A service of the National Library of Medicine, National Institutes of Health.. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-.

The entire digestive system is made up of one muscular tube extending from the mouth to the anus. The stomach is an enlarged pouch-like section of this digestive tube

The stomach’s shape and size vary from person to person, depending on things like people’s sex and build, but also on how much they eat.. At the point where the esophagus leads into the stomach, the digestive tube is usually kept shut by muscles of the esophagus and diaphragm

It produces enzymes (substances that create chemical reactions) and acids (digestive juices). This mix of enzymes and digestive juices breaks down food so it can pass to your small intestine.

The GI tract is a long tube that starts at your mouth. It runs to your anus, where stool (poop) leaves your body

Your stomach’s purpose is to digest food and send it to your small intestine. – Produce enzymes and other specialized cells to digest food.

This book is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits others to distribute the work, provided that the article is not altered or used commercially. You are not required to obtain permission to distribute this article, provided that you credit the author and journal.

Treasure Island (FL): StatPearls Publishing; 2023 Jan-.. Food digestion is the breakdown of large food particles into smaller absorbable nutrients needed for energy production, growth, and cellular repair

Mechanical digestion is the physical degradation of large food particles into smaller pieces that digestive enzymes can access through chemical digestion. Chemical digestion is the enzymatic cleavage of proteins, carbohydrates, and fats into tiny amino acids, sugars, and fatty acids

Pepsin is an enzyme produced in the stomach that attacks proteins to break them down into smaller peptide molecules. Which of the following statements about this enzyme is true?

Pepsin will continue to work at the same rate as it moves through the intestines until all the protein is broken down.. Salivary amylase activates pepsin, converting it to a functioning form in the stomach.

Master Food and Feeding with a bite sized video explanation from Jason Amores SumpterStart learning

This book is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits others to distribute the work, provided that the article is not altered or used commercially. You are not required to obtain permission to distribute this article, provided that you credit the author and journal.

Treasure Island (FL): StatPearls Publishing; 2023 Jan-.. Food digestion is the breakdown of large food particles into smaller absorbable nutrients needed for energy production, growth, and cellular repair

Mechanical digestion is the physical degradation of large food particles into smaller pieces that digestive enzymes can access through chemical digestion. Chemical digestion is the enzymatic cleavage of proteins, carbohydrates, and fats into tiny amino acids, sugars, and fatty acids

In which component of the digestive tract does no digestion occur?. The esophagus is responsible for transporting food from the mouth to the stomach via peristalsis, which consists of smooth muscle contractions, but does not help digest the food content in the process

The mouth introduces enzymes in the saliva, the stomach introduces pepsin, and the small intestine introduces a number of other enzymes for digestion of macromolecules.. Which of the following choices incorrectly pairs a digestive enzyme with the digestive tract component in which it is found?

Cholecystokinin (CCK) is a hormone released by the duodenum to signal and stimulate accessory organs for digestive enzymes. Salivary amylase digests starch in the mouth, while pepsin is used to digest proteins in the stomach.

– Detail the steps involved in digestion and absorption. – Explain the role of both the small and large intestines in absorption

For true animals, the first step is ingestion, the act of taking in food. This is followed by digestion, absorption, and elimination

The large molecules found in intact food cannot pass through the cell membranes. Food needs to be broken into smaller particles so that animals can harness the nutrients and organic molecules

This article needs additional citations for verification. Gastric acid, gastric juice, or stomach acid is a digestive fluid formed within the stomach lining

Gastric acid is regulated in feedback systems to increase production when needed, such as after a meal. Other cells in the stomach produce bicarbonate, a base, to buffer the fluid, ensuring a regulated pH

The pancreas further produces large amounts of bicarbonate and secretes bicarbonate through the pancreatic duct to the duodenum to neutralize gastric acid passing into the digestive tract.. The primary active component of gastric acid is hydrochloric acid (HCl), which is produced by parietal cells in the gastric glands in the stomach

When you eat food, the body’s digestive system breaks down dietary protein into individual amino acids, which are absorbed and used by cells to build other proteins and a few other macromolecules, such as DNA. Let’s follow the path that proteins take down the gastrointestinal tract and into the circulatory system.

