They're not leaf veins, but this tissue's structure can be classified into parallel or pennate types, the latter of which has larger physiological cross-sectional area. In the Cahill cycle, amino groups are transported from this tissue to the liver in the form of alanine. The largest known (*) protein in humans, titin, is found in this tissue. Invaginations of the plasma membrane of its cells are 
They're not leaf veins, but this tissue's structure can be classified into parallel or pennate types, the latter of which has larger physiological cross-sectional area. In the Cahill cycle, amino groups are transported from this tissue to the liver in the form of alanine. The largest known (*) protein in humans, titin, is found in this tissue. Invaginations of the plasma membrane of its cells are termed T-tubules. Cells of this tissue sequester calcium ions in the sarcoplasmic reticulum. For 10 points, name this tissue that contracts and relaxes when you lift weights.
They're not leaf veins, but this tissue's structure can be classified into parallel or pennate types, the latter of which has larger physiological cross-sectional area.
muscle [accept skeletal muscle or striated muscle; don't accept other kinds of muscle]