BIO 250 EXAM 3 QUESTIONS AND VERIFIED
ANSWER; 100% CORRECT; 2026- 2025 UPDATE
__ binds to ACh receptors, causing them to open chemically gated ion
channels. - correct answer- ACh
__ diffuses into the muscle fiber through open chemically gated ion
channels. - correct answer- Na+
__ diffuses out of the muscle fiber through open chemically gated ion
channels. - correct answer- K+
___ is not bound to myosin during the detachment step. - correct
answer- ADP
____ enters the cell and causes depolarization - correct answer-
sodium
________ are found in the CNS and bind axons and blood vessels to each
other. - correct answer- astrocytes
________ is a disease that gradually destroys the myelin sheaths of
neurons in the CNS, particularly in young adults. - correct answer-
multiple sclerosis
,________ potentials are short-lived, local changes in membrane
potential that can be either depolarized or hyperpolarized - correct
answer- graded
A gap between Schwann cells in the peripheral system is called a(n)
________. - correct answer- node of ranvier
A muscle cell runs out of ATP. Even though these are cyclic reactions,
what step of the cross bridge cycle given is most directly inhibited or
terminated? - correct answer- cross bridge detachment
A neuron that has as its primary function the job of connecting other
neurons is called a(n) - correct answer- association neuron
A patient is admitted to the hospital with exacerbation of multiple
sclerosis (MS). She asks the nurse "Why did this have to happen to me
again? I was doing so well." Why are some forms of MS characterized by
periods of remission and exacerbation? - correct answer- The axons
are not damaged; growing numbers of sodium channels appear
spontaneously in the demyelinated fibers, allowing conduction to
resume.
A protein with heads that attach in cross bridging - correct answer-
myosin
, A structure that forms a path from the membrane to the cell interior -
correct answer- T tubule
Actin behavior during the power stroke - correct answer- ratchets
toward the M line
Actin status to begin cross bridge formation - correct answer- actin-
binding sites exposed
Afferent division of PNS - correct answer- carries sensory
information from PNS sensory receptors to CNS
After removal of an elbow cast, Lauren noticed her arm was immovable.
What happened to her arm? - correct answer- The immobilization of
the arm caused some muscle mass to atrophy, and the loss of muscle
was replaced with tough connective tissue that locked her arm in place.
Astrocytes - correct answer- most abundant glial cells in CNS, role is
to make an exchange between capillaries and neurons. also responsible
for cleaning up K+ ions
at the chemical synapse, neuronal membranes are separated by a gap
called the - correct answer-
ANSWER; 100% CORRECT; 2026- 2025 UPDATE
__ binds to ACh receptors, causing them to open chemically gated ion
channels. - correct answer- ACh
__ diffuses into the muscle fiber through open chemically gated ion
channels. - correct answer- Na+
__ diffuses out of the muscle fiber through open chemically gated ion
channels. - correct answer- K+
___ is not bound to myosin during the detachment step. - correct
answer- ADP
____ enters the cell and causes depolarization - correct answer-
sodium
________ are found in the CNS and bind axons and blood vessels to each
other. - correct answer- astrocytes
________ is a disease that gradually destroys the myelin sheaths of
neurons in the CNS, particularly in young adults. - correct answer-
multiple sclerosis
,________ potentials are short-lived, local changes in membrane
potential that can be either depolarized or hyperpolarized - correct
answer- graded
A gap between Schwann cells in the peripheral system is called a(n)
________. - correct answer- node of ranvier
A muscle cell runs out of ATP. Even though these are cyclic reactions,
what step of the cross bridge cycle given is most directly inhibited or
terminated? - correct answer- cross bridge detachment
A neuron that has as its primary function the job of connecting other
neurons is called a(n) - correct answer- association neuron
A patient is admitted to the hospital with exacerbation of multiple
sclerosis (MS). She asks the nurse "Why did this have to happen to me
again? I was doing so well." Why are some forms of MS characterized by
periods of remission and exacerbation? - correct answer- The axons
are not damaged; growing numbers of sodium channels appear
spontaneously in the demyelinated fibers, allowing conduction to
resume.
A protein with heads that attach in cross bridging - correct answer-
myosin
, A structure that forms a path from the membrane to the cell interior -
correct answer- T tubule
Actin behavior during the power stroke - correct answer- ratchets
toward the M line
Actin status to begin cross bridge formation - correct answer- actin-
binding sites exposed
Afferent division of PNS - correct answer- carries sensory
information from PNS sensory receptors to CNS
After removal of an elbow cast, Lauren noticed her arm was immovable.
What happened to her arm? - correct answer- The immobilization of
the arm caused some muscle mass to atrophy, and the loss of muscle
was replaced with tough connective tissue that locked her arm in place.
Astrocytes - correct answer- most abundant glial cells in CNS, role is
to make an exchange between capillaries and neurons. also responsible
for cleaning up K+ ions
at the chemical synapse, neuronal membranes are separated by a gap
called the - correct answer-
