Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NB > physiology lGW > Flashcards

physiology lGW Flashcards

1
Q

What is saltatory conduction?

A

Saltatory conduction is the propagation of action potentials along myelinated axons from one node of ranvier to the next node, increasing the conduction velocity of actio potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does inhibitory transmitters such as GABA reduce the probabilty that apostynaptic cell generate an action potential?

A

It triggers opening cl- channels in the postsynaptic neuron, which hyperpolarizes its membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are metabotropic receptors?

A

Act as G coupled receptors
SLow effects
Change postsynaptc membrane metabolism
CAMP or calciu mobilization
Has a diffuse synaptic connection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Whata are examples of metabotropic receptors?

A

Monoamines, neuropeptides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are ionotropic receptors?

A

Close or open ion channels
Fast effect
CHange postsynaptic membrane polarity
Has a focused synaptic connection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an example of ionotropic receptors?

A

Glutamate, GABA, Glycine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is sensory transduction?

A

Conversion of sensory stimulus from one form to another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the different tye of mechanoreceptors and where are they located?

A
  1. Free nerve endings: epidermis, dermis
  2. Merkel’s disc: superficial epidermis
    3.Meissner’s corpuscle: superficial, papillary dermis of the palm of hands and sole of foot
  3. Pacinian corpuscle: Deep layers of palmar dermis, palmar, subcutaneous tissues and near periosteum of proximal phalanges
  4. Ruffini’s end organ: Deep, encircle hair follicles
    6.Krause’s endings: superficial: superficial layers of dermis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the somatosensory cortex? Name its parts

A

Lies in the postcentral gyrus
Occupying areas 1,2,3,5,7 and 40
Divided into 3 main parts:
1.Somatic sensory area I (SI)
2.Somatic sensory area II (SII)
3.Association sensory cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the effect of lesion on SI?

A

Inability to perceive epicretic sensation
Fine localization is lost but crude localization is present.
Pain sensation is poorly affected (slow pain and extreme temperature are protopathic sensation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the site of somatic sensory area I?

A

Post central gyrus 1,2,3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the charecters of SI?

A

1.Crossed representation
2.Inverted representation of the body
3.Size is proportional to the amount of receptors present
4.Modality orientation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What type of sensation is recieved in the posterior part of SI?

A

Pressure and tactile sensation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What type of sensation is recieved in the anterior part of SI?

A

Proprioceptive sensation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the function of SI?

A

Center of perception of
1.Fine touch: tactile localization and discrimination
2.Localization of paina nd temperature
3.Stereognosis
4.Proprioception (static and dynamic)
5.Vibration sense, pressure, texture of material, weights
6.Discrimination of various grades of temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the site of SII?

A

Behind and below SII
Occupies area 40 above the lateral sulcus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where does SII recieve afferent fibers from?

A

Thalamic nucleus
SI
Other sensory areas e.g.visual and auditory areas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the characters of SII?

A

The body part representation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Which area of the somatosensory cortex is stronger?

A

SI Is stronger than SII

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is represented in the anterior part of SII?

A

The head area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is represented in the posterior part of SII?

A

THe leg area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the function of SII?

A

1.Potentiates the functions of SI
2.Begins to make meaning of the sensory signals (shape or texture of n object placed on a hand)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does a lesion in SII lead to?

A

Deficit learning based on tactile discrimination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Where is the somatic association cortex?

A

Lies behind SI and above SII (areas 5 and 7)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Where does the somatic association cortex recieve signals from ?

A

SI, SII, thalamus, visual and auditory areas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the function of the somatic association area?

A

1.Interpretation of information entering the somatic sensory areas for understanding and giving meaning to them
2.Center for stereognosis
3.Shares in planning of movements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the effect of a lesion in the somatic association area?

A

1.Astreognosis
2.Amorphosynthesis (-autopognosia) forgetting the other side
3.Neglect syndrome: movement occur without planning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

When you are dealing with a neurological case what questions do you ask yourself?

A

Where is the lesion?
What is the lesion?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are the dorsal column syndromes?

