriminative capacity

Pregunta 32

Pregunta
Which of these are NOT an organisation of the sensory system?
Respuesta
  • Parallel pathways
  • Relay nuclei and Interneurons
  • Hierarchical organisation - different levels (highest at the head)
  • Spinal cord and fiber types
  • Neural maps - Parts of brain for different sensations

Pregunta 33

Pregunta
Somatosensory transmission - Choose correct
Respuesta
  • Transmission has specificity and follows topographical organisation
  • Cross-over to decussate through 2 major pathways; Dorsal column and anterolateral pathway.
  • Starts in the neurons of dorsal root ganglia
  • Ends in thalamus nuclei

Pregunta 34

Pregunta
Classification of sensory nerve fibers - Choose correct match
Respuesta
  • Ia = Annulo-spiral ending of muscle spindle - A-alpha Fiber
  • Ia = Golgi tendon organ - A-alpha Fiber
  • II = Flower-spray ending of muscle spindle - A-beta Fiber
  • III = Pain, temp and other receptors - Cdr Fiber

Pregunta 35

Pregunta
Dermatomes; Choose correct
Respuesta
  • Sensory supply to skin
  • All impulses from the receptors first enter the peripheral afferent nerve fiber.
  • After entering the Dorsal Roots it enters spinal ganglion
  • Terminates in spinal cord
  • Each dermatome is innervated by 2 segments of the spinal cord.

Pregunta 36

Pregunta
Somatosensory transmission - Which is NOT a pathway?
Respuesta
  • Ventral columns
  • Dorsal columns
  • Lateral and Anterior spinothalamic tract
  • Anterior and posterior spinocerebellar tracts
  • Spino-olivary cerebellar tract and Trigeminothalamic tract

Pregunta 37

Pregunta
Dorsal columns- Choose correct
Respuesta
  • Primary neurons have cell bodies in dorsal root ganglion.
  • Fasciculus gracilis: sensations from inferior to midthoracic level.
  • Fasciculus gracilis : impulses from above midthorax.
  • Carries sensations of two-point discrimination, proprioception, pressure, vibration to cerebrum, and cerebellum
  • Axons enter spinal cord and ascend to the medulla oblongata by decussating where they synapse with secondary neurons.

Pregunta 38

Pregunta
Lateral spinothalamic tract - Choose correct
Respuesta
  • Picks up pain and temperature
  • Follows a 3 neuron system, where the primary neuron starts in dorsal root ganglia
  • Secondary neuron - thalamus VPL nucleus
  • Tertiary neuron - posterior horn neuron

Pregunta 39

Pregunta
Anterior spinothalamic tract picks up which 4 sensations?
Respuesta
  • Heat
  • Tickle
  • Itch
  • Crude touch
  • Pressure

Pregunta 40

Pregunta
Trigemino-thalamic tract - Choose wrong
Respuesta
  • Fibers join the spinothalamic tract in the brainstem
  • Involves Cranial nerve VI
  • In thalamus synapses on VPL nucleus
  • Carries similar information to that of the spinothalamic and dorsal-column/medial- lemniscal system
  • Carries info from face, Nasal cavity and Oral cavity

Pregunta 41

Pregunta
Spino-olivary cerebellar tract - Choose correct
Respuesta
  • Spino-reticular tract to superior olivary nuclei
  • Spinal dorsal columns to nuclei of the medulla
  • Starts as climbing fibers on Purkinje cells
  • Spino-olivary - contribute to coordination of movement associated with balance
  • Both impulses from Spino-reticular tract and Spinal dorsal columns go to cerebellum

Pregunta 42

Pregunta
Anterior and posterior spino-cerebellar tracts - choose correct
Respuesta
  • Anterior - sensation = Proprioception of muscle, tendon, Joints receptors . Large tactile skin sensation
  • Anterior - sensation = Efferent copy of the anterior horn motor drive
  • Posterior - termination = The same side as its origin. Mossy fibers on cerebellar cortex granular cells
  • Posterior - termination = Both side of cerebellum. Mossy fibers on cerebellar cortex granular cells

Pregunta 43

Pregunta
Sensory tracts - choose correct
Respuesta
  • Cerebellum may reduce the conscious perception of sensations
  • Cortex may reduce the conscious perception of sensations
  • Spinotectal - involved in reflexes that turn the eyes and the head toward point of cutaneous stimulation
  • Corticospinal tracts send branches to ascending tracts and release neuromodulators such as endorphins
  • Corticospinal tracts send branches to descending tracts and release neuromodulators such as endorphins

Pregunta 44

Pregunta
Somatic sensory area 1 - Choose correct
Respuesta
  • Includes areas 3a, 3b, 1, and 2 in postcentral gyrus of the cortex
  • Topographic (somatotopic) projection = the feet - near the midline of the brain,
  • Topographic (somatotopic) projection = the feet - laterally, near the lateral fissure.
  • The cells of the S1 cortex are organized in columns specific to a particular modality.
  • The receptive fields of neurons contain only excitatory zones.

