exam 2

A&P

The axial skeleton includes ________.

Question options:

A)  arms, legs, hands, and feet

B)  the skull, vertebral column, and rib cage

C)  the skull, the scapula, and the vertebral column

D)  the skull, vertebral column, and pelvis

B) the skull, vertebral column, and rib cage

Using the figure, match the following: Attach to ribs. Type the letter.

B

What are the major functions of the intervertebral discs?

Question options:

A)  to prevent hyperextension and allow rotation of the spine

B)  to hold together the vertebra and support the body

C)  to absorb shock and provide flexibility to the spine

D)  to remove curvatures of the spine and provide springiness to the spinal column

C) to absorb shock and provide flexibility to the spine

When administering chest compression to someone whose heart has stopped beating, the heel of the hand should be placed on the sternum on a line drawn between the nipples. Why would it be a problem if the hand was placed at a lower part of the sternum?

Question options:

A)  the compressions could close the jugular notch and block the airway where it enters the chest

B)  the compressions could separate the sternal angle and tear the cartilage of the second rib

C)  the compressions could crush the floating ribs, which have no cartilage in front to protect them

D)  the compressions could break the xiphoid process and drive it into the heart, diaphragm or liver

D) the compressions could break the xiphoid process and drive it into the heart, diaphragm or liver

Suppose a headline says: "Pushing on the left side of the chest breaks ribs 100 percent of the time, twice as often as the standard push." The study behind it compressed the chests of six donated bodies. Ribs broke in four of the four bodies pushed on the left, and in one of the two bodies given the standard push. Which statement best describes the headline?

Question options:

A)  It is supported, because 100 percent against 50 percent is a difference of two to one in any study.

B)  It goes beyond the data, because donated bodies in a study can never tell us anything about living patients.

C)  It is supported, because all four of the bodies in the left-sided group showed exactly the same result.

D)  It goes beyond the data, because the standard group was only two bodies, so one body moves it 50 points.

D) It goes beyond the data, because the standard group was only two bodies, so one body moves it 50 points.

As a person ages, the costal cartilages ossify, that is, they turn to bone. The best prediction for the thoracic cage of an 85-year-old is that it

Question options:

A)  becomes more flexible, because bone is lighter and thinner than the cartilage that it has replaced

B)  becomes larger, because ossified cartilage adds length to each one of the seven true ribs

C)  becomes more rigid, because the part that let the ribs bend at the sternum is now bone

D)  is unchanged, because the ribs never depended on their cartilages for any of their movement at all

C) becomes more rigid, because the part that let the ribs bend at the sternum is now bone

A nurse who needs to count a patient's ribs starts at the sternal angle because

Question options:

A)  the floating ribs end there, so counting upward from that point reaches every other rib

B)  the second rib attaches to the sternum there, and the first rib is hidden behind the clavicle

C)  the first rib attaches to the sternum there, and it is the easiest of the ribs to feel

D)  the xiphoid process ends there, and the seventh rib always lies directly beside its tip

B) the second rib attaches to the sternum there, and the first rib is hidden behind the clavicle

A patient's blood potassium is far too high. The resting membrane potential of her cells

Question options:

A)  becomes more negative - more potassium means more charge, so more K+ leaves and more negative charge is left inside

B)  flips positive and stays there - the extra K+ rushes in and the pump cannot push it back out

C)  moves toward zero - a smaller gradient, so less K+ leaves and less negative charge is left behind inside

D)  is unchanged - the charge inside does not depend on the fluid outside, only on the proteins in the cell

C) moves toward zero - a smaller gradient, so less K+ leaves and less negative charge is left behind inside

In the figure, the region labelled C is the

Question options:

A)  sacral region

B)  thoracic region

C)  cervical region

D)  lumbar region

D) lumbar region

What are the major functions of the intervertebral discs?

Question options:

A)  to remove curvatures of the spine and provide springiness to the spinal column

B)  to absorb shock and provide flexibility to the spine

C)  to prevent hyperextension and allow rotation of the spine

D)  to hold together the vertebra and support the body

B) to absorb shock and provide flexibility to the spine

The soft, gel-like center of an intervertebral disc is called the

Question options:

A)  anulus fibrosus

B)  intervertebral foramen

C)  vertebral foramen

D)  nucleus pulposus

D) nucleus pulposus

A patient lifts a heavy box, feels a sharp pain in the lower back, and over the next day the pain runs down the back of one leg. Which best explains the leg pain?

Question options:

A)  the gel center of a lumbar disc pushed through its weakened outer ring and presses on a spinal nerve

B)  the body of a lumbar vertebra cracked under the load and the broken edge presses on a leg muscle

C)  the lumbar curvature reversed under the load and the straightened column stretches a leg muscle

D)  the spinal cord was crushed between two lumbar vertebrae and the cord carries the leg's nerves

A) the gel center of a lumbar disc pushed through its weakened outer ring and presses on a spinal nerve

An older adult is measured and is shorter than at age 25. Which best explains the lost height?

