Bell Work Please answer these pretest questions 1 Which has a longer length the large intestine or the small intestine 2 True or False Digestion begins as soon as it enters the mouth ID: 780445
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Slide1
Digestive System
Subtitle
Slide2Bell Work
Please answer these “pre-test” questions:
1) Which has a longer length – the large intestine or the small intestine?
2) True or False: Digestion begins as soon as it enters the mouth 3) Which digestive organ is most responsible for food/fluid absorption? 4) Which organ stores concentrated bile?
https://www.youtube.com/watch?v=_QYwscALNng
https://www.youtube.com/watch?v=bo2Ape8JHqA
Slide3Tennessee State Standard 44
Trace food from the time it enters the body until it is released, outlining the organs involved and the digestive processes that occur.
Slide4Overall Objectives:
1. Describe the digestive system and its 6 primary functions.
2. Compare and contrast chemical and mechanical digestion.
3. Describe the pathway of food through the alimentary
canal organs and for each organ, state the type of digestion (mechanical and/or chemical) that occurs. If chemical
digestion occurs, additionally state what enzyme is involved
and what is broken down.
4. Explain the role of the pancreas and describe each of the five
pancreatic secretions
Slide5Toady’s Objective
Describe the digestive system and its 6 primary functions.
But first, some fun facts:
https://www.youtube.com/watch?v=23MenLHC8eM
Slide6Functions of the Digestive System
Ingestion
Mechanical Digestion
Chemical Digestion
Absorption
Metabolism
Elimination
Slide71) Ingestion
The process of consuming food
Materials enter the digestive tract via the mouth
“Eating”Mastication - chewing
Slide82) Mechanical Digestion
Chewing, mixing, churning, cutting, tearing, or mashing of food.
Breaks food into smaller pieces
Food is mixed with saliva
Becomes known as a “bolus”
Slide9Structures for Mechanical Digestion
Teeth
:
chew food
Classification of TeethIncisors – used for biting food
Canines
– used for tearing food
Premolars
(bicuspids) – used for grinding food
Molars
– Used for crushing food
Slide10Salivary Glands
Produce
saliva
- mixture of mucus and serous fluids
Helps to form a food bolus
Contains salivary
amylase
to begin starch digestion
Dissolves chemicals so they can be tasted
Propulsion -
the action of driving or pushing forward (swallowing)
https://www.youtube.com/watch?v=QPM2hwQV-34
Slide11Pharynx
The passageway for air and food
Swallowing:
Reflex that causes the epiglottis to close blocking the trachea (windpipe)
The esophagus opens to receive the bolus
Slide12Esophagus
“Food tube
”
links to the stomach
Muscle layers contract to squeeze food through to the stomach
Longitudinal inner layer
Circular outer layer
https://www.youtube.com/watch?v=Ri8bBhw9msQ
Slide13Peristalsis
alternating waves of muscle contraction
https://www.youtube.com/watch?v=fHbMjvEx8IE
https://www.youtube.com/watch?v=o18UycWRsaA
Slide14Slide15Stomach
Thick-walled, J-shape, muscular organ
on left side of abdominal cavity
Bolus (food) enters through the
cardioesophageal sphincterPrevents backup of stomach acid into esophagus (
acid reflux
)
Slide16Muscles of stomach contract to
churn and mix
food with gastric juices
Deep folds called rugae allow stomach to expandChyme (mix of bolus and digestive juices) exits through
pyloric sphincter to small intestine
Stomach and Mechanical Digestion
Slide173) Chemical Digestion
Definition: the chemical breakdown of food into small fragments suitable for absorption.
https://www.youtube.com/watch?v=bo2Ape8JHqA
https://www.youtube.com/watch?v=_QYwscALNng
Slide18Lining of stomach secretes gastric juices that break down food.
Enzymes
break down food molecules into their building blocks
Hydrochloric acid (
HCl) is a very strong acid that activates enzymes and kills bacteria
Mucous
protects the lining of the stomach from the acid environment
Replaced every few days
Chemical Digestion
Slide19Chemical Digestion
Carbohydrates
are broken down to simple
sugars.
(Amalyse)Proteins are broken down to
amino acids.
(Pepsin)
Fats
are broken down
to fatty acids and alcohols.
(Lipase)
Slide20Bell Work
Of the 6 major functions,
which process do you think takes the longest?
If one of the functions were taken out, what would happen?
Slide214) Absorption
Movement of organic substrates, electrolytes, vitamins, and water across the digestive epithelium into the body for use.
