Chapter 4 Test Flashcards
Kent and Lois both carry a dominant gene for brown eye color (B) and a recessive gene for blue eye color (b). That is, they both carry the combination (B,b). If eye color were determined solely by this gene, which outcome would produce a blue-eyed child?
(b,b)
If the genes for a trait are on the sex chromosomes, the trait is said to be ________ .
sex-linked
deals with how experiences can alter the expression of genes.
Epigenetics
Any estimate of the heritability of a trait is ________ .
specific to a given population
Studies of individuals with PKU have shown that ________ .
heritable does not mean unmodifiable
The operational definition of ________ is the number of copies of one’s genes that endure in later generations.
fitness
What is one reason that humans may have been able to evolve such big brains without sacrificing other functions?
diet
Myelin forms first in the ________ .
spinal cord
What have 14C studies found about neuronal development in human brains?
Humans replace about 2% of the neurons in the hippocampus each year.
Connecting axons are steered by ________ .
neurotrophins
When a nerve from the sympathetic nervous system forms a synapse on a muscle, the muscle releases ________ .
nerve growth factor
Research on fetal alcohol syndrome in humans has demonstrated that ________ .
alcohol interferes with neuronal proliferation, migration, and differentiation
Studies of the differentiation of neurons in the cortex have found that ________ .
neurons may keep some of their original properties and develop new ones
In comparison to sighted individuals, individuals who have been blind since birth ________ .
are more likely to respond to auditory information in the occipital lobe
Examination of the brains of musicians has shown ________ .
thickened gray matter in areas of the cortex associated with visual processing
The impulsivity of adolescents has been associated with immaturity of the ________ .
prefrontal cortex
What has been shown about the relationship between the brain and cognitive function among elderly individuals?
The loss of hippocampal volume corresponds to the decline in certain memory functions.
Following a stroke, the combination of edema and excess sodium provokes excess release of the transmitter ________ .
glutamate
After a cell loses inputs from an axon, it ________ .
forms collateral sprouts from existing axons
Research on the phantom limb experience suggests that it ________ .
is a result of reorganization of somatosensory cortex
