Muscles are required in breathing, talking, running, walking, and any body movement. Actin and myosins are protein filaments present in muscle cells that help to contract and relax or change the shape of muscles. Muscles are responsible for the movement or motion of organisms. Joints are the connection between two or more bones. Most joints are mobile.
Muscle strength is determined by several factors. Some of those are the physical shape, size, and innervation of the muscles.
Weak contraction
- Potassium accumulates in the sarcoplasm.
- Contracted lower sarcoplasm pH.
- Begin contraction with muscle already 50%.
- The circular arrangement of muscle fascicles.
Stronger contraction
- Increase in muscle belly circumference.
- A lesser proportion of motor neurons to muscle fibers.
- Increased recruitment.
- Increased stimulus frequency.
Answer:
The function of the pleura is to allow optimal expansion and contraction of the lungs during breathing. The pleural fluid acts as a lubricant, allowing the parietal and visceral pleura to glide over each other friction free. This fluid is produced by the pleural layers themselves.
When tiny ice crystals in clouds stick together to form snowflakes, the result is snow. If enough crystals form a clump, they'll become heavy enough to fall to the ground. When temperatures are cold and moisture in the form of tiny ice crystals exists in the atmosphere, snow forms.
3. cell wall
The cell wall is a rigid supporting structure.