After absorption,
nutrients are transported to the cells through the bloodstream
– passage of nutrients into blood
The Doctors
https://www.youtube.com/watch?v=_xRjCfZnjnA
https://www.youtube.com/watch?v=ytGii8p1TJY
Slide22Small Intestine
Muscular tube
extending from the pyloric sphincter to the ileocecal valve
Up to approx. 22 feet long!
Small intestine has 3 parts:Duodenoum
First 10-15 inches, attached to the stomach
Receives secretions
from the liver and pancreas to aid in digestion
Jejunum
Next 3 feet
Contains folds and villi for absorption
Ileum
Last 6-7 feet
Extends from jejunum to large intestine
Slide23Small Intestine
Functions
Main digestive organ
– most digestion occurs in the small intestineCarbohydrate
and protein digestion is completedFat digestion beginsMain
site of nutrient absorption
into the blood
Slide24Small Intestine
Accessory organs aid in digestion by secreting enzymes into the small intestine
Bile
from the gall bladder
Breaks down lipids (fat)Pancreatic juices from the pancreasSodium bicarbonate neutralizes the acid
https://www.youtube.com/watch?v=DBvOsL-gg3s
Slide255) Metabolism
all chemical reactions that process any nutrients
converting nutrients into raw materials for production of cellular energy (ATP)
Slide26Large Intestine
Once digestion & absorption of nutrients is complete, the
chyme
moves into the large intestine by peristalsis
Also known as the ColonLarge in diameter, but shorter than the small intestine
Slide27Large Intestine
Functions
Absorption of water
Does not participate in digestion of food
Eliminates indigestible food from the body as FecesGoblet cells produce mucus to act as a lubricant
Slide28Food Breakdown & Absorption in the Large Intestine
Bacteria breaks down indigestible materials
Source of odor
Produce some vitamin K & B
Release gasesWater, vitamins K and vitamin B are absorbedRemaining materials are eliminated as feces
Flatuence
and Belching
https://www.youtube.com/watch?v=3CVoTfcdd4w
Slide296) Elimination
Removal of waste products from the body.
The process is called defecation, and the product is called feces.
Triggered by presence of feces in rectum.
Slide30Rectum
Feces moves from the sigmoid colon of the large intestine to the rectum by peristalsis
Feces is stored in the RECTUM until the involuntary internal anal sphincter is triggered to relax and open
Slide31Additional Digestive System Functions
Lining of the digestive tract also protects body tissues from:
Corrosive digestive acids
Mechanical stressesBacteria swallowed in food or those that reside in the digestive tract
Slide32Accessory Organs
Slide33Accessory Organs
Tongue/salivary glands
GallbladderLiverPancreas
Slide34Gall Bladder
Sac found in hollow fossa of liver
Stores bile produced by the liver
Bile is introduced into the duodenum in the presence of fatty food
Gallstones can cause blockages
https://www.youtube.com/watch?v
=2G1HKOijrR0
Slide35Bile
Bile is a greenish substance that
emulsifies fat
Stored in
Gall BladderComposed of bile salts & pigments (bilirubin from hemoglobin breakdown), cholesterol, phospholipids, & electrolytesHelps to
digest fatty foods
Slide36Role of Liver in Metabolism
Removes drugs and alcohol from blood
Degrades hormones
Produces cholesterol, blood proteins (albumin and clotting proteins)
Plays a central role in metabolismStores products of digestion as glycogen
to be released as needed
Produces and excretes Bile
**Too many toxins: liver disease -
https://www.youtube.com/watch?v=wbh3SjzydnQ
https://www.youtube.com/watch?v=HumRVVLB1Qo
Slide37Pancreas
Produces a wide spectrum of
digestive enzymes
that break down all types of foodEnzymes are
secreted into the duodenum of the small intestine
Slide38Pancreas
Secretions of the Pancreas
1)
Pancreatic Amylase
: helps complete digestion of starch2) Trypsin
: carry out about half of all
protein
digestion
3)
Lipase
: responsible for
fat
digestion
4) Nucleases
: digest
nucleic acids
5)
Sodium Bicarbonate
: neutralize acidic
chyme
Slide39Alimentary Canal
From mouth to anus
Mouth
Pharynx
EsophagusStomachSmall intestines Large intestines
Rectum
Anus
Slide40The Lining of the Digestive Tract
Digestive Epithelium
Oral cavity, pharynx, and esophagus -stratified squamous epithelium
Stomach, small intestine, large intestine - simple columnar epitheliumPlicae –folds that increase surface area for absorption
Slide41Peritoneal Cavity
Contains the organs of the
abdominopelvic
cavity.Mesenteries - Sheets of serous membrane that stabilize the positions of organs Prevent the intestines from becoming entangled during digestive movements
Slide42Control of Digestive Activity
Mostly
controlled by reflexes
via the parasympathetic division of
nervous systemChemical and mechanical receptors are located in organ walls that trigger reflexes
Slide43Procedures
Gastric Bypass
Gastric Bypass
Lap Band Surgery
Slide44https://www.webmd.com/diet/obesity/video/bariatric-surgery
Slide45Digestive Disorders
Slide4646
Diseases and Disorders of the Digestive System
Appendicitis
-
an inflammation of the appendix
Causes
Blockage of appendix with feces
Blockage of appendix with tumor
Treatments
Surgery to remove appendix
Antibiotics to prevent infection
Signs and symptoms
– lack of appetite, pain in and around the navel area or in the abdomen, nausea, slight fever, pain in the right leg, and increased white blood cell content
Slide4747
Cirrhosis
-
a long lasting liver disease in which normal liver tissue is replaced with nonfunctional scar tissue
Causes - Excessive alcohol consumption
Hepatitis C infection
Hepatitis B infection
Treatment -
Liver transplant
Lifestyle changes to stop use of alcohol
Diseases and Disorders of the Digestive System
Slide4848
Colitis
-
defined as inflammation of the large intestine
Causes -
caused by viral or bacterial infection or the use of antibiotics. Ulcers in the large intestine, Crohn’s disease, various other diseases, and stress may contribute.