A

Deficits in touch and proprioception
1.Tabes dorsalis (most common form of neurosyphilis)
2.Friedreich’s ataxia
3.Brown sequard syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are spinothalamic syndromes?

A

Deficits in pain and temperature sense
1.Anterior spinal artery syndrome: atherosclerosis or spinal injury
2.Syringomyelia:Occlusion of crossing pathways by degenerative expansion of the spial centeral canal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the type of lesions found in syringomyelia?

A

1.Congenital
2.Overgrowth of abnormal glial tissue (gliosis) around the central canal of spinall cord which then falls leading to cavitation and damage of the crossing fibers of lateral and ventral spinothalamic tracts
3.Srinex= Cyst ( a rare fluid filled neurological cavity within spinal cord or brain stem)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Where is the lesion in syringomyelia found?

A

1.Spinal cord (lower cervcical and upper thoracic C4-T10)
2.May extend to affect lumbar segments
3.Brain stem (syringobulbia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are most common genre of people with syringomyelia?

A

Middle age and female

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is syringomyelia charcterized by?

A

Loss of pain, Temperature and crude touch on both sides of the body at the level of the affected segments (Jacket ditribution of sensory loss)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Which sensations are not affected in syringomylia?

A

Sensatios carried in dorsal column (dissociated sesnory loss)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are the complications of syringomyelia?

A

Bilateral muscle paralysis at level of lesion (AHCs lesions)
Unilateral or bilateral horner’s syndrome (LHCs lesion)
Syringobulbia (Damage of 9th, 10th, 12th cranial nerve) causing dysphagia & longue atrophy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Which dermatomes are affected by the jacket-like dissociated sensory loss?

A

C4-T2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Explain the sensory loss that occurs in syringomyelia.

A

Due to damage of the crossing fibers of the lateral and ventral spinothalamic tract by the gliosis or fibrosis around the central canal (loss of pain & temperatur) while the dorsal column tract is intact (tactile sensation & proprioception)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

If you examine for light touch, in syrngomeylia, what would you find?

A

It would be partially affected as it is carried to a little extent by the dorsal column (which is intact) together with the ventral spinothalmic tract (which is affected)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is the type of lesion found in Tabes Dorsalis?

A
  1. Infalmmatory (neurosyphilis)
    2.Inflammation of the dorsal roots with comression of the afferent fibers leading to demylination and degeneration of large myelinated fibers, so in early course of the disease, it involves the dorsal column sensations rather than the spinothalamic. later on, all sensations in the regions innervated by affected dorsal nerve root will be affected.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Where is the lesion of tabes dorsalis found?

A

1.Spinal cord (dorsal roots of lumbosacral segments & upper thoracic segments)
2, pretectal area in the midbrain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is the symptom of Tabes dorsalis in the pretectal area in the midbrain?

A

Argyll robertson pupil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is Argyll Robertson’s pupil?

A

The physical exam findings of bilateraly small pupils that do not constrict when exposed to bright light but do constrict when focused on nearby onjects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

In which gender is Tabs dorsalis more common?

A

Males

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are the early manifestations of Tabis dorsalis?

A

Inflammation –> Irritation of pain fibers in the central part of the dorsal root causing attacks of severe pain felt in the lower limbs
Degeneration—> Loss of dorsal colum sensations leading to sensory ataxia (positive romberg’s sign)
Stamping gait

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What are the late manifestations of Tabes dorsalis?