Pregunta 45

Pregunta
Somatic sensory area 1 (homunculus) - Choose correct
Respuesta
  • Regions needing low resolution are represented in the brain in fine detail
  • Regions of the body most richly supplied with sensory receptors have the largest number of neurons in the related areas of the neocortex.
  • High resolution is achieved by having many small receptive fields on the body surface
  • A larger representation in the cortex occurs when less neurons are dedicated to a region of the body.

Pregunta 46

Pregunta
Sensory area 1 - Modality of stimulus - Choose correct
Respuesta
  • Areas 3b, 1- respond to slowly adapting cutaneous receptors
  • Area 1- Deep skin receptors
  • Area 2 - deep skin receptors
  • Area 3a - muscle spindle, tendon and joint receptors

Pregunta 47

Pregunta
Somatic sensory area 1 (homunculus - S1) = destruction to S1 causes inability to ...
Respuesta
  • ...to localize sensations discretely and judge pressure and weight
  • ...to judge shapes and forms and to recognize the position of parts of the body.
  • ...to judge taste and smell
  • ...to judge texture of material and fine gradations in temperature

Pregunta 48

Pregunta
Somatic sensory area 2 - choose correct sentence
Respuesta
  • Impulses come from the ventral column system
  • Impulses come from the spinothalamic system and S1 area
  • Located in postcentral gyrus - posterior and inferior part (area 40 of the cerebral cortex).
  • Localization in this area is good.

Pregunta 49

Pregunta
Somatic association area - Choose wrong
Respuesta
  • Lesion to this area cause inability to recognize own body on same side as the lesion
  • Located behind the S1 area - areas 5 and 7
  • Lesion to this area cause inability to recognize own body opposite to the lesion
  • Lesion of this area lead to inability to recognize the complex forms (feeling for the shape of one's own body is lost).

Pregunta 50

Pregunta
Sensory are of the cerebral cortex - choose correct pairing
Respuesta
  • Visual cortex: occipital lobe
  • Olfactory cortex: superior surface of prefrontal lobe
  • Primary auditory cortex: inferior part of temporal lobe
  • Taste area: lower tip of postcentral gyrus

Pregunta 51

Pregunta
Division of neurons; choose what doesn't belong below.
Respuesta
  • Sensory neuron
  • Dorsal root ganglion
  • Efferent neuron
  • Interneurons of CNS - most reflexes go through these

Pregunta 52

Pregunta
Interneurons - characteristics; choose correct
Respuesta
  • Have both inhibitory and excitatory function
  • Slow neuron
  • Produce action potential
  • Hard neuron to excite

Pregunta 53

Pregunta
Salitatory conduction
Respuesta
  • Fast conduction (120m/s)
  • From one node of ranvier to another
  • Slow conduction (3m/s)
  • Unmyelinated conduction

Pregunta 54

Pregunta
Bell-Magendie Law; choose correct
Respuesta
  • In spinal cord conduction goes uni-aterally between anterior and porsterior root, in one direction only.
  • Anterior spinal nerve roots contain only motor fibers
  • Posterior spinal nerve roots contain only sensory fibers
  • In spinal cord conduction goes bi-laterally between anterior and porsterior root

Pregunta 55

Pregunta
Reflexes; choose wrong
Respuesta
  • Somatic motor reflex - goes to viscera
  • Somatic motor reflex - goes to muscle and skin
  • Autonomic motor reflex - goes to viscera
  • Autonomic motor reflex - goes to muscle and skin

Pregunta 56

Pregunta
Monosynaptic reflex (knee-jerk)- Choose correct
Respuesta
  • Large reflex arc
  • One synaps between sensory and motor neuron
  • Starts in Ia afferent fibers from muscle spindle
  • Complicated reflex
  • Duration of the knee jerk 19-24 ms.

Pregunta 57

Pregunta
Spinal regulation; choose correct
Respuesta
  • Each muscle spindle consists of 10 muscle fibers enclosed in a connective tissue capsule
  • Nuclear bag fibers - thicker, 2 per spindle
  • Nuclear chain fibers - thicker, 2 per spindle
  • Primary - annulospiral endings – rapidly conducting Ia (A-alpha) afferents
  • Secondary - annulospiral endings – rapidly conducting Ia (A-alpha) afferents

Pregunta 58

Pregunta
Spinal regulation; choose correct
Respuesta
  • Static (tonic) response of the nuclear bag region (rapid discharge after fast stretch, less rapid during sustained stretch)
  • Dynamic (phasic) response of the nuclear chain region (discharge at an increased rate throughout the period when the muscle is stretched).
  • Intrafusal muscle fibers - have gamma-motor neurons (S, D)
  • Extrafusal muscle fibers - have alpha-motor neurons

