Sarcomere Flashcards
What is a Sarcomere?
The contractile unit of a muscle cell that makes a myofibril
What is the Sarcolemma?
plasma membrane of skeletal muscle cells (stores calcium)
What is the Sarcoplasm and what is in it?
the cytoplasm of a skeletal muscle cell; Myofibrils, Myoglobin, and Glycogen
What is the sarcoplasmic reticulum?
Modified endoplasmic reticulum that regulates calcium in the cell
What are the T (transverse) tubules?
Tubes continuous with the sarcolemma to increase surface area
True or false: During contraction, the entire sarcomere lengthens.
False;
True or False: In a fully contracted sarcomere, the H zone disappears.
True
True or False: During contraction, the I band decreases in length.
FALSE; it decreases in width
True or False: During contraction, the A band does not change width.
True
What is found in the I band?
Actin and Elastin
During contraction, the strands of myosin are:
not moving anywhere
What are Thick filaments?
Myosin; binds and hydrolyzes ATP
What happens with Thick filaments?
the release of energy allows the head to change shape (FLEX) and ultimately generate force
What are Thin filaments and their two accessory proteins?
Actin + Tropomyosin and Troponin
What do Thin filaments do?
each actin has an active site that can bind to the head of a myosin protein