Question options:

A)  the vertebral bodies grow taller with age, so each disc is squeezed shorter

B)  the nucleus pulposus of each disc loses water with age, so each disc becomes thinner

C)  the lumbar curvature straightens with age, so the column becomes shorter

D)  the anulus fibrosus of each disc thickens with age, so each disc becomes stiffer

B) the nucleus pulposus of each disc loses water with age, so each disc becomes thinner

From the neck down, the vertebral column has how many cervical, thoracic and lumbar vertebrae?

Question options:

A)  5, 12 and 7

B)  7, 5 and 12

C)  7, 12 and 5

D)  12, 7 and 5

C) 7, 12 and 5

The cervical and lumbar curvatures of the vertebral column

Question options:

A)  are the same kind of curve as the thoracic and sacral ones

B)  are present at birth, as part of the fetal C shape

C)  appear only in old age, as the discs lose their water

D)  develop after birth, as a baby lifts its head and then stands

D) develop after birth, as a baby lifts its head and then stands

The elbow is ________ to the wrist, and the wrist is ________ to the fingers.

Question options:

A)  distal; proximal

B)  proximal; proximal

C)  proximal; distal

D)  distal; distal

B) proximal; proximal

In the figure, the structure labelled C is the

Question options:

A)  fibrous layer of the capsule

B)  synovial membrane

C)  periosteum

D)  articular cartilage

D) articular cartilage

Which of these joints has a joint cavity between the bones?

Question options:

A)  the pubic symphysis between the two hip bones

B)  the knee between the femur and the tibia

C)  a suture between two bones of the skull

D)  a tooth held in its socket in the jaw

B) the knee between the femur and the tibia

Torn articular cartilage heals poorly because it

Question options:

A)  has no blood vessels to bring in cells and nutrients

B)  is bathed in synovial fluid that dissolves new tissue

C)  is made of bone cells that have stopped dividing

D)  is too thin for the body to lay down new layers

A) has no blood vessels to bring in cells and nutrients

An older adult's hip aches, and an X-ray shows the cartilage on the head of the femur worn thin. Which tissue is most likely sending the pain?

Question options:

A)  the worn articular cartilage, because the bone ends now grind on it

B)  the ligament of the head of the femur, because it stretches as the cartilage thins

C)  the synovial membrane lining the capsule, because it has nerves and vessels

D)  the synovial fluid, because it thickens with age and no longer lubricates

C) the synovial membrane lining the capsule, because it has nerves and vessels

A headline says a new knee procedure "delivers lasting pain relief," because in 194 people the median pain fell from 7 to 3 out of 10 over a year after the procedure, and every patient had the procedure. Which verdict is best?

Question options:

A)  Supported, because the beads dissolve in hours, so nothing else could explain it.

B)  Supported, because 194 is a large number of knees and the drop lasted a year.

C)  Not yet shown, because no group got the same procedure without the treatment.

D)  Not supported, because pain is a feeling and a feeling cannot be measured.

C) Not yet shown, because no group got the same procedure without the treatment.

The sound of a cracking knuckle comes from

Question options:

A)  the two bone ends striking each other as the joint closes

B)  a bubble of gas bursting as the articular cartilage flexes

C)  a ligament snapping across a bony bump as the joint bends

D)  a gas cavity opening in the synovial fluid as the bone ends separate

D) a gas cavity opening in the synovial fluid as the bone ends separate

The joint that moves the most is also the one that

Question options:

A)  has the thickest articular cartilage

B)  dislocates the most easily

C)  carries the most body weight

D)  has the deepest socket

B) dislocates the most easily

The wall of a capillary, where oxygen and nutrients leave the blood for the tissues, is lined by

Question options:

A)  stratified squamous epithelium: many layers of flat cells, a thick wall to keep the blood in

B)  simple squamous epithelium: one layer of flat cells, the shortest path for diffusion

C)  transitional epithelium: several layers of rounded cells, so the vessel can stretch

D)  simple cuboidal epithelium: one layer of cube-shaped cells, built to absorb the oxygen

B) simple squamous epithelium: one layer of flat cells, the shortest path for diffusion

Which joints are correctly matched?

