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Bpk 142 > Neural control and movement > Flashcards

Neural control and movement Flashcards

1
Q

Divisions of the nervous system

A

Central nervous system (CNS)
1) Brain
Newer more sophisticated regions are piled on top of older, more primitive regions
a) Forebrain
(i) Cerebrum constitutes about 80% of total
brain weight - cerebral cortex, basal nuclei
(ii) Diencephalon - thalamus, hypothalamus
b) Cerebellum
c) Brainstem - continuous with the spinal cord - medulla, pons, midbrain

2) spinal cord
- long cylinder of nerve tissue which extends down from the brain stem to the second lumbar vertebrae. 45 cm long and 2 cm in diameter. Protected by the vertebral column and associated ligaments and muscles, the spinal meninges and the cerebrospinal fluid.

Peripheral Nervous System (PNS)
consists of 12 pairs of cranial nerves and 31 pairs of spinal nerves
1) afferent division
2) efferent division (somatic nervous system AND autonomic nervous system)
- sympathetic division
- parasympathetic division

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2
Q

Afferent division

A

nerve fibres responsible for bringing sensory information back to the CNS

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3
Q

Efferent division

A

Somatic nervous system
- nerve fibres that innervate skeletal muscle

Autonomic nervous system
- nerve fibres that innervate smooth muscle, cardiac muscle and glands
–> sympathetic (fight or flight) and parasympathetic (rest and digest)

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4
Q

Neurologia

A
  • comprised about 90% of cells in CNS
  • occupy 1/2 of the volume of the brain
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5
Q

Glial cells

A

there are 4 major types of glial cells that serve as connective tissue of the CNS which help support the neurons physically and metabolically

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6
Q

Neuron

A

A nerve cell specialized to transmit electrical signals/ pass messages from one part of the body to another.

Consists of:
- cell body
- axon
- dendrites

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7
Q

Cell body

A

soma, contains nucleus

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8
Q

Axon

A

a long fiber that conducts impulses away from the cell body
can be known as “nerve fiber”

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9
Q

Dendrites

A

Short projections from the cell body that transmits impulses toward the cell

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10
Q

Myelin sheeth

A

discontinuous sheath around the axon, primarily composed of lipids and proteins
- myelinated nerve fibres have a much faster conduction velocity than unmyelinated fibers

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11
Q

Nodes of ranvier

A

the spaces in between the segments of myelin sheath

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12
Q

synapse

A

the connection of an axon of one nerve to the cell body or dendrites of another nerve

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13
Q

Multiple sclerosis

A

Autoimmune disease where the body attacks myelin sheath
- break down in communication
- exposed nerves can be destroyed irreversibly
- fatigue

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14
Q

Neurons can be divided into 3 functional classes

A
  1. Afferent neurons: carry impulses from sensory receptors into spinal cord and brain
  2. Efferent neurons: transmit impulses from CNS out to the effector organs - muscle (motor neurons, glands )
  3. Inter neurons. Lie entirely in the CNS, they account for 99% of nerve cells
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15
Q

Spinal nerve

A
  • actually a nerve trunk
  • it contains hundreds of afferent and efferent nerve fibers that are bound together w/ connective tissue sheaths
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16
Q

Resting membrane potential

A

Due to selective permeability characteristics of nerve cell fiber, a high potential difference exist inside and outside of nerve fiber. A high concentration of sodium ions outside of the nerve membrane causes it to be electrically positive and on the inside of the nerve membrane electrically negative

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17
Q

Action potential

A

An appropriate stimuli suddenly causes sodium ions to rush inside of the nerve —> reversal polarity
Once AP has started it spread along the entire length of the nerve fibre

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18
Q

Tetrodotoxin

A
  • blocks sodium channels
  • prevent AP in nerve cells
  • acts on CNS AND PNS
  • death wishing 4-6 hours
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19
Q

Nerve to nerve synapses

A
  • nervous informations relays across synaptic cleft by means of a chemical substance transmitter
  • transmitter substances can be other inhibitory or excitatory
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20
Q

What are the impacts of different transmitter substances

A

They are additive
1. Spatial - when multiple different inputs from different regions add together
2. Temporal- when the same input happens overtime fast enough to add up enough to cause an action potential

