Test 5 Review Flashcards
What is an action potential?
The action potential is the membrane potential of a neuron that is conducting an impulse.
What is an action potential commonly referred to as?
Nerve impulse.
What is membrane potential?
Slight excess of positively charged ions on the outside of the membrane and slight deficiency of positively charged ions inside of the membrane.
Difference in electrical charge between the outside and inside of the plasma membrane.
What is resting membrane potential?
Membrane potential maintained by a nonconducting neuron’s plasma membrane.
Typically -70mV.
What is refractory period?
Is a brief period during which a local area of an axon’s membrane resists restimulation.
What is the absolute refractory period?
Brief period during which a local area of a neuron’s membrane resists restimulation and will not respond to stimulus, no matter how strong.
Lasts approximately 0.5 milliseconds.
What is the relative refractory period?
Time during which the membrane is repolarizing and restoring the resting membrane potential.
Is a few milliseconds after the absolute refractory period, during which the membrane only responds to a very strong stimulus.
What is a synapse?
A membrane to membrane junction between a neuron and another neuron, effector cell, or sensory cell.
Functions to propagate nerve impulses.
How many types of synapses are there?
2.
What are the two types of synapses?
- Electrical
2. Chemical
Electrical synapses
Occur where cells joined by gap junctions allow an action potential to simply continue along postsynaptic membrane.
Where do some electrical synapses occur?
- between cardiac muscle cells.
- between some types of smooth muscle cells.
Chemical synapses
Occur where the presynaptic cells release chemical transmitters (neurotransmitters) across a tiny gap to the postsynaptic cell, possibly inducing an action potential there.
How many structures make up the chemical synapse?
3.
Which three structures make up the chemical synapse?
- A Synaptic knob
- A synaptic cleft
- Arrangements of synapses
What is a synaptic knob
A tiny bulge at the end of a terminal branch of a presynaptic neuron’s axon that contains vesicles housing neurotransmitters.
What is a synaptic cleft
The space between a synaptic knob and the plasma membrane of a postsynaptic neuron.
Axodendritic
Axon signals postsynaptic dendrite (common)
Axosomatic
Axon signals postsynaptic soma (common)
Axoaxonic
Axon signals postsynaptic axon
What is saltatory conduction
Process in which a nerve impulse travels along a myelinated fibre by jumping from one node of ranvier to the next.
What are neurotransmitters
The means by which neurons talk to one another.
How are neurotransmitters classified?
Function
Chemical structure
What does the thalamus do?
It plays an important role in arousing or alerting the cerebrum.
What are meninges?
Three membranous layers
What is dura mater?
Outer layer of the meninges and inner periosteum of the cranial bones
Strong, white fibrous tissue.
What are the three important layers of the dura mater
Falx cerebri
Falx cerebelli
Tentoriym cerebelli
falx cerebri
Projects downwards into the longitudinal fissure between the two cerebral hemispheres