Question options:

A)  ankle; hinge

B)  interphalangeal; plane

C)  wrist; saddle

D)  knee; pivot

A) ankle; hinge

Starting from the anatomical position, turning the forearm so that the palm faces backward is called

Question options:

A)  pronation, as the ulna turns and crosses over the radius

B)  medial rotation, as the humerus turns at the shoulder

C)  supination, as the radius turns and crosses over the ulna

D)  pronation, as the radius turns and crosses over the ulna

D) pronation, as the radius turns and crosses over the ulna

After a hip replacement, a patient is told not to cross the legs. Crossing one leg over the other is

Question options:

A)  extension of the hip, taking the thigh behind the body

B)  adduction of the hip, bringing the thigh across the midline

C)  abduction of the hip, taking the thigh away from the midline

D)  flexion of the hip, raising the thigh toward the trunk

B) adduction of the hip, bringing the thigh across the midline

The ligaments that protect the alignment of the femoral and tibial condyles and limit the movement of the femur anteriorly and posteriorly are called

Question options:

A)  cruciate ligaments

B)  patellar ligaments

C)  tibial collateral ligaments

D)  anterior ligaments

A) cruciate ligaments

A three-year-old is pulled up by one hand. Now she holds the forearm still, palm down, and cries when anyone turns her palm up. Which structure has most likely slipped?

Question options:

A)  the head of the humerus, down and out of the glenoid cavity

B)  the head of the radius, partly out from under the anular ligament

C)  the trochlea of the humerus, out of the trochlear notch of the ulna

D)  the olecranon of the ulna, off the back of the humerus

B) the head of the radius, partly out from under the anular ligament

Compared to the shoulder, displacements of the hip joints are

Question options:

A)  rare because of the ligament reinforcement

B)  rare because the rotator cuff stabilizes the hip joint

C)  common due to the weight bearing the hip endures

D)  common in all people who are overweight

A) rare because of the ligament reinforcement

Ten years of one hospital's records show the elbow came back out less often after the palm-down twist than after the palm-up twist. Each of 29 surgeons chose the twist he or she preferred. A headline says the palm-down twist prevents repeat injuries. Which verdict is best?

Question options:

A)  Not yet shown, because the surgeons chose the twists, so the two groups may differ.

B)  Supported, because trials that assigned the twist found it works better the first time.

C)  Supported, because the records cover more than a thousand children over ten years.

D)  Not supported, because a repeat injury depends only on a child's own ligaments.

A) Not yet shown, because the surgeons chose the twists, so the two groups may differ.

A digestive enzyme made for export leaves the cell by this route:

Question options:

A)  the Golgi apparatus, then a ribosome on the rough ER, then a vesicle that fuses with the plasma membrane, then out

B)  the smooth ER, then the nucleus, then a vesicle that fuses with the nuclear envelope, then out

C)  a lysosome, then a mitochondrion, then a vesicle that fuses with the plasma membrane, then out

D)  a ribosome on the rough ER, then the Golgi apparatus, then a vesicle that fuses with the plasma membrane, then out

D) a ribosome on the rough ER, then the Golgi apparatus, then a vesicle that fuses with the plasma membrane, then out

A heart drug binds myosin and holds some of its heads back from actin. During each heartbeat, what happens in the heart muscle's sarcomeres?

Question options:

A)  They stop shortening, because a sarcomere needs every myosin head attached before it can move at all.

B)  They still shorten as the thin filaments slide, but fewer cross bridges pull, so the force is smaller.

C)  Their Z discs come apart, so the sarcomeres lose their alignment and the heart wall becomes thinner.

D)  Their thick filaments shorten less, so the A bands stay wider and the heart squeezes more gently.

B) They still shorten as the thin filaments slide, but fewer cross bridges pull, so the force is smaller.

Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer overlapped,

Question options:

A)  maximum force production would result because the muscle has a maximum range of travel

B)  ATP consumption would increase because the sarcomere is "trying" to contract

C)  cross bridge attachment would be optimum because of all the free binding sites on actin

D)  no muscle tension could be generated

D) no muscle tension could be generated

The sliding filament model of contraction involves

Question options:

A)  actin and myosin sliding past each other and partially overlapping

B)  actin and myosin lengthening in order to slide past each other

C)  the Z discs sliding over the myofilaments

D)  the shortening of thick filaments so that thin filaments slide past

A) actin and myosin sliding past each other and partially overlapping

Which of the following surrounds an individual muscle cell?

Question options:

A)  perimysium

B)  fascicle

C)  epimysium

D)  endomysium

D) endomysium

When a sarcomere contracts and thin filaments move over thick filaments you would expect to see

Question options:

A)  the I bands to appear wider

B)  the H zone to appear wider

C)  the I bands to appear smaller

D)  the A band to appear darker

C) the I bands to appear smaller

A)  I band

B)  Z disc

C)  H zone

D)  A band

D) A band

During development embryonic cells will fuse to form muscle fibers. This will result in

Question options:

A)  interlocking of cells that can prevent the filaments from sliding

B)  multinucleated muscle fibers that can extend as long as 30 centimeters

C)  the coordination of nerve signals to muscle fibers

D)  the striations that appear in skeletal and cardiac muscle tissues

B) multinucleated muscle fibers that can extend as long as 30 centimeters

The wall of a capillary, where oxygen and nutrients leave the blood for the tissues, is lined by

Question options:

A)  stratified squamous epithelium: many layers of flat cells, a thick wall to keep the blood in

B)  transitional epithelium: several layers of rounded cells, so the vessel can stretch

C)  simple cuboidal epithelium: one layer of cube-shaped cells, built to absorb the oxygen

D)  simple squamous epithelium: one layer of flat cells, the shortest path for diffusion

D) simple squamous epithelium: one layer of flat cells, the shortest path for diffusion

A toxin stops axon terminals from releasing acetylcholine. When the motor neuron fires, what happens at the muscle fiber?