21
Q

Neuromuscular junction

A

Nerve to muscle synapse
The chemical transmitter substance: acetylcholine

22
Q

The spinal cord is enlarged in two regions for innervation of the limbs

A
  1. Cervical enlargement which extends from C4 through T1 segments of the spinal cord
  2. Lumbosacral enlargement which extends from T11 through L1 segments of the spinal cord
23
Q

Structure of spinal nerves

A

8-Cervical
12-thoracic
5-lumbar
5-sacral
1-coccygeal

24
Q

Plexus

A

A network of diverging and converging nerve fibers and blood vessels

25
Q

Brain and spinal cord are composed of…

A

White and grey matter

26
Q

Grey matter

A

The nerve cell body lie and constitute the grey matter

27
Q

White matter

A

Interconnecting tracts of nerve fibers form white matter

28
Q

What kind of fibres do the following have

a) dorsal roots
b) ventral roots

A

a) afferent (sensory) fibres that carry information from the periphery to the brain and spinal cord

b) efferent (motor) fibers to the skeletal muscle

29
Q

Where are the cell bodies of the motor axon making up the ventral roots located?

A

located in the ventral gray horns of the spinal cord

30
Q

Where are the cell bodies of the sensory axons making up the dorsal roots located

A

located outside of the spina cord in the spinal ganglia

31
Q

Ganglion

A

a collection of nerve cell bodies located outside the CNS

32
Q

Spinal cord injury

A

most often due to trauma to the spinal cord, but can be associated with congenital and degenerative disease.

33
Q

Transection

A

transection is complete cut of the spinal cord that results in loss of sensation and voluntary movement inferior to the point of damage

34
Q

If the cord is transected superior to C5

A

patient is quadriplegic

35
Q

What transection will cause the patient may cause the patient to die or have respiratory failure

A

if the transection is above C4

36
Q

A patient is paraplegic is the transection occurs where

A

if the transection occurs below the cervical segment of the spinal cord

37
Q

ischemia

A

a deficiency of blood supply to the spinal cord cause by fractures, dislocations, atherosclerosis

–> can lead to muscle weakness and paralysis

38
Q

proprioceptors

A

conduct sensory information to the CNS from muscles, tendons, ligaments and joints

39
Q

kinesthetic sense

A

gives information about the location of parts of our body in relation to their environment

40
Q

Muscle spindles

A

several modified muscle fibres, 4-10 millimeters in length, contained in a capsule with a sensory nerve spiralling down its center.

41
Q

Spindle fibers

A

lie parallel to the regular muscle fibers

42
Q

Function of muscle fibres

A

send information to the CNS regarding the degree of muscle stretch
- activation of the exact number of motor units to overcome a given resistance
- with increasing degree of stretch of the muscle spindles, frequency of impulse transmission up the afferent neuron to the spinal cord progressively increases

43
Q

3 ways that the muscle spindles can activate the alpha motor neurone to cause the muscle to contract

A
  1. Tonic stretch - concerned with the final length of the muscle
  2. phasic stretch - spindle responds to the velocity of the change of length
  3. Gamma system - gamma efferent fibers innervate the contractile ends of intrafusal fibers (when alpha motor neurone are activated so are gamma motor neuron)
44
Q

Stretch reflex

A

patellar tendon tap

45
Q

Golgi tendon organ (GTO)

A

Location: encapsulated in the tendon fibers near the junction of the muscle and the tendon fibers

  • approx 1 millimetre long and 0.1 millimetre in diameter
  • in series with muscle fibers rather than parallel as are the spindle fibers
  • when muscle contracts GTO is stretched
46
Q

The function of GTO

A

The firing rate of GTO is very sensitive to changes in tension of the muscle
- sensory input about the tension produced by the muscle is used in a variety of different motor acts such as maintaining a stable grip on an object
- when stimulated by excessive tension or stretch–> sensory information is sent to the CNS–>causes the contracted muscle to relax

47
Q

Joint receptors

A

supply information to the CNS regarding joint angle, acceleration of the joint, pain, and pressure

48
Q

Control of motor functions

A

the cerebral cortex and cerebellum are the main center employed in learning new motor skills. These areas of the brain initiate voluntary control of movement patterns

Bpk 142 (14 decks)

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