BIOL 2401 Lone Star College -BIOL 2401 Lecture Exam 3
Questions | 2026/2027 | Answers Correct | With Complete
Solutions
-90 Correct Answers If plasma membrane allowed K freely, the
equilibrium potential would be ___ mV
(F) fibrous ... two intertwined strands with string of globular
subunits (G) with tropomyosin molecules over active sites and
troponin complex on tropomyosin Correct Answers Actin
+66 Correct Answers If plasma membrane allowed Na freely,
the equilibrium potential would be
1-Another neuron via axolemma, 2-a muscle via telodendria and
neuromuscular junctions, 3-a gland Correct Answers Describe
3 things upon which axon terminals may end
1-Na+ local potential axon hillock, depolarize membrane, 2-
threshold potential (-55) opens voltage gated ion channels, 3-
depolarize by Na+ fast channels open first then K+ slow gates
open, 4 - depolarization peaks (+35) as Na+ gates close, 5-
repolarization as slow K+ channels open and K+ leaves and
back to negative, 6- hyperpolarized more neg than rest as K+ ion
gates stay open, 7- back to resting potential Na/K pumps and K+
diffusion Correct Answers Describe the 7 events of an action
potential
abduct/laterally roate thigh Correct Answers Action of
piriformis
,abduct/medially rotate thigh Correct Answers Action of gluteus
medius
abduct/medially rotate thigh Correct Answers Action of gluteus
minimus
abduct/medially rotate thigh Correct Answers Action of tensor
fasciae latae
abducts arm Correct Answers Action of supraspinatus
abducts thumb Correct Answers Action of abductor pollicis
longus
abducts/extends/flexes arm Correct Answers Action of deltoid
Acetabulum of coxal bone - head of femur Correct Answers
Bony articulations of hip joint
AChE breaks down ACh, Ca removed from troponin pumped
into SR (binds calsequestrin), tropomyosin blocks actin active
sites, resting length of muscle Correct Answers Describe
relaxation
Actin pulled toward center of myosin and sarcomere shortens (H
zone shortens, I band narrows, A band unchanged) Correct
Answers Explain what happens to each component of a
sarcomere when a contraction occurs
,acts within body area but origin elsewhere, example flexor
digitorum superficialis originates at forearms and moves hand
Correct Answers extrinsic muscles
adduct thigh, flex leg at knee Correct Answers Action of
gracilis
adduct/flex thigh, posteriorly extend thigh Correct Answers
Action of adductors
Aerobic - lots of mitochondria, Endurance, smaller in diameter,
Dark (high myoglobin), Postural/Soleus Correct Answers Type
I "Slow twitch" Slow Oxidative muscle fibers
Aerobic cellular pathway (first glucose and fatty acids, then just
fatty acids) Correct Answers How does aerobic respiration in
muscle provide ATP starting from 40 seconds to hours of
activity?
Aerobic respiration from myoglobin then phosphagen system
(ATP + CP) Correct Answers Describe how muscle can
make/regenerate ATP supplies for the first 6 seconds of effort
(immediate energy sources)
Amphiarthrosis Correct Answers Slightly movable joint
Anaerobic, Fatigues easily, Powerful, larger in diameter, light
(less myoglobin), eye/hand/gastrocnemius/biceps brachii
Correct Answers Type II "Fast-Twitch" Fast Glycolytic muscle
fibers
, anchor structures, regulate EC environment, blood-brain barrier,
form scar tissue after injury (CNS) Correct Answers Astrocytes
Angle decreases Correct Answers Flexion
anterior Correct Answers The iliofemoral lig. and pubofemoral
lig. are _______ ligaments
Anterior movement Correct Answers Protraction
anterograde (unidirectional), ATP independent, conducted by
sliding/polymerizing/protein interactions,
microfilaments/tubules/neurofilaments/cytosolic protein
complexes Correct Answers Slow axonal transport and what
substances moved
AP spreads down T tubules, voltage-gated ion channels and Ca
in SR open, Ca enters cytosol, Ca binds troponin, troponin-
tropomyosin complex exposes actin active sties Correct
Answers Describe excitation-contraction coupling
area between axon hillock and first glial cell Correct Answers
initial segment
area of fiber covered with myelin Correct Answers internode
Arm abducted and blow from above Correct Answers How
does displacement of the shoulder joint normally occur?
