support and movement test 3

Short Hint: Myoglobin is a protein found in muscle tissues that has a very specific function. This function does not relate to glycogen degradation or muscle contraction. Instead, it plays a key role in oxygen storage in muscle tissues. Therefore, the correct answer is C, "It conserves an auxiliary supply of oxygen in the muscle".

Short Hint: Muscles can be divided into various categories based on their control mechanism and structure. Among these categories, cardiac muscles are specific to the heart and function without our conscious control. Therefore, the correct answer is B, "Involuntary".

Short Hint: Chondrocytes are specialized cells that produce and maintain the matrix of cartilage. Type II collagen, a key component of cartilage, is primarily produced by these chondrocytes. Therefore, the answer is C, "Cartilage".

Short Hint: Muscle contraction requires energy, primarily derived from ATP (adenosine triphosphate). Creatine phosphate also serves as an immediate energy source by donating phosphate to form ATP. Therefore, the correct answer is D, "Both A and B".

Short Hint: Osteoclasts are one of the three types of cells that are essential for maintaining bone structure. Unlike the other cell types, osteoclasts are characterized by multiple nuclei. Therefore, the correct answer is B, "Multinucleated Cells".

Short Hint: A myofibril, a component of muscle cells, is divided into sections by Z-lines. These sections, termed as sarcomeres, are the functional units of muscle contraction. Therefore, the correct answer is B, "Sarcomere".

Short Hint: Bones play a range of roles in the body, from supporting structure to mineral storage. They are not dry and non-living as stated in option B, but are dynamic and living tissues with blood supply. Therefore, the incorrect statement, and thus the correct answer, is B, "Bones are dry and non-living supporting structures".

Short Hint: The process of bone resorption plays a crucial role in maintaining bone health by removing old bone tissue, a process largely carried out by osteoclasts. This cell type employs a mechanism similar to macrophage phagocytosis to break down bone tissue. Therefore, the correct answer is A, "Osteoclasts".

Short Hint: Cartilage, a flexible connective tissue, varies in type depending on its location and function. While structures like the trachea, larynx, and nasal cartilage are made of hyaline cartilage, the epiglottis and pinna are formed from elastic cartilage. Therefore, the correct answer is B, "Elastic".

Short Hint: For a muscle to contract, motor nerve impulses must be transmitted to the muscle fibers. These impulses are relayed at specific sites known as neuromuscular junctions. Therefore, the correct answer is A, "Neuromuscular Junctions".

Detailed Hint: Calcium ions (Ca++) play a crucial role in muscle contraction. They do not primarily store in the mitochondria, and their translocation across the plasma membrane is not the primary method of maintaining muscle contraction. The increase in intracellular calcium allows actin to interact with myosin, leading to muscle contraction. Thus, the correct answer is C, "An increase in intracellular Ca++ permits the interaction of actin and myosin".

Detailed Hint: The formation of bone involves several types of cells. Osteoclasts dissolve bone, but they do not initiate bone formation. Osteoblasts, on the other hand, contribute to bone formation through processes such as the synthesis of type I collagen. Therefore, the correct answer is C, "Osteoblasts".

Detailed Hint: The matrix of bone comprises both organic and inorganic components. The organic portion, which makes up about 30% of the matrix, primarily consists of collagen and proteins (e.g., glycoproteins). The inorganic part, constituting the remaining 70%, is mostly composed of minerals like calcium phosphate and calcium carbonate. Thus, the correct answer is C, "Both protein and collagen".

Detailed Hint: In the physiology of muscle contraction, calcium plays a pivotal role. Upon release into the muscle cell cytosol, calcium binds to a regulatory protein called troponin. This binding initiates the translocation of tropomyosin, thereby exposing the binding sites for myosin on actin filaments and facilitating muscle contraction. Thus, the correct answer is B, "Troponin".

Detailed Hint:

• Myofibrils are composed of thick and thin filaments.
• The thin filaments mainly consist of Actin, Tropomyosin, and Troponin.
• Z-Line, Chloride ions, and Sarcomere are other components of myofibrils but they don't make up the thin filaments.
• Therefore, the correct answer is A, "Actin, Tropomyosin, Troponin".

Detailed Hint:

• Bone remodeling is a constant process of renewal and repair in the bone tissue.
• The two main cell types responsible for this process are Osteoblasts (forming new bone) and Osteoclasts (resorbing old bone).
• Chondrocytes, Chondroblasts, and Osteocytes are also involved in bone metabolism, but they do not directly participate in bone remodeling.
• Thus, the correct answer is B, "Osteoblasts and Osteoclasts".

Detailed Hint:

• The matrix of cartilage is composed of various types of collagen.
• In the case of cartilage, it primarily consists of Type II Collagen.
• Type I Collagen is more commonly found in the bone matrix, not cartilage.
• Therefore, the correct answer is B, "Type II Collagen".

Detailed Hint:

• Several changes occur within skeletal muscle during the process of contraction.
• One key change is the shortening of the I Band.
• The A Band does not shorten, the Z-Line does not slide farther apart, and the actin filament does not contract by itself.
• Hence, the correct answer is B, "The I Band shortens".

Detailed Hint:

• Post muscle contraction, the sarcoplasmic reticulum plays a vital role in re-accumulating calcium ions.
• This re-accumulation process is not achieved via Diffusion, but rather through Active Transport.
• Though Diffusion and Active Transport are both methods of ion movement, only Active Transport is involved in this context.
• Consequently, the correct answer is B, "Active Transport".