A

1.Loss of all sensations in the regions innervated by affected dorsal nerve root= deafferentation
slow pain remains for long period (resists compression)
2.Loss of all reflexes (both superficial, deep and visceral) which have its centers in the affected segment due to irritation of the afferents fibers of these reflexes
3.Micturition disturbance: in form of retetion with overflow
4.Loss of pain sensation: (very late) due to affection of the pain fiber
5.May be accompanied with (Argyll robertson pupil) where the pupil is irregular, shows miosis in response to near objects (intact acocommodatio) but no miosis in response to light (lost pupillary light reflex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Explain the loss of position and vibration sensation Tabes dorsalis

A

The lost position and vibration sensations are due to compression on the afferent fibers (AB fibers) that carry the sensations at the dorsal rooot lesion, leading to failure of sensory impulse transmission to the cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Explain the absent deep reflexes in tabes dorsalis

A

The absent deep reflexes are dut to compression on the afferent fibers of reflexes (muscle spindle reflex) at the dorsal root

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Explain the positive Romberg’s sign in Tabes dorsalis

A

The positive romberg’s sign is due to proprioceptive sensations from lower limbs leading to inability to maintain balance while closing eye

50
Q

What are the other effects of a dorsal column lesion in tabes dorsalis?

A

Loss of fine touch
Loss of stereognosis
Loss of superficial reflexs (flexor withdrawl)
Loss of visceral reflxes

51
Q

Why do patients complain of pain in Tabes dorsalis?

A

Due to irritation of pain conducting fibers at the dorsal root by the inflammatory process, leading to transmission of impulses through the fibers to the brain and perception of pain

52
Q

What is brown-sequard syndrome?

A

Damaged one side of the spinal cord

53
Q

What is the clinical picture of brown-sequard syndrome when it is above the level of lesion?

A

Cutaneous hyperthesia (increased sensitivity to sensations due to irritation of dorsal roots)

54
Q

What is the clinical picture of Brown-sequard syndrome at the level of the lesion?

A

Loss of all sensations in corresponding dermatomes on the same side
Motor affection=Flaccid paralysis (LMNL) and loss of all reflexes mediated via the affected segments

55
Q

What is the clinical picture of Brown-sequard syndrome below the level of lesion?

A

Loss of pain and temperature on the opposite side of the lesion= Cotralateral analgesia and athermia
Crude touch is decreased on both sides but not lost
Loss of fine touch, proprioceptie sensations, vibratio, pressure on the same side due to interruption of fibers of the dorsal column tract

56
Q

Where in brown sequard syndrome does UMNL occurs?

A

Same side

57
Q

Where in brown sequard syndrome does Horner’s syndrome occur?

A

Cervical lesion

58
Q

What are the symptoms of brown sequard on the same side as lesion?

A

UMN weakness
Loss of position & vibration

59
Q

What are the symptoms of brown sequard syndrome on the same side of the lesion?

A

Loss of pain and temperature

60
Q

What are the disorders produced by diesease of the basal ganglia?

A

Either hyperkinesia (excess involuntary spontaneous movements) or hypokinesia (lack of spontaneous movement, sloing of voluntary movement)
No weakness
Ballisus (jumping about)
Dystonia (extreme contractions forcing unusual movements)
Athetosis (Continul uncontrolled writhing)
Chorea (COntinuing series of rapid, jerky movements that are fragments of purposeful movements )
No apraxia (Movements can be conceptualized)

61
Q

what are diseases in the basal ganglia with hyperkinetic symptoms?

A

Ballism: Damage to the subthalamic nucleus-leads to disinhibition of movement via the indirect pathway
Huntington’s disease: Degeneration of the cuadate/putamen (striatum) causes choreiform movements. Striatal spiny neurons that inhibit the indirect pathway are most affected initially

62
Q

What are tics?

A

Repeated, stereotyped fragments of movement

63
Q

What are basal ganglia diseases with hypokinetic syndromes?

A

Parkinson’s disease: Degeneration of dopamine producing neurons i the substania nigra pars compasta. Low dopamine input to the striatum cannot energize movements through the direct and the indirect pathways.

64
Q

What are other symptoms of parkinsons?

A

Bradykinesia, resting tremor, rigidity- incuding cog-wheel rigidity

65
Q

Explain the cerebellar control of movement.

A

1.Cerebellar control is ipsilateral- damage to the right side impairs movements onn the same side
2.The flocculo-nodular lobe controls balance and eye movements
3.The vermis and pars intermedia adjust ongoing movement of the whole ody
4.The cerebellar hemispheres help coordinate the planning of limbe movements- they project in particular in PM cortex.

