Week 2 - Nervous System Structure Flashcards

1
Q

Types of receptors

A

Thermoreceptors- change in temp
Mechanoreceptors- mechanical pressure or distortion
Chemoreceptors- chemical change
Photoreceptors- Light

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2
Q

2 parts of nervous system

A
  1. The central nervous system (CNS)
    Includes the brain and spinal cord
    Functions: integrates and coordinates the
    processing of sensory data and the transmission
    of motor commands. Coordinates higher functions.
  2. The peripheral nervous system (PNS)
    Includes all neural tissue outside the CNS
    Functions: Deliver sensory information to the CNS.
    Carry motor commands to peripheral tissues and
    systems
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3
Q

Organisation of nervous system

A

Receptors - special sensory receptors monitor smell taste vision balance and hearing. Visceral sensory receptors monitor internal organs. Somatic Sensory receptors monitor skeletal muscles, joints, and skin surface.
CNS
PNS - Includes Somatic and Autonomic Nervous systems. ANS has sympathetic and parasympathetic divisions.
Effectors- Skeletal muscle (SNS), Smooth muscle,cardiac muscle, glands, adipose tissue(ANS)

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4
Q

4 Types of neurons

A

Axonic
Bipolar
Unipolar
Multipolar

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5
Q

Describe anaxonic neurons

A

Found in brain and special sense organs, very small. No anatomic features that distinguish dendrites from axon, functions not fully understood.

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6
Q

Describe Bipolar neurons

A

Have 2 processes, 1 dendrite and 1 axon with cell body between them.
Rare
Occur in special sense organs.

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7
Q

Describe Unipolar Neurons

A

Dendrites and axon are continuous, cell body lies off to one side.
Most sensory neurons of PNS are unipolar.

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8
Q

Describe Multipolar neurons

A

2 or more dendrites and one axon
Most common neurons in CNS
All motor neurons that control skeletal muscle are multipolar.

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9
Q

Describe the spinal chord.

A

Major Passageway of sensory and motor impulses to/from the brain.
Integrates information on its own and controls spinal reflexes and automatic motor responses.
Consists of 31 segments.
Each segment contains a pair of dorsal root ganglia, containing the cell bodies of sensory neurons.
Dorsal rootsbring sensory info to SC
A pair of ventral roots contain axons of motor neurons.
Sensory(dorsal) and motor(ventral) roots are bound together into a single spinal nerve.

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10
Q

Sectional anatomy of the spinal chord

A

Gray Matter - contains cell bodies and neuroglia(glial) cells.
White matter - contains myelinated and unmyelinated axons.
Horns - projections of grey matter.

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11
Q

Describe spinal nerves

A

31 pairs of SN are grouped according to the region of the vertebral column where they originated.
Each pair of SN monitors a specific region of the body surface known as a dermatome.
Damage of a spinal nerve or of dorsal root ganglia produces a characteristic loss of sensation in the corresponding region of the skin.

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12
Q

Describe a reflex arc

A

Stimulus
Sensory neurons activated
Relayed to motorneuron skipping cns
Activation of motor neuron
Effector responds

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13
Q

Describe muscle spindles

A

highly specialised encapsulated muscle fibres(intrafusal) positioned parallel to normal muscle fibres
(extrafusal).

Sensitive to changes in muscle length
Afferent neuron wraps around the muscle spindle
Efferent neuron (Gamma) cause muscle spindles to
contract to maintain tension in middle of the fibres
Hence if muscle is stretching rapidly, a vigorous
contraction is caused to prevent overstretching

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14
Q

Describe 3 parts of brain

A

 Reptilian Brain - brain stem
 Mammalian Brain - the limbic system
 Higher Brain - neocortex (cerebral cortex), which sets us apart from
ALL other animals

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15
Q

What are the 6 regions of the brain

A

Cerebrum
Diancephalon (Thalamus and Hypothalamus)
Cerebellum
Midbrain(Mesencephalon)
Pons
Medulla oblongata

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16
Q

Cerebrum Function

A

• Conscious thought processes,
intellectual functions
• Memory storage and processing
• Conscious and subconscious regulation
of skeletal muscle contractions

17
Q

Cerebellum Function

A

• Coordinates complex
somatic motor
patterns
• Adjusts output of
other somatic motor
centers in brain and
spinal cord

18
Q

Function of Diancephalon

A

Thalamus
• Relay and processing
centers for sensory
information

Hypothalamus
• Centers controlling
emotions, autonomic
functions, and
hormone production

19
Q

Mensencephalon function

A

• Processing of visual
and auditory date
• Generation of reflexive
somatic motor
responses
• Maintenance of
consciousness

20
Q

Pons Function

A

• Relays sensory
information to
cerebellum and
thalamus
• Subconscious
somatic and visceral
motor centers

21
Q

Medulla Oblongata function

A

• Relays sensory information to thalamus and
to other portions of the brain stem
• Autonomic centers for regulation of visceral
function (cardiovascular, respiratory, and
digestive system activities)

22
Q

Describe Cerebral Cortex

A

Frontal Lobe - voluntary motor activity, speech, Elaboration of thoughts. Has precentral gyrus.
Parietal Lobe - Receiving and processing sensory information.
Occipital Lobe - Initial processing of visual.
Temporal lobe - Initial reception of audio/auditory.

23
Q

How is the brain protected and supported

A

Physical - Bones of cranium, cranial meninges, cerebrospinal fluid
Biochemical Isolation - Blood-brain barrier: isolation of CNS from general circulation through variation in permeability of CNS capillaries (Astrocytes)

24
Q

3 layers of cranial meninges

A

Dura mater
Arachnoid mater
Pia mater
Protects brain from cranial trauma

25
Q

Describe Cerebrospinal fluid

A

Surrounds all exposed surfaces of CNS
Interchanges with interstitial fluid of brain.
Functions: Cushion, support, transport of nutrients and chemical messengers and waste products.

26
Q

What are the 12 cranial nerves?

A
  1. Olfactory
  2. Optic
  3. occulomotor
  4. Trochlear
  5. Trigeminal
  6. Abducens
  7. Facial
  8. Vestibulocochlear
  9. Glossopharyngeal
  10. Vagus
  11. Accessory
  12. Hypoglossal