6.5 Neurones and Synapses

Question 1

Neurons transmit electrical impulses. What are the two systems that are used for these internal communications?

Answer 1

1) endocrine system = glands that release neurons
2) nervous system = nerve cells called neurons that transmit ner impulses (which are electrical signals

Question 2

Where in neurons do nerve impulses travel from?

Answer 2

• they travel from nerve fibres
  - dendrites = short branched fibers that transmit impulses between nuerons on one part of the prain or spinal cord
  - axon = elongated nerve fibers that transmit impulses from tips of the toes or fingers to the spinal cord

Question 3

State the structure of nerve fibers.

Answer 3

• cylindicular in shape
• plasma membrane enclosing narroe region of cytoplasm
• about 1 um in diameter, conducts nerve impulses 1 m/s

Question 4

Explain and describe myelin.

Answer 4

• myelin, which consists of many phopholipd bilayers, coats the length of some nerve cells
• Schwann cells deposit myelin by growing round and round the nerve fiber, each time they grow they grow and create a double phospholipid bilayer

Question 5

What is saltatory connection?

Answer 5

• in mylinated nerve fibers, nerve impulses can jump from one node of Ranvier to the next (much faster than unmylinated nerve fibers)

Question 6

What is the node of Ranvier?