Review Muscular System(lecture)

Question 1

Which list of organs contains smooth muscle tissue?

a) blood vessels, stomach, esophagus
b) bladder, uterus, small intestine
c) biceps brachii, triceps brachii (muscles of the arm)
d) heart
e) both blood vessels, stomach, esophagus and bladder, uterus, small intestine

Answer 1

e) both blood vessels, stomach, esophagus and bladder, uterus, small intestine

Question 2

Which type of muscle tissue is involuntary (can’t be consciously controlled)?

a) skeletal muscle
b) smooth muscle
c) cardiac muscle
d) a and b only
e) b and c only

Answer 2

e) b and c only (Smooth & Cardiac)

Question 3

Which of the following is not a function of skeletal muscle tissue?

a) moving your eyes from left to right as you read this question
b) holding your head up
c) shivering to generate body heat when you’ve become chilled
d) moving food through the small intestine
e) stabilizing joints and helping to maintain body positions

Answer 3

d) moving food through the small intestine

Question 4

Skeletal muscle is covered, surrounded and protected by various layers of connective tissue. Which layer of connective tissue would surround a bundle of muscle fibers (muscle cells)?

a) epimysium
b) hypodermis
c) fascia
d) perimysium
e) endomysium

Answer 4

d) perimysium

Question 5

Muscular tissue has several important properties, such as electrical excitability. Another property of muscular tissue is that it is able to stretch, and return to its original size and shape. Which property of muscular tissue is this?

a) Conductivity
b) Elasticity
c) Extensibility
d) Plasticity
e) None of these are correct

Answer 5

b) Elasticity

Question 6

In the drawing, the circle is indicating a:

a) somatic motor neuron.
b) filament.
c) myofibril.
d) muscle fiber.
e) myofibril fascicle.

Answer 6

d) muscle fiber.

Question 7

Which of the following is not a function of the structure indicated in the image?

a) It is similar to the smooth endoplasmic reticulum found in non-muscle cells.
b) When a muscle cell is contracting, it stores calcium ions.
c) It stores calcium ions in enlarged regions called terminal cisterns.
d) This system of tubules surrounds each myofibril in a muscle cell.

Answer 7

b) WHEN A MUSCLE CELL IS CONTRACTING, IT STORES CALCIUM IONS.

Question 8

The contractile organelle of skeletal muscle fibers is:

a) the endoplasmic reticulum
b) the myofilament
c) the T tubule
d) the myofibril
e) the sarcomere (basic functional unit of a myofibril)

Answer 8

d) the myofibril

Question 9

The site where a somatic motor neuron releases acetylcholine to stimulate a skeletal muscle fiber is called the:

a) neuromuscular junction
b) synaptic end bulbs
c) motor end plate
d) myofibril
e) sarcolemma

Answer 9

a) neuromuscular junction

Question 10

Native people of the Amazon basin in South America use curare, a poison, on arrows and blow darts, to paralyze and bring down small game. Which part of the sequence of events at the neuromuscular junction does curare specifically disrupt?

a) release of acetylcholine (ACh)
b) activation of ACh receptors
c) production of a muscle action potential
d) activation of acetylcholinesterase
e) release of calcium from the terminal cisterns

Answer 10

b) activation of ACh receptors

Question 11

Which of the following molecules found in skeletal muscle cells binds oxygen that can later be used during aerobic metabolism to help generate ATP?

a) creatine
b) creatine phosphate
c) myoglobin
d) titin
e) glycogen

Answer 11

c) myoglobin

Question 12

Which structure occurs at the border between two adjacent sarcomeres? Consult the image for assistance.

a) thin filament
b) thick filament
c) Z disc
d) M line
e) A band

Answer 12

c) Z disc

Question 13

At which stage of the contraction cycle (see diagram) do the myosin heads bind ATP, causing the crossbridges to detach from the actin filament?

a) Stage 1
b) Stage 2
c) Stage 3
d) Stage 4
e) That stage is not shown

Answer 13

d) Stage 4

Question 14

During the contraction cycle, ATP attaches to

a) actin
b) troponin
c) myosin
d) tropomyosin
e) none of these choices

Answer 14

c) myosin

Question 15

Which of the following is directly responsible for transmitting an action potential from a motor neuron to a skeletal muscle fiber?

a) gap junctions
b) intercalated discs
c) myofibrils
d) creatine phosphate
e) acetylcholine

Answer 15

e) acetylcholine

Question 16

Why does skeletal muscle require more ATP than many other tissues in the body?
1. both contraction and relaxation require ATP to occur

2.the sarcoplasmic reticulum uses ATP to “pump” calcium ions back into the terminal cisterns after contraction

3. ATP is needed to convert creatine into creatine phosphate needed to provide energy at the beginning of muscle contraction
   a) 1 only
   b) 2 only
   c) 3 only
   d) 1,2 &3
   e) Only 1 and 3

