Chapter 4: Human Digestion & Absorption

Lacteals

They are the lymphatic vessels of the small intestine that absorb digested fats.

disorders

GI *blank* occur when the GI tract malfunctions.

Flatulence

Intestinal Gas is also known as...

Pyloric Sphincter

It controls the flow of stomach contents into the small intestine.

Lower Esophageal Sphincter (LES)

This prevents the back-flow (reflux) of stomach contents into the esophagus.

Submucosa

This second innermost layer consists of loose connective tissue, glands, blood vessels, and nerves.

Muscle

This second outermost layer consists of an inner layer of circular smooth muscle & an outer layer of longitudinal muscle fibers; they work together to move food forward through the GI tract.

diarrhea (treatment)

Treatment for this includes consuming fluids to replace those lost + electrolytes.

IBS

Treatments for this include relaxation techniques, peppermint oil, avoiding large & high-fat meals, and avoiding food triggers. (Give acronym)

small intestine (water)

~ 70% to 90% of total water ingested is absorbed here.

small intestine (alc)

~ 80% of total alcohol ingested in absorbed here.

Microbes

*Blank* in the large intestine have the following health functions: - produce antimicrobial substances. - block pathogens. - provide nutrients that promote epithelial cell health. - make nutrients, such as vitamin K & biotin. digest & metabolize complex carbs, fibers, and starches to form short-chain fatty acids. - modulate inflammation.

Fat-soluble nutrients

*Blank-blank nutrients* are absorbed by the lymphatic system.

G cells

*These* Gastric Gland Cells secrete Gastrin.

Chief

*These* Gastric Gland Cells secrete Pepsinogen & Gastric Lipase.

Mucous

*These* Gastric Gland Cells secrete mucus, which protects the stomach mucosa from HCl & enzymes.

Parietal

*These* Gastric Gland Cells secrete the components that form HCl (H+ ions &Cl- ions) & intrinsic factor.

bolus

A *blank* from a meal can expand the stomach to hold 4-6 cups, compared to 2 oz when empty.

Segmentation

A back & forth movement in the small intestine that breaks food into smaller pieces.

Facilitated Diffusion

Absorption in which a carrier shuttles substances into the absorptive cell but not energy is expended. Absorption is driven by a concentration gradient that is higher in the intestinal contents than in the absorptive cell.

Passive Diffusion

Absorption that requires permeability of the substance through the wall of the small intestine & a concentration gradient higher in the intestinal contents than in the absorptive cell.

Active Transport

Absorption using a carrier & expending ATP energy. The absorptive cell can absorb nutrients, such as glucose, against a concentration gradient.

Endocytosis (phagocytosis & pinocytosis)

Active absorption in which the absorptive cell forms an indentation in its membrane, and then particles (phagocytosis) or fluids (pinocytosis) entering the indentation are engulfed by the cell.

water-soluble

Are these *water-soluble* OR *fat-soluble* nutrients? - Proteins & carbs. - Short-chain fatty acids & medium-chain fatty acids. - B-vitamins & vitamin C.

fat-soluble

Are these *water-soluble* OR *fat-soluble* nutrients? - Vitamins A, D, E, and K. - Long-chain fatty acids. - Large proteins.

liver, gallbladder

Bile is produced in the *blank* & stored in the *blank*.

72 or more hours

Contents remain in the large intestine for about how many hours?

Ulcers

They are small erosions of the top layer of cells in the stomach or duodenum.

amylase

Carbohydrate digestion is temporarily halted in the stomach because stomach acid inactivates *blank*.

Constipation

Difficult or infrequent bowl movements due to the slow movement of feces through the large intestine.

both Mechanical & Chemical

Does the mouth engage in *both Mechanical & Chemical* digestion OR *just Mechanical* digestion?

mucus

During chemical digestion, *blank* is secreted to protect the stomach lining.

Heartburn & GERD

Eating small & lower-fat meals, avoiding trigger foods, NOT laying down for at least 2 hours post-meal, losing weight if overweight, ceasing smoking, limiting alcohol intake, and elevating the head of your ed at least 6in are all lifestyle changes to treat...

75% water & 25% solids

Feces is *blank% water & blank% solids*.

rectum, anus

Feces is held in the *blank* & removed via the *blank*.

Mouth & salivary glands (flow)

Fill in the blank for correct GI tract flow: - ??? - Esophagus. - Stomach. - Small intestine. - Large Intestine. - Rectum. - Anus.

Esophagus (flow)

Fill in the blank for correct GI tract flow: - Mouth & salivary glands. - ??? - Stomach. - Small intestine. - Large Intestine. - Rectum. - Anus.

