The Digestive System Health Science 1 - PowerPoint Presentation

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The Digestive System

Health Science 1

Silver

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What is Digestion

The process of changing complex solids foods into simpler soluble forms which can be absorbed by cells.

Enzyme – chemical substance that can promote reactions in living things

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Terminology

Alimentary canal

Also known as the GI (gastrointestinal tract)

Begins with the mouth and ends with the anus

Include

MouthPharynxEsophagusStomachSmall intestinesLarge intestine

Accessory Organs

Teeth

Tongue

Salivary

glands

Pancreas

Liver

Gallbladder

Connected to the GI tract by series of ducts

Aid in chemical breakdown and absorption of food.

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Alimentary canal

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Accessory Organs included

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Lining the Digestive System

Peritoneum

Double layered serous membrane that lines the abdominal cavity

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Digestive System Functions

Physical Breakdown of food

Chemical digestion of food into the end products of fat, carbohydrates and protein

Absorb nutrients into blood capillaries of the small intestines

Eliminate waste products of digestion

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6 Activities of

Digestion

(in order)

1 –

Ingestion

Getting food into the bodyMouth, teeth, lips and tongue2 – Mechanical Breakdown Smaller pieces of food (chewing, churning in stomach, churning by muscular contraction in small intestine)

3

–

Propulsion

Initiated by swallowing (pharynx)

Peristalsis (symmetrical contraction of muscles that moves food along the GI tract

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6 Activities of Digestion

(in order)

4 –

Chemical breakdown

Commonly called “digestion”

Enzymes breakdown food5 – AbsorptionMovement of small molecules from small intestine into the blood to be carried to other parts of the body6 – Defecation

Expulsion of the food that was not absorbed through the anus.

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Mouth (oral cavity)

Assist in

Ingestion (food in mouth)

Mechanical breakdown

(chewing)- also called mastication

Chemical breakdown (enzymes in saliva)PTYALIN- converts starches into simple sugars – under control of the nervous systemPropulsion (pushing food back to pharynx for swallowing)

Lips – grab food and pull into mouth

Tongue – contain papillae that help to grip food better (sense of taste from taste buds)

Palate (roof of mouth)

hard and soft

Uvula

Keeps food out of nasal cavity when swallowing

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Mouth cont

…

Teeth and Gums

Digestive enzymes help to chemically break down food once chewing begins

Mastication

– process of chewing (mechanical digestion)Children have 20

deciduous

(temporary)

Start to appear around 6 months

Usually all are visible by 2

yrs

of age

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Permanent teeth begin to form around 6 years of age in the jawbones

32 total (16 in mandible and 16 in maxilla)

As these grow, the deciduous teeth are pushed out

The wisdom teeth are generally the last to appear, usually late teens to early twenties.

Incisors

CaninePremolarsmolars

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2123 System

– 2 incisors, 1 canine, 2premolars, 3 molars

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Salivary glands

Secrete saliva into the mouth via connecting ducts. Contains mucus, antibodies, and enzymes to help moisten food and protect the mouth from bacterial infection.

Parotid (largest)-

under skin, just below and in front of the ears.

Submandibular –

medial side of the lower back part of the mandible.Sublingual – under each side of the tongue.

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Pharynx

Food at this point is called a

BOLUS

Passage way for food and air

Propulsion of food by peristalsis

Most commonly considered part of the respiratory systemEpiglottis at end that guides food to the esophagus when swallowing – Remember ---- Air goes to the trachea 

Swallowing = deglutination

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Esophagus

Flexible muscular tube that connects the pharynx to the stomach.

About 10 inches long

Travels through the diaphragm

Food is propelled through by waves of

peristalsis (muscular contraction to push food downward)

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Stomach

Located in upper more left part of abdominal cavity filled with gastric juices.

Acidic in nature – protected by mucus membrane

Pepsin- breaks down protein

Hydrochloric acid destroys unwanted bacteria

Reservoir where food is broken down both mechanically and chemically.Contains cardiac sphincter (top)- circular muscular layer that controls the passage of food into the stomach.

Pyloric sphincter

(bottom) – valve that regulates the entrance of food into the duodenum of small intestine.

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Stomach cont

….

Rugae

– mucous coated lining inside the stomach (folds of tissue)

Peristalsis continues in the stomach

The bolus of food now is known as CHYME – semi liquid, creamy substanceChyme leaves the stomach through the

pyloric sphincter

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Parts of the stomach

Fundus- upper part

Body – middle part

Pyloric region – lower end

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Small Intestines

Gets its name from its diameter….much smaller than the large intestine even though it is longer

Site of most of the chemical breakdown of food. Food is broken down into usable substances which can now be used by the tissue in the body.

Site for

Absorption

– in small intestine, digested food passes into the bloodstream and on to body cells. Undigestible parts pass on to the large intestine.

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3 segments of small intestines

Duodenum

– 1

st

segment (curves around the pancreas.

Is about 12 inches longJejunum- 2nd section, about 8 foot longIleum- final portion, 10 to 12 feet in length

Chemical digestion, absorption, and propulsion by peristalsis occur in all three segments of the small intestine.

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Pancreas

Located behind the stomach

Secretes digestive enzyme (pancreatic juice) into the duodenum. It travels through the pancreatic duct and common bile ducts to get to small intestine.

Enzymes here help digest proteins and fats.

