Lecture 22- The Nervous System Flashcards
Nervous system consists of
- circuits
- neurons
- supporting cells
Neurons
process and transmit information through electrical and chemical signals
action potential
rapid, temporary change in membrane potential
Membrane potential
Voltage difference across a cell membrane
Membrane potential results from ____
the unequal distribution of ions inside and outside the cell
Three phases of action potential
- depolarization phase
- repolarization phase
- Hyperpolarization phase
Depolarization phase
the initial change in the membrane potential, making the charge closer to 0
repolarization phase
returning the charge to the resting potential
hyperpolarization phase
charge becomes more negative that resting potential
resting potential
the normal negative charge of the membrane potential
if the depolarization phase doesn’t reach the _____ then no signal is sent
threshold potential
SImplest animals with nervous systems possess interconnected neurons arranged in _____
nerve nets
More complex animals have _____
nerves
Cephalization
the clustering of sensory organs at the front end of the body
Which type of animals exhibit cephalization?
bilaterally symmetrical