Answer 16

d) 1,2 &3

Question 17

Which of the following statements about creatine are correct?

a) some studies have shown it boosts athletic performance when taken as a supplement
b) some studies have shown no benefit to athletic performance when it is taken as a supplement
c) it is harmful, and will cause kidney damage
d) all of these choices are correct
e) some studies have shown it boosts athletic performance when taken as a supplement and some studies have shown no benefit to athletic performance when it is taken as a supplement

Answer 17

e) some studies have shown it boosts athletic performance when taken as a supplement and some studies have shown no benefit to athletic performance when it is taken as a supplement

Question 18

A skeletal muscle fiber can produce ATP in a variety of ways (metabolic pathways), however one method produces enough ATP to support physical activity for many hours. Which statement below is correct about this pathway?

a) This is the pathway that produces lactic acid.
b) This is the pathway that uses creatine phosphate to convert ADP to ATP.
c) This pathway is anaerobic.
d) This pathway is aerobic.
e) This is the pathway that produces lactic acid and is anaerobic.

Answer 18

d) This pathway is aerobic.

Question 19

Which of the following would not be a contributing factor to muscle fatigue?

a) release of excessive amounts of acetylcholine at the neuromuscular junction
b) a feeling that you want to quit, that the activity is too difficult (central fatigue)
c) depletion of adequate supplies of oxygen and ATP
d) a buildup of lactic acid
e) all of these contribute to muscle fatigue

Answer 19

a) release of excessive amounts of acetylcholine at the neuromuscular junction

Question 20

Which of the following muscle groups would be more likely to have many small motor units (one motor neuron, and just a few muscle fibers under its control)?

a) the muscles that control eye movement
b) the postural muscles that control standing
c) the muscles that control the many movements of the hands
d) all of these choices would have many small motor units
e) only a and c would have many small motor units

Answer 20

e) ONLY A AND C WOULD HAVE MANY SMALL MOTOR UNITS

Question 21

To delay the onset of muscle fatigue, not all the motor units in a muscle will contract at the same time. Some will remain relaxed while others are contracting. If the contraction continues, and greater force is needed, more motor units will be recruited. T/F?

Answer 21

a) True

Question 22

A small amount of muscle tension and muscle definition (the appearance of muscle beneath the skin) is present even in a relaxed muscle. A person who is physically fit due to regular exercise, will have more of this characteristic of muscle tissue than someone who is not fit. What is this characteristic?

a) muscle contraction
b) muscle refraction
c) muscle tone
d) muscle refraction
e) muscle recruitment

Answer 22

c) muscle tone

Question 23

Which of the following statements is correct about why a person’s muscles get larger after weeks of regular exercise and strength training?

a) the person has been able to change the proportion of skeletal muscle fiber types in the exercised muscles (i.e., they’ve added more slow oxidative fibers to their muscles)
b) the person has stimulated some of their muscle fibers to reproduce—they have added additional cells to their exercised muscles
c) the person has added more thin and thick filaments to their muscles
d) all of these choices can happen with exercise
e) none of these choices explain muscle enlargement

Answer 23

c) the person has added more thin and thick filaments to their muscles

Question 24

Stretching is most effective at reducing injury and promoting greater flexibility if it is done over the course of many weeks, and always when the muscle is cold (before beginning to exercise). T/F?

Answer 24

b) False

Question 25

This structure is unique to cardiac muscle cells, and allows individual cells to be firmly attached to each other (to provide mechanical strength during contraction), and also allow the action potential to spread rapidly through the cardiac muscle tissue, so that contractions are smooth and coordinated.

a) desmosomes
b) gap junctions
c) intercalated discs
d) Z discs
e) sarcomeres

Answer 25

c) intercalated discs

Question 26

Smooth muscle fibers do not have striations like skeletal and cardiac muscle cells do. This is because:

a) the sarcomeres are smaller than in cardiac muscle cells and skeletal fibers, and aren’t visible even when smooth muscle fibers are examined microscopically
b) smooth muscle fibers contain only intermediate filaments, which aren’t arranged in sarcomeres
c) smooth muscle fibers contain thin and thick filaments, as well as intermediate filaments, but none of them are arranged in sarcomeres
d) visceral smooth muscle fibers don’t have striations, but multiunit smooth muscle cells do, but these cells are more rare, and so we rarely have a chance to view them with a microscope
e) both b and d are correct

Answer 26

c) smooth muscle fibers contain thin and thick filaments, as well as intermediate filaments, but none of them are arranged in sarcomeres

Question 27

Nearly all muscles of the body develop from an early embryonic layer of cells called the mesoderm. T/F?

Answer 27

a) True

Question 28

Most people don’t notice they’ve lost muscle strength until around age 60 –65. By this time, what percentage of muscle mass has the average person lost?

a) 10%
b) 20%
c) 30%
d) 40%
e) 50%

Answer 28

e) 50%