66
Q

Which part of the cerebellar is incharge of controlling balance and eye movements?

A

The flocculo-nodular lobe

67
Q

Which part of the cerebellar is in charge of adjusting ongoing movement of the whole body ?

A

The vermis and pars intermedia

68
Q

Which part of the cerebellar is in charge of helping coordinate the planning of limb movements?

A

Cerebellar hemisphere it projects in particula to PM cortex

69
Q

describe the characteristic signs ofDUMNLs.

A

Spasticity
Hyperactive reflexes
No signs of muscle denervation
Positive babinski sign
Positive Bing sign

70
Q

What are the 3 main types of stroke?

A

Thrombosis
Embolism
Hemorrhage

71
Q

What are examples of lMN syndromes?

A

Poliomyelitis
Tabes dorsalis
Myasthenia gravis
Injury in dorsal/ventral root
Muscular atrophy

72
Q

What is apraxia?

A

Inability to conceptualize and plan movement

73
Q

What is the gait associated with UMNLs?

A

Scissoring gait/ walking with increased antogonist muscle reflexes

74
Q

Describe upper motor neuron symptoms due to brainstem lesions.

A

UMN deficits on the contralateral side of the body
often, LMN deficits of cranial nerve nuclei

75
Q

List different forms of motor disturbances

A

Weakness
Spasticity
Rigidty
Ataxia
Hypokinesia or hyperkinesia
Apraxia

76
Q

What are the UMN symptoms due to spinal cord transections?

A

Looss of voluntary movement
Anesthesia
Temporry loss of reflexes (spinal shock) followed by hyper-reflexia
Cervical transections produce quadriplegia
Transections below cervical enlargement produce paraplegia

77
Q

What is Ballism?

A

Degeneration of the subthalamic nucleus, leads to disinhibition of movement via the indirect pathway

78
Q

What is hypotonus?

A

Loss of muscle tone-reduced spindle discharge

79
Q

What is ataxia?

A

Loss of co-ordinaton

80
Q

What is dysmetria?

A

Deficiencies in movement distance, velocity and rhythm of muscle contractions.

81
Q

What is asyngeria?

A

Loss of co-ordination between different muscle groups

82
Q

What is the affect of cerebellar lesions on cerebellar control?

A

Ataxia
Hypotonus
Dysmetria
Asynergia
Postural abnotmalities
Ataxia of trunk and legs lead to ataxia of gait
Ataxia of arms-loss of smooth movements with intention tremor
Force and rhythm deficits revealed as dysdiadochokinesia

83
Q

When is dopamine excitatory and when is it inhibitoy?

A

Inhibtory = indirect
Excitatory = direct

84
Q

What is the most characteristic initial physcial symptoms of huntington’s disease?

A

Jerky, random and uncontrollable movements called chorea
(Chorea can be initially exhibited as general restlessness, small unintentionally initiated or uncompleted motions, lack of coordination, or slow saccadic eye movements)

85
Q

what is the lateral descending system?

A

Lateral corticospinal and rubrospinal

86
Q

Where does the lateral descending system terminate?

A

Terminate on lateral alpha motor neurons in one segment only and terminate on interneurons too

87
Q

What does the lateral desending system supply?

A

Distal limb muscles

88
Q

What is the lateral descending system responsible for?

A

Responsible for fine movements

89
Q

What is the medial descending system?

A

Ventral corticospinal, reticulospinal, vestibulospinal and tectospinal

90
Q

Where does medial descending system terminate?

A

On medial alpha motor neurons in many segments

91
Q

What does the medial descending system supply ?

A

Axial & proximal limb muscles

92
Q

What is medial descending system responsible for?

A

Gross movements, balance, posture, stabilization

93
Q

Which tract controls posture of the head and neck?

A

Medial vestibulospinal and tectospinal tracts

94
Q

what do lesions in the lateral descending system lead to?

A

Loss of fine wrist and finger movement
Preserved gross movement

95
Q

What do lesions only in LCST lead to?

