Cardiac muscle (heart muscle) is involuntary striated muscle that is found in the walls and histological foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle.These three types of muscle all form in the process of myogenesis. The cells that constitute cardiac muscle, called cardiomyocytes or myocardiocytes, contain only three nuclei.nother histological difference between cardiac muscle and skeletal muscle is that the T-tubules in the cardiac muscle are bigger and wider and track laterally to the Z-discs. There are fewer T-tubules in comparison with skeletal muscle.
The four main economic variables (in macroeconomics) are 1. Real Gross Domestic Product (GDP) 2. The unemployment rate 3. The inflation rate 4. The interest rate-----5. Level of the stock market 6. Exchange rate
Economics is part of the social structure of a society and is concerned with how people produce and consume goods and services. What types of goods and services are produced and consumed in a society depend on geography and social customs. The three major economic sectors are: primary, secondary and tertiary. [for QUATERNARY ... see final paragraph, below]. The PRIMARY economic sector includes obtaining and refining raw materials such as wood, steel and coal. Primary economic sector workers include loggers, steelworkers and coalminers. All types of natural resources industries such as fishing, farming, forestry and mining are a part of the primary economic sector. The SECONDARY economic sector deals with the processing of raw materials into finished goods.