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Med310A > Lecture 9: Reflexes > Flashcards

Lecture 9: Reflexes Flashcards

1
Q

____ extends from brain stem

A

Spinal cord

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2
Q

Spinal cord has 2 functions :
- serves as the neuronal link between the ___ and the _____
- is the integrating centre for the spinal ____

A

Brain and peripheral nervous system
Reflexes

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3
Q

___ pairs of spinal nerves emerge from spinal cord through spaces between adjacent vertebrae

A

31

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4
Q

Spinal nerves connect with each side of the spinal cord by a ___ and a ____

A

Dorsal root
Ventral root

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5
Q

a spinal nerve consists of both ___ and ___ fibres

A

Efferent
Afferent

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6
Q

A ___ is a bundle of peripheral neuronal axons enclosed by a connective tissue covering and following the same pathway

A

Nerve

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7
Q

White matter is organized into ___

A

Nerve tracts

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8
Q

_________: Bundles of nerve fibres with a similar function. Each tract begins or ends within a particular area of brain

A

Nerve tracts

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9
Q

____ tracts: afferent, sensory input

A

Ascending

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10
Q

____- tracts : efferent motor output

A

Descending

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11
Q

What are the 3 horns that gray matter is divided into ?

A

Dorsal
Ventral
Lateral

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12
Q

_____ horn contain cell bodies of interneurons on which afferent neurons terminate
_____ horn contains cell bodies of efferent motor neurons supplying skeletal muscles
_____ horn contains cell bodies of autonomic nerve fibres

A

Dorsal

Ventral
Lateral

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13
Q

A ____ is an involuntary stereotyped response to a sensory input

A

Reflex

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14
Q

2 types of reflexes ?

A

Simple /basic
Acquired / conditional

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15
Q

2 types of reflexes :
______ : built in , unlearned response
______ : result of practice and learning

A

Simple/basic
Acquired/ conditioned

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16
Q

___________
-> somatic motor neurons and skeletal muscles
- > spinal - integrated in spine
-> cranial - integrated in brain

__________
-> involve autonomic neurons
-> spinal- urination/defecation
-> integrated in brain - brainstem , hypothalamus , thalamus (homeostasis -gag, vomiting, sneezing, coughing, swallowing)

A

Somatic
Autonomic

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17
Q

What are the 5 reflex pathway components?

A

Sensory receptor
Afferent pathway
Integrating centre
Efferent pathway
Effector

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18
Q
  1. A ______ (muscle spindles in the case of somatic muscle reflexes)
    2.an _______ to the CNS (sensory axon)
  2. An _____ consisting of one or more synapses in the CNS
  3. An ____- to the periphery ( motor axon)
  4. An ___ (the muscle)
A

Sensory receptor
Afferent pathway
Integrating centre
Efferent pathway
Effector

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19
Q

A _____ has a single synapses between the afferent and efferent neurons

A

Monosynaptic reflex

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20
Q

______ have two or more synapses

A

Polysynaptic reflexes

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21
Q

What are 3 Proprioceptors :

A

Muscle spindle
Golgi tendon organ
Joint receptors

22
Q

Skeletal muscle reflex sensory receptors ( proprioceptors)
_______- in muscles, sense stretch
________- in tendon , sense force
________- sense pressure , position

A

Muscle spindles
Golgi tendon organ
Joint receptors

23
Q

Muscle stretch triggers a _____

A

Stretch reflex

24
Q

_____- alpha motor neurons are stimulated to generate contraction

A

Isotonic contraction

25
Q

Muscle contraction and receptor responses
-Length changes, but the ____ remains constant

A

Tension

26
Q

When the whole muscle mass shortens the _____ also passively shorts

A

Spindles

27
Q

The firing rates of the spindle afferent axons are reduced because the tension in the receptor portion of the ________ is relieved

A

Interafusal fibres

28
Q

_______ modulate the sensitivities of the spindles

A

Y motor neurons

29
Q

The _______ slacken when a muscle shortens (unloading spindles)

A

Intrafusal fibres

30
Q

To ensure that info on changes in muscle length are transmitted , the CNS regulates the loading of the intrafusial fires with _______

A

Y motor neurons

31
Q

The rapid contraction of the intrafusial fibres increases the ____ on the central sensory element of the spindle and restores the sensitivity of the spindle
During voluntary movement, a and y motor neurons are coactivated by the ____

A

Tension
CNS

32
Q

______: The addition of a load stretches the muscle and the spindles , creating a reflex contraction

A

Muscle spindle reflex

33
Q

_______ respond to changes in muscle tension

A

Golgi tendon organs

34
Q

Encapsulated receptors consisting of______ from the muscle intertwined with the endings of tendon afferent axons

A

collagen fibres

35
Q

Applying tension to collagen fibres, squeezes the axons, ____ them and triggering ___ in tendon afferents

A

Depolarizing
Action potentials

36
Q

Afferents terminate on ________ in ventral Horn and clarke’s nucleus

A

Inhibitory interneurons

37
Q

Primary function of Golgi tendon organs is to provide _______

A

Sensory information on muscle tension

38
Q

_____ reflex
- monosynaptic reflex
- ex: patellar tendon reflex
- preliminary assessment of nervous system function

A

Stretch

39
Q

Classic example of the stretch reflex ?

A

Patellar tendon reflex

40
Q

____ reflex: stretch reflex and reciprocal inhibition

A

Patellar

41
Q

____ reflex is an example of a polysynaptic reflex

A

Flexion

42
Q

____ injury-> damage to any part of PNS reduces or laminates the muscle stretch reflex and reduces muscle tone

A

LMN

43
Q

_______: Reduction/elimination of muscle stretch reflex

A

Hyporeflexia

44
Q

LMN injury causes loss of _____ to muscle

A

Innervation to muscle

45
Q

_____ injury-> increased tone , hyperreflexia

A

UMN

46
Q

____- lower motor neuron, effector neuron in spinal cord
_____- upper motor neuron, neurons in higher brain levels that influence neurons in spinal cord

A

LMN
UMN

47
Q

______ are important because they provide an objective sign medicating an abnormality and some indication to the level of the abnormality

A

Reflexes

48
Q

The responsiveness of reflexes can be altered by ____ or ____

A

Trauma or disease

49
Q

__________
- interruption of reflex arc by either peripheral sensory or lower motor neuron (LMN) lesions

A

Loss/reduction of reflex

50
Q

__________
- injury to upper motor neuron (UMN) above the anterior horn cell leads to loss of descending inhibition

A

Increased reflex and muscle tone

Med310A (29 decks)

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