Understand Human Digestive System

This document provides an overview of the human digestive system, including the anatomy of the digestive tract, the origin and functions of digestive secretions, and the role of gut flora in digestion. It discusses the process of ingestion, digestion, absorption, and egestion, as well as the various enzymes and secretions involved in food breakdown. The document also explores the factors that affect gut flora and its importance in maintaining human health.

Running Head: Biology Nutrition and Digestion 1
Understand Human digestive system
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Biology Nutrition and Digestion 2
3.0 Understand Human digestive system
3.1 Anatomy of digestive tract
Ingestion is the introduction of food in the mouth and fauces helps in its opening. Salivary
glands (paratoids, sublingual and submandibular) produces salivary amylase which breakdown
starch into smaller carbohydrates. Uvula helps block the nasal cavity during swallowing of food
and tongue helps to roll food into a bolus. Muscles found in the esophagus walls helps in
peristalsis mechanisms which push the bolus into the stomach. It is then digested by various
enzymes such as amylase which breaks starch further to small carbohydrates and pepsinogen
digest proteins into amino acids.
In the small intestines the presence of villi, mucosal folds and microvilli help in food absorption
where nutrients from the intestinal lining are absorbed into the bloodstream. Assimilation also
takes place where nutrients absorbed reach their target cells for utilization.
Egestion which is the discharge of undigested matter from the digestive tract takes place via the
anus (Kong and Singh, 2010).
3.2 Origin and functions of digestive secretions
Digestive system produces various secretions that help in food digestion and protect the
alimentary canal. These substances are either provided by cells or glands along the alimentary
canal. Type of flows varies with the kind of food to be digested. Salivary glands secrete salivary
amylase produced in the mouth acts on the starch and also have an antibacterial function. In the
stomach, gastric cells produce mucus which protects the stomach walls and tissues from acidity.
It also acts as a food lubricant. The gastric cells also produce pepsinogen which helps in protein
digestion. The pancreas produces enzyme amylase for carbohydrates breakdown and pancreatic
lipase for lipids and phospholipids digestion. Also produces trypsin enzyme which is inactive to

Biology Nutrition and Digestion 3
protect the pancreas tissues from corrosion. The gall bladder produces bile juice for fat
emulsification, neutralizing acids and digestion of fats. In the large intestines, the Brunner glands
produce highly alkaline mucus which neutralizes chyme acidity. Goblet cells produce a mucus
secretion that protects the tissues from corrosion by acidity environment.
3.3 Role of gut flora and factors that affect it
The gut flora entails all the microbes in the intestines that are essential for human health. The gut
microbiome performs many functions which include fiber digestion, controlling brain health and
metabolism of breast milk. There exist some factors that affect gut flora which provides for,
infections, genetics, and mode of delivery at birth, diet and medications and infants feeding
(Ramakrishna, 2013).

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References
Kong, F. and Singh, R.P., 2010. A human gastric simulator (HGS) to study food digestion in
human stomach. Journal of food science, 75(9),E627-E635.
Ramakrishna, B.S., 2013. Role of the gut microbiota in human nutrition and
metabolism. Journal of gastroenterology and hepatology, 28.Role of the gut microbiota in
human nutrition and metabolism. Journal of gastroenterology and hepatology, 28.9-17.