Neurology Anatomy and Physiology Flashcards Preview

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Flashcards in Neurology Anatomy and Physiology Deck (50)
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1
Q

Central Nervous 1. Structures involved? 2 2. Function? 1

A
  1. Brain and Spinal cord
  2. Integrative and control centers
2
Q

Peripheral nervous system (PNS) 1. Structures? 2 2. Function? 1

A
  1. Cranial nerves and spinal nerves 2. Comminication lines b/w the CNS and the rest of the body
3
Q

Sensory (afferent) division 1. Structures? 2 2. Function? 1

A
  1. Somatic and visceral sensory nerve fibers 2. Conducts impulses from receptors to the CNS
4
Q

Motor (efferent) division 1. Structure? 1 2. Function? 1

A
  1. Motor nerve fibers 2. Conducts impulses from the CNS to effectors (muscles and glands)
5
Q

Autonomic nervous system (ANS) 1. Structure? 1 2. Function? 1

A
  1. Visceral motor (involuntary) 2. Conducts impulses from the CNS to cardiac muscles, smooth muscles, and glands
6
Q

Somatic nervous system (SNS) 1. Function?1 2. Structure? 1

A
  1. Somatic motor (voluntary) 2. Conducts impulses from the CNS to skeletal muscles
7
Q

Sympathetic division of the ANS function?

A

Mobilizes body systems during activity

8
Q

Parasympathetic division of the ANS function? 2

A
  1. Conserves energy 2. Promotes housekeeping functionsduring rest
9
Q

Describe the development of the neural tube from embryonic ectoderm? 3

A
  1. The neural plate forms from surface ectoderm. 2. The neural plate invaginates, forming the neural groove, flanked by neural folds. 3. Neural fold cells migrate to form the neural crest, which will form much of the PNS and many other structures.
10
Q
  1. What are the primary brain vesicles? 3
  2. What are the secondary brain vesicles and where do they come from? 5
A
11
Q

What are the adult brain structures that come from the following:

  1. Telencephalon? 1
  2. Diencephaon? 3
  3. Mesencephalon? 1
  4. Metencephalon? 2
  5. Myelencephalon? 1
  6. What is below the brain vescicles?
A
  1. Cerebrum - cerebral hemispheres
  2. Diencephalon- thalamus, hypothalamus, epithalamus
  3. Midbrain (brainstem)
  4. Pons (brainstem) and the Cerebelllum
  5. Medulla oblongata (brain stem)
  6. spinal cord
12
Q

What are the adult neural canal regions associated with the adult brain structures? 5

A
  1. Lateral ventricles
  2. Third ventricles
  3. Cerebral aquaduct
  4. Fourth Ventricle
  5. Central canal
13
Q

What are the types of nervous system cells? 5

A
  1. Atrocytes
  2. Microglial cells
  3. Ependymal cells
  4. Oligodendrytes
  5. Sensory neurons with Schwann cells and satellite cells
14
Q
  1. Action potentials are considered what types of events?
  2. What is the threshold voltage?
  3. What are action potenital initiated by?
  4. Action potentials can be induced in nerve and muscle by what kind of stimulation?
  5. Action potentials do not summate- information is coded by what?
  6. Describe the relationship between conduction and nerve fiber diameter?
A
  1. all or none events
  2. usually 15 mV positive to resting potential
  3. depolarization
  4. extrinsic (percutaneous) stimulation

5. APs do not summate - information is coded by frequency not amplitude.

6. Larger diameter equals faster conduction

15
Q
  1. Depolarization causes Na channels to what? 2
  2. By contrast, K channels do what?
  3. Describe what is happening to close, open and inactivate Na+ channels?
A
  1. Na channels to activate (open)

but it also causes inactivation

  • inactivated channels do not pass any ions (non-conducting state)
    2. By contrast, K channels show activation but not inactivation
    3. See picture
16
Q
  1. Where do APs only occur? Why?
  2. What is the purpose of the myelin sheath? 2
A
  1. AP’s only occur at the nodes. Because they are the spaces inbetween the myelin sheath which acts as insulation. They conduction jumps from node to node.

2.

  • increased velocity
  • energy conservation
17
Q

Conduction velocity

Describe the difference between

- non-myelinated vs myelinated -

A

See picture

18
Q
  1. What is edema in the CNS caused by?
  2. Why is this a special problem in the brain and spinal cord? 3
A
  1. Increase in tissue mass that results from the excess movement of body fluid from the vascular compartment or its abnormal retention in the tissue.

