1C. Neurons and Other Cells Flashcards
adult human brain contains approximately ___ neurons on average
86 billion
he used Golgi’s staining method, but he applied it to infant brains, in which the cells are smaller and easier to examine on a single slide
Santiago Ramon y Cajal
he came to the opposite conclusion: nerve cells remain separate instead of merging from one another
Santiago Ramon y Cajal
TRUE OR FALSE: the brain, like the rest of the body, does not consist of individual cells
false (it does)
he found a way to stain nerves cells with silver salts in the 1800s, that enabled researchers to examine the brain
Camilio Golgi
they received Nobel Prize for Physiology and Medicine, use the occasion to give acceptance speech that contradicted each other
Golgi and Cajal
a structure that separates the inside of the cell from the outside environment
membrane (or plasma membrane)
TRUE OR FALSE: most chemicals cannot cross the membrane, but protein channels in the membrane permit a controlled flow of water, oxygen, sodium, potassium, calcium, chloride, and other important chemicals
true
the structure that contains the chromosomes
nucleus
the chemical that forms the chromosomes; not stable for long in water solution
DNA
structures that synthesize new protein molecules
ribosomes
some ribosomes float freely within the cell, but others attach to the ___, a network of thin tubes that transport newly synthesized proteins to other locations.
endoplasmic reticulum
performs metabolic activities, providing energy that the cell uses for all activities
mitochondrion
have their own genes, separate from those in the nucleus of a cell; inherited in the cytoplasm of the egg cell
mitochondria
decreased mitochondrial function means decreased ___ and a high probability of ___
mental energy, depression
with its soma in the spinal cord, receives excitation through its dendrites and conducts impulses along its axon to a muscle
motor neuron
specialized at one end to be highly sensitive to a particular type of stimulation, such as touch
sensory neuron
are branching fibers that get narrower near their ends; the term comes from a Greek root word meaning “tree”
dendrites
he offers the analogy: if you expanded a dendrite to the height of the tree, the dendrites would be as thin as spaghetti, and the cell’s axon would extend for more than 25 city blocks
Giorgio Ascoli
many dendrites contain ___, short outgrowths that increase the surface area available for synapses
dendritic spines
contains the nucleus, ribosomes, and mitochondria; Greek for “body”
cell body (soma)
range of cell bodies of neurons in diameter in mammals
0.005 to 0.1 mm
a thin fiber of constant diameter; conveys an impulse to other neurons, an organ, or a muscle
axon
many vertebrates axons are covered with an insulating material called a ___ with interruptions known as nodes of Ranvier
myelin sheath
TRUE OR FALSE: invertebrate axons do not have myelin sheaths
true
this axon brings information into a structure, and intrinsic
afferent axon
this axon carries information away from a structure
efferent axon
