PHYSIOLOGY OF CHEMICAL DIGESTION AND ABSORPTION

VIII. Chemical Digestion

 XII. Absorption (pp.898-901)

      A. Lipid Absorption

Small Intestine and Associated Structures

A.    Gross Anatomy of Small Intestine

1.     It extends from the pyloric sphincter to the ileocecal valve where it joins the large intestine. It has three subdivisions: the duodenum, the jejunum, and the ileum.

        B. Microscopic Anatomy of Small Intestine

               1. Modifications for absorption

        a. It is highly adapted for absorption with three microscopic modifications: plicae

circulares, villi, and microvilli [brush border]

2. Histology of the wall

        a. Simple columnar epithelial tissue with tight junctions and goblet cells

        b. Theintestinal crypts, or the crypts of Lieberkühn, secrete intestinal juice that

serves as a carrier fluid for absorbing nutrients from chyme.

c. Enteroendocrine cells and the enterogastrones secretin and cholecystokinin

        d. Intraepithelial lymphocytes [IELs]

        e. Paneth cells: defensins and lysozyme

                f. Peyer's patches: part of GALT

C.   The liver

               1. Functions [more than 200 functions!]

                        a. Metabolic regulation: regulation of blood composition,  removes and stores              nutrients, mobilizes stored reserves, performs synthetic activities, plays a role in                  carbohydrate, lipid & protein metabolism, waste removal, vitamin [A, D, E, K &                                B₁₂] and mineral [converts iron reserves to ferritin], drug inactivation

                        b. Hematological regulation: phagocytosis and antigen presentation [Kupffer cells],                                     synthesis of plasma proteins, removal of circulating hormones, removal of                                                    antibodies, removal or storage of toxins

                        c. Synthesis and secretion of bile [mostly water, with minor amounts of ions,                  bilirubin, cholesterol and an assortment of lipids known as bile salts, that function                                    in the emulsification of lipids

               2. Gross Anatomy

        a. Hepatic portal vein

3. Microscopic Anatomy

        a. Hepatocytes, liver sinusoids, Kupffer cells

        D. Gallbladder

        1. Stores and concentrates bile

        E.   Pancreas

               1. Functions: secretion of a watery buffer solution of a pH of 7.5-8.8 and a "bucket full

of enzymes" [pancreatic amylase, lipase, nucleases and proteases]

        F. Regulation of Bile and Pancreatic Secretion and Entry into the Small Intestine

A. Functions

                1.Absorption of water, bile salts, and bacterial-generatedvitamins K, biotin [glucose                           metabolism] & vitamin B₅ (pantothenic acid) [manufacture of steroids and some                             neurotransmitters]

        B. Gross Anatomy

                1. Teniae coli, haustra, &epiploic appendages

                2. Subdivisions: cecum, appendix, colon, rectum, anal canal

                3. Colon: ascending, transverse, descending, sigmoid

FUNCTIONAL ANATOMY OF THE DIGESTIVE SYSTEM

A. Functions

              1. Storage

              2. Mechanical breakdown of food

             3. Chemical breakdown of food

             4. Production of intrinsic factor [a glycoprotein required for absorption of

Digestive System Organs: Relationships

A.    Relationship of Digestive Organs to the Peritoneum

1.     The visceral peritoneum covers the external surfaces of most of the digestive organs, and the parietal peritoneum lines the body wall of the abdominopelvic cavity.

2.     The peritoneal cavity is located between the visceral and parietal peritoneum and is filled with serous fluid.

3.     Mesentery is a double layer of peritoneum that extends to the digestive organs from the body wall. It allows blood vessels, lymphatics, and nerves to reach the digestive organs, and holds the organs in place as well as stores fat.

4.     Retroperitoneal organs are found posterior to the mesentery, lying against the dorsal abdominal wall [most of pancreas and parts of the large intestine].

Help for a Stomach Bloating

Natural Remedies
Many herbal and homeopathic remedies have been formulated with specific
ingredients to lessen stomach bloating and promote healthy digestion. Herbs such
as Foeniculum Vulgare (Sweet Fennel) and Pulsatilla Vulgaris (Pasque Flower)
The content of this ebook is intended for
informational purposes only.
It is not intended to diagnose or treat any
medical condition. Nothing in this ebook is
intended to be a substitute for
professional medical advice, diagnosis, or
treatment. Always seek the advice of your
physician or other qualified health
provider with any questions you may have

Stomach Bloating

What is Stomach Bloating?

Bloating in the stomach can be a common occurrence – most of us will experience

a bloated stomach at some stage of our lives. The feeling of ‘pressure’ and

‘fullness’ in the stomach, that can make it feel as though we are stretched to

capacity or weighted down.

