Login with Facebook

How Digestive System Works

The digestive system of human is composed of salivary glands, liver, gall bladder, and pancreas which produce different substances that contribute to digestion. The alimentary canal then does not have a uniform diameter and, in some sections, folds numerous times on it to increase the surface useful for digestion and absorption.

The path of food is from the mouth, it passes into the pharynx and from here into the esophagus; then accumulates in the stomach and finally pours into the intestine. Digestion begins in the mouth due to the mechanical shredding action of the teeth and the biochemical action of saliva, secreted by three pairs of salivary glands. Saliva contains the enzyme amylase, which begins the demolition of starch (a polysaccharide) into maltose (a disaccharide sugar). While it is shredded, the food is also fluidized by the aqueous component of the saliva, until it becomes dough called a bolus. The bolus is swallowed through the pharynx by means of coordinated acts and reflexes of the tongue.

The pharynx is the canal that connects the mouth with the esophagus and the trachea. At the base of the pharynx, there is a membrane, the epiglottis, which during swallowing, lowers and closes the entrance to the trachea to prevent the bolus from passing into the respiratory system.

The esophagus is a muscular canal about 25 cm long, which runs along the thorax, parallel to the trachea. Its function is to convey the bolus into the stomach by means of peristaltic movements (coordinated contractions of the circular and transverse muscle bundles surrounding the esophagus). The passage of the bolus from the esophagus to the stomach is regulated by a muscle ring, the cardia.

The stomach

The stomach is a muscle bag, capable of accommodating 2 to 4 liters of liquid and solid substances, in which food remains for 2 to 5 hours, depending on its composition. The mucous membrane of the stomach is provided with numerous glands that secrete gastric juice, composed of pepsinogen (the inactive form of the pepsin enzyme), hydrochloric acid, and mucus.

The stomach performs four functions:

1. Stores food and regulates its flow to the intestine.

2. It breaks down the food mechanically, by means of numerous contractions.

3. Transforms pepsinogen into pepsin, which splits proteins into shorter chains of amino acids.

4. Creates a very acidic environment (pH 1 to 3), which, in addition to promoting the action of pepsin, has an antibacterial action.

The mucus produced by the gastric glands covers the internal wall of the stomach to protect it from the aggression of hydrochloric acid and pepsin (which could act on the proteins of the gastric cells themselves). In the stomach, the bolus is transformed into mush, the chyme, which gradually passes through the muscular ring of the pylorus, which enters the intestine.

The gut

The intestine is divided into two parts, the small intestine and the large intestine, distinguished by the shape and function they perform. In the small intestine, digestive processes are completed, and most of the absorption of nutrients occurs. The secretions of two annexed organs of the digestive tract pour into the liver and pancreas.

About 6 m long in an adult man, the small intestine wraps itself several times. It is divided into three portions i.e. the duodenum (where the ducts that come from the liver and pancreas), the jejunum, and the ileum. The intestinal wall is home to numerous glands that produce enteric juice. It is composed of several enzymes like protease, which acts on proteins completing their cleavage into amino acids, lactase, maltase, and saccharase. They split carbohydrates into monosaccharides, lipase, which acts on lipids.

Other glands produce mucus, which protects the walls of the intestine.

The internal wall of the small intestine folds in on itself and is covered with villi, tiny overtones, which in the duodenum reach a few thousand per 2 cm. In turns, the villi are covered with microvilli, cells whose wall facing the lumen. Villi and microvilli contribute to increasing the absorption surface of the small intestine. Each villus is internally traversed by blood capillaries and a lymphatic vessel, which absorb nutrients like water and mineral salts. They rapidly absorb the carbohydrates in the form of monosaccharides (glucose, galactose) and proteins. The protein split into amino acids and lipids in the form of fatty acids.

The large intestine is made up of three parts i.e. colon (ascending, transverse, and descending) rectum and cecum. The appendix protrudes from the blind pouch, a small worm-like diverticulum that plays no role in the digestion.

Digestion residues, mainly water, and undigested substances reach the colon. The water is absorbed, and the waste substances reach the rectum in a semi-solid form (feces), ready to be expelled through the anus.

Liver and pancreas

The liver is the most voluminous gland in the human body, located in the upper right part of the abdomen. It has an ovoid shape and a reddish-brown color; it consists of two large lobes (right and left) and two smaller parts. It intervenes in digestion by secreting bile.

The liver also performs multiple other functions, including stores glycogen.

- Transforms excess amino acids compared to the needs of protein synthesis into sugars and fats. It transforms fats into sugars and converts ammonia, which forms as a nitrogen waste substance into urea; demolishes toxic or harmful substances.

Bile is a greenish mixture containing water, cholesterol, and bile salts. Bile salts are not enzymes, they emulsify fats, that is, they disperse them in minute droplets, thus preparing them for the action of lipase. The liver produces about 1 liter of bile per day, which it stores in its small bag, the gallbladder. During the meal, bile is discharged into the duodenum through the bile duct.