Stomach (flow)

Fill in the blank for correct GI tract flow: - Mouth & salivary glands. - Esophagus. - ??? - Small intestine. - Large Intestine. - Rectum. - Anus.

Small intestine (flow)

Fill in the blank for correct GI tract flow: - Mouth & salivary glands. - Esophagus. - Stomach. - ??? - Large Intestine. - Rectum. - Anus.

Large intestine (flow)

Fill in the blank for correct GI tract flow: - Mouth & salivary glands. - Esophagus. - Stomach. - Small intestine. - ??? - Rectum. - Anus.

Rectum (flow)

Fill in the blank for correct GI tract flow: - Mouth & salivary glands. - Esophagus. - Stomach. - Small intestine. - Large Intestine. - ??? - Anus.

Anus (flow)

Fill in the blank for correct GI tract flow: - Mouth & salivary glands. - Esophagus. - Stomach. - Small intestine. - Large Intestine. - Rectum. - ???

GI Tract & Accessory Organs

Fill in the blank: The digestive system has two components, which are the *blank blank & blank blank*.

water-soluble nutrients, cardiovascular system, hepatic portal vein

Fill in the blanks: *Blank-blank nutrients* are absorbed directly into capillary beds in villi & then transported by the *blank system* to the liver via the *blank blank vein*.

3-10 hours

Food being digested remains in the stomach for about how many hours?

LES

Food reaches the *blank* & enters this stomach; it then shuts when the food is in the stomach. (Answer with acronym)

2-3 hours

Food remains in the stomach for about how many hours on average?

pancreatic enzymes

In regard to chemical digestion in the small intestine, amylase, lipase, and proteases are all *blank enzymes*.

intestinal enzymes

In regard to chemical digestion in the small intestine, peptidases, disaccaridases, and lipases are all *blank enzymes*.

Chyme

In the stomach, the mixing and churning of a bolus (mechanical digestion) with gastric secretions creates what is known as...

Diarrhea

Loose, watery stools occurring more than 3x a day.

sodium bicarbonate

Made by the pancreas, this neutralizes acidic chyme.

Facilitated diffusion

Nutrient transport out of microvilli uses 1 of 4 methods. What's the missing one? - Active transport. - Passive diffusion. - Endocytosis. - ???

Passive diffusion

Nutrient transport out of microvilli uses 1 of 4 methods. What's the missing one? - Endocytosis. - Active transport. - Facilitated diffusion. - ???

Active transport

Nutrient transport out of microvilli uses 1 of 4 methods. What's the missing one? - Facilitated diffusion. - Endocytosis. - Passive diffusion. - ???

Endocytosis

Nutrient transport out of microvilli uses 1 of 4 methods. What's the missing one? - Passive diffusion. - Facilitated diffusion. - Active transport. - ???

lacteals

Once fat-soluble nutrients are absorbed, *blank* transport them to large lymphatic vessels that connect with the bloodstream at the left subclavian vein.

Enzymes

Proteins that speed up chemical reactions.

Sphincters

Ring-like muscles that open & close like valves to control the flow of contents along the GI tract + allow digestive enzymes to be thoroughly mixed.

Pepsinogen

Secreted by Chief cells, this digests protein AFTER its conversion to Pepsin.

Gastric lipase

Secreted by Chief cells, this digests small amounts of fat.

gastrin

Secreted by G cells, this stimulates stomach motility + gastric gland activity.

components of HCl (H+ ions & Cl- ions)

Secreted by Parietal cells, these activate pepsinogen & destroy many food-borne microbes.

intrinsic factor

Secreted by Parietal cells, this facilitates the absorption of vitamin B-12.

GI tract

The *blank blank* is a long, muscular tube that extends from the mouth to the anus.

small

The *blank* (small/large) intestine is longer in length but has a smaller lumen.

large

The *blank* (small/large) intestine is shorter in length but has a larger lumen.

mouth

The *blank* is the starting point of digestion.

Pancreas

The *blank* makes sodium bicarbonate, amylase, lipase, and proteases.

Alimentary Canal

The GI tract is also known as the...

villi & microvilli

The Lumen of the small intestine has folds, which are composed of *blank & blank* that increase the absorptive capacity of the small intestine.

Irritable Bowel Syndrome (IB

The cause for this is currently unknown; however, stress & diet may play a role. Symptoms include irregular bowl function, abdominal pain, and abdominal distension that's often worse after eating.

carbs

The digestion of *blank* (carbs, fats, proteins) is temporarily halted in the stomach.

ulcers (prevention)

The following are ways to prevent what? - cease smoking. - avoid large doses of aspirin, ibuprofen, and other NSAIDs. - limit intake of coffee, tea, alc, and spicy foods. - lose weight if overweight.

large intestine

The following describes the nutrient absorption of which part of the digestive system? - 10% to 30% of total water ingested. - electrolytes (sodium & potassium). - some fatty acids. - vitamin k & biotin (made by microbes in microbiota).