Question options:

A)  The fiber fires an action potential, but its sarcoplasmic reticulum keeps all of its calcium.

B)  No end plate potential forms, so the fiber fires no action potential and stays relaxed.

C)  The fiber contracts and cannot relax, because acetylcholine builds up in the synaptic cleft.

D)  The fiber contracts weakly, because calcium still enters the axon terminal and the muscle.

B) No end plate potential forms, so the fiber fires no action potential and stays relaxed.

If a muscle fiber were to suddenly and permanently stop producing ATP the fiber would no longer be able to actively transport calcium out of the cytoplasm (sarcoplasm) and the intracellular calcium concentration would rise. Which of the following would you expect to happen?

Question options:

A)  No change would occur in a muscle that was relaxed to begin with, because a relaxed fiber does not need any ATP.

B)  The fiber would twitch uncontrollably, because the excess calcium bound to troponin would keep firing new contractions.

C)  Myosin would be able to bind to the exposed binding sites on thin filaments but it would not be able to detach.

D)  Calcium would be transported back into the sarcoplasmic reticulum, therefore all contractions would cease and the fiber would relax.

C) Myosin would be able to bind to the exposed binding sites on thin filaments but it would not be able to detach.

Curare is a poisonous plant extract. Curare molecules have a chemical structure like the neurotransmitter ACh. Curare can bind to the ACh receptor site on the chemically gated ion channels in the motor end plate. Even though curare will bind to the receptor site it will not open the ion channel and no ions will pass through. What do you think the symptoms of curare poisoning would look like?

Question options:

A)  Curare will only affect cardiac muscle, causing fibrillations of the heart.

B)  Curare will only affect muscles with ACh receptors, paralyzing them.

C)  Muscles will respond too quickly and cause a severe tremor.

D)  Smooth muscles will become stimulated causing quick movement of nutrients through the digestive system.

B) Curare will only affect muscles with ACh receptors, paralyzing them.

After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction?

Question options:

A)  acetylcholinesterase breaks apart the ACh

B)  the tropomyosin blocking the myosin once full contraction is achieved

C)  the action potential stops going down the overloaded T tubules

D)  calcium ions returning to the terminal cisternae

A) acetylcholinesterase breaks apart the ACh

What is the role of tropomyosin in skeletal muscles?

Question options:

A)  Tropomyosin is the chemical that activates the myosin heads.

B)  Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.

C)  Tropomyosin is the receptor for the motor neuron neurotransmitter.

D)  Tropomyosin serves as a contraction inhibitor by blocking the actin binding sites on the myosin molecules.

B) Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.

Question options:

A)  synaptic vesicles

B)  calcium ions

C)  ion channels

D)  postsynaptic membrane

A) synaptic vesicles

What structure in skeletal muscle cells functions in calcium storage?

Question options:

A)  mitochondria

B)  myofibrillar network

C)  intermediate filament network

D)  sarcoplasmic reticulum

D) sarcoplasmic reticulum

In one cycle, the sodium-potassium pump

Question options:

A)  moves 3 Na+ out of the cell and 2 K+ in, against their gradients, spending one ATP

B)  moves 3 Na+ into the cell and 2 K+ out, down their gradients, spending no ATP at all

C)  moves equal numbers of ions each way, down their gradients, so the cell's charge does not change

D)  moves water into the cell along with the sodium, against its gradient, spending one ATP

A) moves 3 Na+ out of the cell and 2 K+ in, against their gradients, spending one ATP

After two weeks of bed rest following surgery, a patient's muscles have lost mass. Which muscles would you expect to have lost the most, and why?

Question options:

A)  The heart, because cardiac muscle stops contracting strongly during long bed rest

B)  The calf muscles that hold you upright, whose slow fibers lost their all-day load

C)  All muscles equally, because bed rest removes the same load from every muscle

D)  The arm muscles, because a patient in bed no longer lifts or carries anything

Selected

B)The calf muscles that hold you upright, whose slow fibers lost their all-day load

A marathoner's calf muscle and a sprinter's calf muscle are sampled. The marathoner's sample is redder and has more capillaries around each fiber. What best explains the difference?

