Lab Quiz 8 Material (03/27/2025) Flashcards
Muscle tissue is characterized by aggregates of specialized, elongated cells arranged in {…} array that have the primary role of {…}.
1) Parallel
2) Contraction
This type of myofilament is primary composed of actin.
What is a thin filament?
This type of myofilament is composed primarily of myosin II.
What is a thick filament?
Each thin filament of fibrous actin (i.e., {…}) is a polymer primarily formed from globular actin molecules (i.e., {…}).
1) F-actin
2) G-actin
Myofilaments occupy the bulk of the cytoplasm, which, in muscle cells, is called this.
What is sarcoplasm?
This type of muscle has striations at the light microscope level.
What is striated muscle?
This type of muscle does not have striations.
What is smooth muscle?
This type of striated muscle is attached to bone and is responsible for movement of the axial and appendicular skeleton and maintenance of body position and posture. In addition, it provides precise eye movement via the extraocular muscles.
What is skeletal muscle?
This type of striated muscle is morphologically identical to skeletal muscle but is restricted to the soft tissues, namely, the tongue, pharynx, lumbar part of the diaphragm, and upper part of the esophagus. These muscles play essential roles in speech, breathing, and swallowing.
What is visceral striated muscle?
This type of striated muscle is a type of striated muscle found in the wall of the heart and in the base of the large veins that empty into the heart.
What is cardiac muscle?
In skeletal muscle, each muscle cell, more commonly called a muscle {…}, is actually a multinucleated {…}. A muscle fiber is formed during development by the fusion of small, individual muscle cells called {…}.
1) Fiber
2) Syncytium
3) Myoblasts
The nuclei of a skeletal muscle fiber are located in the cytoplasm immediately beneath the plasma membrane, also called the {…}, which consists of the plasma membrane of the muscle cell, its external lamina, and the surrounding reticular lamina.
Sarcolemma
A skeletal muscle consists of striated muscle fibers held together by {…} tissue.
Connective
This connective tissue is the delicate layer of reticular fibers that immediately surrounds individual muscle fibers.
What is endomysium?
This connective tissue is a thicker connective tissue layer that surrounds a group of fibers to form a BUNDLE or FASCICLE.
What is perimysium?
This connective tissue is the sheath of dense connective tissue that surrounds a collection of fascicles that constitutes the muscle.
What is epimysium?
In gross anatomy, the epimysium is also referred to as this structure, which can surround not only individual muscles but also groups of muscles to form compartments.
What is the deep investing fascia?
What are the 3 factors that characterize skeletal muscle?
1) Contractile speed
2) Enzymatic velocity
3) Metabolic profile
The {…} profile indicates the capacity for ATP production by oxidative phosphorylation or glycolysis.
Metabolic
Fibers characterized by {…} metabolism contain large amounts of myoglobin and an increased number of mitochondria, with their constituent cytochrome electron transport complexes.
Oxidative
This is a small, globular, 17.8-kDa oxygen-binding protein that contains a ferrous form of iron (Fe+2). It resembles hemoglobin in the erythrocytes and is found in various amounts in muscle fibers.
What is myoglobin?
Traumatic injuries to skeletal muscles (e.g., crash injuries) cause breakdown (rhabdomyolysis) and release of {…} from the injured muscle cells into the circulation.
Myoglobin
The breakdown of skeletal muscles as a result of injury.
What is rhabdomyolysis?
What renal tissue is a large amount of myoglobin toxic to?
The tubular epithelium
What renal problem can rhabdomyolysis ultimately cause?
Acute renal failure
List the 3 types of skeletal muscle fibers that can be identified by color in vivo.
1) Red
2) White
3) Intermediate
List the 3 oxidative enzymes in which the histochemical reactions of skeletal muscle fibers are based on.
1) Succinic dehydrogenase
2) Nicotinamide adenine dinucleotide-tetrazolium reductase (NADH-TR)
3) Myosin ATPase
Based on their enzymatic activity, these types of muscle fibers are small fibers that appear red in fresh specimens and contain many mitochondria and large amounts of myoglobin and cytochrome complexes. Their high levels of mitochondrial oxidative enzymes are demonstrated by their strong succinic dehydrogenase and NADH-TR histochemical staining reactions.
What are Type I (slow oxidative)?
Type I (slow oxidative) fibers are {…}, {…} motor units.
1) Slow-twitch
2) Fatigue-resistant
This muscle group of the back is adapted to the long, slow contraction needed to maintain an erect posture.
What are the erector spinae muscles?
Based on their enzymatic activity, these skeletal muscle fibers are the intermediate fibers seen in fresh tissue. They are of medium size with many mitochondria and high myoglobin content.
What are Type IIa (fast oxidative glycolytic)?
The myosin ATPase reaction velocity of Type IIa (fast oxidative glycolytic) fibers is high. They make up {…}, {…} motor units that generate high-peak muscle tension.
1) Fast-twitch
2) Fatigue-resistant
Based on their enzymatic activity, these skeletal muscle fibers are large fibers that appear light pink in fresh specimens and contain less myoglobin and fewer mitochondria than type I and type IIa fibers. They have a low level of oxidative enzymes but exhibit high anaerobic enzyme activity and store a considerable amount of glycogen.
What are Type IIb (fast glycolytic)?
Type IIb (fast glycolytic) fibers are {…}, {…} motor units and generate high-peak muscle tension.
1) Fast-twitch
2) Fatigue-prone
Type IIb (fast glycolytic) fibers are adapted for rapid contraction and {…}, fine movements. They constitute most fibers of the {…} muscles and the muscles that control the movements of the {…}.
1) Precise
2) Extraocular
3) Digits
Why do Type IIb (fast glycolytic) fibers allow for more precise control and movement?
They have a large number of neuromuscular junctions (greater than Type I fibers)
Short-distance sprinters, weight lifters, and other field athletes have a high percentage of type {…} fibers.
IIb (fast glycolytic)