around entire muscle, outer turns to fascia, inner into
perimysium, fibrous Correct Answers epimysium
Questions | 2026/2027 | Answers Correct | With Complete
Solutions
-90 Correct Answers If plasma membrane allowed K freely, the
equilibrium potential would be ___ mV
(F) fibrous ... two intertwined strands with string of globular
subunits (G) with tropomyosin molecules over active sites and
troponin complex on tropomyosin Correct Answers Actin
+66 Correct Answers If plasma membrane allowed Na freely,
the equilibrium potential would be
1-Another neuron via axolemma, 2-a muscle via telodendria and
neuromuscular junctions, 3-a gland Correct Answers Describe
3 things upon which axon terminals may end
1-Na+ local potential axon hillock, depolarize membrane, 2-
threshold potential (-55) opens voltage gated ion channels, 3-
depolarize by Na+ fast channels open first then K+ slow gates
open, 4 - depolarization peaks (+35) as Na+ gates close, 5-
repolarization as slow K+ channels open and K+ leaves and
back to negative, 6- hyperpolarized more neg than rest as K+ ion
gates stay open, 7- back to resting potential Na/K pumps and K+
diffusion Correct Answers Describe the 7 events of an action
potential
abduct/laterally roate thigh Correct Answers Action of
piriformis
,abduct/medially rotate thigh Correct Answers Action of gluteus
medius
abduct/medially rotate thigh Correct Answers Action of gluteus
minimus
abduct/medially rotate thigh Correct Answers Action of tensor
fasciae latae
abducts arm Correct Answers Action of supraspinatus
abducts thumb Correct Answers Action of abductor pollicis
longus
abducts/extends/flexes arm Correct Answers Action of deltoid
Acetabulum of coxal bone - head of femur Correct Answers
Bony articulations of hip joint
AChE breaks down ACh, Ca removed from troponin pumped
into SR (binds calsequestrin), tropomyosin blocks actin active
sites, resting length of muscle Correct Answers Describe
relaxation
Actin pulled toward center of myosin and sarcomere shortens (H
zone shortens, I band narrows, A band unchanged) Correct
Answers Explain what happens to each component of a
sarcomere when a contraction occurs
,acts within body area but origin elsewhere, example flexor
digitorum superficialis originates at forearms and moves hand
Correct Answers extrinsic muscles
adduct thigh, flex leg at knee Correct Answers Action of
gracilis
adduct/flex thigh, posteriorly extend thigh Correct Answers
Action of adductors
Aerobic - lots of mitochondria, Endurance, smaller in diameter,
Dark (high myoglobin), Postural/Soleus Correct Answers Type
I "Slow twitch" Slow Oxidative muscle fibers
Aerobic cellular pathway (first glucose and fatty acids, then just
fatty acids) Correct Answers How does aerobic respiration in
muscle provide ATP starting from 40 seconds to hours of
activity?
Aerobic respiration from myoglobin then phosphagen system
(ATP + CP) Correct Answers Describe how muscle can
make/regenerate ATP supplies for the first 6 seconds of effort
(immediate energy sources)
Amphiarthrosis Correct Answers Slightly movable joint
Anaerobic, Fatigues easily, Powerful, larger in diameter, light
(less myoglobin), eye/hand/gastrocnemius/biceps brachii
Correct Answers Type II "Fast-Twitch" Fast Glycolytic muscle
fibers
, anchor structures, regulate EC environment, blood-brain barrier,
form scar tissue after injury (CNS) Correct Answers Astrocytes
Angle decreases Correct Answers Flexion
anterior Correct Answers The iliofemoral lig. and pubofemoral
lig. are _______ ligaments
Anterior movement Correct Answers Protraction
anterograde (unidirectional), ATP independent, conducted by
sliding/polymerizing/protein interactions,
microfilaments/tubules/neurofilaments/cytosolic protein
complexes Correct Answers Slow axonal transport and what
substances moved
AP spreads down T tubules, voltage-gated ion channels and Ca
in SR open, Ca enters cytosol, Ca binds troponin, troponin-
tropomyosin complex exposes actin active sties Correct
Answers Describe excitation-contraction coupling
area between axon hillock and first glial cell Correct Answers
initial segment
area of fiber covered with myelin Correct Answers internode
Arm abducted and blow from above Correct Answers How
does displacement of the shoulder joint normally occur?
around entire muscle, outer turns to fascia, inner into
perimysium, fibrous Correct Answers epimysium