One egg, whether raw, hard-boiled, scrambled, or fried, supplies about six grams of protein.. In the image below, follow the numbers to see what happens to the protein in our egg at each site of digestion.

The teeth begin the mechanical breakdown of large egg pieces into smaller pieces that can be swallowed. The salivary glands secrete saliva to aid swallowing and the passage of the partially mashed egg through the esophagus.

Discuss how proteins are digested and absorbed by our bodies.. How do the proteins from foods, denatured or not, get processed into amino acids that cells can use to make new proteins? When you eat food the body’s digestive system breaks down the protein into the individual amino acids, which are absorbed and used by cells to build other proteins and a few other macromolecules, such as DNA

Eggs are a good dietary source of protein and will be used as our example to describe the path of proteins in the processes of digestion and absorption. One egg, whether raw, hard-boiled, scrambled, or fried, supplies about six grams of protein.

Unless you are eating it raw, the first step in egg digestion (or any other protein food) involves chewing. The teeth begin the mechanical breakdown of the large egg pieces into smaller pieces that can be swallowed

The stomach is a gastrointestinal organ that is responsible for preliminary digestion and destroying any potential pathogenic microorganisms that may have been ingested. It is an acidic environment with a pH that can vary between 1.5-3.5.

HCl is produced by the parietal cells of the stomach. To begin with, water (H2O) and carbon dioxide (CO2) combine within the parietal cell cytoplasm to produce carbonic acid (H2CO3), which is catalysed by carbonic anhydrase

The hydrogen ion that is formed is transported into the stomach lumen via the H+– K+ ATPase ion pump. This pump uses ATP as an energy source to exchange potassium ions into the parietal cells of the stomach with H+ ions.

Acetylcholine, the first neurotransmitter discovered, was originally described as “vagus stuff” by Otto Loewi because of its ability to mimic the electrical stimulation of the vagus nerve. It is now known to be a neurotransmitter at all autonomic ganglia, at many autonomically innervated organs, at the neuromuscular junction, and at many synapses in the CNS.

In the autonomic nervous system, acetylcholine (ACh) is the neurotransmitter in the preganglionic sympathetic and parasympathetic neurons. These are shown in Figure 11.2 as the red ACh in the ganglion

ACh is also the neurotransmitter at the sweat glands, and at the piloerector muscle of the sympathetic ANS (Labeled in blue in Figure 11.2).. In the peripheral nervous system, ACh is the neurotransmitter at the neuromuscular junction between the motor nerve and skeletal muscle.

Which gastrointestinal layer is characterized by having tough, fibrous connective tissue?. Which intestinal layer accounts for the action of the peristaltic waves?

The frenulum is the membrane attached to the inferior surface of the _____.. The following are true of the tongue except which one?

Which lymphatic areas are most commonly the site of inflammation?. How many teeth will be produced in an average lifetime?

