Nerve transmission Flashcards
neuron function
receive and send info to other cells
glia function
supports neurons in their functions
What is the cell body (soma) made up of?
Nucleus, ribosomes , mitochondria
describe dendrites
branching fibres , receive info via synaptic receptors
What is an axon?
thin fibre of constant diameter, information sender of the neuron
what is the myelin sheath
insulates axon, nodes of ranvier are interruptions in the myeline sheath
what is the presynaptic terminal ?
point from which axon transmits info
axons can be ______ or ________
afferent or efferent
What is an afferent axon?
afferent brings info to a structure e.g sensory neuron
What is an efferent axon?
efferent carries info away e.g motor neuron
what is temporal summation?
repeated stimuli , excitation follows the first excitation and then the combination exceeds the threshold of the postsynaptic neuron producing an action potential.
what is spatial summation
summation over space , inputs from different places combine their effects on a neuron
what is inhibition?
an active brake that suppresses excitation
what did Loewi conclude?
concluded nerves send messages by releasing chemicals
what is exocytosis ?
bursts of release of neurotransmitters from the presynaptic neuron
how do drugs work?
drugs act by binding to receptors such as nicotine and opiate drugs (morphine, heroin)
- endorphins is a natural neuropeptide - opiate drugs bind to the same receptors as endorphins
what are neuropeptides? what are they useful for?
neuropeptides are a special type of neurotransmitter , they are synthesised in the cell body .
How are neurotransmitters inactivated?
being broken down by enzymes into fragments or reuptake
what is a gap junction?
pores always open (when one neuron membrane comes into direct contact with the membrane of another
hormone definition
a chemical secreted by cells in one part of the body and conveyed by the blood to influence other cells
