BIO 168 EXAM 3 COMPLETE EXAM
STUDY QUESTIONS WITH
CORRECT ANSWERS
1. Three types of muscular tissue - ANSWER -skeletal muscle
-cardiac muscle
-smooth muscle
2. Function of skeletal muscle - ANSWER -produce skeletal movement
-maintain body position/stability
-guard body openings
-maintain body temperature
3. Endomysium - ANSWER Each muscle fiber is surrounded by a connective
tissue layer called this
4. Fasicle - ANSWER A bundle of muscle fibers that is surrounded by a
connective tissue later called perimysium
5. Epimysium - ANSWER connective tissue that surrounds the entire muscle
6. structure of smooth muscle - ANSWER non striated muscle tissue
7. 7 characteristics of smooth muscle fiber - ANSWER 1) Long, slender, and
spindle shaped.
,2) Have a single, central nucleus.
3) Have no T tubules or sarcomeres.
4) Have no tendons or aponeuroses.
5) Have scattered myosin fibers. Myosin fibers have more heads per thick
filament.
6) Have thin filaments attached to dense bodies.
7) Dense bodies transmit contractions from cell to cell.
8. cellular electricity-electrophysiology- relies on: - ANSWER resting
membrane potential "RMP"
graded local potentials
action potentials "AP"
9. what are ion channels? (types) - ANSWER integral proteins across the cell
membrane that allow the passage of certain ions
the diffusion is passive according to the concentration gradient
can be non gated (leak) channels or gated channels
10.small motor units mean - ANSWER fine control of movement
11.what is released from the axon terminal - ANSWER Ach acetylocholine
,12.where does acetylocholine bind to its receptors ? - ANSWER motor end
plate
13.do myofilaments shorten during contraction - ANSWER no, it doesn't, they
slide past each other
14.when is a cross bridge formed - ANSWER when a myosin head is attached
to actin
15.describe the steps in skeletal muscle contraction from release of the
neurotransmitter to the sliding of the filaments? - ANSWER 1. Action
potential reaches the motor neuron terminal.
2. Acetylcholine (ACh) is released into the synaptic cleft.
3. ACh binds to receptors on the motor end plate, triggering an action potential
in the sarcolemma.
4. The action potential travels down the T-tubules.
5. This stimulates the sarcoplasmic reticulum to release Ca²⁺.
6. Ca²⁺ binds to troponin, causing tropomyosin to shift and expose myosin-
binding sites on actin.
7. Myosin heads bind to actin, forming crossbridges.
8. The power stroke occurs as myosin heads pivot, pulling thin filaments toward
the center of the sarcomere.
9. ATP binds to myosin, causing it to release actin and reset for another cycle.
10. This cycle repeats as long as Ca²⁺ and ATP are present.
16.what are the anaerobic sources of energy for muscle contraction? -
ANSWER phosphagen system (creatine phosphate) and anaerobic glycolysis
, 17.Compare and contrast the different types of muscles based on the
predominant fiber type present. - ANSWER 1. Slow oxidative (Type I):
High endurance, lots of mitochondria, red color, used in posture and
endurance activities.
2. Fast oxidative (Type IIa): Intermediate fatigue resistance and speed, aerobic
and anaerobic capacity.
3. Fast glycolytic (Type IIb/x): Fatigue quickly, strong, white color, used in
short bursts of power.
18.twitch - ANSWER A single, brief contraction and relaxation of a muscle
fiber.
19.treppe (staircase effect) - ANSWER Repeated stimuli cause progressively
stronger twitches as Ca²⁺ builds up.
20.tetany - ANSWER Sustained muscle contraction due to rapid, repeated
stimulation without relaxation.
21.non gated ion channels - ANSWER aka leak channels
always open
always allowing some Na+ in and more K+ out
22.gated ion channels - ANSWER open and close in response to stimuli, at
RMP, the gated channels are closed
two types:
STUDY QUESTIONS WITH
CORRECT ANSWERS
1. Three types of muscular tissue - ANSWER -skeletal muscle
-cardiac muscle
-smooth muscle
2. Function of skeletal muscle - ANSWER -produce skeletal movement
-maintain body position/stability
-guard body openings
-maintain body temperature
3. Endomysium - ANSWER Each muscle fiber is surrounded by a connective
tissue layer called this
4. Fasicle - ANSWER A bundle of muscle fibers that is surrounded by a
connective tissue later called perimysium
5. Epimysium - ANSWER connective tissue that surrounds the entire muscle
6. structure of smooth muscle - ANSWER non striated muscle tissue
7. 7 characteristics of smooth muscle fiber - ANSWER 1) Long, slender, and
spindle shaped.
,2) Have a single, central nucleus.
3) Have no T tubules or sarcomeres.
4) Have no tendons or aponeuroses.
5) Have scattered myosin fibers. Myosin fibers have more heads per thick
filament.
6) Have thin filaments attached to dense bodies.
7) Dense bodies transmit contractions from cell to cell.
8. cellular electricity-electrophysiology- relies on: - ANSWER resting
membrane potential "RMP"
graded local potentials
action potentials "AP"
9. what are ion channels? (types) - ANSWER integral proteins across the cell
membrane that allow the passage of certain ions
the diffusion is passive according to the concentration gradient
can be non gated (leak) channels or gated channels
10.small motor units mean - ANSWER fine control of movement
11.what is released from the axon terminal - ANSWER Ach acetylocholine
,12.where does acetylocholine bind to its receptors ? - ANSWER motor end
plate
13.do myofilaments shorten during contraction - ANSWER no, it doesn't, they
slide past each other
14.when is a cross bridge formed - ANSWER when a myosin head is attached
to actin
15.describe the steps in skeletal muscle contraction from release of the
neurotransmitter to the sliding of the filaments? - ANSWER 1. Action
potential reaches the motor neuron terminal.
2. Acetylcholine (ACh) is released into the synaptic cleft.
3. ACh binds to receptors on the motor end plate, triggering an action potential
in the sarcolemma.
4. The action potential travels down the T-tubules.
5. This stimulates the sarcoplasmic reticulum to release Ca²⁺.
6. Ca²⁺ binds to troponin, causing tropomyosin to shift and expose myosin-
binding sites on actin.
7. Myosin heads bind to actin, forming crossbridges.
8. The power stroke occurs as myosin heads pivot, pulling thin filaments toward
the center of the sarcomere.
9. ATP binds to myosin, causing it to release actin and reset for another cycle.
10. This cycle repeats as long as Ca²⁺ and ATP are present.
16.what are the anaerobic sources of energy for muscle contraction? -
ANSWER phosphagen system (creatine phosphate) and anaerobic glycolysis
, 17.Compare and contrast the different types of muscles based on the
predominant fiber type present. - ANSWER 1. Slow oxidative (Type I):
High endurance, lots of mitochondria, red color, used in posture and
endurance activities.
2. Fast oxidative (Type IIa): Intermediate fatigue resistance and speed, aerobic
and anaerobic capacity.
3. Fast glycolytic (Type IIb/x): Fatigue quickly, strong, white color, used in
short bursts of power.
18.twitch - ANSWER A single, brief contraction and relaxation of a muscle
fiber.
19.treppe (staircase effect) - ANSWER Repeated stimuli cause progressively
stronger twitches as Ca²⁺ builds up.
20.tetany - ANSWER Sustained muscle contraction due to rapid, repeated
stimulation without relaxation.
21.non gated ion channels - ANSWER aka leak channels
always open
always allowing some Na+ in and more K+ out
22.gated ion channels - ANSWER open and close in response to stimuli, at
RMP, the gated channels are closed
two types:
