Nervous system

Question 1

Three types of Neurons

Answer 1

• Sensory neurons
• Interneurons
• Motor neurons

Question 2

Glial Cells

Answer 2

• Outnumber neurons 10 to 1
• Support and nourish neurons
• Remove waste
• Make the Shwann cells

Question 3

Sensory Neurons

Answer 3

• Gather information from sensory
  receptors and transmit the impulses
  to the CNS
  eg: Photoreceptors (Eyes), Chemoreceptors (Nose, olfactory receptors)

Question 4

Interneurons

Answer 4

• Found only in CNS
• Act as link between sensory and motor neurons
• Process and integrate incoming sensory info and
  relay outgoing motor info

Question 5

Motor Neurons

Answer 5

• Transmit information from CNS to muscles, glands, and other organs

Question 6

Neuron Structure

Answer 6

Each type of neuron has a different shape,
but there are some common parts:
* Dendrites
* Cell body (soma)
* Axon
* Myelin sheath
* Schwann cells
* Node of Ranvier

Question 7

White matter

Answer 7

• In CNS neurons that are
  myelinated are called white
  matter

Question 8

Grey matter

Answer 8

• In CNS neurons that are
  NOT myelinated are called
  grey matter
• No myelin so cannot repair
  itself so damage is
  permanent

Question 9

Neural Pathway

Answer 9

1. Sensor recognizes stimulus
2. Sensory neuron carries impulse to spin al cord (CNS)
3. Interneuron selects appropriate response circuit
4. motor neuron carries impulse away from spinal cord
5. Effector muscle produces response

Question 10

Reflex arc

Answer 10

• Simplest neural pathway fewer neurons involved,
• Impulse travels through
  spinal cord and out to effector
• Involuntary/ no conscious control
• Response is innate (automatic)

Question 11

Threshold

Answer 11

• -55mV
• Needs to reach threshold before a nerve responds to stimulus

Question 12

resting potential

Answer 12

• -70mV

Question 13

Depolarization

Answer 13

Voltage going up, nerve responding tto the stimulus after crossing threshold

Pottasium channels close and sodium channels open

Question 14

Action potential

Answer 14

Maximum voltage

Question 15

Repolarization

Answer 15

Voltage going down, nerve resetting

Sodium channels close, pottasium channels reopen

Question 16

Refractory period

Answer 16

Voltage goes below -70mV, preparing for another stimulus, then returning to resting potential

unable to react