The pancreas is a large, elongated gland located transversely in the upper part of the abdomen. The activity of the pancreas is twofold i.e. as an endocrine gland, it produces the hormones insulin and glucagon, which regulate glucose metabolism, the exocrine part secretes the pancreatic juice. In pancreatic juice, there are several digestive enzymes, amylase, lipase, and protease, which are respectively responsible for the demolition of sugars, lipids, and proteins. The pancreatic juice has a high concentration of sodium bicarbonateDigestive System, which neutralizes the acidity of the chyme coming from the stomach and helps to maintain an alkaline environment inside the intestine.


Author: Vicki Lezama


Comments

Need a custom
essay?

We will write it for you.
Order now

Free Essay Examples

Free essays:

All you need to know about Neuroendocrinology
All you need to know about Big data management
All you need to know about digital special effects
All you need to know Technical Writing?
Basics the Game Theory in Cryptoeconomics
Business innovation ideas for making money
Biosensors for cancer diagnosis
Business Analysis: Pricing strategies and Demand Curve
Conservation Economics
Cybersecurity in business: challenges, risks, and practices
Corporate Behavior
Compare and contrast the political theories
Determinants of Wages
Deontology Vs. Utilitarianism
Development of Advertising
Digital Illiteracy
Economy and Air Pollution
Economic Externalities and How to Deal with Them
Economic Analysis of Market Structure
Expected Utility
Factors Affecting Purchasing Behavior
Financial Statement Analysis
Factors Influencing Interest and Exchange Rates
Fiscal and Monetary Policies in Response to 2008/2009
Game theory in microeconomics
Globalization: definition, causes, social impact and risks
Gene expression: what it is and why it is important
Global environmental issues
How women can manage sexual harassment
How to conduct economic research?
How to define the Enterprise Value
How cancer is developed - Cancer biology
Introduction to Labor Markets
Investment in Human Capital
Intellectual Property and Product Liability
Introduction to Social Choice and Incarceration
Journalism: What is News?
Journalism: Broadcast media and Television Presenters
Journalism: Sources of News
Journalism and Law
Key Determinants of National Income
Key Factors That Affect Pricing Decisions
Kinetic models in biology and Related fields
Know about the different forms of traditional African dances
Latest technology trends
Latest dance trends
Microeconomic Analysis to the Demand for Labor
Modern journalism
Neuromuscular disorders
National Economies, Fluctuation, and Responses to Fluctuations
Neurotransmitters: what they are and different types
Nanomedicines to target tumors
Organizational motivation and its effects
Overcoming Hiring Challenges for Nonprofit Organization
Policy in Corporate Mergers
Political theories of John Locke
Research and Development
Risk Sharing in Insurance and Asset Markets
Risk and the value of information
Reverse discrimination.
Structure of a Corporation
Schizoaffective disorder: how to live better with it
Segregation in the US.
Stages of the Consumer Decision-Making Process
The Role of Internal Audit in Corporate Risk Management
The Use of Law on Economics and Vice Versa
The political theory of Thomas Hobbes
The Game Theory in Social Media
Unemployment
Utilitarianism Vs. Kantianism
Understanding Auctions and Auction Theory: Part 2
Understanding Auctions and Auction Theory: Part 1
Various theoretical perspectives of sociology
Virtual reality, what it is and how it works
What is Neuroplasticity?
What is the 7 layers of OSI model?
4 Facts about Origin of Mathematics!
5 techniques to create an animation
10 emerging technologies according to World Economic Forum
10 strategies to maximize corporate profits
3d Model Of Building
6 Medical Technologies that revolutionized the healthcare in 2020
All you need to know about the ACA Code of ethics
Architecture and Democracy: An Introduction
Architecture and Democracy: Democratic Values
Architecture and Democracy: Democratic Procedures
All You Need to Know About a Synthesis Essay
An essential guide to understanding Film Theory
Application of Artificial Intelligence in Cyber Security
Applications of electrical engineering
Augmented reality: what it is, how it works, examples
Advantages And Disadvantages Of Social Networking
All you need to know about Cryptography
Applications of astrophysical science
All you need to know about architecture engineering
Applications of geological engineering
Artificial intelligence and medicine: an increasingly close relationship
An insight into Computational Biology
ACA code of conduct
A Rose for Emily
Applications of Mathematics in daily life
Architecture mistakes to avoid
All you need to know about Toxicology
All you need to know about Holistic Medicine
All you need to know about linguistics
An introduction to Linguistics and its subfields
All you need to know about Anxiety disorder
All you need to know about Drones
A Brief Insight into Political Science
Assumptions related to feminism
All you need to know about Byzantine emperors
All you need to know about labour economics
An insight into xenobots -the first-ever robots
An ultimate guide about Biomaterials
A Comprehensive Introduction to the Mona Lisa
Analysis methods of Transport through biological membranes
An ultimate guide about biochemical reactions
Analysis of brain signals
Artificial Gene Synthesis
Application to synthetic biology of CAD methods
