Unit 7: Movement and Nervous Systems Flashcards
What are the two parts of the nervous system?
- central nervous system
- peripheral nervous system
Peripheral Nervous System (2)
- nerves extending from the spinal cord
- nerves radiate from spinal cord and connect to tissue
Central Nervous System
brain and spinal cord
How does the nervous system communicate with the body? (2)
- nerve impulses are sent by the nervous system
- there are electrical impulses carried along neurons to target tissues
What does the body have interpret the outside world?
sensory receptors
What do sensory receptors detect? (5)
- heat
- pressure
- chemicals
- pain
- light
What does the sense of sight use to perceive things?
light
What does the sense of hearing use to perceive things? (2)
- vibrations
- changes in air pressure
What do the senses of smell and taste use to perceive things?
chemicals
What does the sense of touch use to perceive things?
pressure
What is the process of receiving information through receptors?
receptors send signals through sensory neurons to CNS through relay neurons
What is a response to a signal?
an action
Where are actions to stimuli sent to from the CNS?
motor neurons
Neuron
cell in the nervous system
What is function of a neuron?
sending and receiving information
Dendrites (2)
- projections from neurons that receive information
- because there are several dendrites, neurons can receive a lot of information at once
Axon (2)
- signal travels down
- covered in myelin
Myelin Sheath
discontinuous covering around the axon that speeds up the process of signal transmission
Nodes of Ranvier
non-myelinated areas of axon where signal transmission is slowed down
Diffusion
spreading of something
Facilitated Diffusion
still passive, but a channel is needed
Active Transport
require energy to move against gradient
Ion
charged molecule
Na-K Pump
pumps ions across a membrane
How are impulses transmitted in an axon during action potential?
through the reversal of charges on 2 sides of a membrane
How does the reversal of charges take place?
through the movement of ions
Where does a neuron have a negative charge?
on the inside
Action Potential (2)
- reversal of charges occurs and the impulse is transmitted
- arises due to differential concentrations of Na+ and K+
What is action potential measured in?
volts
How many steps are there in nerve impulse?
6
What are the stages of sending a nerve impulse? (6)
- Resting Potential
- Threshold
- Depolarization
- Repolarization
- Refractory Period
- Restoration
Resting Potential (4)
- both ion channels are closed
- resting potential is -70 mV
- the negative charge is due to unequal distribution of ions around membrane, no equilibrium
- ions want to move across because there is a gradient
Threshold (3)
- for something to happen there must be a strong enough threshold
- action potential arrives and Na+ and K+ gates open in response to voltage change
- critical voltage is -55 mV
Depolarization (3)
- sodium gates open quickly, allowing sodium into the cell
- sodium enters because there is more sodium on the outside vs. inside
- the charge of the membrane becomes positive
What type of diffusion happens in depolarization?
facilitated diffusion
Repolarization (3)
- sodium gates close and potassium gate open
- potassium gate are slower voltage gated channel, they open to allow K+ to flow out membrane
- restore charge to negative on the inside of the membrane
Refractory Period (3)
- Na+ gates are closed and K+ gates are closing
- K+ gates are slower to respond than Na+ gates
- the membrane potential goes lower than resting potential during this time, no new action potential can occur
Restoration (3)
- the Na-K pump restores the Na+ and K+ back to their original positions
- requires ATP
- for 1 ATP 3 Na+ is pumped out and 2 K+ are pumped in
Synaptic Transmission
the signal goes down the axon to the end of the neuron to be transferred
How are signals sent from neuron to neuron?
as an electrical signal
How are signals sent from neuron to organ or muscle?
the signal will be converted into a neurotransmitter
What is another word for action potential
nerve impulse
What is the process of Synaptic Transmission? (7)
- an action potential arrives at the end of the axon, called the synaptic knob. This is the pre-synaptic neuron
- The action potential opens Ca+ channels, allowing Ca+ to enter the cell. This triggers regulatory proteins to allow exocytosis to occur
- Neurotransmitter vesicles bind to the plasma membrane and release their contents into the synaptic gap
- Neurotransmitter cross gap and bind with receptor of the post-synaptic neuron
- Na+ channels are opened by neurotransmitters, and Na+ flows in and causes depolarization
- Action potential passes along post-synaptic neuron
- Ca+ is pumped out by active transport as the neurotransmitter is quickly broken. Na+ is also pumped out
