Three pairs of salivary gland located in buccal cavity
Parotid gland
Sublingual gland
Submandibular gland/ Submaxillary gland
Salivary gland is an Exocrine gland. Salivary gland secret saliva. It contain amylase, lysozyme, electrolyte etc. Amylase enzyme digest starch by 30%. Lysozyme enzyme prevent bacterial infection.
Liver :
Structural and functional unit of liver cell is hepatic cell. Hepatic cell secrete bile juice. Bile juice store in gall bladder. Bile juice contain bilirubin, bilivirudin, bile salts, cholestrol. Bile juice breakdown lipid that process called Emulsification.
Pancreas:
Pancreas is an Exocrine and Endocrine gland. Exocrine part of pancreas involved in digestion process. Endocrine part of pancreas contain three type of cells. It secrete hormones. Pancreas secrete pancreatic juice it digest carbohydrate, protein, lipid
Humans can’t digest cellulose because we lack the enzyme cellulase, which is needed to break the β-1,4 glycosidic bonds in cellulose.
So it just passes through our gut as dietary fiber, helping bowel movement but not giving energy.
Cellulose cannot be digested by the human body and is excreted unchanged. However, it plays an important role in promoting smooth bowel movements, supporting the growth of beneficial gut bacteria, preventing constipation, and aiding in weight management.
Humans are unable to digest cellulose because our digestive system does not produce the enzyme cellulase, which is necessary to break the β-1,4 glycosidic bonds present in cellulose. As a result, cellulose passes through the gastrointestinal tract without being broken down into glucose.
Instead of being digested, cellulose functions as dietary fiber (roughage). It adds bulk to stool, improves bowel movements, and helps prevent constipation. While some herbivorous animals can digest cellulose due to cellulase-producing bacteria in their gut, humans lack such sufficient microorganisms, making cellulose indigestible for us.