A

Inability to fractinate finger movements
Preserved wrist movements

96
Q

What do lesions in the medial descending system lead to?

A

Difficulty in sitting, standing and walking
Paralysis of body axis and proximal parts of limbs

97
Q

Where do all the corticospinal systems originate from?

A

The cortex

98
Q

What are all the corticospinal systems?

A

1.Cortico-spinal tracts
2.Cortico-bulbar tracts
3.Cortico-nuclear tract

99
Q

Where does the cortico-spinal tract terminate at?

A

AHCs odf spinal cord

100
Q

What is the origin of the cortico-spinal tracts?

A

Primary motor cortex (30%)
Premotor cortex (30%)
SOmatosensory areas (40%)

101
Q

What are the types of cortico-spinal tracts?

A

Lateral corticospinal tract
Vetral cortico-spinal tract
Uncrossed cortico-spinal tract

102
Q

what is the pathway of the cortico-spinal tracts?

A

Cortex –> anterior 2/3 of posterior limb and genu of internal capsule –> Brain stem –> upper medulla —> forming pyramid in lower medulla

103
Q

What is the function of the lateral cortico-spinal system?

A

Initiate fine skilled movements of the distal parts of the opposite side of the body

104
Q

What is the function of the ventral corticospinal tract?

A

Iitiate gross movements of the proximal parts of the opposite side of the body

105
Q

What is the function of the uncrossed corticospinal tract?

A

Bilateral supply of abdominal and thoracic muscle

106
Q

What are other corticospinal system functions?

A
  1. Help in controlling muscl tone and postural background
    2.Contribute the correct excitabillities for the normal plantar reflex, which is altered by CST damage leading to babiniski’s sign
107
Q

what is the origin of the cortico-bulbar tracts?

A

Sam as corticospinal tract

108
Q

What is the pathway of cortico-bulbar tract?

A

Cortex –> anterior 2/3 of posterior lim and genu of interal capsule brainstem–> cranial nerve nuclei V, VII, IX, X, XI, XII, supplying the head and neck

109
Q

What i sthe function of the cortico-bulbar tracts?

A

INitiate voluntary movement of head, face and tongu muscles
Regulation of stretch reflex and mucle tone

110
Q

What is the origin of the cortico-nuclear tract?

A

FRontal eye field area 8

111
Q

What is the pathway of the corico-nuclear tract?

A

Cortex –> anterior 2/3 of posterior limb and genu of internal capsule -> parapontine reticular nucleus in braintem –> cranial nevre nuclei III, IV, VI, supplying extraocular muscles of both sides

112
Q

What is the function of the cortic-nuclear tract?

A

Voluntary conjugate deviation of both eyes to the opposite side

113
Q

Which body parts of the corticospinal system do not recieve contralateral innervation?

A

Trunk, neck, respiratory and abdominal muscles which receive bilateral innervation (contra and ipsi-lateral)

114
Q

Which cranial nuclei do not revieve bilateral fibers in the corticospinal system?

A

Lower part of facial nerve nucleus and the part of hypoglossal nerve nucleus supplying genoglossus muscle which receive contralateral fibers only

115
Q

What are the extrapyramidal tracts?

A

1.Retculospinal tract
2.Rubrospinal tract
3.Vestibulospinal tract
4.Tectospinal tract

116
Q

what is the origin or the rubrospinal tract?

A

Red nucleus

117
Q

What are the functions of the rubrospinal tracts?

A

Accessory route for initiation of fine movements
- of stretch reflex
+ flexors & - of extensors
involved in comparator function of cerebellum

118
Q

What are the fibers in the rubrospinal tracts?

A

Cortex –> red nucleus–> crossing —> lateral a in spinal cord

119
Q

Where do reticulospinal medullary R.F recieve impulses from?

A

Red nucleus
Basal ganglia
Paleocerebellum

120
Q

What are the fibers in reticulospinal tract of medullary R.F?

A

Lateral reticulosp. descends bilaterally

NB (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions