The muscular system and the digestive system interact in various way for the benefit of the body. The muscles of muscular system involved are the smooth and skeletal muscles that protect and facilitate the process of digestion like
- Chewing food
- Swallowing
- regulation of movements
- Mechanical breakdown of food
- Peristalsis
- Defecation
- Physical protection.
1. Voluntary Muscle Action in the Mouth
- Skeletal muscles in the mouth, tongue, and jaw control the process of chewing.
- This voluntary action helps break down food into smaller particles mixing it with saliva to start the chemical digestion process.
- The tongue, a skeletal muscle, also helps in the swallowing process by pushing the food bolus to the back of the mouth and initiating the reflex that moves food down the esophagus.
2. Swallowing and Esophageal Movement
- The act of swallowing involves the coordination of both skeletal muscles (in the mouth and throat) and smooth muscles in the esophagus.
- After swallowing, the smooth muscles in the esophagus contract and relax to move food toward the stomach in a series of coordinated waves, aided by gravity and the process of peristalsis.
3. Churning in the Stomach
- In the stomach, smooth muscles contract to churn and mix food with stomach acid and digestive enzymes.
- This mechanical breakdown of food helps form a substance called chyme, which is then moved into the duodenum part of small intestine for further digestion and nutrient absorption.
4. Regulation of Digestive Organs
- The muscular sphincters in various parts of the digestive system (like the lower esophageal sphincter, pyloric sphincter, and anal sphincters) regulate the flow of food and digestive fluids, ensuring that food moves in the right direction and at the right time.
- These sphincters open and close at specific times to allow food to pass through and to prevent the backflow of contents, which would disrupt the digestive process.
5. Mechanical Digestion (Peristalsis)
- Smooth Muscles in the walls of the digestive organs (like the esophagus, stomach, and intestines) contract rhythmically in a process called peristalsis.
- These contractions push food along the digestive tract from the mouth to the stomach, and through the intestines, aiding in the digestion and absorption of nutrients.
- The circular and longitudinal muscles in the digestive tract work together to propel food and break it down mechanically.
- This is critical for moving food from one section to another and for mixing it with digestive enzymes and acids.
6. Defecation
- The muscles in the rectum and anal canal (involving skeletal and smooth muscles) are responsible for the voluntary and involuntary processes of defecation.
- The rectum stores feces until it’s time to be expelled, and coordinated contractions of the pelvic floor muscles help in the elimination of waste.
7. Physcial protection
- The skeletal muscules in the abdominal region serve to safe guard the gut.
- While the lungs, brain, heart are encased inside bony chambers like the the rib cage and skull, this is not so for the gut.
- The digestive system is deficit in skeletal support and hence, the anterior and posterior abdominal walls in the abdomen have skeletal muscules.
- These skeletal muscles save the internal organs from injury and also help in pushing the inner content either upwards or downwards as per need.
- In case of food poisoning and infections, the abdominal muscles help in creating pressure for vomiting out the content.
- Similarly, they can create pressure for defecation.
- Overall, they provide flexibility, hold organs in place, regulate internal pressure and protect from injury.
Conclusion:
In summary, the muscular system plays a key role in mechanical digestion, moving food through the digestive tract, mixing it with digestive enzymes, facilitating the absorption of nutrients and also protecting it.
The two systems work together, with skeletal muscles controlling voluntary actions like chewing and swallowing, while smooth muscles carry out the involuntary tasks of digestion, peristalsis, and waste elimination.