Chapter 12 A&P HW Flashcards
What does the somatic nervous system do?
provides motor signals and conscious control to skeletal muscles
Does the somatic nervous system control voluntary or involuntary actions?
voluntary
Does the autonomic nervous system control voluntary or involuntary actions?
involuntary
Does the enteric nervous system control voluntary or involuntary actions?
involuntary
What does integration do?
processes information by analyzing it and deciding upon an appropriate response
What are some functions of the nervous system?
detecting stimuli, processing information, sending responses to muscles or glands
Is gray matter myelinated or unmyelinated?
unmyelinated
Is white matter myelinated or unmyelinated?
myelinated
What is the other name for myelin sheath gaps?
node of Ranvier
What are sensory impulses carried to the central nervous system by?
afferent neurons
What is a cluster of neuronal cell bodies in the CNS called?
nucleus
What type of central nervous system tissue contains neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, and neuroglial cells?
gray matter
What is a graded potential?
a small deviation from resting membrane potential that occurs because ligand-gated or mechanically-gated channels open or close
What causes a resting nerve fiber to be polarized?
the concentration of Na+ is higher on the outside and K+ is higher on the inside
What type of communication are graded potentials used for?
localized and short duration
What type of channel allows for more potassium to exit the neuron and helps in maintaining the resting membrane potential?
leak channel
Which electrical signal can allow for rapid long-distance communication within the nervous system?
nerve action potential
What is the difference in electrical charges on either side of the cell membrane called?
membrane potential
Movement of ions through an open channel is due to what?
diffusion
What is the membrane transport protein that uses ATP to move ions against their concentration gradient called?
pump
True or false: to establish and maintain resting membrane potential, more potassium ions move out of the cell than sodium ions move into the cell
true
What is it called when the inside of the membrane becomes less negative?
the membrane potential is depolarized
What principle states that a stimulus either causes an action potential or does not cause an action potential?
all-or-none principle
What happens when the accumulation of graded potentials in the trigger zone reaches threshold?
voltage-gated channels open
True or false: the depolarization of one area of the cell membrane provides enough positive charge to cause neighboring voltage-gated channels to reach threshold allowing the action potential to spread across the membrane
true
What maintains resting membrane potential?
leak channels and sodium-potassium pumps
What results in the depolarization of the cell membrane?
voltage-gated sodium channels open allowing sodium ions to enter the cell to cancel the negative charges on the inside of the membrane
Does the voltage diminish with distance in a graded potential?
yes
What is the typical resting membrane potential of a neuron?
-70mV
Why are N+/K+-ATPase pumps considered to be an electrogenic pump?
they contribute to the negativity of the resting membrane potential
Where do graded potentials typically occur?
dendrites and cell body
What does a depolarizing graded potential do?
makes the membrane less polarized
What happens during repolarization?
K+ flows out of the cell
How does size affect the speed of conduction of action potentials?
the larger the diameter of axons, the faster conduction of action potentials
How does temperature affect the speed of conduction of action potentials?
warmer temperatures allow for faster conduction
How does more stimuli affect action potentials?
increasing application of stimuli increases frequency of action potentials
What is continuous conduction?
step-by-step depolarization and repolarization of each adjacent segment of the axolemma
What is saltatory conduction?
the impulse jumps from each node of Ranvier to node of Ranvier
How does myelination affect the speed of propagation of action potentials?
myelination increases the speed
How can the nervous system distinguish between a light and heavy touch?
the frequency of impulses sent to sensory centers is changing