All you need to know about metabolic pathways
Applications of BIOMEMS
All you need to know about the epidemiology
Asian vs. western leadership styles
All you need to know about Smart prosthesis
Analysis of Economy: Output of Goods and Services (GNP), and GDP on Economic success
A Guide to Pricing Strategies
An Overview Of Economic Studies
Analysis of Fiscal and Monetary Policies
Analysis of Business Cycles
Analysis of Consumption and Investment
A Look into Regression Analysis
Analysis of Household's Consumption and Savings Behavior
All you need to know about Capital Budgeting
All you need to know about risk management
Art looted in wartime.
Appropriate use of Data in Economics
All you need to know about reaction kinetics?
A historical overview of Financial Crises
All you need to know about management discipline?
An insight into the error-correction models
All you need to know about Data visualization
All you need to know about Work-family balance
All you need to know Technical Writing?
All you need to know about digital special effects
All you need to know about Big data management
All you need to know about Neuroendocrinology
How to Write a Personal Essay
Housing Needs in America
How to Write a Description Essay
How to Create an Excellent Scholarship Essay?
How to write a cause and effect essay
How to Hire the Best Essay Writing Service Provider?
How to Write a College Application Essay?
How to get the most out of your English lectures
How to write Expository Essay
How to succeed in your psychology class?
How to Write an Academic Essay in the Shortest Time?
History of Journalism
How Different Sectors are Using Artificial intelligence (AI)
How to write an informative essay
How to deliver persuasive essays?
How to Give a Convincing Presentation
How to write an essay on leadership?
Historical Art Still Around Today
Humanoid robot: what it is, how it works and price
History of Chemistry
Healthcare Advanced Computer Power: Robotics, Medical Imaging, and More
Healthcare AI: Game Changers for Medical Decision-Making and Remote Patient Monitoring
How to understand different types of English
How to Cope with Chronic Pain
How African American choreographers and dancers have influenced American dance
How mobile robot can do in logistics or in production
How To Become a Successful Entrepreneur
History of the Philosophy of Feminism
How is the climate changing?
How to Track Your Content Marketing ROI
How to Gun control In the USA?
Historical and contemporary role of labour in the modern world
How breast cancers are classified?
How the cells of our body communicate?
How the Lymphatic System Works?
How Digestive System Works
How to complete your capstone projects effectively?
How to write a research project
Healthcare technologies that help patients with better self-management
How to choose the topic of the senior capstone project
How to make your business survive at economic crisis
How can immigrants blend in the American society?
How does the economics of war affect society?
Hate speech on social media.
How to Build an Economic Model
How to start a healthcare startup?
How can financial illiteracy harm you?
How cancer is developed - Cancer biology
How to define the Enterprise Value
How to conduct economic research?
How women can manage sexual harassment
Introduction to Urban Studies
Importance of dance in education
InMoov: how to build an open source humanoid robot
Importance of KYC verification to making the Blockchain secure
Importance of Rhythm
Importance of dance student evaluation
I/O control methods -types and explanations
Identity theft: what to do?
Introduction to Utilitarianism
Importance of 3d Modelling in Architecture
Importance of online journalism
Image processing in medical diagnosis
Introduction to USA Politics
Introduction to Comparative Politics
International Relations as a Major in Political Science
Importance of modern trade policy
Introduction to Journalism
Introduction to Writing a TV Script
Introduction of Microfabrication techniques
Introduction to Microeconomics
Interaction of Consumer and Firm Choices in Markets
Importance of corporate sustainability
Issues in International Monetary Macroeconomics
Introduction to Statistics and Data for Economics
Introduction to Data and Probability for Economics
Introduction to the Game Theory
Introduction to Econometrics
Introduction to Economic Information
Introduction to Market Equilibrium
Introduction to Economic Models and Application
Introduction to Empirical Research
Introduction to Econometric Data
Importance of Critical Thinking, Principles, and Goals
Introduction to Identification and Causal inferences
Introduction to Econometric Application
Intermediaries and Government in Financial Crisis
Importance and seven principles of quality management
Illiteracy in the USA
Introduction to Economics of Law
Introduction to Coase Theorem
Introduction to Social Choice and Incarceration
Intellectual Property and Product Liability
Investment in Human Capital
Introduction to Labor Markets
The Looming Energy Crisis in America
Top benefits of performance-based engineering
The More Languages You Know, The More Times You Are a Man
Things to consider while writing an Argumentative Essay
Top Ways to Improve Your Academic Writing Skills
Tips to Excel in Creative Writing
The origins of films in the early 19th century
Top career options in Architecture
The Elevator Pitch
Top finance trends 2020
The basic Structure and functionality of robots
The Way to Success
