1 Each muscle fibre ( muscle cell ) is covered by a plasma membrane sheath which is called the sarcolemma. 2  Tunnel-like extensions from the sarcolemma pass through the muscle fibre from one side of it to the other in transverse sections through the diameter of the fibre.keletal muscles consist of 100,000s of muscle cells (also known as muscle fibers) that perform the functions of the specific muscle of which they are a part.
Another leafy vegetable high in beta carotene in the form of vitamin A, kale has 478 milligrams of the nutrient and 20 calories per half cup serving. Kale recipes to try: â¢ Kale Chips. â¢ Roast Cod with Bacon, Potatoes, and Kale. â¢ Kale Salad with Glazed Onions and Cheddar.
One cup of shredded green leaf lettuce contains 133 micrograms of vitamin A, which is 15 percent of the 900 micrograms men need each day and 19 percent of the 700 micrograms women should have on a daily basis.eaf lettuce is the star in salads, and salads are perhaps one of the most nutritious foods, provided that they're not drowning in high-fat salad dressing and topped with unhealthy ingredients such as bacon.