Module 5 - Chapter 13 Flashcards Preview

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Flashcards in Module 5 - Chapter 13 Deck (18)
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Why is coordination important in the nervous system?

To maintain a constant internal environment


How is the nervous system coordinated?

Cell signalling coordinates cellular activities


What is the function of neurones?

To conduct and process information: thought perception, and control of movement


What type of signal do neurones send in the nervous system send?

Electrical (action potential)


What type of signal is in the blood in the endocrine system?

Chemical (hormones)


What is the speed of signals in the nervous system compared to in the endocrine system)?

Faster in the nervous system


What is the type of action/response in the nervous system?

It can be voluntary or involuntary


What is the type of action/response in the endocrine system?

It’s always involuntary


What is the target of the signal in the nervous system?

Localised (the cells connected to the neurone)


What is the target of the signal in the endocrine system?

The target is often distant (many cells are effected)


What are the key features of neurones?

cell body, dendrons, axons


Describe the cell body in neurones

•contain DNA located in a nucleus
•contain rough endoplasmic reticulum and mitochondria

•these are in abundance for neurotransmitter production by ribosomes


Describe the dendrons in neurones

They input synapses by receiving signals from axons and carry impulses towards the cell body


Describe the axons in neurones

Signals are taken away from the cell body (a for axon = away)

Axons can be very long - for example the sciatic nerve from the toes to the spine

However they are only 1 micrometre in diameter


List the structures in a typical neurone

Dendrites, nucleus, cell body, axon, myelin sheath, Schwann’s cells, Nodes of Ranvier, axon terminals


What are Nodes of Ranvier?

The gaps between the Schwann cells on the axon/dendron

Not a structure (a gap) so don’t label as a structure if asked to so specifically


Describe the myelin sheath in neurones

•made of many layers of cell membranes of Schwann cells - a double layer of phospholipid bilayer is established each time

•there are 20 layers of membranes

•myelin is a lipid


What happens if the myelin sheath breaks down?

It degenerates so the impulses are slower and there is a lack of insulation

Myelinated neurones have an impulse speed of 100m/s but unmyelinated = 1 m/s