What Causes Stomach Bloating?

Bloating is most often caused by trapped gas in the small intestine. This can cause

flatulence (passing of excessive gas/wind) painful stomach ache and an

uncomfortable feeling when wearing tight clothes. There are a variety of

things that can cause this bloated feeling, including digestion problems such as:

● Indigestion

● Intestinal Gas

● Trapped wind

● Irritable Bowel Syndrome (IBS)

● Dysmotility (a slow digestive system)

Other conditions that may result in a bloated stomach include:

● Candidiasis

● Coeliac Disease

● Premenstrual Syndrome (PMS)

Bloating can also occur as a result of food intolerance, insufficient Hydrochloric

acid in your stomach, insufficient digestive enzymes in your stomach or lack of

good intestinal flora (good bacteria normally present in the gut). Whatever the

cause, the fact remains that for some reason digestion is hampered and

undigested foods are reaching your gut where fermentation takes place causing the

bloating.

As a bloated stomach can indicate more serious conditions, if bloating persists or

worsens, it is advised that you seek medical advice.

The Digestive System ["A man does not live on what he eats, an old proverb says, but on what he digests." Jean Anthelme Brillat-Savarin, The Physiology of Taste: Or Meditations on Transcendental Gastronomy]

Objectives      

1. Describe stimuli and controls of digestive activity.

2. Describe the location and function of the peritoneum.

3. Define retroperitoneal and name the retroperitoneal organs.

4. Define splanchic circulation.

5. Indicate the importance of the hepatic portal system.

6. Describe the tissue composition and the general function of each of the four layers of the

alimentary canal.

7. Identify structural modifications of the wall of the stomach that enhance the digestive process.

8. Name the cell types responsible for secreting the various components of gastric juice and

indicate the importance of each component in stomach activity.

9. Describe stomach structure and indicate changes in the basic alimentary canal structure that

aid its digestive function.

10. Explain how gastric secretion and stomach motility are regulated.

11.  Identify and describe structural modifications of the wall of the small intestine that enhance the digestive process.

12.  Differentiate between the roles of the various cell types of the intestinal mucosa.

13.  Describe the function of local intestinal hormones and paracrines.

14.  State the role of bile in digestion and describe how its entry into the small intestine is regulated.

15.  Describe the role of the gallbladder.

16.  State the role of pancreatic juice in digestion.

17.  Describe how entry of pancreatic juice into the small intestine is regulated.

18.  List the major functions of the large intestine.

19.  List the enzymes involved in chemical digestion; name the foodstuffs on which they act.

20.  Describe the process of absorption of breakdown products of foodstuffs that occurs in the small intestine.

21.  Describe some of the structural and functional properties of smooth muscle.

Part 1: Overview of the Digestive System (pp. 852–858; Figs. 23.1–23.6)

A.    Digestive system organs fall into two main groups: the alimentary canal and the accessory organs.

1.     The alimentary canal, or gastrointestinal (GI) tract, is the continuous muscular digestive tube that winds through the body digesting and absorbing foodstuff; its organs include: the mouth, pharynx, esophagus, stomach, small intestine, and large intestine.

2.     Accessory digestive organs aid digestion physically and produce secretions that break down foodstuff in the GI tract; the organs involved are the teeth, tongue,

gallbladder, salivary glands, liver, and pancreas.

I. Digestive Processes

A.    Ingestion is the simple act of putting food into the mouth.

B.    Propulsion moves food through the alimentary canal and includes both swallowing andperistalsis.

C.    Mechanical digestion is the physical process of preparing the food for chemical digestion and involves chewing, mixing, churning, and segmentation.

D     Chemical digestion is a series of catabolic steps in which complex food molecules are broken down to their chemical building blocks by enzymes.

E.    Absorption is the passage of digested end products from the lumen of the GI tract through the mucosal cells into the blood or lymph.

F.     Defecation eliminates indigestible substances from the body via the anus as feces.

II.  Basic Functional Concepts (p. 854; Fig. ]23.4)

A.    The digestive system creates an optimal internal environment for it's functioning in the lumen of the GI tract, an area that is technically outside of the body.

1.     Digestive activities within the GI tract are triggered by mechanical and chemical stimuli [e.g., stretching of organ by food, osmolarity, pH, etc.]

2.     The activities of the digestive system are regulated by

                a. Neural mechanisms [Enteric Nervous System (ENS)]: the ENS has roughly as                                many neurons as the spinal cord, and as many neurotransmitters as the brain,                              but whose functions remain largely unknown...

