Final answer:
The muscular system is made up of skeletal, cardiac, and smooth muscles, which enable voluntary and involuntary movements. Muscle cells contract to create motion, and muscles can experience hypertrophy or atrophy based on levels of activity and other factors.
Step-by-step explanation:
Structure and Function of the Muscular System
The muscular system consists of all the muscles in the body and is essential for movement and support. There are three primary types of muscle tissue: skeletal, cardiac, and smooth muscle. Skeletal muscles are connected to bones by tendons, support voluntary actions like walking, and work in pairs due to the need for balance and coordination. Cardiac muscle is found in the heart's walls, ensuring heartbeats and blood circulation; it works involuntarily. Smooth muscles are located in the walls of internal organs and manage involuntary movements within these structures.
On a cellular level, muscle cells are specialized for contraction. When muscles contract, they pull on bones or internal organs resulting in motion. Muscle hypertrophy occurs when muscles increase in size, which can happen due to exercise or other stimuli; while muscle atrophy is the loss of muscle mass from a lack of activity or other causes.