Exam #4 chapter 11 Flashcards
(98 cards)
with graded potentials when channels close what happens?
the ions diffuse away and the membrane returns to the resting membrane potential
what will ions do with graded potentials?
flow through an open channel and make the membrane more polarized (hyperpolarized) or less polarized (depolarized)
what is the structure of a dendrite?
branched, short and tapering processes
what are glial cells of the CNS?
supporting cells
what is the cation, potassium level ?
intracellular: 148 and extracellular: 5
what is the structure of an axon?
usually unbranched, long and do NOT taper
what does the ANS do?
sends commands to the smooth and cardiac muscles and glands (involuntary)
what do axons do?
branch and form enlarged presynaptic (axon) terminals
why is the plasma membrane selectively permeable? (2) (PC)
1) proteins are too large to pass through
2) charged ions cannot pass through the membrane but they can pass through ion channels in the membrane
what does ependymal cells do?
produce, monitor and circulate CSF
what are the characteristics of bipolar neurons? (3) (HHS)
1) has one dendrite
2) has one axon
3) small sensory neurons
what is the functional classification of sensory (afferent) neurons?
they conduct action potential to the CNS
where is the enteric nervous system located?
part of the ANS in the wall of the GI tract that controls the GI tract.
what are some types of glial cells of the CNS? (4) (AEMO)
1) astrocytes
2) ependymal cells
3) microglia cells
4) oligodendrocytes
what can be done with graded potentials?
they can be summed or added together
what are unlyelinated axons in the PNS enclosed by?
schwann cells
what do schwann cells do?
wrap a portion of one axon and form a myelin sheath
what is the similarity and difference between the extracellular fluid and intracellular fluid?
they have the same amount of cations and anions but differ the concentrations of different ions
what does the sympathetic division do?
functions in stressful situation (or exercise)
with graded potentials what is the change at a distance from the site of ion flow?
smaller
what are the characteristics of leak channels? (3) (AAP)
1) always open
2) allow certain ions to pass through the membrane continuously
3) put in the membrane by the cell
what does the PNS consist of?
the nervous tissues outside the CNS
what does the motor (efferent) division consist of?
1) the somatic nervous system (SNS)
2) the autonomic nervous system (ANS)
why does the resting membrane potential exist?
because of an unequal distribution of ions