                                Short[myenteric] reflexes control smooth muscle contraction and                                            glandular secretion as relatively localized activities involving small                                          segments of the digestive tract; this mechanism is usually                                                             considered parasympathetic, but the plexus also contains sensory                                         neurons, motor neurons and interneurons for local reflexes whose                                    internal workings operate entirely outside the control of the CNS.

                                Long reflexesinvolve interneurons and motor neurons in the CNS and                                   provide a higher level of control over digestive and glandular activities.

                b. Hormonal mechanisms involve as many as 18 hormones, affecting almost                           every aspect of digestive function...

                c. Local mechanisms involve prostaglandins, histamine and other chemicals                           released into the interstitial fluid and affecting adjacent cells...

Digestive System 1

Digestive System

The Digestive System ["A man does not live on what he eats, an old proverb says, but on what he digests."  Jean Anthelme Brillat-Savarin, The Physiology of Taste: Or Meditations on Transcendental Gastronomy]

Objectives      

1. Describe stimuli and controls of digestive activity.

2. Describe the location and function of the peritoneum.

3. Define retroperitoneal and name the retroperitoneal organs.

4. Define splanchic circulation.

5. Indicate the importance of the hepatic portal system.

6. Describe the tissue composition and the general function of each of the four layers of the

alimentary canal.

7. Identify structural modifications of the wall of the stomach that enhance the digestive process.

8. Name the cell types responsible for secreting the various components of gastric juice and

indicate the importance of each component in stomach activity.

9. Describe stomach structure and indicate changes in the basic alimentary canal structure that

aid its digestive function.

10. Explain how gastric secretion and stomach motility are regulated.

11.  Identify and describe structural modifications of the wall of the small intestine that enhance the digestive process.

12.  Differentiate between the roles of the various cell types of the intestinal mucosa.

13.  Describe the function of local intestinal hormones and paracrines.

14.  State the role of bile in digestion and describe how its entry into the small intestine is regulated.

15.  Describe the role of the gallbladder.

16.  State the role of pancreatic juice in digestion.

17.  Describe how entry of pancreatic juice into the small intestine is regulated.

18.  List the major functions of the large intestine.

19.  List the enzymes involved in chemical digestion; name the foodstuffs on which they act.

20.  Describe the process of absorption of breakdown products of foodstuffs that occurs in the small intestine.

21.  Describe some of the structural and functional properties of smooth muscle.

Part 1: Overview of the Digestive System (pp. 852–858; Figs. 23.1–23.6)

A.    Digestive system organs fall into two main groups: the alimentary canal and the accessory organs.

1.     The alimentary canal, or gastrointestinal (GI) tract, is the continuous muscular digestive tube that winds through the body digesting and absorbing foodstuff; its organs include: the mouth, pharynx, esophagus, stomach, small intestine, and large intestine.

2.     Accessory digestive organs aid digestion physically and produce secretions that break down foodstuff in the GI tract; the organs involved are the teeth, tongue,

gallbladder, salivary glands, liver, and pancreas.

Digestive System Questions

1.	The correct sequence for the layers within the walls of the alimentary canal from inside to outside is the
A)	mucous membrane, muscular layer, serous layer, submucosa.
B)	mucous membrane, submucosa, muscular layer, serous layer.
C)	serous layer, muscular layer, mucous membrane, submucosa.
D)	submucosa, mucous membrane, serous layer, muscular layer.

2.	The teeth that are best adapted for biting off relatively large pieces of food are the
A)	incisors.

Cinnamon and Honey

 Cinnamon and Honey ~ Bet the drug companies won't like this one getting around.~

 Facts on Honey and Cinnamon : It is found that a mixture of honey and cinnamon cures most diseases. honey is produced in most of the countries of the world. Scientists of today also accept honey as a 'Ram Ban' (very effective) medicine or all kinds of diseases.

 Honey can be used without any side effects for any kind of diseases.


