Chapter 1 Test Flashcards
In his studies of infant brains, Santiago Ramón y Cajal demonstrated that _______
nerve cells remain separate rather than merging into each other
The surface of a cell is called the _______
plasma membrane
Chromosomes are contained in the cell ________
nucleus
A motor neuron, with its soma in the spinal cord, receives excitation through its ________ .
dendrites
The surfaces of ________ are lined with synaptic receptors that receive information from other neurons.
dendrites
A(n) ________ conveys an impulse toward other neurons, an organ, or a muscle.
Axon
________ wrap around the presynaptic terminals of a group of functionally related axons.
Astrocytes
In the periphery of the body, ________ build the myelin sheaths that surround and insulate certain vertebrate axons.
Schwann cells
________ guide the migration of neurons and their axons and dendrites during embryonic development.
Radial glia
The brain uses active transport to move ________ across the blood-brain barrier.
glucose
In people with Alzheimer’s disease or similar conditions, the ________ cell(s) lining the brain’s blood vessels shrink, and harmful chemicals enter the brain.
endothelial
The brain’s primary source of energy is ________ .
glucose
The slightly negative electrical potential of the inside of a resting neuron relative to the outside is called a resting ________ .
potential
The difference in distribution of ions across the neuron membrane is called the ________ .
concentration gradient
The sodium-potassium pump is effective only because of the membrane’s ________ .
selective permeability
At the peak of the action potential, ________ .
sodium channels CLOSE
The permeability of the proteins that allow sodium and potassium to cross a neuron’s membrane depends on the ________ .
voltage difference across the membrane
Transmission of the action potential down an action is called ________ .
propagation
The jumping of action potentials from node to node is referred to as ________ conduction.
saltatory
Local neurons lack ________ .
axons