2.

–Enclosed space

–Lack of lymphatics

–Lack of anastomoses in venous drainage

19
Q
  1. When does vasogenic edema occur?
  2. How does it occur? 3
  3. What causes the swelling?
  4. Plasma filtrate accumulation alters what? 2
A
  1. Occurs when the blood-brain barrier is upset

2.

–Inflammation due to infection

–Toxic agents that damage capillary endothelium

–Abnormal capillaries associated with malignant neoplasm

  1. Leakage of proteins fluid into interstitium

4.

  • ionic balance
  • impairs function
20
Q
  1. Cytotoxic edema is what kind of phenomenon?
  2. What can cause this? 2
A
  1. Intracellular phenomenon
  2. Hypoxia or toxic substances
21
Q
  1. What would cause hypoxia and eventually cytotoxic edema? 4
  2. Toxic substances that cause cytotoxic edema do this how? 2
A

1.

–Cardiac arrest

–Near drowning

–Strangulation

–Focal edema due to blockage of an end artery

2.

–Impair sodium/potassium pump

–Impair production of ATP

22
Q
  1. How should we treat cytotoxic edema?
  2. How should we treat vasogenic?
A
  1. can give I.V. bolus of a hypertonic solution such as mannitol to draw water into the vasculature and out of the brain
  2. If the cause is vasogenic would this help?

No! would draw fluid into interstitial space and increase swelling!!

  • Corticosteriods
  • Diuretucs
23
Q
  1. What is the normal intracranial pressure?
  2. What could intracranial pressure IICP? 4
A
  1. Normal intracranial pressure is 5-15 mm Hg
  2. May be due to:

–Tumor growth

–Edema

–Excess cerebrospinal fluid

–Hemorrhage

24
Q
  1. Contents of the Cranium 3
  2. An increase in any of these increases what?
A

1.

  • Tissue of the Central Nervous System
  • Cerebrospinal Fluid (CSF)
  • Blood
  1. An increase in any one of these increases intracranial pressure.
25
Q

Clinical hallmarks of IICP?

3

A

•Clinical hallmarks of IICP:

  1. Headache
  2. Vomiting
  3. Papilledema – swelling of the optic discs
26
Q
  1. Since the brain is encased in the cranium, the only way pressure can be relieved is by what?
  2. What is most readily displaced?
A
  1. decreasing cranial contents
  2. Most readily displaced in CSF
27
Q
  1. If ICP still high, cerebral blood volume is altered. This happens in stages. What is Stage I? 2
  2. What kind of symptoms do you see?
A
  1. Stage 1

– vasoconstriction and

–external compression of the venous system

  1. Compensating, so few symptoms
28
Q

If ICP continues to increase, may exceed brain’s ability to adjust. Stage 2:

1.

  • IICP (gradually rising) causes a decrease of what?
  • Systemic vasoconstriction occurs to increase what?
    2. Clinical manifestations transient? 4
A

1.

  • a decrease of oxygenation of neural tissue
  • blood pressure to get blood to brain

2.

  • episodes of confusion
  • restlessness
  • drowsiness
  • slight pupillary and breathing changes
29
Q
  1. When do you start gettiing a lack of compensation and start decompensating?
  2. Clinical presentation? 6
  3. Treatment?
A
  1. When ICP begins to equal arterial pressure

2.

  • Hypoxia and hypercapnia → cytotoxic edema
  • Decreasing levels of arousal
  • Widened pulse pressure
  • May begin Cheynes-Stokes respirations
  • Bradycardia – due to increased pressure in carotid arteries
  • Pupils small and sluggish
  1. Surgical or medical intervention needed
30
Q

When all compensatory mechanisms have been exhausted:

•Stage 4:

  1. How would you describe the timeline in the rise in ICP?
  2. Autoregulation is lost so what do we get? 2
  3. The decrease in cerebral perfusion leads to what? 2
  4. Brain contents shift (herniate) from where to where?
A
  1. Dramatic rise in ICP in a short time

2.

  • vasodilation,
  • further increasing intracranial volume

3.

