Human Anatomy and Physiology : Systems Physiology

Study concepts, example questions & explanations for Human Anatomy and Physiology

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Example Questions

Example Question #301 : Systems Physiology

Type I muscle fibers __________.

Possible Answers:

are fast-twitch with red fibers

are slow-twitch with white fibers

are slow-twitch with red fibers

None of these

are fast-twitch with white fibers

Correct answer:

are slow-twitch with red fibers

Explanation:

Type I muscle (slow oxidative) consists of slow-twitch muscle fibers. Its fibers are red due to high concentrations of myoglobin, and it has a high density of mitochondria (and thus increased oxidative phosphorylation). This leads to a sustained contraction, and resistance to fatigue. Think "one slow red ox."

Example Question #302 : Systems Physiology

Which of the following is correct in regards to individual skeletal muscle fibers?

Possible Answers:

They do not repeat

They contain thick filaments only

They are mononucleate

The are multinucleate

Correct answer:

The are multinucleate

Explanation:

Individual skeletal muscle fibers are multinucleate and behave as single units. They contain bundles of myofibrils which are surrounded by a sarcoplasmic reticulum and is invaginated by transverse tubules. Each myofibril contains interdigitating thick and thin filaments arranged longitudinally in sarcomeres. Repeating units of sarcomeres account for the unique banding pattern in striated muscle.

Example Question #303 : Systems Physiology

The vastus medialis is supplied by __________.

Possible Answers:

the posterior tibial artery

the anterior tibial artery

the dorsalis pedis artery

the popliteal artery

the femoral artery

Correct answer:

the femoral artery

Explanation:

The vastus medialis, one of the quadricep muscles is located in the anterior compartment of the thigh and is supplied by the femoral artery. 

Example Question #304 : Systems Physiology

____________________, and __________ are examples of pennate muscles, because __________

Possible Answers:

Vastus medialis . . . rectus femoris . . . deltoid . . . their proximal attachment is wider than their point of insertion

Sternocleidomastoid . . . sartorius . . . biceps brachii . . . they are made of fibers that insert obliquely into their tendons

Sternocleidomastoid . . . sartorius . . . biceps brachii . . . they are spindle-shaped, with a muscle belly that is wider than the origin and insertion 

Vastus medialis . . . rectus femoris . . . deltoid . . . they are made of fibers that insert obliquely into their tendons

Sternocleidomastoid . . . sartorius . . . biceps brachii . . . their proximal attachment is wider than their point of insertion

Correct answer:

Vastus medialis . . . rectus femoris . . . deltoid . . . they are made of fibers that insert obliquely into their tendons

Explanation:

The term pennate describes muscles whose fibers insert obliquely into the tendon. The vastus medialis, rectus femoris, and deltoid are all examples of this type of muscle. 

Example Question #305 : Systems Physiology

Which of the following statements is false?

Possible Answers:

The fibularis longus and fibularis brevis should be strengthened in people who have had inversion sprains of the ankle joint. 

The fibularis longus becomes tendon halfway down the leg. 

The fibularis longus is supplied by the popliteal artery. 

The fibularis longus is anterior to the soleus. 

The fibularis longus has a tendon that makes an abrupt turn of approximately 90 degrees. 

Correct answer:

The fibularis longus is supplied by the popliteal artery. 

Explanation:

The fibularis longus is supplied by the fibular artery, a branch of the posterior tibial artery. All other statements are true.

Example Question #306 : Systems Physiology

Which of the following muscles attaches from the proximal anterior fibula to the dorsal surface of toes 2 through 5?

Possible Answers:

Extensor digitorum longus

Flexor digitorum longus

Extensor hallucis longus

Flexor hallucis longus

Extensor digitorum brevis

Correct answer:

Extensor digitorum longus

Explanation:

The extensor digitorum longus attaches from the proximal anterior fibula to the dorsal surface of toes 2 through 5. 

Example Question #307 : Systems Physiology

Which of the following are characteristics of only skeletal muscle?

Possible Answers:

Multinucleated

Troponin-tropomyosin complex regulates contraction

Striated

Calcium required for contraction

Correct answer:

Multinucleated

Explanation:

Characteristics of smooth muscle include: striated, somatic innervation, multinucleated, and requiring calcium for contraction. Furthermore, similar characteristics are seen in cardiac muscle such as: striations, autonomic innervation, 1-2 nuclei, requires calcium for contraction. Finally, smooth muscle is nonstriated, has autonomic innervation, mononucleated, and requiring calcium for contraction.

Example Question #12 : Muscle Physiology

To which of the following molecules does calcium released from the sarcoplasmic reticulum bind?

Possible Answers:

Actin

Tropomyosin

Troponin

Myosin

Correct answer:

Troponin

Explanation:

Calcium is released from the sarcoplasmic reticulum into the the sarcoplasm. It binds the troponin molecules on the thin filaments, causing the strands of tropomyosin to shift, exposing the myosin-binding sites on the thin filaments. 

Example Question #308 : Systems Physiology

Where is calcium stored in the skeletal muscle cell?

Possible Answers:

Calcium is stored extracellularly, and only allowed into the skeletal muscle cell after neuronal signals.

Calcium is not particularly stored in any location in the skeletal muscle cell, and is equally distributed.

None of the answers are correct.

Calcium is stored in the sarcoplasmic reticulum, awaiting a signal for release into the cytoplasm.

Calcium is stored in the cytoplasm, awaiting a signal for release into the cytoplasm.

Correct answer:

Calcium is stored in the sarcoplasmic reticulum, awaiting a signal for release into the cytoplasm.

Explanation:

Calcium is stored in the sarcoplasmic reticulum at high concentrations. When neurons signal the contraction of muscle, calcium is released from the sarcoplasmic reticulum, and facilitates the contraction of muscle fibers and ATP hydrolysis, to generate muscle contraction force.

Example Question #309 : Systems Physiology

The perimysium surrounds which of the following parts of a skeletal muscle fiber?

Possible Answers:

muscle

fascicle

myofilament

myofiber

myofibril

Correct answer:

fascicle

Explanation:

The perimysium surrounds the fascicles in a skeletal muscle fiber. From largest to smallest, the sequence goes as follows: the Epimysium surrounds the entire muscle; the Perimysium surrounds the fascicles inside the muscle; the Endomysium surrounds the myofiber (muscle cell).

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