The election system of the President in the United States of America
Two-party System in United States of America
Top trends in urban design
The history and theory of African American filmmaking
Top benefits of creative writing
Tinnitus Guide: Common Symptoms and Treatment Options
The language of dance
The digital image processing management
Top famous politicians of the World
Top methods of political science!
The history of the feminist movement
The blood flow in cardiovascular system - Biofluid Mechanics
The best of Leonardo Da Vinci
The Structure and Function of Macromolecules
The structure of cell: a research on the bricks of the human body!
Tissue and organ construction: Adhesion and recognition between cells
The kinetics of the transformation processes
The Modeling of Biological Systems
Tips for writing a great thesis statement
The Defense mechanisms against infections
The impact of the technological innovations in medicine
Top journalism trends to know about
The relation between mass media & politics
Theranostics: Diagnosis and Care through Nanoparticles
The practical Applications of X-rays
The applications of Ultrasound in medicine
Transfer mechanisms of genetic information in Bacteria
The regulation of cellular metabolism in the diagnosis
The Principles of MRI Contrast agents
The technical basis of optical coherence imaging
The New Media: Emerging Trends
The Structure of Interest Rates and the Yield Curve
Technological perspectives and reflections of neural engineering
Types of bioreactors and their applications
The Role of Government Policy in Improving Economic Outcomes
Types of corporate responsibility
The Role of IMF in International Monetary Macroeconomics
Tools for investment decision making
The concept of Organizational Culture and its applications
The Conduct of Monetary and Fiscal Policy
The Basics of Financial Accelerator Models
Tips for labeling medical devices- Medical Entrepreneurship
The different medical imaging techniques
The Economics of Uncertainty – Introduction
Theories of Public Policy
The Game Theory in Social Media
The political theory of Thomas Hobbes
The Use of Law on Economics and Vice Versa
The Role of Internal Audit in Corporate Risk Management
What is a Definition Essay?
What are diagnostic essays?
What is the relation between art structural engineering?
What is a Narrative Essay
What are robotics and intelligence systems?
What are the benefits of studying health sciences?
What is artificial intelligence and why it matters?
What is comparative Literature?
Why study neuroscience
What is Wi-Fi and how does it works
What is French history famous for?
What are Humanistic Studies?
What is covered in Biophysics?
What is modern journalism?
What is Virtualization? Benefits & Applications
What are modern public relations?
What is plasma physics?
What is teacher preparation?
What is rapid prototyping for 3D printing?
What is contemporary European Politics?
Why should you learn American Ballet?
What is engineering physics?
What is the purpose of African American Literature?
Ways to learn the Rhythm
What is digital art used for?
What are Enzymes and how do they work
Who is the father of political science?
Why Study Political Science - Job?
What is the Philosophy of Feminism?
What is a quantum computer?
Ways B2B Startups Streamline Their Conversion Strategies
Why do biomedical signals need processing?
What are the long term effects of climate change?
Why study labour relations
What is Holoprosencephaly?
What is antisocial disorder?
What are the important principles of evolution?
What is the cytoplasm and its function?
What is biopolymers?
What Makes a Good Leader
Women empowerment in modern generation
What is the history of political thought?
What is Gene recombination
What is synthetic biology
What is business cost analysis?
What is Inflation
What are the consequences of unemployment?
What is lithotripsy and its types?
What is transition elastography?
What is the purpose of deep brain stimulation?
What is a Brain-Computer Interface (BCI)
What is neuroethics?
What is Market and Supply and Demand
What is optogenetics?
What are the techniques to record brain activity?
What happens if the interest rate increases?
What is immunotherapy?
What is the economic role of the financial market?
What are the factors behind illegal immigration?
What is the lymphocyte activation?
What is financial market and its types?
What is the structure of financial markets?
What are the methods of measuring business performance?
What is the Credit market?
What is business ethics and code of ethics
What are the Causes of financial instability?
What is MBA with Concentrations
What is regenerative medicine?
What is Population ecology?
What is Microfinance: evolution, and practices?
What is biotechnology and its applications?
What are Workplace diversity and its benefits?
What is the difference between a leader and a manager?
What Is Branding and best branding Business strategies?
Why are microelectronics important?
What are biologic drugs.
What is the Foreign Exchange market?
What is the role of scientific research in times of crisis?
What are the risks of international trade?
What is financial management?
What is gene therapy?
What is education economics?
What is regression analysis, and why should you use it?
What Is Technology Marketing And How Should It Work?
What is Management Accounting
What are the methods of valuation of companies?
What is Immune System and Immunotherapy?
What is big data analytics?
What is the 7 layers of OSI model?
What is Neuroplasticity?