Neurons Flashcards
The peripheral nervous system (PNS) is made up of..
cranial nerves and spinal nerves
Central Nervous (CNS) is made up of
brain and spinal cord
The Autonomic nervous system (ANS) is made up of
the sympathetic and parasympathetic nerves
How many neurons are in the brain?
100 billion
Each neuron has between _____ and _____ synapses
1,000 and 10,000
The gut contains some ______ neurons
100 million
The diameter of a neuron is in between __ and ___ microns (or __ millimeters)
Between 4 and 100, .1 mm.
Velocity of a signal transmitted through a neuron is between __ and ___ mph
1.2 and 250
A neuron is an ______ cell that processes and transmits information by _____ and _____ signaling
electrically excitable; electrical/chemical
The fundamental task of a nerve cell is to ____, ______, and ______ signals
receive, conduct, transmit signals
Neurons connect via ____ to each other to form neural networks
synapses
Dendrites transmit electrical impulses to the ______
cell body
The axon transmits information away from the _____
cell body
The myelin sheath is made up of _________ (type of glial cells)
oligodendrocytes
Nodes of Ranvier are ______ in between myelin sheath that allow for ____
Permeable gaps; the exchange of ions
Pre-synaptic terminal is located at the end of the ____
axon
The glia of the brain and spinal chord are called ____
astrocytes
Astrocytes support the _______, provide _______ to the nervous tissue, maintain _______, and repair of the brain and spinal cord following traumatic injuries.
blood-brain barrier; nutrients to the nervous tissue; extracellular ion balance
Action potential is the _______ conducted along neuronal axons
electrical signal
Action potentials are generated by special types of _______ embedded in a cell’s ______
voltage-gated ion channels; plasma membrane
What are the two types of action potentials?
One type is generated by the voltage-gated sodium channels in the axon and the other by voltage-gated calcium channels in the pre-synaptic terminal
Sodium-based action potentials last for________
less than one millisecond
Calcium based action potentials last for _____
100 milliseconds or longer
The resting membrane potential in neurons is ____
-70mV
The sodium potassium pump is activated during _____ and sends 3 ____ ions out for every 2 ____ ions in
hyperpolarization; sodium, potassium
During the depolarization of the axon ____ enter through the ____
sodium ions; Nodes of Ranvier