BIOL 2160 Exam 3 Crousillac Study
Guide Questions with Actual Detailed
Answers 2025-2026 Updated.
Test Questions - Answer Exam 3
Inhibitory Postsynaptic Potential - Answer MP -70 to -90
What occurs during temporal summation? - Answer A single cell sends signals to sub-
threshold that are close enough in space and time to reach threshold
Benefit of action potentials over graded potentials - Answer Travel great distances without
getting smaller
Cells permeability to sodium is highest during - Answer Rising phase
Why does the rising phase happen before the falling phase? - Answer Because potassium
channels activate more slowly than sodium channels
At rest, at which conformation are most sodium channels found in? - Answer Closed and
capable of being opened
Phase 3 of AP the undershoot - Answer Slow to closing of K+ channels
The increase of size of stimulus - Answer Increase of frequency of AP's
Release of neurotransmitter the direct result of - Answer Opening up of calcium channels
Postsynaptic response, which channel opens as a result of IPSP - Answer Potassium
Which of these won't turn off synaptic transmission - Answer Pumping calcium into the
cytoplasm
Smooth muscle contractions - Answer Control sympathetic nervous system
Commissures found in - Answer CNS
,Membrane conduction is lower than conductance in - Answer Both intracellular and
extracellular solution
Which glial cell is apart of the immune response - Answer Microglia
The gastrointestinal tract is controlled by - Answer Division of the autonomic nervous system
T/F: Both cell bodies and axons of interneurons are found in the CNS - Answer True
Autoimmune disease that attacks myelin sheaths in CNS - Answer Oligodendrocytes
What makes membrane responsible for creating membrane potential - Answer High
resistance
When calculating ionic current, which does not influence driving potential - Answer
Conductance because only MP & EP influence it
Spatial Summation - Answer Involves more than one synaptic input (two cells)
Cells permeability to sodium will be lowest at an MP that is - Answer More negative than -70
During the falling phase, sodium channels are - Answer Closed and incapable of being
opened
During absolute refractory period - Answer All voltage-gated channels will either be open or
inactivated (closed and incapable of being opened)
Which of the following does not contribute to relative refractory period - Answer Sodium
channels still open (they are NOT)
Why is stronger stimulus needed to invoke AP during relative refractory period - Answer
Membrane is still leaking potassium and a lot of sodium channels are still inactivated
The transition from rising phase to falling phase - Answer Due to opening of voltage-gated
potassium channels
,During relative refractory period, activation gate of sodium channels - Answer Will be closed
Why is propagation in a myelinated axon faster than an unmyelinated axon? - Answer Myelin
does not have any ion channels
Nicotinic acetylcholine receptors are permeable to both sodium and potassium, when they
open you get an - Answer EPSP
Reason for this - Answer Driving force for sodium is greater than the potassium driving force
Exocytosis of synaptic vesicles is a direct result of - Answer Increase calcium in synaptic
terminals
G-Protein - Answer Muscarinic receptors
Purpose of ryanodine receptors - Answer To release calcium from SR
Which event immediately precedes the power stroke in crossbridge cycle? - Answer Removal
of inorganic phosphate (Pi)
When SERCA pumps destroyed - Answer Calcium can't be pumped back into SR, so you
won't be able to relax skeletal muscles
At the neuromuscular junction, the end plate potential occurs on the - Answer Skeletal
muscle cell membrane
Crossbridges and ATPase activity are characteristics of - Answer Thick filaments
Tropomyosin covers up myosin binding sites on action when calcium levels are what? - Answer
Low
Majority of calcium during skeletal muscle contraction comes from? - Answer SR
Purpose of DHP receptors in skeletal muscle is to? - Answer Detect APs along T tubules
Myosin has highest affinity for actin - Answer When it is bound to ADP plus inorganic
phosphate
, The immediate result of ATP hydrolysis during crossbridge cycle - Answer Cocking of the
myosin head
What determines whether fiber is fast twitched or slow twitched? - Answer How fast myosin
can hydrolyze ATP to ADP and P
Low intensity exercise will most likely result in - Answer Increase in oxidative fibers
Which type of muscle is darker in color? - Answer Oxidative fibers
Where does the majority of calcium for smooth muscle contractions come from? - Answer
Outside the cell
In smooth muscle contraction, calcium binds directly to - Answer Calmodulin
What shuts off smooth muscle contraction? - Answer Phosphatase
What makes glucose from fats and proteins? - Answer Gluconeogenesis
What is an anabolic hormone? - Answer Insulin
Chapter 21 & 24 - Answer Energy Balance and Diabetes
Glucose requirement, especially for nervous system, is what? - Answer Continuous
The body must have a way to store and to mobilize nutrients to maintain what? - Answer
Blood glucose at a constant level
What is blood glucose? - Answer Blood sugar
What does our body continue to supply without limit? - Answer Glucose
Where can glycogen be stored in the human body? - Answer Liver and skeletal muscles
What process takes excess glucose and turns it into glycogen? - Answer Glycogenesis
Guide Questions with Actual Detailed
Answers 2025-2026 Updated.