Geissler & Powers: Human Nutrition 13e Chapter 8: Multiple choice questions Instructions Answer the following questions and then press ‘Submit’ to get your score. Question 1 What are the functions of dietary fat? a) Provide energy to the body b) Form part of cellular membranes c) Cell signalling d) All options given are correct Question 2 Which membrane fatty acids are precursors for eicosanoids? a) C20 and C22 saturated fatty acids b) C18 and C22 polyunsaturated fatty acids c) C20 and C22 monounsaturated fatty acids d) C20 and C22 polyunsaturated fatty acids Question 3 Which of the following statements about plasma lipoproteins is correct? a) They have a hydrophobic core of triacylglycerol and cholesterol esters b) They have a hydrophobic core of phospholipids and free cholesterol c) They have a hydrophilic core of triacylglycerol and cholesterol esters d) They have a hydrophobic core of phospholipid and apolipoproteins Question 4 Which are the FIVE main series of apoproteins that have been identified? a) apoA, apoB, apoC, apoD, and apoE b) apoA, apo(a), apoB, apoC and apoE c) apoA, apoB, apoC, apo E, and apoL d) apoB, apoC, apoD, apoE and apoM Question 5 Which of the following lipoproteins is produced via the exogenous lipoprotein pathway? a) High density lipoproteins b) Very low density lipoproteins c) Chylomicrons d) Low density lipoproteins Question 6 The Atherogenic Lipoprotein Phenotype (ALP) is a collection of which lipoprotein abnormalities? a) Reduced levels of HDL, a high proportion of small dense LDL and raised triglycerides b) Reduced levels of HDL, a high proportion of small dense LDL and normal triglycerides c) Raised levels of HDL, a high proportion of small dense LDL and raised triglycerides d) Reduced levels of HDL, a low proportion of small dense LDL and raised triglycerides Question 7 The amount and composition of dietary fat are important factors for influencing blood lipid metabolism

b) The mechanism by which non-esterified fatty acids are taken up by cells is by a combination of diffusion and carrier-mediated transport involving fatty acid binding, translocase and transport proteins. c) The mechanism by which non-esterified fatty acids are taken up by cells is by a combination of diffusion and carrier-mediated transport involving fatty acid esterification, synthesis and transport proteins

Question 9 De novo fatty acid synthesis usually signifies which of the following? a) An excess of fat intake b) A depletion of energy yielding substrates c) Only occurs with prolonged fasting d) An excess of energy yielding substrates Question 10 Which of the following statements is incorrect regarding fatty acid ß-oxidation? a) The major site of fatty acid ß-oxidation is the peroxisomes, the mitochondria also contain enzymes for this pathway b) Within the liver peroxisomes serve to oxidise very long chain fatty acids to medium chain products c) The rate of b-oxidation is regulated by the availability of fatty acids and the rate of utilisation of b-oxidation products d) Peroxisomes are the site for the degradation of xenobiotics and eicosanoids Question 11 Which of the following rules regarding the interconversion of fuels are central to the integration of metabolic pathways? a) Fatty acids can be made from and converted to carbohydrates and amino acids b) Carbohydrates can be made from and converted to amino acids and fatty acids c) Fatty acids can be made from but not converted to carbohydrates and amino acids d) Amino acids can be made from and converted to fatty acids Question 12 After consumption of a mixed meal, a complex cascade of events takes place that integrates fat metabolism at the whole body level. Which of the following is correct? a) Consumption of a meal leads to suppression of lipase activity within adipose tissue leading to a decrease in plasma NEFA concentrations b) Adipose tissue lipoprotein lipase is activated by insulin and therefore is most active following meal consumption c) During the postprandial period the VLDL synthesis pathway is suppressed in favour of hydrolysis of chylomicrons d) All options given are correct

Carbohydrates, proteins, and fats are the main types of macronutrients in food (nutrients that are required daily in large quantities). They supply 90% of the dry weight of the diet and 100% of its energy

These nutrients also differ in how quickly they supply energy. Carbohydrates are the quickest, and fats are the slowest.

The body uses these basic units to build substances it needs for growth, maintenance, and activity (including other carbohydrates, proteins, and fats).. Depending on the size of the molecule, carbohydrates may be simple or complex.

This chapter discusses the process of digestion and absorption of proteins in monogastric and ruminant animals. The different enzymes involved in protein digestion and the mode of absorption of amino acids are also discussed.

– To introduce different types of protein-digesting enzymes, their sites of release, and their mode of action. – To discuss the similarities and differences between monogastric and ruminant animals in protein digestion

In the case of proteins, it involves denaturing of proteins to expose the peptide bonds, followed by hydrolysis and release of free amino acids.. Protein-digesting enzymes are either endopeptidase or exopeptidase