Question options:

A)  More slow oxidative fibers, rich in myoglobin and mitochondria, built for long, steady work

B)  More myofibrils in every fiber, because long runs add thickness to each muscle fiber

C)  More blood pooled inside the muscle, because long runs leave the fibers filled with blood

D)  More fast glycolytic fibers, rich in glycogen, built for short bursts of powerful work

A) More slow oxidative fibers, rich in myoglobin and mitochondria, built for long, steady work

Reduction in blood flow to a muscle fiber would have the greatest effect on

Question options:

A)  both slow and fast oxidative

B)  fast oxidative fibers

C)  slow oxidative fibers

D)  fast glycolytic fibers

C) slow oxidative fibers

Exhaustion of glycogen storage within a muscle fiber would have the biggest effect on

Question options:

A)  slow oxidative fibers

B)  both slow and fast oxidative fibers

C)  fast oxidative fibers

D)  fast glycolytic fibers

D) fast glycolytic fibers

Most skeletal muscles contain

Question options:

A)  a mixture of fiber types

B)  muscle fibers of the same type

C)  a predominance of fast oxidative fibers

D)  a predominance of slow oxidative fibers

A) a mixture of fiber types

Which of the following describes the cells of unitary smooth muscle?

Question options:

A)  They consist of muscle fibers that are structurally independent of each other.

B)  They exhibit spontaneous action potentials.

C)  They depend upon recruitment using the autonomic nervous system.

D)  They are used for vision and hair raising.

B) They exhibit spontaneous action potentials.

The mechanism of contraction in smooth muscle is different from skeletal muscle in that

Question options:

A)  actin and myosin interact by the sliding filament mechanism

B)  ATP energizes the sliding process

C)  the trigger for contraction is a rise in intracellular calcium

D)  the site of calcium binding differs

D) the site of calcium binding differs

In the figure, the structure labelled C is the

Question options:

A)  H zone

B)  I band

C)  M line

D)  A band

B) I band

A weightlifter tears the tendon that attaches the biceps brachii to the forearm. She can still bend her elbow, though weakly. What best explains this?

Question options:

A)  The biceps brachii still pulls on the forearm through its two heads at the shoulder

B)  The antagonist on the back of the arm now pulls the forearm up instead of down

C)  The deltoid, the prime mover at the shoulder, bends the elbow once the biceps fails

D)  The brachialis and brachioradialis, synergists of elbow flexion, still pull on the forearm

D) The brachialis and brachioradialis, synergists of elbow flexion, still pull on the forearm

A headline says Achilles tendon injuries in the NBA are a new trend, because a medical news site counted seven in one season. Which verdict on the headline is best?

Question options:

A)  Supported, because seven injuries in a single season is a large number for any one league

B)  Not yet supported, because seven means little without the usual number in earlier seasons

C)  Supported, because several of the injuries happened to famous players during the playoffs

D)  Not supported, because the injured players are all expected to recover after surgery

B) Not yet supported, because seven means little without the usual number in earlier seasons

What is a muscle that provides the major force for producing a specific movement called?

Question options:

A)  an antagonist (opposing muscle)

B)  a synergist (helping muscle)

C)  an agonist (prime mover)

D)  a fixator (stabilizing muscle)

C) an agonist (prime mover)

Which of the following muscles inserts to the posterior calcaneus via the calcaneal tendon?

Question options:

A)  the tibialis anterior

B)  the gastrocnemius

C)  the sartorius

D)  the semitendinosus

B) the gastrocnemius

Which of the following muscles serves as a common intramuscular injection site, particularly in infants as the buttocks and arm muscles are poorly developed?

Question options:

A)  the vastus lateralis

B)  rectus femoris

C)  the vastus intermedius

D)  the vastus medialis

A) the vastus lateralis

Which of the following is NOT a muscle primarily involved in the breathing process?

Question options:

A)  diaphragm

B)  latissimus dorsi

C)  internal intercostal

D)  external intercostal

B) latissimus dorsi

When the calf muscles contract to lift the heel, what shortens inside each muscle fiber?

Question options:

A)  The thick and thin filaments themselves, which coil up as they work

B)  The sarcomeres, as the thin filaments slide past the thick ones

C)  The nuclei of the fiber, which squeeze closer together as it works

D)  The tendon fibers, which shrink to pull the heel bone upward

B) The sarcomeres, as the thin filaments slide past the thick ones

In the figure, the lever labelled A is a

Question options:

A)  second-class lever

B)  first-class lever

C)  third-class lever

D)  fourth-class lever

B) first-class lever

A headline says contaminated water paralyzed more than 200 people in one city. The outbreak study found a stomach bacterium in 72 of 148 patients tested, in 1 of 208 water samples, and in chicken droppings. Which verdict on the headline is best?

Question options:

A)  Supported, because the bacterium was found in one water sample, and one positive sample proves the water carried it.

B)  Not supported as stated: what was measured was the bacterium in the patients and the chickens, almost never in the water.