Test Questions - Answer Exam 3
Inhibitory Postsynaptic Potential - Answer MP -70 to -90
What occurs during temporal summation? - Answer A single cell sends signals to sub-
threshold that are close enough in space and time to reach threshold
Benefit of action potentials over graded potentials - Answer Travel great distances without
getting smaller
Cells permeability to sodium is highest during - Answer Rising phase
Why does the rising phase happen before the falling phase? - Answer Because potassium
channels activate more slowly than sodium channels
At rest, at which conformation are most sodium channels found in? - Answer Closed and
capable of being opened
Phase 3 of AP the undershoot - Answer Slow to closing of K+ channels
The increase of size of stimulus - Answer Increase of frequency of AP's
Release of neurotransmitter the direct result of - Answer Opening up of calcium channels
Postsynaptic response, which channel opens as a result of IPSP - Answer Potassium
Which of these won't turn off synaptic transmission - Answer Pumping calcium into the
cytoplasm
Smooth muscle contractions - Answer Control sympathetic nervous system
Commissures found in - Answer CNS
,Membrane conduction is lower than conductance in - Answer Both intracellular and
extracellular solution
Which glial cell is apart of the immune response - Answer Microglia
The gastrointestinal tract is controlled by - Answer Division of the autonomic nervous system
T/F: Both cell bodies and axons of interneurons are found in the CNS - Answer True
Autoimmune disease that attacks myelin sheaths in CNS - Answer Oligodendrocytes
What makes membrane responsible for creating membrane potential - Answer High
resistance
When calculating ionic current, which does not influence driving potential - Answer
Conductance because only MP & EP influence it
Spatial Summation - Answer Involves more than one synaptic input (two cells)
Cells permeability to sodium will be lowest at an MP that is - Answer More negative than -70
During the falling phase, sodium channels are - Answer Closed and incapable of being
opened
During absolute refractory period - Answer All voltage-gated channels will either be open or
inactivated (closed and incapable of being opened)
Which of the following does not contribute to relative refractory period - Answer Sodium
channels still open (they are NOT)
Why is stronger stimulus needed to invoke AP during relative refractory period - Answer
Membrane is still leaking potassium and a lot of sodium channels are still inactivated
The transition from rising phase to falling phase - Answer Due to opening of voltage-gated
potassium channels
,During relative refractory period, activation gate of sodium channels - Answer Will be closed
Why is propagation in a myelinated axon faster than an unmyelinated axon? - Answer Myelin
does not have any ion channels
Nicotinic acetylcholine receptors are permeable to both sodium and potassium, when they
open you get an - Answer EPSP
Reason for this - Answer Driving force for sodium is greater than the potassium driving force
Exocytosis of synaptic vesicles is a direct result of - Answer Increase calcium in synaptic
terminals
G-Protein - Answer Muscarinic receptors
Purpose of ryanodine receptors - Answer To release calcium from SR
Which event immediately precedes the power stroke in crossbridge cycle? - Answer Removal
of inorganic phosphate (Pi)
When SERCA pumps destroyed - Answer Calcium can't be pumped back into SR, so you
won't be able to relax skeletal muscles
At the neuromuscular junction, the end plate potential occurs on the - Answer Skeletal
muscle cell membrane
Crossbridges and ATPase activity are characteristics of - Answer Thick filaments
Tropomyosin covers up myosin binding sites on action when calcium levels are what? - Answer
Low
Majority of calcium during skeletal muscle contraction comes from? - Answer SR
Purpose of DHP receptors in skeletal muscle is to? - Answer Detect APs along T tubules
Myosin has highest affinity for actin - Answer When it is bound to ADP plus inorganic
phosphate
, The immediate result of ATP hydrolysis during crossbridge cycle - Answer Cocking of the
myosin head
What determines whether fiber is fast twitched or slow twitched? - Answer How fast myosin
can hydrolyze ATP to ADP and P
Low intensity exercise will most likely result in - Answer Increase in oxidative fibers
Which type of muscle is darker in color? - Answer Oxidative fibers
Where does the majority of calcium for smooth muscle contractions come from? - Answer
Outside the cell
In smooth muscle contraction, calcium binds directly to - Answer Calmodulin
What shuts off smooth muscle contraction? - Answer Phosphatase
What makes glucose from fats and proteins? - Answer Gluconeogenesis
What is an anabolic hormone? - Answer Insulin
Chapter 21 & 24 - Answer Energy Balance and Diabetes
Glucose requirement, especially for nervous system, is what? - Answer Continuous
The body must have a way to store and to mobilize nutrients to maintain what? - Answer
Blood glucose at a constant level
What is blood glucose? - Answer Blood sugar
What does our body continue to supply without limit? - Answer Glucose
Where can glycogen be stored in the human body? - Answer Liver and skeletal muscles
What process takes excess glucose and turns it into glycogen? - Answer Glycogenesis