Lumen

The inside of a tube, such as the inside cavity of the GI tract; the walls that form it are made up of 4 layers.

Peristalsis

The movement of food toward the anus.

Prebiotics

They are non-digestible food ingredients, such as Inulin which it found in chicory, wheat, onions, garlic, asparagus, and bananas.

Digestion

The process by which large compounds in foods are broken down into smaller ones.

chyme

The pyloric sphincter controls the release of *blank* into the small intestine.

feces

The solid part of *blank* is made of indigestible plant fibers, connective tissues from animal foods, bacteria from the large intestine, and shed epithelial cells.

stomach

There is minimal absorption of nutrients in this organ; it absorbs water + 20% of total alcohol, even though alcohol is not a nutrient.

Probiotics

These are live microbes that colonize the large intestine. They can be found in fermented foods & supplements, which include yogurt, kefir, and miso.

immune

These are the *blank* functions of the Gastrointestinal system: - acts as a physical barrier. - produces immune components. - houses microbes, especially bacteria.

enzymes

These digestive secretions are produced in the mouth, stomach, small intestine, and pancreas. They function to breakdown carbs, fats, and proteins into forms small enough for absorption.

Hormones

These digestive secretions are produced in the stomach, small intestine, and pancreas. They function to regulate food intake, digestion, and absorption.

disaccaridases

These intestinal enzymes breakdown disaccharides into monosaccharides.

peptidases

These intestinal enzymes breakdown partially digested proteins.

lipases

These intestinal enzymes digest fat.

proteases

These pancreatic enzymes partially digest proteins.

Accessory organs

These produce emulsifiers, hormones, and enzymes that help with digestion in the small intestine.

prebiotics

They are also digestion-resistant starches which ca be found in unprocessed whole grains, seeds, legumes, unripe fruit, pasta, potatoes, and rice.

Food Intolerances

They are caused by the inability to digest certain food components due to deficiencies in digestive enzymes.

diarrhea (causes)

This can be caused by bacteria infections, viral infections, parasites, food intolerances, medications, megadoses of vitamin C, intestinal diseases, and IBS.

Lymphatic System

This circulatory system absorbs larger molecules that can't be absorbed by capillary beds.

Accessory Organs

This component of the digestive system has parts that assist with GI functions.

GI Tract

This component of the digestive system is the hollow muscular tube.

Bile

This digestive secretion is produced in the liver. It functions to emulsify fat.

Mucus

This digestive secretion is produced in the mouth, stomach, and intestines. It functions to protect GI tract cells & lubricate digesting food.

Saliva

This digestive secretion is produced in the mouth. It functions to dissolve taste-forming compounds, aid swallowing, and protect your teeth.

Bicarbonate

This digestive secretion is produced in the pancreas & small intestine. It functions to neutralize stomach acid when it reaches the small intestine.

Acid (HCl)

This digestive secretion is produced in the stomach. It functions to promote digestion, destroy microbes, and increase the solubility of minerals.

saliva

This enhances our perception of taste & flavor by dissolving compounds in foods.

Mucosa

This innermost layer of GI tract tissue is lined with epithelial cells & glands. It's not smooth due to the villi that extend from it to increase its surface area.

Gastric Lipase

This is an enzyme the stomach that breaks down some fats.

Intestinal Gas

This is created from the fermentation of undigested carbs by bacteria in the large intestine.

Hydrochloric Acid (HCl)

This is in the stomach & has the following qualities. - inactivates ingested proteins. - kills harmful bacteria & viruses. - decreases stomach pH.

constipation

This is often reported by older individuals & caused by ignoring the normal urge to defecate, Diabetes mellitus, IBS, Depression, Pregnancy, Medications (antacids, antidepressants) Ca & Fe supplements, and low-fiber diets.

Intrinsic Factor

This is something in the stomach that is needed for the absorption of vitamin B-12.

Chemical Digestion

This is the chemical breakdown of large nutrients into their component parts. It involves enzymes, acids, emulsifiers, and other gastric secretions.

Small intestine

This is the major site of digestion & nutrient absorption. It digests & absorbs water, glucose, amino acids, fats vitamins, minerals, and non-nutrients like alcohol & bile.

Esophagus

This is the organ that food passes though, via peristalsis, to the stomach.

Mechanical Digestion

This is the physical breakdown of food into smaller pieces. It involves chewing, mixing, and segmentation.

GERD (gastroesophageal reflux disease)

This occurs when someone has heart burn symptoms 2+ times a week.

Heartburn

This occurs when stomach acid back flows into the esophagus.

