Chapter 5 - Nerve Cells and Nerve Impulses Flashcards
What are the two parts of the nervous system?
Central Nervous System and the Peripheral nervous system
What is the central nervous system and what does it consist of?
Its the control centre of the whole nervous system and contains the brain and spinal cord
What is the peripheral nervous system made up of?
Nerves that connect the central nervous system with receptors, muscles and glands
What do axons do?
Carry nerve impulses away from the cell body
What do myelinated fibres have?
They have a myelin sheath
What are neurotransmitters?
A molecule that carries a nerve impulse across the small gap between branches of adjacent nerve cells
What is a synapse?
The junction between the branches of adjacent neurons
What are nerve impulses?
Messages that travel along nerve fibres
What do nerve impulses do?
Transmitted quickly making the body respond rapidly to any change
What is an electrochemical change?
Change in the electrical voltage brought about by changes in the concentration of ions
Unmyelinated fibres..:
Travel steadily along the fibre
Why do myelinated nerves travel faster
Due to saltatory conduction
What does extracellular fluid contain?
High concentration of sodium chloride
What does intracellular fluid contain?
Low concentration potassium
What is resting membrane potential?
The membrane potential of unstimulated nerve cells
What is the nervous system?
Is the commnication network and control centre - maintains homeostasis
What does the term polarised mean?
When the inside of the membrane of nerve cells is negatively charged
What does the term depolarised mean?
When there is no difference in electrical charge between the inside and outside of the membrane
What is the all or none response
A response of constant size regardless of the strength of the stimulus
What is action potential?
When sodium ions move into a nerve cell at a particular place on the membrane
What is a refractory period?
A short period following a stimulus during which a nerve cell cannot be stimulated
What are interneurons?
Have branches/ send and receive messages from the neuron
What is grey matter
Consists of nerve cell bodies
Unmyelinated fibres
What is white matter?
Consists of myelinated fibres