Pregunta 59

Pregunta
Spinal regulation - muscle spindle; choose correct
Respuesta
  • Only the ends of the muscle spindle contract, due to lack of actin and myosin in the centre
  • The mid-portion of the muscle spindle can stretch
  • Gamma motor neurons contract extrafusal muscle fibers and plates, contracting outer part of muscle spindle
  • Ia fibers only gives nuclear chain fiber

Pregunta 60

Pregunta
Reflex patterns; choose correct
Respuesta
  • Dynamic response –increase spindle sensitivity to steady stretch
  • Gamma motoneurons cause contraction of spindle- stretch of nuclear bag portion – activation of Ia – reflex
  • Gamma discharge increases with alpha discharge
  • Static response - increase spindle sensitivity to rate of stretch

Pregunta 61

Pregunta
Reflex patterns; choose correct
Respuesta
  • Gamma discharge with muscle stretch – increase of discharge in Ia
  • Dynamic response – decrease spindle sensitivity to rate of stretch
  • Control – descending tracts from CNS – postural control
  • Gamma discharge decreases with alpha discharge

Pregunta 62

Pregunta
Inverse stretch reflex; choose correct
Respuesta
  • Sensory innervation: Ib - EPSP on motor neurons via interneurons
  • Activation: passive stretch, active contraction of muscle
  • Receptors: in muscle spindle (nerve endings among fascicles of tendon)
  • Very high muscle tension produces – cessation of contraction (autogenic inhibition)
  • Regulate muscle force

Pregunta 63

Pregunta
Withdrawal reflex; choose correct
Respuesta
  • Receptor: in muscle
  • Stimuli - nociceptive, noxious, painful
  • Response - flexor muscle- contraction (limb is moved away from the range of the irritating stimulus), extensor – inhibition
  • Effectors - recruitment of motor units – after discharge
  • Center - inhibition of stimulus in spinal cord

Pregunta 64

Pregunta
Functions of spinal cord; choose correct
Respuesta
  • Regulation of the sensory function, contains motor centers and efferent pathways.
  • Regulation of the motor function, contains sensory centers and efferent pathways
  • Spinal modulation of impulses performed by sensory, motor, and interneurons in particular spinal segment
  • Spinal modulation of impulses performed by sensory, motor, and interneurons among various spinal segments

Pregunta 65

Pregunta
Function of spinal cord - spinal centers; choose correct
Respuesta
  • Grey matter – neural centers for somatic-motor & sensory, and autonomic-motor & sensory
  • White matter – neural centers for somatic-motor & sensory, and autonomic-motor & sensory
  • Grey matter – neural pathways afferent and efferent
  • White matter – neural pathways afferent and efferent

Pregunta 66

Pregunta
Which does not belong as a division of the functions of the spinal cord?
Respuesta
  • Convergence and divergence
  • After-effect
  • Contraction and relaxation
  • Summation and facilitation
  • Inhibition

Pregunta 67

Pregunta
Spinal cord; choose correct
Respuesta
  • alpha-motor neuron is a final common pathway, it connects impulses
  • Central inhibition - presynaptic is only EPSP
  • Central inhibition - Postsynaptic and autoinhibition are EPSP
  • Central inhibition - Autoinhibition is IPSP and mediated by renshaw cells

Pregunta 68

Pregunta
Inhibitory interneurons; choose correct
Respuesta
  • Inhibitory interneurons modulating alpha-motoneurons through (IPSP) renshaw cells
  • Inhibitory interneurons in stretch reflex.
  • Inhibitory interneurons in inverse-stretch reflex.
  • Inhibitory interneurons in withdrawal reflex.
  • Use glycine in its synapses

Pregunta 69

Pregunta
Afferent pathways to cerebral cortex - Spino reticular tract
Respuesta
  • Crosses midline and ascends to brain stem reticular formation
  • Projects bi-laterally through intralaminar nuclei of the thalamus to regions of the cerebral cortex
  • Plays major role in general alertness and arousal in response to tactile (painful) stimuli
  • Does not cross midline before ascending to brain stem reticular formation

Pregunta 70

Pregunta
Afferent pathways to cerebral cortex - spinotectal (spinomesencephalic) tract; choose wrong
Respuesta
  • Does not cross midline
  • Crosses midline
  • Projects to and synapses with anterior colliculi, play major role in orientating eyes and head towards visual stimuli
  • The tract send fibers to grey matter with axons to post. horn of the spinal cord, can suppress incoming pain signal

Pregunta 71

Pregunta
Spinal cord tests; choose correct
Respuesta
  • Turck exam - Examines withdrawal reflex in spinal frog
  • Brondgest - facilitation and inhibition of the reflex
  • Sechenov - Component of the reflex arc
  • Turck exam - Relation between strength of the stimulus and response

Pregunta 72

Pregunta
Neurological examinations; choose correct
Respuesta
  • Always consider left side symmetry
  • Consider central vs. peripheral deficits
  • Organize your thinking into seven categories
  • Organize your thinking into five categories
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