Review Flashcards

1
Q

Where do action potentials begin?

A

Initial segment

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

How are action potentials propagated?

A

An AP elicited at any point on an excitable membrane excites adjacent portions of the membrane

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

Common neurotransmitters

A

Class I: ACh
Class II: Amines - Epi, Dopamine, Serotonin, Histamine
Class III: Amino acids - GABA, glycine, glutamate, aspartate
Class IV: NO

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

Local anesthetics

A

Act on Na+ channel activation gates (block), reducing excitability

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

Fast vs slow conducting nerves

A
Fast = large diameter myelinated axon
Slow = thin myelinated axon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Basic ion channels and action potentials

A

Ionophore component of post synaptic neuron
Cation channels allow Na+ to enter- excitatory
Anion channels allow Cl- to enter- inhibitory (stops excessive propagation of pain signals)

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

Skeletal muscle contraction

A
  • AP travels along motor nerve to NMJ
  • Nerve secretes ACh; opens ACh-gated channels
  • Na+ diffuses in initiating AP
  • AP travels along muscle membrane, T tubules
  • AP depolarizes muscle, causing sarcoplasmic reticulum to release Ca++
  • Ca++ initiates actin and myosin sliding
  • Ca++ pumped back into sarcoplasmic reticulum, stopping contraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What produces CSF and where does it live?

A

Choroid plexus

Lateral, third, and fourth ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What cranial nerves are sensory?

A

I, II, VIII

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

What cranial nerves are motor?

A

III, IV, VI, XI, XII

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

What cranial nerves are both sensory and motor?

A

V, VII, IX, X

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

Signs of forebrain disease

A

o Seizures- only come from forebrain
o Altered mentation, behavioral change, dementia, loss of training
o Pacing, wandering, wide circles- typically towards side of lesion
o Head turn- same side as lesion
o Postural reaction deficits- opposite side of lesion
o Visual impairment, cortical blindness- opposite side of lesion
o Head pressing, star-gazing, fly-biting
o Hemiparesis on side opposite lesion
o Typically normal gait, but proprioceptive ataxia
o Hemi-inattention, hemi-neglect: if blindfold one side of them they may ignore that side if you poke them in the face
o Brain pain

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

Where is gait controlled?

A

Midbrain and brainstem

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

Where are cranial nerves located?

A
  • Cerebrum: CN I
  • Diencephalon: CN II
  • Midbrain: III-IV
  • Pons: V
  • Medulla oblongata: VI-XII
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What produces CSF and where does it live?

A

Choroid plexus

Lateral, third, and fourth ventricles

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

Paresis vs plegia

A

Paresis - weakness

Plegia - no voluntary movement

17
Q

Reflexes

A

Do not go to brain

Synapses on efferent neuron in ventral horn

18
Q

UMN vs LMN signs

A
UMN:
o	Normal/increased reflexes
o	Increase in tone
o	Paresis to paralysis
o	Weak and stiff
LMN:
o	Loss of reflexes (interrupts part of reflex arc)
o	Loss of tone
o	Paresis to paralysis
o	Weak and floppy
19
Q

Decerebellate posture

A

Acute cerebellar lesion
Extended TLs, flexed PLs
Opisthotonus (extended neck)

20
Q

Schiff-Sherrington posture

A

severe, acute T3-L3 lesions
Not prognostic
Mentation is normal

21
Q

Pirmary epilepsy

A

• No identifiable structural brain abnormality
• Typically pure-bred dogs (genetic likely); 1-5 yrs old
• Seizures are mostly generalized; can be partial
o Often at rest or sleep; frequency is highly variable
• Documented in cats
• Treatment: Phenobarbital, KBr, Levetiracetam (Keppra), Zonisamide
• Emergency anti-convuslants: phenobarbital (IV), diazepam (IV, per rectum), Levetiracetam (IV, per rectum)

22
Q

Can we treat seizures? How?

A

Yes. Phenobarbital, KBr, Levetiracetam (Keppra), Zonisamide

• Emergency anti-convuslants: phenobarbital (IV), diazepam (IV, per rectum), Levetiracetam (IV, per rectum)

23
Q

How to localize a lesion?

A

o Forebrain clinical signs
• Seizures, circling, compulsion, behavior changes, blindness, postural rxn deficits, gait should be normal
o C1-C5
• Tetraparesis, ataxia (thoracic limb signs more subtle than pelvic limb)
• Reflexes normal to increased in all limbs
o C6-T2
• “two engine” gait, tetraparesis, ataxia
• Normal to decreased thoracic limb reflexes (LMN), normal to increased pelvic limb reflexes (UMN)
o T3-L3
• Paraparesis (increased pelvic limb tone), normal to increased reflexes in pelvic limb
• Pelvic limb ataxia, +/- kyphosis
• Schiff-Sherrington
• Loss of ascending inhibition
• Extensor hypertonia of thoracic limbs, normal mentation
• Plegia in pelvic limbs
• Distinguished from decrebrate by mentation, pelvic limb involvement
o L4-S3
• Pelvic limb ataxia; decreased to absent pelvic limb reflexes
• Poor anal tone, perineal reflex, tail tone, tail sensation
o LMN
• No ataxia, no pain, decreased to absent reflexes
• +/- CN weakness (facial, gag); exercise intolerance

24
Q

Imaging techniques

A

CT, MRI, Myelography

Ultrasound, Radiographs

25
Q

Where do proprioceptive pathways cross over?

A

Midbrain (medulla oblongata)

26
Q

Central vs peripheral vestibular

A

Both head tilt towards lesion
Central: change in mentation
Peripheral: no change in mentation, may see CN VII deficits

27
Q

What does the MLF do?

A

connects III, IV, VI to VIII

28
Q

What can cause seizures?

A
Primary epilepsy (familial, idiopathic)
Metabolic (Hyper-, Hypoglycemia)
Neoplasia
Infection
Inflammation
Toxins
Reactive
Cryptogenic