Chemical Digestion: Enzymes and Hormones Involved

Chemical digestion involves breaking down large molecules of food into smaller nutrients using enzymes and hormones. This presentation discusses the types of enzymes involved in carbohydrate, protein, lipid, and nucleic acid digestion. It also explains the role of hormones in controlling food intake and digestion.

CHEMICAL
DIGESTION
Introduction
Human body utilizes two different types of
digestion: one is chemical digestion and another is
mechanical digestion. Mechanical digestion
processes includes chewing, swallowing and the
muscular movements which help the food through
the digestive tract which is further supported by
chemical digestion by using some enzymes that
helps to breaks the food particles in more smaller
molecules enough so that they can be absorbed
easily (Panawala, 2017).

 Chemical digestion is basically the breakdown of the large molecules or food
into the smaller nutrients so that it can be used by the body cells easily. There are
various enzymes and hormones involved in the chemical digestion of food.

 (Source: Anatomy and physiology, 2018)
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 Chemical digestion is not started in the
stomach but in the mouth. The moment
when the people see, smell or even
think about the food, their mouth begins
to secrete extra saliva. Chemical
digestion is happens in the mouth,
stomach and small intestine.

Role of enzymes
 Digestion basically involves engulfing the
large food portions and breaking them
into the micronutrients that are small
enough to be absorbed by the body cells.
Although chewing and peristaltic
movement help the body to break those
molecules but it is not possible for them to
break particle small enough. This why
body needs chemical agents to act on the
food partials

Types of enzymes involved in
chemical digestion
 Salivary enzyme
 Pancreatic amylase
 Maltase
 Pepsin
 Trypsin
 Peptidases
 Nuclease
 Nucleosidases
 lipases

Enzymes in Carbohydrate
digestion
 Pancreatic amylase: it does heavy lifting
 Alpha-dextrinase: works to break single
unit
 Sucrase : it acts on sucrose
 Maltase: it acts on maltose
 Lactase: it splits lactose

Enzymes in protein
digestion
 Proteins are the amino acids that are
consumed in the diet as the essential
nutrition. The digestion starts in the
stomach where the pepsin and HCL
catabolise the protein into smaller
particles or polypeptide. These molecules
are than reach to small intestine where is
further processed by various enzymes
such as amino peptidase and dipptidase.

Enzymes helpful in lipid digestion
 Lipids are the nutrients that consumed is
calorie and accounts for 35 per cent of
total calories intake. There are three
enzymes that are responsible for lipid
digestion: gastric lipase, lingual lipase
and pancreatic lipase.

Enzymes responsible for Nucleic
acid digestion
 The nucleic acids RNA and DNA are
available in most if the food products
that are consumed by people. the
digestion of these molecules takes place
with the help of two pancreatic enzymes
called nucleosidase and phosphatase.

Hormones role in chemical
digestion
 It has been well understood that
hormones play a key important role in
the control of food intake and digestion.
Gut is the largest produces of hormones
in the body. It releases more than twenty
different peptide hormones that are
helpful in various reaction associated
with digestion.

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 Ghrelin: increases the appetite
 Gastrin: trigger gastric juice production
 Secretin: triggering alkaline production
from pancreas

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 Cholecystokinin: reduce appetite and
stimulate bile production
 Peptide YY: increase the efficacy of
digestion and absorption
 Glucagon Like Peptide 1: it inhibits
gastric emptying and trigger insulin
secretion.

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 Leptin: the increased level of this
hormone reduce hunger (due to eating
food)
 Motilin: raise the speed of intestinal and
stomach activity
 Glucose dependant insulinotrophic
peptide (GIP): triggers release of insulin
hormone form pancreas.