  • severe hypoxia
  • acidosis
    4. Brain contents shift (herniate) from area of high pressure to areas of lower pressure ↓ blood flow
31
Q
  1. In Stage 4 of IICP what will develop?
  2. Ipsilateral pupil dilation and fixation progresses to what?
  3. When does cerebral blood flow cease?
A
  1. Small hemorrhages develop
  2. progressing to bilateral fixed and dilated pupils
  3. When mean systolic arterial pressure equal ICP
32
Q

What makes up the cerebral circulation’s arterial supply?

6

A
  1. Anterior cerebral artery
  2. Middle cerebral artery
  3. Internal carotid artery (70%)
  4. Posterior cerebral artery
  5. Basilar artery
  6. Vertebral artery

(5 and 6 make up 30%)

33
Q

Function of the blood brain barrier?

3

A
  1. Low # of brain infections
  2. Protection from circulating amino acids and other molecules that might act as neurotransmitters
  3. Protection Drugs and Antibiotics
34
Q

What are the three components that make up the BBB?

What are the cells that also help regulate migration into the brain? 2

A

1.

  • Tight junctions
  • Endothelial cell
  • Basement membrane
    2. Astrocytes and Microglia
35
Q

Classification of
Somatic Sensations

3

A
  • Mechanoreceptive - stimulated by mechanical displacement
  • Thermoreceptive
  • Nociceptive
36
Q

What are the two kinds of mechanoreceptive sensations?

A
  1. Tactile
  2. position or proprioceptive
37
Q

What are the types of sensory receptors?

9

A

See Picture

38
Q

Posterior column–medial lemniscus pathway is asensory pathway of the central nervous system that conveys localized sensations of what? 4

A
  1. fine touch,
  2. vibration,
  3. two-point discrimination, and
  4. proprioception (position sense) from the skin and joints.
39
Q

Describe the route of the dorsal coulmn-medial lemniscal pathway? 4

A

See picture

Pons > Midbrain > Thalamus >Primary somatosensory cortex

40
Q

The ventral spinocerebellar tract conveys what information where?

A

proprioceptive information from the body to the cerebellum.

41
Q
  1. The spinothalamic tract is a sensory pathway originating where?
  2. It transmits information to the thalamus about what? 4
A
  1. spinal cord

2.

  • pain,
  • temperature,
  • itch
  • crude touch.
42
Q

What do the pyramidal tracts control?

A

motor nerves of the face (corticobulbar tracts) and body (corticospinal tracts)

43
Q

What does the rubrospinal tract control?

A

Voluntary movement/Large muscle movement

44
Q
  1. What do the Neospinothalamic tracts control?
  2. Paleospinalthalamic tract?
A
  1. Fast pain fibers
  2. Slow pain fibers
45
Q

Where is the highest level of the CNS that reflex actiity goes?

A

spinal cord

46
Q

What are the 5 steps in the reflex pathway ?

A
  1. Receptor
  2. Sensory neuron
  3. Integration center (interneuron)
  4. Motor neuron
  5. Effector
47
Q

Describe the stretch relfex pathway 3

A

See picture

48
Q

Signs of Upper Motor Neuron Lesions (UMNL)

7

A
  1. Paralysis or weakness of movements of the affected side but gross movements may be produced. No muscle atrophy is seen initially but later on some disuse atrophy may occur.
  2. Babinski sign is present: The great toe becomes dorsiflexed and the other toes fan outward

in response to sensory stimulation along the lateral aspect of the sole of the foot. The normal response is plantar flexion of all the toes.

Babinski Reflex

  1. Loss of performance of fine-skilled voluntary movements especially at the distal end of the

limbs.

  1. Superficial abdominal reflexes and cremasteric reflex are absent.
  2. Spasticity or hypertonicity of the muscles.
  3. Clasp-knife reaction: initial higher resistance to movement is followed by a lesser resistance
  4. Exaggerated deep tendon reflexes and clonus may be present.
49
Q

Signs of lower motor neuron lesions

8

A
  1. Flaccid paralysis of muscles supplied
  2. Atrophy of muscles supplied
  3. Loss of reflexes of muscles supplied
  4. Muscle fasciculations
  5. Muscle fibrillation
  6. Muscle contracture
  7. Presence of muscle wasting
  8. Reaction of degeneration to response to electrical stimulus
50
Q

Describe the length of the preganglionic axons and postganglionic axons in the sympathetic and parasympathetic divisions of the ANS?

Which axons are myelinated?

A
  1. Sympathetic = short pre, long post

Parasympathetic = long pre, short post

  1. Somatic