C)  Supported, because more than 200 cases in one city within a few weeks can only come from a shared water supply.

D)  Not supported, because a stomach bacterium cannot cause a nerve disease, so the cases cannot be an outbreak at all.

B) Not supported as stated: what was measured was the bacterium in the patients and the chickens, almost never in the water.

An experimental drug kills oligodendrocytes and nothing else. Over the following weeks, which nerve fibers lose their myelin?

Question options:

A)  None of them, because the myelin already laid down stays in place after the cell that made it dies.

B)  Fibers in the brain and spinal cord only, because oligodendrocytes make the myelin there.

C)  Fibers in the nerves of the limbs only, because oligodendrocytes make the myelin out there.

D)  Every myelinated fiber in the body, because oligodendrocytes make all of the body's myelin.

B) Fibers in the brain and spinal cord only, because oligodendrocytes make the myelin there.

Schwann cells are functionally similar to which of the following cells?

Question options:

A)  ependymal cells, which line the cavities

B)  astrocytes, which cling to capillaries

C)  microglia, which clean up debris

D)  oligodendrocytes, which wrap axons in myelin

D) oligodendrocytes, which wrap axons in myelin

These cells in the central nervous system have cilia that move in order to circulate cerebrospinal fluid.

Question options:

A)  ependymal cells

B)  oligodendrocytes

C)  Schwann cells

D)  astrocytes

A) ependymal cells

Some axons of the peripheral nervous system have the ability to regenerate after damage has occurred. Which of the following cells is most responsible for aiding in this regeneration?

Question options:

A)  astrocytes

B)  satellite cells

C)  Schwann cells

D)  oligodendrocytes

C) Schwann cells

The term central nervous system refers to the

Question options:

A)  somatic nerves

B)  spinal nerves

C)  brain and spinal cord

D)  sensory (afferent) nerves

C) brain and spinal cord

In the figure, the neuron labelled A is a

Question options:

A)  sensory neuron

B)  multipolar neuron

C)  unipolar neuron

D)  bipolar neuron

B) multipolar neuron

A neuron at rest keeps more sodium outside and more potassium inside. In each cycle, the pump that does this moves

Question options:

A)  3 sodium ions out and 2 potassium ions in, spending one ATP

B)  3 potassium ions out and 2 sodium ions in, spending one ATP

C)  3 sodium ions out and 2 potassium ions in, making one ATP

D)  equal numbers of sodium and potassium both ways, spending no ATP

A) 3 sodium ions out and 2 potassium ions in, spending one ATP

A 2026 report says that after surgery, 76 percent of patients taking a new non-opioid painkiller needed no opioid at all. That study followed 47 patients who all took the drug, with no comparison group. Earlier, two trials of about 1,100 patients each compared the drug with a placebo and with an opioid tablet: it relieved pain better than the placebo and did not beat the opioid. Which verdict on the 76 percent claim is best?

Question options:

A)  Weak on its own: with no comparison group, nobody knows how many would have skipped opioids anyway, so the trials against placebo are the real evidence.

B)  Worthless: a drug that did not beat an opioid tablet in the trials cannot be relieving any pain at all, so the 76 percent is noise.

C)  Strong on its own: 76 percent is a large majority of the patients, so the drug clearly works better than the opioid tablet does.

D)  Strong on its own: 47 patients is a large enough group for any result to count as proof, whatever the earlier trials found.

Selected

A) Weak on its own: with no comparison group, nobody knows how many would have skipped opioids anyway, so the trials against placebo are the real evidence.

A toxin from a pufferfish blocks the voltage-gated sodium channels of a nerve fiber and nothing else. The fiber's resting membrane potential is normal. What happens when a stimulus depolarizes that fiber to threshold?

Question options:

A)  The action potential fires normally, because the resting potential, not sodium entry, is what drives the spike.

B)  No action potential fires, because sodium cannot rush in to drive the depolarizing phase past threshold.

C)  A larger action potential fires than usual, because the potassium channels open earlier to make up the loss.

D)  An action potential fires but travels backward along the fiber, because blocked channels reverse its direction.

B) No action potential fires, because sodium cannot rush in to drive the depolarizing phase past threshold.

Immediately after an action potential has peaked, which of the following channels will open?

Question options:

A)  voltage-gated potassium channels

B)  chemically-gated chloride channels

C)  voltage-gated calcium channels

D)  voltage-gated sodium channels

A) voltage-gated potassium channels

Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials?

Question options:

A)  voltage-gated channel

B)  mechanically-gated channel

C)  ligand-gated channel

D)  leakage channel

A) voltage-gated channel

The period after an initial stimulus when a neuron is not sensitive to another stimulus is

Question options:

A)  the absolute refractory period

B)  the depolarization phase

C)  the repolarization phase

D)  the resting period

A) the absolute refractory period

Saltatory conduction is made possible by

Question options:

A)  diphasic impulses

B)  the myelin sheath

C)  large axons

D)  erratic transmission of action potentials

B) the myelin sheath

Which of the following is NOT true of graded potentials?

