Wk 8 Flashcards

The Nervous System

1
Q

What are the functions of the nervous system?

A
  • response to stimuli
  • integration of body processes
  • control/mediation of voluntary effectors (skeletal muscle)
  • control/mediation of involuntary effectors (smooth muscle, cardiac muscle, glands, heart rate, BP)
  • responsible for conscious thought, perception, emotions, personality, mind
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2
Q

What are the different functional classes of neuron?

A
  • sensory (afferent); towards CNS
  • motor (efferent); away from CNS
  • interneurons; connect neurons in CNS pathway
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3
Q

What is the structure of a sensory neuron?

A
  • cell body has no dendrites and presynaptic inputs
  • located adjacent to spinal cord
  • sensory receptor is end of axon
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4
Q

What is the structure of a motor neuron?

A
  • cell bodies situated in CNS
  • receive many inputs that influence outputs to other organs
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5
Q

What is the structure of an interneuron?

A
  • entirely within CNS
  • more complex the action the more interneurons required
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6
Q

How are the peripheral nerve fibres classified?

A

Group A
Group B
Group C

*Structure effects conductance velocity

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7
Q

What is Group A?

A
  • large diameter
  • highly myelinated
  • transmit up to 150m/s (fastest)
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8
Q

What are the subgroups of Group A?

A

A alpha - somatic motor neurons, proprioceptor sensory neurons

A beta - sensory neurons for touch, pressure

A c - motor neurons to muscle spindles

A delta - some thermal and pain sensory neurons

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9
Q

What is Group B?

A
  • intermediate diameter
  • lightly myelinated
  • transmit up to 15m/s
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10
Q

What is Group C?

A
  • smallest diameter
  • unmyelinated
  • transmit up to 1m/s
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11
Q

What is a reflex arc?

A

An involuntary response to a stimulus (does not pass through brain - only neurons and spinal cord).

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12
Q

What are the components of a reflex arc?

A
  1. Sensory receptor - site of stimulus action
  2. Sensory neuron - transmit afferent impulses to CNS
  3. Integrating centre - within CNS
  4. Motor neuron - efferent impulses integration centre –> effector organ
  5. Effector - responds to efferent impulses
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13
Q

What are the 4 major regions of the brain?

A
  1. Cerebrum
  2. Diencephalon (thalamus, hypothalamus)
  3. Brain stem (midbrain, pons, medulla)
  4. Cerebellum
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14
Q

What is the primary function of the cerebrum?

A
  • controls conscious thoughts and actions
  • largest part of brain
  • divided into temporal lobe, occipital lobe, parietal lobe, frontal lobe
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15
Q

What is the primary function of the diencephalon?

A

Thalamus
- relay station for sensory impulses

Hypothalamus
- homeostasis
- regulates autonomic function, body temp, fluid balance, hormone release

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16
Q

What is the primary function of the brainstem?

A
  • includes the midbrain, pons, medulla oblongata
  • control of cardiovascular system, respiratory rhythm
  • vision/hearing
  • consciousness, sleep/wake cycles
17
Q

What is the primary function of the cerebellum?

A
  • coordinates balance/posture
  • automatic processing centre
  • programs ongoing movements
18
Q

What are the two divisions of the peripheral nervous system (PNS)?

A
  1. Sensory (afferent)
  2. Motor (efferent)
19
Q

What are the two systems of the motor division?

A
  1. Somatic nervous system
  2. Autonomic nervous system
20
Q

What are the functions of the somatic nervous system?

A
  • supplies skeletal muscle
  • CNS –> effector
  • Release ACh to activate nicotinic receptors
21
Q

What are the functions of the autonomic nervous system?

A
  • supplies smooth, cardiac muscle and glands
  • regulates internal environment
  • operates without conscious control
22
Q

What are the two divisions of the autonomic nervous system?

A
  1. Sympathetic
  2. Parasympathetic
    *Antagonistic (opposite effects)
23
Q

What is the sympathetic system?

A
  • fight or flight
  • associated with fear or stress
  • releases NE
    E.g. blood vessels, sweat glands, adrenal medulla
24
Q

What is the parasympathetic system?

A
  • rest and digest
  • associated with housekeeping & conserving energy
  • releases ACh
    E.g. food digestion, pooing
25
Q

What is monosynaptic?

A

A direct single synapse (no interneuron).

26
Q

What is polysynaptic?

A

One or more interneurons connect sensory and motor signals.

27
Q
A