Treatments
Treating underlying causes
Changing antibiotics
Fluids
Repair of ulcers
Slide4949
Colorectal cancer
usually comes from the lining of the rectum or colon.
Causes
- mostly unknown. Polyps in colon or rectum can become cancerous.
Signs
Changes in bowel movement
Blood in feces
Anemia
Abdominal pain
Weight loss
Narrow feces
Diseases and Disorders of the Digestive System
Slide5050
Crohn’s disease
-
a common type of inflammatory bowel disease; can affect any part of the GI tract, but usually affects the ileum and beginning of the colon
Causes
–
Cause unknown, but diet and stress can aggravate condition; it is thought that
Crohns
is likely due to an abnormal response from the immune system
Treatment
Medications to reduce inflammation
Antibiotics
Surgery to remove affected part of intestine
Changes in diet
(
high-calorie, high-protein diet)
Diseases and Disorders of the Digestive System
Slide5151
Diverticulitis
-
inflammation of diverticuli in the intestine.
Diverticuli
are abnormal dilations in the intestinal wall
Causes
– mostly unknown. Lack of fiber in diet and bacterial infection of the
diverticuli
.
Signs
Abdominal pain
Constipation
Diarrhea & nausea
Fever
Blood in feces
High white blood cell count
Diseases and Disorders of the Digestive System
Slide5252
Gastritis
-
an inflammation of the stomach lining
Causes -
bacteria or viruses, some medications, alcohol, spicy foods, excessive eating poisons, and stress.
Treatment
Cook food properly to kill bacteria/viruses
Avoid foods/medications that irritate stomach linings
Begin acid reducing medications
Diseases and Disorders of the Digestive System
Slide5353
Heartburn
-
called gastroesophageal reflux disease (GERD) - occurs when stomach acids are pushed into the esophagus
Causes
– alcohol, some foods, defective esophageal sphincter, pregnancy, obesity, hiatal hernia, and repeated vomiting.
Treatment
Reducing weight
Diet changes
Reduce alcohol consumption
Medications
Not lying down after meal
Diseases and Disorders of the Digestive System
Slide5454
Hemorrhoids
-
varicose veins of the rectum or anus
Causes
– constipation, excessive straining during bowel movements, liver disease, pregnancy, and obesity.
Treatment
Eating high fiber
Stool softeners
Medications
Surgery
Diseases and Disorders of the Digestive System
Slide5555
Hepatitis
-
inflammation of the liver.
Causes
- bacteria, viruses, parasites, immune disorders, the use of alcohol and drugs, and overdose of acetaminophen.
Treatment
Avoid drugs and alcohol
Prescribed medications
Diseases and Disorders of the Digestive System
Slide5656
Hiatal hernia
-
occurs when a portion of the stomach protrudes into the chest through an opening in the diaphragm.
Inguinal hernias
- occurs when a portion of the large intestine protrudes into the inguinal canal.
Pancreatic cancer
– 4th leading cause of death in the U.S.
Stomach cancer
- most common in the upper part of the stomach.
Stomach ulcers
- occur in the lining of the stomach
Diseases and Disorders of the Digestive System
Slide57Bell Work
Answer these questions to prepare for today’s lesson:
What kind of “muscle” is used throughout the digestive system?
We learned about 5 body cavities at the beginning of the year – which cavity would contain our digestive organs?
Slide58Crash Course Part 3
https://www.youtube.com/watch?v=jGme7BRkpuQ