SCDV 108 Exam 3 Anatomy and Physiology (50pts)
Use the answer sheet to fill in your answers.
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Date:____________________
1. In most cases, skeletal muscle cells may be functionally classified as __________ muscle.
(1pt)
a) Voluntary
b) Involuntary
c) Polarized
d) Fusiform
e) Unstriated
2. The plasma membrane of a muscle fiber is called the ____________ and its cytoplasm is
called the ________________________. (1pt)
a) Neurolemma, cytosol
b) Muscle membrane, myoplasm
c) Sarcolemma, sarcoplasm
d) Sarcolemma, sarcoplasmic reticulum
3. What is the purpose of the triad? (1pt)
a) The triad stores sodium.
b) The triad synthesizes ATP.
c) The triad maintains the resting membrane potential.
d) The triad removes acetylcholine from the synaptic cleft.
e) The triad allows for Ca2+ release when a muscle fiber is excited.
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4. The process of muscle contraction and relaxation has four major phases. These phases are 1)
excitation, 2) excitation-contraction coupling, 3) contraction, and 4) relaxation. The following
questions relate to these major phases.
Excitation-contraction coupling refers to events that link action potentials on the sarcolemma
to activation of the myofilaments preparing them to contract. Action potentials spread from the
motor end plate in all directions. When the excitation reaches _________, it propagates down
them into the cell interior. Action potentials open voltage-gated ion channels in ___________
that ultimately open channels that release _____________from sarcoplasmic reticulum. (1pt)
a) Actin, Tropomyosin, sodium
b) Troponin, Troponin, calcium
c) the T tubules, the T tubules, calcium
d) Mitochondria, A-Band, calcium
5. In the diagram above, which of the following structure carries and facilitates action potentials
that cause ion channels to open in muscle cell organelles? This eventually leads to muscle
contraction. It is part of the “triad”. (1pt)
a) 1
b) 2
c) 3
d) 4
e) 5
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6. In the diagram above, which of the following structures designates the “I” or isotropic band?
(1pt)
a) 1
b) 2
c) 3
d) 4
e) 5
7. Fill in the correct answer:
Arrival of an action potential at the axon terminal of a motor neuron causes the fusion of
acetylcholine-containing synaptic vesicles with the pre-synaptic plasma membrane of the axon
terminal. Acetylcholine then diffuses across the synaptic cleft to bind to and activate
acetylcholine receptors. Activation of the acetylcholine receptors leads to an initial
depolarization BEFORE a skeletal muscle action potential is initiated. The initial depolarization
of the skeletal muscle plasma membrane at the neuromuscular junction is referred to as a
__________________________.(1pt)
8. Which of the following is (are) true about the H zone in a striated muscle sarcomere unit?
a) This zone is the distance between the ends of the thin filaments that extend from
opposite ends (Z disks) of the same sarcomere unit. (1pt)
b) Its length is constant
c) Its length is variable
d) A and B only
e) A and C only
9. The thin filaments of muscle fibers are made of the following protein: (1pt)
a) Actin
b) Myosin
c) Tubulin
d) Albumin
e) Tropomyosin
10. Which of the following is (are) true about the H band or zone in a striated muscle sarcomere
unit? (1pt)
a) This zone is the distance between the ends of the thin filaments that extend from
opposite ends (Z disks) of the same sarcomere unit
b) Its length is constant regardless of relaxation or contraction of the sarcomere
c) Its length varies based on the contraction or relaxation of the sarcomere
d) A and B only
e) A and C only
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11. What happens when acetylcholine stimulates its receptors in the neuromuscular junction?
a) The release of Ca2+ from the sarcoplasmic reticulum decreases. (1pt)
b) The permeability of the sarcolemma to Na+ increases.
c) The positive charge on the sarcolemma decreases.
d) The threshold of the muscle fiber lowers.
12. The image above shows part of the sliding filament theory of muscle contraction where the
muscle is being prepared to contract. Label the four components that you see in the diagram.
(4pts)
1. _________________(don’t forget to name the cation too)
2. __________________
3. ________________(two yellow ovals)
4. __________________
13. Based on the image above, what is happening to the globular head of myosin? (1pt)
a) Cocking and activation
b) Performing the power stroke
c) Cross-bridging
d) Binding calcium
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14. The process of muscle contraction and relaxation has four major phases. These phases are
1) excitation, 2) excitation-contraction coupling, 3) contraction, and 4) relaxation. The following
questions relate to these major phases.
During excitation, an action potential arrives at the axon terminal of a neuron at the
neuromuscular junction and opens voltage-gated calcium channels that (1 pt)
a) stimulate synaptic vesicles to release a neurotransmitter
b) inhibit postsynaptic potentials
c) flood the neuron with inhibitory charges
d) block acetylcholine receptors
15. A volleyball player depends on the gastrocnemius muscles for plantarflexion, whereas a
marathon runner depends more on the soleus muscles for the same action. What characteristic
of the soleus muscles makes this so? (1 pt)
a) They have smaller mitochondria.
b) They have more glycogen in them.
c) They don't have as many blood capillaries per gram of tissue.
d) They make more use of aerobic respiration.
e) They break ATP down to ADP and Pi faster.