It also makes the hormone insulin (endocrine system)

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Liver

Largest organ in body

Located below the diaphragm, RUQ

Connected to gallbladder and small intestine by ducts

Produces and stores glucose in the form of glycogen

Detoxify alcohol, drugs and other harmful substancesManufactures blood proteinsManufactures bileStores vitamins A, D and B complex

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Gallbladder

Small green organ, inferior surface of the liver

Stores and concentrates bile until it is needed by the body

Releases bile to help break down fatty foods via the common bile duct

Fat is then stored in

lacteals in the intestinal wall until needed by the bodyYou can live without your gallbladder, but you have to keep your liver 

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Large Intestine

Larger diameter than small intestine but shorter in length

Approximately 2 inches in diameter

Major segments – cecum, colon, rectum and anal canal (anus)

Nutrients and water not absorbed in small intestines are absorbed here.

Contains E. Coli (bacteria) Main function is propulsion and elimination of waste products not absorbed in the small intestinesIn the colon…

Chyme

becomes FECES

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Parts of the large intestine

Cecum

– first part in lower right portion.

Appendix

– small fingerlike projection that extends from the cecum (not needed). It does contain lymphocytes.

Colon- 4 segments- Ascending colon, transverse colon, descending colon, and sigmoid colonRectum - last portion of the colonAnus -

external opening

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Defacation

= Elimination of feces

Flatulence

= gas Bacteria causes

the odor

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GERD – Gastroesophageal

Reflux Disease

Heartburn or acid reflux symptoms include chronic cough and chest pain and burning. Knowing your triggers, such as certain foods, medications, obesity, or even stress, can help prevent heartburn. Heartburn treatment may include medications, home remedies, or diet changes

.

http://www.webmd.com/heartburn-gerd/ss/slideshow-heartburn-overview

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Gastroenteritis

Gastroenteritis is inflammation of the stomach and intestines, which leads to diarrhea and vomiting. Gastroenteritis is most often due to a bacterial or viral infection. Gastroenteritis that results from a virus is called viral gastroenteritis. Many different viruses cause gastroenteritis, including some rotaviruses, noroviruses, and adenoviruses. Viral gastroenteritis is contagious. Bacterial gastroenteritis is often caused by infection with E. coli and salmonella. Other causes of gastroenteritis include parasite infection, exposure to harmful chemicals in seafood or water, use of certain medications, and irritation from particular foods

.

http://www.webmd.com/children/ss/nausea-vomiting-remedies-treatment

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Peptic ulcer

http://www.webmd.com/digestive-disorders/tc/peptic-ulcer-disease-topic-overview

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Appendicitis

Appendix becomes inflamed

If it ruptures, bacteria will spread to peritoneal cavity causing a very dangerous infection.

Symptoms - fever, acute pain in LRQ

RX- surgical removal & antibiotics

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Hepatitis

Inflammation of the liver

Types A, B, C

http://www.webmd.com/hepatitis/ss/slideshow-hepatitis-overview

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Cirrhosis

Cirrhosis is a slowly progressing disease in which healthy liver tissue is replaced with scar tissue, eventually preventing the liver from functioning properly. The scar tissue blocks the flow of blood through the liver and slows the processing of nutrients, hormones, drugs, and naturally produced toxins. It also slows the production of proteins and other substances made by the liver

.

JAUNDICE – yellow discoloration of the skin and sclera of the eyes.

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Cholecystitis

Cholecystitis

is inflammation of the

gallbladder

, a small organ near the

liver that plays a part in digesting food. Normally, fluid called bile passes out of the gallbladder on its way to the small intestine. If the flow of bile is blocked, it builds up inside the gallbladder, causing swelling, pain, and possible infection.

Commonly caused by CHOLELITHIASIS

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Cholelythiasis

A

gallstone stuck in the cystic duct

, a tube that carries bile from the gallbladder, is most often the cause of sudden (acute)

cholecystitis

. The gallstone blocks fluid from passing out of the gallbladder. This results in an irritated and swollen gallbladder. Infection or trauma, such as an injury from a car accident, can also cause cholecystitis.

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Diarrhea

Diarrhea is a loose, watery bowel movement and is not usually a serious problem in the U.S. It can occur due to illness, intestinal problems, food poisoning, and many others factors. It usually goes away on its own, but you should drink plenty of fluids and can take over-the-counter medications to help ease the discomfort. For prolonged cases of diarrhea, medical attention is recommended

.

http://www.webmd.com/digestive-disorders/video/drossman-diarrhea-overview

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Constipation

Constipation is a common but painful condition that occurs when bowel movements become infrequent or difficult. It can be caused by nutritional deficiencies, stress, pregnancy, cancer, depression, and more. The best way to prevent constipation is eating a healthy diet, exercising, and drinking plenty of water. Laxatives can help relieve constipation.

http://www.webmd.com/digestive-disorders/ss/slideshow-constipation-facts-10

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Irritable bowel syndrome

Irritable bowel syndrome or IBS affects mostly women. Causes are unknown. IBS symptoms include diarrhea, constipation, and abdominal cramps. IBS treatments include diet and lifestyle changes and medications

.

http://www.webmd.com/ibs/ss/slideshow-ibs-overview

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Anorexia Nervosa

Anorexia

Intense fear of gaining weight

Restrict food intake, especially those with fat content

Weight is 85% less than expected body weight

Over exercisingAvoiding food altogether, or only allowing minimal low calorie intake.

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Physical Symptoms

Common physical

signs of malnutrition

from anorexia include

:

A low body weight.Constipation and slow emptying of the stomach.Thinning hair, dry skin, and brittle nails.Shrunken breasts.Stopping or never getting a monthly menstrual period.

Feeling cold, with a lower-than-normal body temperature.

Low blood pressure

.

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Treatment

All people with

anorexia

need treatment. In most cases, this involves seeing a doctor and having regular counseling sessions. A hospital stay is needed for those who are seriously underweight or who have severe medical problems. The goals of treatment are to restore a

healthy weight

and healthy eating habits.