The brain and behaviour Flashcards
Describe neurons
Neurons are the basic building blocks of the nervous system
Describe dendrites
Dendrites are specialised receiving units, like antennae, that collect messages from neighbouring neurons and send them onto the cell body
Describe axons
Axons conduct, electrical impulses away from the cell body to other neurons, muscles or glands
Describe glial cells
Glial cells do not send or receive nerve impulses. They manufacture, chemicals that provide nutrients neurons, need and absorb toxins and waste materials that can damage neurons.
Describe resting potential
Resting potential is the uneven distribution of positive and negative ions that make the interior of the cell negative compared to the outside. This internal difference of around 70 mV is the neurons resting potential
Describe action potential
Action potential is an electrical shift within the neuron that lasts a millisecond that creates a nerve impulse
Describe absolute refractory period
The membrane is not excitable and cannot discharge another impulse
Define the all or non law
Action potentials occur at a uniform and maximum intensity, or they do not occur at all
Define graded potentials
Changes in the negative resting potential that do not reach the -50 mV action potential threshold
Describe the Myelin sheath
A white fatty insulation layer derived from glial cells during development
Describe synaptic space
A tiny gap between the axon terminal and the dendrites, or cell body of the next neuron
Describe neurotransmitters
Chemical substances that carry messages across the synaptic space to other neurons, muscles or glands
What are synaptic vesicles?
Chambers within the axon terminals used to store synthesised neurotransmitters
Explain receptor sites
Large protein molecules embedded in the receiving neurons cell membrane. Each site has a specifically shaped surface that fits a specific transmitter molecule
Explain reuptake
Reuptake is, when the transmitter molecules are taken back into the presynaptic, axon terminals
What is acetylcholine?
A neurotransmitter involved in muscle activity and memory
Describe the function of a neuro modulator?
Neuro modulators have a more widespread and generalised influence on synaptic transmission
Describe the three primary effects of an agonist drug
An agonist drug increases the activity of a neurotransmitter by enhancing a neurons ability to synthesise store, or release neurotransmitters; mimic the action of a neurotransmitter, by binding, with and stimulating, postsynaptic receptor sites; or making it more difficult for neurotransmitters to be deactivated, such as by inhibiting reuptake
What are the primary effects of an antagonist drug?
Antagonist drugs inhibit, or decrease the action of a neurotransmitter. And antagonist may reduce a neurons ability to synthesise store or release neurotransmitters; or prevent a neurotransmitter from binding with the postsynaptic neuron by fitting into and blocking receptor sites on the postsynaptic neuron.
Describe the function of sensory neurons
Sensory neurons carry input messages from the sense organs to the spinal-cord and brain.
Describe the function of motor neurons
Motor neurons transmit output impulses from the brain and spinal cord to the bodies, muscles and organs
Describe the function of interneurons
Interneurons outnumber sensory and motor neurons and perform connective or associative functions within the nervous system