1.
What is the outer connective tissue covering of a muscle?
Correct Answer
A. Epimysium
Explanation
The outer connective tissue covering of a muscle is the epimysium. Within the muscle, there are subdivisions called fascicles. The perimysium surrounds these muscle fascicles. The endomysium is the covering around an individual muscle fiber. The sarcolemma is the plasma membrane of a muscle cell. The sarcoplasm is the cytoplasm of a muscle cell.
2.
What is myosin?
Correct Answer
D. Myofilament
Explanation
Myofilaments are the contractile protein within a muscle cell. The myofilaments are actin and myosin. The thin filaments are actin and the thick filaments are myosin. The muscle cell is a muscle fiber. The term "muscle cell" and "muscle fiber" are synonymous. A myofibril is a longitudinal bundle of myofilaments within a muscle cell. Myocardium is the muscular layer of the heart. Thus, the myocardium is composed of cardiac muscle.
3.
Where is cardiac muscle found?
Correct Answer
E. Myocardium
Explanation
Myofilaments are the contractile protein within a muscle cell. The myofilaments are actin and myosin. The thin filaments are actin and the thick filaments are myosin. The muscle cell is a muscle fiber. The term "muscle cell" and "muscle fiber" are synonymous. A myofibril is a longitudinal bundle of myofilaments within a muscle cell. Myocardium is the muscular layer of the heart. Thus, the myocardium is composed of cardiac muscle.
4.
What type of muscle has visible cross striations?
Correct Answer
D. Both "a" and "b"
Explanation
Both skeletal muscle and cardiac muscle have visible striations. Collectively, skeletal muscle and cardiac muscle are classified as "striated muscle".
5.
What type of muscle is specialized for contraction?
Correct Answer
E. "a" "b" and "c"
Explanation
The fundamental property of muscle tissue is that it is specialized for contraction.
6.
What is released at a synapse?
Correct Answer
E. Neurotransmitter
Explanation
A single motor neuron and the aggregation of muscle fibers innervated by that single neuron is called the motor unit. A motor neuron is a neuron which innervates a muscle cell. The point of contact where a neuron contacts a muscle is the motor end plate. A neuromuscular spindle is a receptor which is sensitive to stretching of the muscle. A neurotransmitter is the chemical released by a nerve at a synapse.
7.
What is the plasma membrane of a muscle cell called?
Correct Answer
B. Sarcolemma
Explanation
The outer connective tissue covering of a muscle is the epimysium. Within the muscle, there are subdivisions called fascicles. The perimysium surrounds these muscle fascicles. The endomysium is the covering around an individual muscle fiber. The sarcolemma is the plasma membrane of a muscle cell. The sarcoplasm is the cytoplasm of a muscle cell.
8.
What are the thin filaments?
Correct Answer
C. Myofilaments
Explanation
Myofilaments are the contractile protein within a muscle cell. The myofilaments are actin and myosin. The thin filaments are actin and the thick filaments are myosin. The muscle cell is a muscle fiber. The term "muscle cell" and "muscle fiber" are synonymous. A myofibril is a longitudinal bundle of myofilaments within a muscle cell. Myocardium is the muscular layer of the heart. Thus, the myocardium is composed of cardiac muscle.
9.
Which of the following is composed of skeletal muscle?
Correct Answer
A. Tongue
Explanation
There are two chief categories of muscle: striated and non striated muscle (smooth muscle).
Striated muscle can be sub-categorized into cardiac muscle and skeletal muscle. The tongue, biceps muscle, and upper esophagus are made of striated muscle. The heart is composed of cardiac muscle.
Non striated muscle is also called smooth muscle. Smooth muscle is involuntary muscle. It is found in viscera and blood vessels.
10.
What type of muscle is composed of spindle shaped cells?
Correct Answer
C. Smooth muscle
Explanation
Smooth muscle is composed of spindle shaped cells.
11.
What type of muscle is always multinucleated?
Correct Answer
A. Skeletal muscle
Explanation
Skeletal muscle is multinucleated. The nuclei are seen on the periphery. Occasionally, cardiac muscle is bi-nucleated.
12.
What is line that bisects the light band in muscle?
Correct Answer
C. Z line
Explanation
The A band is the darker staining band. The I band is the light band. The I band is made of thin filaments. The Z line runs through the I band. The H band bisects the A band. The M line runs through the H band.
A sarcomere is the segment that runs from Z line to Z line.
13.
What is the name of the tissue which surrounds muscle fascicles?
Correct Answer
A. Perimysium
Explanation
The perimysium is the connective tissue sheath which surrounds muscle fascicles.
The periosteum is the connective tissue covering of a bone.
The perichondrium is the connective tissue which surrounds cartilage.
The perineurium is the covering of nerve fascicles.
The endosteum is the lining of the inner bone (the side which abuts the
medullary cavity).
Note from Sarah Bellham: The prefix "peri" means around, such as in the word
"perimeter". The prefix "endo" means within or inner, such as in "endosteum",
"endocrine", "endoscope".
14.
Contraction in all types of muscle requires calcium ions. Which of the following muscle components can bind or sequester calcium ions?
Correct Answer
C. Troponin
Explanation
Troponin is a muscle component that can bind or sequester calcium ions. It is a protein complex found on the regulatory protein tropomyosin, which is located on the thin filament of muscle cells. When calcium ions bind to troponin, it causes a conformational change in the troponin-tropomyosin complex, allowing the myosin heads to bind to the active sites on actin and initiate muscle contraction. Therefore, troponin plays a crucial role in regulating muscle contraction by controlling the availability of active sites on actin for myosin binding.
15.
Which of the following is true for skeletal muscle?
Correct Answer
D. It possesses Triads
Explanation
Skeletal muscle possesses triads. Triads are structural arrangements in skeletal muscle fibers that consist of a T tubule and two adjacent terminal cisternae of the sarcoplasmic reticulum. These triads play a crucial role in the excitation-contraction coupling process, allowing for the transmission of electrical signals deep into the muscle fiber and the release of calcium ions from the sarcoplasmic reticulum, which is essential for muscle contraction.