Bio 252 Exam 1 Review Questions and Correct Answers
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Course
BIO 252
Institution
BIO 252
CNS brain and spinal cord
PNS Cranial nerves and spinal nerves (nerves and sensory receptors)
Somatic nervous system division of PNS Skeletal muscles (muscles attached to our bones). Diaphragm is somatic because it is skeletal but it is inside the body.
Autonomic nervous system division of PNS S...
Bio 252 Exam 1 Review Questions and
Correct Answers
CNS ✅brain and spinal cord
PNS ✅Cranial nerves and spinal nerves (nerves and sensory receptors)
Somatic nervous system ✅division of PNS
Skeletal muscles (muscles attached to our bones). Diaphragm is somatic because it is
skeletal but it is inside the body.
Autonomic nervous system ✅division of PNS
Smooth (intestines, blood vessels) and cardiac (heart muscles) muscles, glands (cells
or many cells that can synthesize and secrete molecules to the body)
Sympathetic nervous system ✅division of ANS
Fight or flight. NOREPINEPHRINE. Ganglia closer to spinal cord.
Parasympathetic nervous system ✅division of ANS
Rest and digest. ACETYLCHOLINE. Ganglia closer to organs
Are thermoreceptors part of the PNS or CNS? ✅PNS
A child eats a whole bottle of salt (nacl) tablets. What effect does this have on the
resting membrane potential? ✅because there is already a high concentration of Na+
ions outside of the neuron and eating the salt tablets won't really make a difference to
the concentration gradient. (taking a handful of sand and pouring it on the beach
analogy)
Why are potassium ions the major factors that determine the resting membrane
potential? ✅Potassium ions have the greatest influence on the RMP because the
plasma membrane is more permeable to potassium than to any other ion (leak
channels)
Leak channels ✅these help to maintain resting membrane potential because sodium
and potassium can leak out slowly. Leak channels allow specific ions to move through.
Really important to think about 3D configuration
Ion gated channels ✅Ion channels allow ions to move through the plasma membrane
driven by electrochemical gradient. Ions do not like to have different concentrations
across the membrane
, Chemical gradient ✅concentration gradient. If you have more sodium outside, it is
gonna want to move inside to where a lower concentration is
Electrical gradient ✅ions have electrical charge. Measure the inside. If inside is more
negative, this means electrical potential is negative
If you decrease the K+ concentration outside of the cell (hypokalemia), would lead to
hyper- or de- polarization? ✅Since there is less potassium outside of the cell,
potassium would leak outside of the cell, thus becoming hyperpolarized
Definition of action potential ✅a change in electrical potential
Why does an AP not get smaller as it propagates? ✅Nodes of ranvier are packed with
voltage gated sodium channels so it can leap down myelin sheath to these and get
propagated. Saltatory conduction
A stronger stimulus cannot generate a greater action potential, but it can increase the
frequency of action potentials generated in the trigger zone. Explain ✅A stronger
stimulus can overcome the relative refractory period and make it fire even though it's
harder to
EPSP ✅make AP more likely to fire (sodium moving in)
IPSP ✅make AP less likely to fire. (Chloride ions going in or a ligand that will bind to
potassium ions to make them go out. When the membrane becomes more permeable to
K and Cl ions)
Two cells are identical except that the extracellular concentration of Na+ is less for cell
A than for cell B. How would the magnitude of the graded potential in cell A differ from
that in cell B if stimuli of identical strength were applied to each? ✅In cell A the graded
potential (depolarization) would be of a smaller magnitude than in cell B
Neurons generally start repolarizing once membrane potential reaches approximately
+30mv because ✅because voltage-gated potassium channel open up
Astrocytes ✅form BBB
Microglia ✅immune defense of the brain
Ependymal cells ✅circulation of CSF
Oligodendrocytes ✅form myelin in CNS
Schwann cells ✅form myelin in periphery
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