Cardiac muscle (heart muscle). This type of muscle is found solely in the walls of the heart. It has similarities with skeletal muscles in that it is striated and with smooth muscles in that its contractions are not under conscious control. However this type of muscle is highly specialised.t has similarities with skeletal muscles in that it is striated and with smooth muscles in that its contractions are not under conscious control. However this type of muscle is highly specialised.
There are few natural sources of vitamin D. For that reason, most of the vitamin D in your diet comes from fortified foods, such as dairy products and alternatives, breakfast cereals, juices and margarine.
Foods. Very few foods naturally supply vitamin D. Beef liver, cheese, egg yolks and fatty fish, which contain small amounts of D3, are the best dietary sources of D3. Cod liver oil provide a time-honored potent source of D3, although the taste might be a turnoff.hoosing D2 or D3. Getting either vitamin D2 and D3 from supplements, sunlight exposure or foods will raise your 25(OH)D level. Some researchers believe that your body absorbs D3 more efficiently.