Conclusion
There are two different methods of digestion mechanical
digestion and chemical digestion. In Chemical digestion is the
large molecules of food splits in large molecules into the
smaller essential nutrients so that these molecule can enter the
blood stream and can be used by the cells. The enzymes help to
digest c carbohydrates in the body includes Pancreatic amylase,
alpha-dextrinase, Sucrase, Maltase & Lactase. Digestion of
protein carried out by enzymes like aminopeptidase , dipeptidase,
chymotrypsin and trypsin. pancreatic lipase, gastric lipase and
lipase involved in lipid digestion and deoxyribonuclease and
ribonuclease plays key role in nucleic acid digestion. Some
hormones that are essential for chemical digestion includes
ghrelin, gastrin, secretin, cholecystokinin, peptide YY, and
glucagon like peptide 1.

References
 Anatomy and Physiology . (2018) . Chemical Digestion and absorption: A closer look. Retrieved from:
https://opentextbc.ca/anatomyandphysiology/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/
 El Kaoutari, A., Armougom, F., Gordon, J. I., Raoult, D., & Henrissat, B. (2013). The abundance and variety of carbohydrate-
active enzymes in the human gut microbiota. Nature reviews Microbiology, 11(7), 497.
 Guerra, A., Etienne-Mesmin, L., Livrelli, V., Denis, S., Blanquet-Diot, S., & Alric, M. (2012). Relevance and challenges in
modeling human gastric and small intestinal digestion. Trends in biotechnology, 30(11), 591-600.
 Hata, T., Mera, Y., Ishii, Y., Tadaki, H., Tomimoto, D., Kuroki, Y., & Kakutani, M. (2011). JTT-130, a novel intestine-specific
inhibitor of microsomal triglyceride transfer protein, suppresses food intake and gastric emptying with the elevation of plasma
peptide YY and glucagon-like peptide-1 in a dietary fat-dependent manner. Journal of Pharmacology and Experimental
Therapeutics, 336(3), 850-856.
 Hur, S. J., Lim, B. O., Decker, E. A., & McClements, D. J. (2011). In vitro human digestion models for food applications. Food
Chemistry, 125(1), 1-12.
 Marengo, K. (2018). Understanding Digestion. Retrieved from: https://www.healthline.com/health/chemical-digestion
 Minekus, M., Alminger, M., Alvito, P., Ballance, S., Bohn, T. O. R. S. T. E. N., Bourlieu, C., & Dufour, C. (2014). A standardised
static in vitro digestion method suitable for food–an international consensus. Food & function, 5(6), 1113-1124.
 Panawala, L. (2017). Difference between mechanical and chemical digestion. Retrieved form:
https://www.researchgate.net/publication/320413508_Difference_Between_Mechanical_and_Chemical_Digestion
 Sayegh, A. I. (2013). The role of cholecystokinin receptors in the short-term control of food intake. In Progress in molecular
biology and translational science (Vol. 114, pp. 277-316). Academic Press.
 Singh, H., Ye, A., & Horne, D. (2009). Structuring food emulsions in the gastrointestinal tract to modify lipid digestion. Progress
in lipid research, 48(2), 92-100.
 Stipanuk, M. H., & Caudill, M. A. (2018). Biochemical, Physiological, and Molecular Aspects of Human Nutrition-E-Book (4th
ed.). Amsterdam, Netherlands: Elsevier health sciences. Suzuki, K., Simpson, K. A., Minnion, J. S., Shillito, J. C., & Bloom, S.
R. (2010). The role of gut hormones and the hypothalamus in appetite regulation. Endocrine journal, 57(5), 359-372.
 Beglinger, S., Drewe, J., Schirra, J., Goke, B., D'amato, M., & Beglinger, C. (2010). Role of fat hydrolysis in regulating
glucagon-like Peptide-1 secretion. The Journal of Clinical Endocrinology & Metabolism, 95(2), 879-886.
 Suzuki, K., Simpson, K. A., Minnion, J. S., Shillito, J. C., & Bloom, S. R. (2010). The role of gut hormones and the
hypothalamus in appetite regulation. Endocrine journal, 57(5), 359-372.
 McIntosh, C. H., Widenmaier, S., & Kim, S. J. (2009). Glucose‐dependent insulinotropic polypeptide (gastric inhibitory
polypeptide; GIP). Vitamins & Hormones, 80, 409-471.
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