Question options:

A)  They increase amplitude as they move away from the stimulus point.

B)  They can be called postsynaptic potentials at a synapse.

C)  They can form on the receptor endings of sensory neurons.

D)  They are short-lived changes in the membrane potential.

A) They increase amplitude as they move away from the stimulus point.

A poison stops every sodium-potassium pump in a neuron and nothing else. Over the next hours, what happens to the neuron's resting membrane potential?

Question options:

A)  It becomes more negative, because potassium is no longer pumped into the cell to cancel the charge.

B)  It vanishes at once, because the pump's own current is what makes the inside negative in the first place.

C)  It stays exactly the same forever, because the leak channels set the voltage and need no gradients.

D)  It fades toward zero, because the sodium and potassium gradients the pump maintained slowly run down.

D) It fades toward zero, because the sodium and potassium gradients the pump maintained slowly run down.

A report describes four children with tetanus whose muscles went rigid and spasmed. The toxin does not damage muscle or motor axons; it is carried into the spinal cord, and it is known to cut a protein that synaptic vesicles need in order to fuse. A classmate claims the toxin must be making the motor neurons' action potentials bigger. Which verdict on that claim is best?

Question options:

A)  Supported: muscles that contract harder must be receiving bigger action potentials from their nerves, because the size of the spike sets the force.

B)  Ruled out: the toxin never damages muscle, which proves it never reached the nervous system at all and must have acted somewhere else entirely.

C)  Ruled out: an action potential is all-or-none and cannot get bigger, and a toxin that stops vesicles fusing acts on release, not on the spike.

D)  Supported: a vesicle protein is part of the axon's membrane, so cutting it would change the shape of every action potential that passes along it.

C) Ruled out: an action potential is all-or-none and cannot get bigger, and a toxin that stops vesicles fusing acts on release, not on the spike.

At an excitatory synapse, the neurotransmitter is normally cleared by a reuptake pump in the presynaptic membrane. A drug blocks that pump and does nothing else. What happens at that synapse when the presynaptic neuron fires?

Question options:

A)  The action potential cannot reach the terminal, because the pump is what carries it along the final stretch of axon.

B)  The postsynaptic cell is hyperpolarized instead of depolarized, because a blocked pump turns an EPSP into an IPSP.

C)  No transmitter is released at all, because the pump is what moves the vesicles up to the terminal's membrane.

D)  The transmitter stays in the cleft longer, so each EPSP lasts longer and sums more easily toward threshold.

D) The transmitter stays in the cleft longer, so each EPSP lasts longer and sums more easily toward threshold.

Which of the following describes the excitatory postsynaptic potential?

Question options:

A)  opens K+ or Cl- channels

B)  short distance hyperpolarization

C)  short distance depolarization

D)  moves membrane potential away from threshold

C) short distance depolarization

An inhibitory postsynaptic potential (IPSP) is associated with

Question options:

A)  hyperpolarization

B)  opening of voltage-regulated channels

C)  lowering the threshold for an action potential to occur

D)  a change in sodium ion permeability

A) hyperpolarization

If a postsynaptic neuron is stimulated to threshold by spatial summation this implies that

Question options:

A)  the postsynaptic cell has many synapses with many presynaptic neurons

B)  the postsynaptic cell has a lower than normal threshold

C)  the postsynaptic cell has many voltage gated ion channels

D)  the postsynaptic cell is slow to repolarize

A) the postsynaptic cell has many synapses with many presynaptic neurons

If a postsynaptic cell is stimulated to threshold by temporal summation this implies that

Question options:

A)  a presynaptic neuron is sending frequent EPSPs

B)  the postsynaptic cell can be influenced by only one presynaptic cell

C)  the postsynaptic cell is sending frequent action potentials

D)  the presynaptic neuron is sending frequent IPSPs

A) a presynaptic neuron is sending frequent EPSPs

In the figure, the structures labeled C are the

Question options:

A)  postsynaptic receptors

B)  calcium ions

C)  synaptic vesicles

D)  ion channels

C) synaptic vesicles

After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction?

Question options:

A)  acetylcholinesterase breaks apart the ACh

B)  the tropomyosin blocking the myosin once full contraction is achieved

C)  calcium ions returning to the terminal cisternae

D)  the action potential stops going down the overloaded T tubules

A) acetylcholinesterase breaks apart the ACh

A headline says creatine builds muscle even without exercise. In the study, adults who took creatine and did not exercise gained about 2.4 pounds of lean tissue on a DXA scan, more than a placebo group. Which verdict is best?

Question options:

A)  Proven, because a university ran the study and a journal then published it.