16. Fill in the correct answer:
A motor neuron and all of the skeletal muscle fibers it controls are collectively referred to as a
_________________________. (1 pt)
17. Sort each movement by the type of motor unit used to achieve the movement. (3pts)
a) Typing text message
b) Climbing a rope at the CrossFit gym
c) Lifting a 25lb dumbbell over your head
d) Playing the flute
e) Reading your textbook
f) Standing on the deck of a moving boat
Small motor units
1._______________
2.______________
3.______________
Large motor units
4. _______________
5. _______________
6. _______________
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18. A skeletal muscle generates the greatest tension when it is __________. (1 pt)
a) greatly stretched before being stimulated
b) partially stretched before being stimulated
c) fully relaxed before being stimulated
d) well-rested and low in creatine phosphate
e) high in lactate concentration
19. The somatic sensory division of the peripheral nervous system carries signals (1 pt)
a) From receptors in the skin, muscles, bones, and joints
b) To skeletal muscles
c) From viscera of the thoracic cavities mainly
d) To glands, cardiac muscle, and smooth muscle
e) From the spinal cord to muscles
20. Fill in the blank:
Myelinated axons allow the action potential to
"jump" from node to node. This type of action
potential propagation is known as __________
conduction. (1 pt)
21. Label the components in the image above
using some (not all) of the terms listed: Node of
Ranvier, Soma, Myelin, Axon, Axon hillock,
Dendrite, Oligodendrocyte, Astrocyte, Axon
collateral, Synaptic terminal, Neurofibril (6pts)
1.______________
2.______________
3.______________
4.______________
5.______________
6.______________
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22. These glial cells are responsible for the secretion of the cerebrospinal fluid (CSF). (1 pt)
a.
Astrocytes
b.
Oligodendrocytes
c.
Schwann cells
d.
All ependymal cells lining the brain ventricles
e.
Ependymal cells of the choroid plexuses
23. The most abundant glial cells of the nervous system are: (1 pt)
a.
Astrocytes
b.
Oligodendrocytes
c.
Schwann cells
d.
Ependymal cells
e.
Microglia
24. What is occurring in number 2? (1 pt)
a) Action potential from presynaptic neurons are depolarizing the dendrites and soma of the
postsynaptic neuron leading to graded stimulation.
b) The neuron is hyperpolarized at this stage and is unable to carry an action potential.
c) Voltage-gated sodium channels are open along the axon of the postsynaptic neuron
d) The neuron is repolarizing and potassium ions are leaking into the intracellular fluid.
25. What is occurring in number 6 above? (1 pt)
a)
b)
c)
d)
Sodium channels are wide open and sodium is pouring into the intracellular fluid.
Potassium channels are wide open and potassium is pouring in to the intracellular fluid
Slow potassium channels are fully open and potassium is leaving the cell.
The neuron is hyperpolarized at this stage
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26. A change in the membrane potential from the resting value of −50mV to a new value of
−10mV is referred to as: (1 pt)
a. Depolarization
b. Hyperpolarization
c. Repolarization
d. resting membrane potential
27. Which of the following is NOT true about the neuronal action potential? (1 pt)
a) Action potentials are all-or-nothing
b) Action potentials travel along axons in a non-decremental fashion (i.e. does not
decrease)
c) The spike phase of the action potential is due to the opening of voltage-gated Na+
channels
d) Repolarization and hyperpolarization are due to the activity of K+ channels
e) All of the above are true about action potentials
28. For every ATP molecule hydrolyzed by the Na+/K+ ATPase (also referred to as the Na+
pump): (1 pt)
a) 2 Na+ ions are transported into the cell and 3 K+ ions are transported out of the cell
b) 2 Na+ ions are transported out of the cell and 3 K+ ions are transported into the cell
c) 3 Na+ ions are transported into the cell and 2 K+ ions are transported out of the cell
d) 3 Na+ ions are transported out of the cell and 2 K+ ions are transported into the cell
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29. In the diagram above, number 1 refers to (1 pt)
a) The relative refractory phase of an action potential. If a second stimulus is applied to the neuron
(no matter how strong the stimulus), during this phase a second action potential will not be
generated.
b) The absolute refractory phase of an action potential. If a second stimulus is applied to the
neuron (no matter how strong the stimulus), during this phase a second action potential will not
be generated.
c) The tetanus phase of an action potential. If a second stimulus is applied to the neuron (no
matter how strong the stimulus), during this phase a second action potential will not be
generated.
d) The depolarization phase of an action potential. If a second stimulus is applied to the neuron
during this phase, and it is strong, a second action potential will be generated.
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30. Label the diagram below of a spinal cord in traverse section. (4 pts)
1. ______________________________
2.______________________________
3. ______________________________
4._____________________________
31. Which of the following fractures would be the least likely to cause a spinal cord injury? (1
pt)
A fracture of vertebra C2
A fracture of vertebra C6
A fracture of vertebra T5
A fracture of vertebra T12
A fracture of vertebra L4
32. Reflex arcs that only use two neurons are called ____________ reflex arcs. (1 pt)
a) ipsilateral
b) contralateral
c) polysynaptic
d) monosynaptic
e) autonomic
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33. In the patellar tendon reflex arc, the patellar ligament is stretched, which stretches the
quadriceps femoris muscle of the thigh. This reflex will cause the quadriceps femoris to
__________ and the hamstrings to __________. (1 pt)
a)
b)
c)
d)
contract; relax
contract; contract
relax; contract
relax; relax
34. You go to the movies after a long day and you begin to nod off as soon as the movie starts.
Your head starts to lower a little, but a reflex causes your head to rise. This is called the
__________ reflex. (1 pt)
a) tendon
b) crossed extension
c) withdrawal
d) stretch (myotatic)
e) flexor (withdrawal)
35. A nurse pricks your finger to type your blood. You flinch at the pain, pulling your hand back.
This is called the __________ reflex. (1 pt)
a) painful
b) stretch
c) flexor (withdrawal)
d) tendon
e) crossed extension
36. Tendon organs are __________. (1 pt)
a) chemoreceptors
b) visceral receptors
c) proprioceptors
d) pain receptors
e) nociceptors
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