IB Neurone Structure Identification/ Function

What does structure X represent in a neurone?

• Axon

• Myelin sheath

• Cell body

• Dendrite

What does structure Y represent in a neurone?

• Axon

• Myelin sheath

• Cell body

• Dendrite

What does structure Z represent in a neurone?

• Axon

• Myelin sheath

• Cell body

• Dendrite

What is the role of dendrites in the nervous system?

• Store energy for the neuron

• Transmit nerve impulses between neurons

• Protect the neuron from damage

• Produce neurotransmitters

Which of the following describe the structure of Y from the image

• Contains a single layer of phospholipid bilayer

• Grows around the neuron/axon

• Gaps between each cell

• Produces hormones

• Containes Many layers of phospholipid bilayer

It has been estimated that a neurone without structure Y present can conduct nerve impulses at speeds of 0.5 m/s whereas a neurone with structure Y present can conduct impulses at speeds of 150 m/s.

How many times faster is impulse conduction in the presence of structure Y compared to without it?

• 10 times faster

• 100 times faster

• 300 times faster

• 150 times faster

The graph below shows changing membrane potential in an axon within a human leg.

Identify the type of membrane potential present in the axon at 0.5 ms.

• Resting potential

• Action potential

• Threshold potential

• Hyperpolarization

Tags

NGSS.HS-PS2-5

Explain how the resting membrane potential has been achieved.

• By the influx of sodium ions

• By the efflux of potassium ions

• By the sodium-potassium pump maintaining ion gradients

• By the influx of calcium ions

Resting potential is achieved by...

• Sodium-potassium pumps using ATP to move ions across the membrane

• Sodium ions diffusing into the cell faster than potassium ions

• Positively charged proteins inside the axon

• Equal movement of sodium and potassium ions

Identify structure A in the diagram of a junction between two neurons.

• Synaptic cleft

• Presynaptic knob

• Postsynaptic cell

• Vesicle