quiz 2 Flashcards
heredity
the total set of characteristics biologically transmitted from parent to
offspring.
genotype
is all of an individual’s genetic inheritance.
phenotype
The actual expression of the genotype as the person’s visible characteristics and behavior
CNS
consists of the spinal cord and brain
center of coordination and the mechanism that determines the most appropriate response to incoming impulses.
transmits info from environment & info from body to brain where is it reported, stored, & compaired with other info
transmit information about the environment and the body to the brain
PNS
branching network of nerves, including the somatic system that controls all the skeletal muscles.
which is made up of all the nerve fibers that enter or leave the brain stem and spinal cord to supply the sensory receptors, muscles, and glands
lines of communication
Motor Unit
A neuron and all the muscle fibers innervated by it are referred to as a motor unit because all the muscle fibers contract as a unit when stimulated by the motoneuron
A motor unit is a neuron and the muscle fibers it controls, which contract together when the neuron sends a signal.
Critical periods
in which experience may be most effective in forging connections (wiring
the brain). From another perspective, these critical periods have more recently
been referred to as windows of opportunity, the theory that nature opens certain windows for the experience effect starting before birth and then “narrows” each opportunity, one by one.
-child who misses an opportunity may not develop the brain’s
circuitry to its full potential for a specific function.
Brain plasticity
brains ability to change & reorganize neural pathways based on new experiences
what contributes to an individuals development?
both nature (genetics) & nurture (environment)
what is the basic unit of heredity found within a chromosome?
a gene
what does the DNA molecule contain?
the genetic code
how many genes does the human body contain?
20,000-25,000
what are the primary functions of the nervous system?
-sensory function
-integrative function, which includes
the memory and thought processes
-motor function.
somatic vs autonomic
both part of PNS
-somatic: voluntary & transmits signals to CNS
-autonomic: involuntary; ex: heart beat & breathing
what does the cerebellum do?
it facilitates coordination & balance
what is the sequence of CNS development?
- cell proliferation & changes
- migration
- integration & differentiation
- myelination
- cell death
what is integration & differentiation?
integration:the intricate interweaving of neural mechanisms toward their target destination
differentiation: the process
by means of which structure, function, or forms of behavior become more specialized
when can differentiation occur?
after synaptogenesis
what neurological changes occur with aging?
-loss of brain weight & neurons
-loss of vestibular awareness (balance)
-loss of nerve conduction velocity (slowing movements)
what does the corpus callosum do?
it provides the link between the left & right brain
what do both the left & right brain do?
left: logic, language, & sequential processing
right: nonverbal, visuospatial functions (e.g., music awareness, map reading, and figure drawing)
what is pruning
the elimination of connections due to lack of use & stimulation
what are pyramidal & extrapyramidal pathways?
what are the parts of the CNS & what do they do?
-spinal cord: transmission pathway from body to brain, reflex behavior
-brain
—brainstem: posture, metabolic functions, involuntary reflexes
—cerebral cortex: critical thinking, info processing, precise motor movements
—basal ganglia: gross body movements
—cerebellum: coordination & balance
what are the parts of the PNS & what do they do?
somatic: voluntary (skeletal muscles)
autonomic: involuntary (smooth muscles)
what are the two types of nerve fibers?
afferent: signals from outside to spinal cord & brain
efferent: sends motor impulses from CNS to muscles & glands
parts of neurons
cell body:
dendrite:
axon:
synapse: space or connection between axon & another neuron for purpose of sending messages
what is a motor unit
a neuron & all the muslce fibers that a neuron controls
ascending tracks: sensory impulses to brain
descending tracks: sensory impulses from brain to rest of the body
what are action potentials
brief impulses or wave of electricity sent from neurons through their axons in the form of single electrical clicks
what are nerve conduction velocity
speed of which info travels from one nerve fiber to another
what controls speed of impulses? & what is the reason for that?
-the presence or absence of myelin
-myelinated one will travel further
-nodes of ranvier allow for the conduction to jump quickly through saltatory conduction from one node to next
what does schwann cell do?
insulating cell that forms myelinated sheath around axon
what are the early developmental changes?
- cell proliferation & changes
- migrate & elaborate
- integration & differentiation
- myelination
- cell death
what is the degree of myelination closely related to?
maturation
when does pruning actually occur?
around 10 years old
does the brain develop new neurons?
yes
-a study on exercising mice showed that they produce 2.5 times the growth of new neurons than sedentary mice.
-environmental manipulations
may affect neurogenesis in a positive manner.
exercise increases cell proliferation
what happens as you age
decrease in vestibular awareness (balance), brain weight, neurons, and dendritic density (forgetful), loss of nerve conduction velocity (reaction time)
