SB2g The Nervous System Flashcards
What makes up the central nervous system (CNS)?
The brain and spinal cord
What makes up the nervous system?
Brain, spinal cord and nerves
What are impulses?
Electrical signals in the nervous system that the body uses to communicate
What is the sciatic nerve
The thickest nerve connecting the heel and the spinal cord
How long is the spinal cord in adults?
43 - 45 cm
What is the vertebra
24 bones which form the backbone and protect the spinal cord
What is a stimulus?
Anything your body is sensitive to and causes an electrical impulse
What are receptor cells?
Cells in sense organs like eyes and ears that receive the electrical impulse
What is a response?
Your reaction the the stimulus
In which sense organ would you find receptor cells that detect changes in light?
Eyes
What is neurotransmission?
The travelling or transmission of impulses
What do neurones have to carry impulses?
A cell body and long extensions
What is the function of a sensory neurone?
It’s function is to carry impulses from receptor cells toward the central nervous system
What is a dendrite?
A tiny branch in a neurones that receives impulses from receptor cells
What do axon terminals do?
Pass impulses to other neurones
What is the direction the impulse travels in a sensory neurone?
From the dendron to the axon
What are the two extensions of a sensory neurone called?
Dendron and axon
What is the pathway of a nerve impulse?
- Stimulus causes the impulse
- impulses detected at receptor cells
- passes along sensory neurone
- impulse travels to CNS
- Impulse passes along motor neurone
- effector receives impulse
- Response in triggered
Why are dendrons and axons long?
To allow fast neurotransmissions over long distances
What is the myelin sheath?
A fatter layer surrounding the dendron and axon
What is the function of the myelin sheath?
to electrically insulate the neurone from neighbouring neurones to prevent energy loss in the signal, and speeds up neurotransmission by making the impulse jump along the cell between gaps in the myelin