B)  Proven, because the scan showed more lean tissue than in the placebo group.

C)  Disproven, because muscle can grow only when a person exercises against a load.

D)  Overstated, because the scan's lean tissue includes water that creatine draws into fibers.

D) Overstated, because the scan's lean tissue includes water that creatine draws into fibers.

You lift a box onto a shelf, lower it slowly back down, and then hold it still at chest height. Which list names the contraction of your biceps in each step, in that order?

Question options:

A)  concentric, then isometric, then eccentric

B)  eccentric, then concentric, then isometric

C)  isometric, then concentric, then eccentric

D)  concentric, then eccentric, then isometric

D) concentric, then eccentric, then isometric

Creatine phosphate functions in the muscle cell by

Question options:

A)  forming a chemical compound with actin that exposes its binding sites

B)  inducing a conformational change in the myofilaments that starts a power stroke

C)  forming a temporary chemical compound with myosin that holds each cross bridge

D)  storing energy that will be transferred to ADP to resynthesize ATP

D) storing energy that will be transferred to ADP to resynthesize ATP

Which of the following is the correct order for the phases of a muscle twitch?

Question options:

A)  contraction, relaxation, latent

B)  relaxation, contraction, latent

C)  latent, contraction, relaxation

D)  latent, relaxation, contraction

C) latent, contraction, relaxation

What is the primary function of wave summation?

Question options:

A)  produce smooth, continuous muscle contraction

B)  prevent the muscle from relaxing at all

C)  prevent the muscle from tiring during use

D)  increase the tension of each single twitch

A) produce smooth, continuous muscle contraction

Which of the following would be recruited later in muscle stimulation when contractile strength increases?

Question options:

A)  many small motor units with the ability to stimulate other motor units

B)  motor units with larger, less excitable neurons

C)  motor units with the longest muscle fibers

D)  large motor units with small, highly excitable neurons

B) motor units with larger, less excitable neurons

The 100-meter dash is a quick and short run requiring explosive speed. On completion of the dash, the runners will continue to breathe hard for several seconds to minutes even though they are no longer running. Which of the following is the best explanation for why this is so?

Question options:

A)  The runners' fast oxidative muscles are so slow to utilize oxygen, they only begin aerobic respiration by the time the run has finished.

B)  Slow oxidative fibers are recruited last and have only started to work at completion of the run.

C)  Since the exercise was mostly aerobic exercise, the runners' bodies have not yet realized the run is over.

D)  The runners' use of stored oxygen, glucose, and creatine phosphate is being replenished and this requires a prolonged increase of oxygen intake.

D) The runners' use of stored oxygen, glucose, and creatine phosphate is being replenished and this requires a prolonged increase of oxygen intake.

The elbow is ________ to the wrist, and the wrist is ________ to the fingers.

Question options:

A)  proximal; distal

B)  distal; distal

C)  proximal; proximal

D)  medial; lateral

B) distal; distal

In April 2026 the CDC warned clinicians that people arriving after an overdose may breathe again once naloxone is given and still show profound, often prolonged sedation, because a second drug in the supply acts at an adrenergic receptor rather than an opioid one. A classmate says this proves naloxone must have worn off within seconds. Which verdict on that claim is best?

Question options:

A)  Ruled out: naloxone is known to last for many hours, which proves no second drug was ever involved in these cases at all.

B)  Ruled out: the breathing stayed restored, which means the naloxone was still occupying opioid receptors the whole time.

C)  Supported: a drug whose effect ends quickly explains every finding here, since the sedation returned once the blocker was gone.

D)  Supported: the sedation outlasting the reversal shows the blocker must leave the receptor long before the opioid does.

B) Ruled out: the breathing stayed restored, which means the naloxone was still occupying opioid receptors the whole time.

A neuron carries channel-linked receptors for one transmitter and G protein-linked receptors for another. A drug blocks the G protein-linked receptors only, and does nothing else. What happens at that neuron?

Question options:

A)  Every response of the neuron stops at once, because a blocked receptor cannot pass a signal of any kind onward.

B)  The fast, brief responses continue as before, and the slower changes that reach the genes are lost.

C)  The neuron depolarizes continuously, because blocking any receptor leaves its ion channel stuck in the open position.

D)  The fast responses are lost first, because a channel-linked receptor needs a G protein to open its own channel.

B) The fast, brief responses continue as before, and the slower changes that reach the genes are lost.

The effect of acetylcholine can be stimulating or inhibiting. Which of the following gives the best explanation for why this is so?

Question options:

A)  Different postsynaptic cells will have different receptors.

B)  Acetylcholine has many different forms.

C)  Postsynaptic cells have a dynamic and changing metabolism and respond differently at different times.

D)  Acetylcholine has a dose effect, so larger doses are stimulating while small doses inhibit.

A) Different postsynaptic cells will have different receptors.