Low bone mass Generally speaking, the term "osteopenia" can continue to be used, but "low bone mass" or "low bone density" should be preferred. For premenopausal women and men under 50 years old, Z value (not T value) should be preferred.

1, osteoporosis: osteopenia osteopenia

2. The bone mass of osteon in osteon is scarce; Osteosclerosis with osteopenia ...

3. Peak bone mass: PBM PBM

4. Decreased bone mass: osteopenia; ; Osteopenia

Extended data:

First, fat

1, the supply of fat

There is no supply standard for fat. Due to the differences in economic development level and eating habits in different regions, the actual intake of fat varies greatly. The Nutrition Society of China suggested that the dietary fat supply should not exceed 30% of the total energy, and the ratio of saturated, monounsaturated and polyunsaturated fatty acids should be 1: 1: 1.

The energy provided by linoleic acid can reach 1%~2% of the total energy, which can meet the needs of human body for essential fatty acids.

2, the source of fat

The sources of fat can be divided into the following two types:

Animal sources: fats stored in animals: such as lard, butter, sheep oil, fish oil, bone marrow, fat meat, cod liver oil, etc. Fat in animal milk: such as cream.

Plant source: Plant fat source is mainly extracted from plant fruits, such as sesame, sunflower seeds, tea, walnuts, pine nuts, soybeans and so on.

The main sources of fat are cooking fat and the fat contained in food itself. Table 5 shows the fat content in several foods. As can be seen from the figures in the table below, the fat content of nuts is the highest, all kinds of meat are in the middle, and the content of rice, flour, vegetables and fruits is very small.

Second, muscle classification

1, skeletal muscle

It is a type of muscle that can be seen and touched. When bodybuilders increase muscle strength through exercise, they exercise skeletal muscle. Skeletal muscles are attached to bones and appear in pairs: one muscle moves bones in one direction and the other moves bones in the opposite direction.

These muscles usually contract at will, which means that when they want to contract muscles, the nervous system will instruct them to do so. Skeletal muscle can contract for a short time (twitching) or for a long time (tetanus).

2. Red and white muscle fibers

Skeletal muscle of human body can be divided into red muscle and white muscle. Red muscle fibers rely on hemoglobin for continuous oxygen supply and long-term contraction and stretching, so that we can carry out daily behavior activities. White muscle fibers expand and contract rapidly through internal rapid chemical reaction (mostly in emergency), which is characterized by long duration and short reaction time, and its reaction time is one quarter of that of red muscle fibers.

3. Smooth muscle

It exists in digestive system, blood vessels, bladder, respiratory tract and female uterus. Smooth muscle can stretch and maintain tension for a long time. These muscles don't contract at will, which means that the nervous system will automatically control them without thinking. For example, the muscles of the stomach and intestines perform tasks every day, but people generally don't notice them.

4. Myocardium

Only in the heart, its biggest feature is endurance and firmness. It can stretch as limited as smooth muscle or contract as powerfully as skeletal muscle. It's just a twitching muscle that doesn't automatically contract.