Nervous system

This organ system has receptors in the GI tract that sense the presence of food & send signals to start the process of digestion and/or absorption.

Gastrointestinal system

This organ system is controlled by the nervous system + hormones. Its function is to digest & absorb nutrients. It also aides in immune function.

Immune system

This organ system protects the body from foreign microbes; good nutrition keeps it strong.

Endocrine system

This organ system regulates metabolism & blood levels of certain nutrients.

Urinary system

This organ system removes waste products from the body + maintains pH & water balance.

Circulatory system

This organ system transports nutrients absorbed from the GI tract to the body's cells.

Serosa

This outermost layer protects the GI tract by secreting fluid that cushions the GI tract & reduces friction as it + other organs move.

Heartburn & GERD (contributing factors)

Using alcohol, smoking being overweight, and eating citrus fruits, chocolate, caffeinated drinks, fatty & fried foods, garlic, onion, spicy food, and tomato-based foods are all contributing factors to...

Amylase, Lipase, Lysozyme

What are the 3 enzymes present in the mouth?

Mucosa, Submucosa, Muscle, Serosa

What are the 4 layers that make up the walls of the lumen, from innermost to outermost?

Sweet, Salty, Sour, Bitter, Umami

What are the 5 tastes?

Cecum, Ascending Colon, Transverse Colon, Descending Colon, Sigmoid Colon

What are the components of the large intestine in order?

Duodenum, Jejunum, Ileum

What are the components of the small intestine in order?

ulcers (treatment)

What are the following treatments for? - antibiotics for those infected with the specific bacteria. - proton pump inhibitor to suppress acid production. - cease smoking. - avoid foods that increase symptoms.

chemical, cell, tissue, organ, organ system, organism

What are the levels of organization, from small to large?

cardiovascular system & lymphatic system

What are the two circulatory systems that the microvilli of the small intestine will transport nutrients to?

connective, epithelial, muscle, nervous

What are the types of tissue, in alphabetical order?

Peptic Ulcer

What do you call an ulcer that occurs in the stomach?

gastroesophageal reflux disease

What does GERD stand for?

bile

What does the following describe? - assists with fat digestion by emulsifying fats. - made in the liver. - stored in the gallbladder.

sodium & potassium

What electrolytes are absorbed in the large intestine?

infection with Helicobacter pylori

What's the missing main cause of Ulcers? - heavy use of NSAIDs. - ???

heavy use of NSAIDs

What's the missing main cause of Ulcers? - infection with Helicobacter pylori. - ???

Lactobacilli (bacteria)

What's the missing microbe commonly found in probiotic foods? - Bifidobacteria (bacteria). - Saccharomyces (yeast). - ???

Saccharomyces (yeast)

What's the missing microbe commonly found in probiotic foods? - Lactobacilli (bacteria). - Bifidobacteria (bacteria). - ???

Bifidobacteria (bacteria)

What's the missing microbe commonly found in probiotic foods? - Saccharomyces (yeast). - Lactobacilli (bacteria). - ???

Peptide YY

Which major regulatory GI hormone is this? It's released by the ileum & large intestine in response to fat in the large intestine. It functions to inhibit gastric & pancreatic secretions.

Secretin

Which major regulatory GI hormone is this? It's released by the small intestine in response to acidic chyme & as digestion progresses. It functions to stimulate the release of pancreatic bicarbonate.

Cholecystokinin (CCK)

Which major regulatory GI hormone is this? It's released by the small intestine in response to dietary fat in chyme. It functions to stimulate the release of pancreatic enzymes & bile from the gallbladder.

Glucose-dependent Insulinotropic Peptide (GIP)

Which major regulatory GI hormone is this? It's released by the small intestine in response to glucose, amino acids, and fat. It functions to inhibit gastric acid secretion + stimulate insulin release.

Gastrin

Which major regulatory GI hormone is this? It's released by the stomach & duodenum in response to food reaching the stomach. It functions to trigger the stomach to release HCl & pepsinogen; it also stimulates gastric & intestinal motility.

Somatostatin

Which major regulatory GI hormone is this? It's released by the stomach, small intestine, and pancreas. It functions to inhibit the release of HI hormones + slow gastric emptying, GI motility, and perfusion to the intestine.

form & remove feces

Which of the large intestines 3 main functions is missing? - absorb water & electrolytes. - house microbiota. - ???

house microbiota

Which of the large intestines 3 main functions is missing? - form & remove feces. - absorb water & electrolyes. - ???

absorb water & electrolytes

Which of the large intestines 3 main functions is missing? - house microbiota. - form & remove feces. - ???

vitamin k & biotin

Which vitamins are made by microbes in the large intestine?

10% to 30%

about how much of total water ingested is absorbed in the large intestine?