Today's science says that even though honey is sweet, if taken in the right dosage as a medicine, it does not harm diabetic patients. Weekly World News, a magazine in Canada, in its issue dated 17 January,1995 has given the following list of diseases that can be cured by honey and cinnamon as researched by western scientists:
 
HEART DISEASES :
 Make a paste of honey and cinnamon powder, apply on bread, instead of jelly and jam, and eat it regularly for breakfast. It reduces the cholesterol in the arteries and saves the patient from heart attack. Also those who have already had an attack, if they do this process daily, they are kept miles away from the next attack. Regular use of the above process relieves loss of breath and strengthens the heart beat. 
 Arthritis patients :
 may take daily, morning, and night, one cup of hot water With two spoons of honey and one small teaspoon of cinnamon powder. If Taken regularly even chronic arthritis can be cured. In a recent research conducted at Copenhagen University, it was found that when the doctors treated   their patients with a mixture of one tablespoon of Honey and half teaspoon of Cinnamon powder before breakfast, they found that within a week, out of the 200 people so treated, practically 73 patients were totally Relieved of pain, and within a month, mostly all the patients who could not walk or move around because of arthritis started walking without pain.  
 BLADDER INFECTIONS:
 Take two tablespoons of cinnamon powder and one teaspoon of honey in a Glass of lukewarm water and drink it. It destroys the germs in the bladder.  
 CHOLESTEROL:
 Two tablespoons of honey and three teaspoons of Cinnamon Powder mixed in 16 ounces of tea water, given to a cholesterol patient, was found to reduce The level of cholesterol in the blood by 10 percent within two hours. As Mentioned for arthritic patients, if taken three times a day, any chronic Cholesterol is cured. According to information received in the said Journal, pure honey taken with food daily relieves complaints of cholesterol.
 COLDS:
 Those suffering from common or severe colds should take one tablespoon Lukewarm honey with 1/4 spoon cinnamon   powder daily for three days. This Process will cure most chronic cough, cold, and clear the sinuses.
 UPSET STOMACH:
 Honey taken with cinnamon powder cures stomach ache and also clears Stomach ulcers from the root.
 GAS:
 According to the studies done in India and Japan, it is revealed that if Honey is taken with cinnamon powder the stomach is relieved of gas.  > IMMUNE SYSTEM:> Daily use of honey and cinnamon powder strengthens the immune system and Protects the body from bacteria and viral attacks. Scientists have found That honey has various vitamins and iron in large amounts. Constant use of    Honey strengthens the white blood corpuscles to fight bacteria and viral Diseases.  
 INDIGESTION:
 Cinnamon powder sprinkled on two tablespoons of honey taken before food Relieves acidity and digests the heaviest of meals.
 INFLUENZA:
 A scientist in Spain has proved that honey contains a natural 'Ingredient' Which kills the influenza germs and saves the patient from flu.
 LONGEVITY:
 Tea made with honey and cinnamon powder, when taken regularly, arrests the Ravages of old age. Take four spoons of honey, one spoon of cinnamon powder And three cups of water and boil to make like tea. Drink 1/4 cup, three to Four times a day. It keeps the skin fresh and soft and arrests old age. Life spans also increases and even a 100 year old, starts performing the   Chores of a 20-year-old.  
 PIMPLES:
 Three tablespoons of honey and one teaspoon of cinnamon powder paste Apply this paste on the pimples before sleeping and wash it next morning with Warm water. If done daily for two weeks, it removes pimples from the root.
 SKIN INFECTIONS:
 Applying honey and cinnamon powder in equal parts on the affected parts Cures eczema, ringworm and all types of   skin infections.
 WEIGHT LOSS:
 Daily in the morning one half hour before breakfast on an empty stomach And at night before sleeping, drink honey and cinnamon powder boiled in one Cup of water. If taken regularly, it reduces the weight of even the most obese person. Also, drinking this mixture regularly does not allow the fat to accumulate in the body even though the person may eat a high calorie diet.
 CANCER:
 Recent research in Japan and   Australia has revealed that advanced cancer of the stomach and bones have been cured successfully. Patients suffering from these kinds of cancer should daily take one tablespoon of honey with one teaspoon of cinnamon powder for one month three time s a day.
 FATIGUE:
 Recent studies have shown that the sugar content of honey is more helpful rather than being detrimental to the strength of the body. Senior citizens, who take honey and cinnamon powder in equal parts, are more alert and flexible. Dr. Milton, who has done research, says that a half Tablespoon of honey taken in a glass of water and sprinkled with cinnamon powder, taken daily after brushing and in the   afternoon at about 3:00 P.M. When the vitality of the body starts to decrease, increases the vitality of the body within a week.
 BAD BREATH:
 People of South America, first thing in the morning, gargle with one teaspoon of honey and cinnamon powder mixed in hot water, so their breath stays fresh throughout the day.  
 HEARING LOSS:
 Daily morning and night honey and cinnamon powder, taken in   equal parts restore hearing. Remember when we were kids? We had toast with real butter and cinnamon sprinkled on it!  
 ARTHRITIS:
 In America and Canada, various nursing homes have treated patients successfully and have found that as you age, the arteries and veins lose their flexibility and get clogged; honey and cinnamon revitalize the arteries and veins.