Transcript Slide 14.2a - TCHS Anatomy and Physiology

Bell Ringer: 1.28.2015
Name 2 organs that are found in the
alimentary canal.
2. Name 2 accessory organs of the
digestive system.
1.
Bell Ringer: 1.30.2015

Describe the process of peristalsis.

What are two types of digestion?
Bell ringer: 2.3.2015

Name 2 enzymes the pancreas secretes
and what they digest.
Come to the bookmark in
February!!
Buy you and
your sweetie a
drink!!
$1.00/ea
Bell Ringer: 2.2.2015

Name 3 organs found in the digestive
system.
The Digestive System
and Body Metabolism
The Digestive System and Body
Metabolism
 Digestion
Breakdown of ingested food
 Absorption
 Passage of nutrients into the blood
 Metabolism
 Production of cellular energy (ATP)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 14.1
Organs of the Digestive System
 Two main groups
 Alimentary canal – continuous coiled hollow
tube
 Accessory digestive organs
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Organs of the Digestive System
Figure 14.1
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Organs of the Alimentary Canal
 Mouth
 Pharynx
 Esophagus
 Stomach
 Small intestine (duodenum, jejunum, ileum)
 Large intestine (ascending, transverse, decending,
sigmoid colon)
 Anus
Accessory Digestive Organs
 Salivary glands
 Teeth
 Pancreas
 Liver
 Gall bladder
Digestive Processes
“disassembly line” in which food becomes less
complex at each step of processing and its nutrients
become available to the body.
6 Essential Activities
• Ingestion: simply taking food into the digestive tract
• Propulsion: moves food through the alimentary canal,
includes swallowing and peristalsis (major means or
propulsion.
• Mechanical Digestion: physically prepares food for chemical
digestion. Processes include chewing, mixing of food with
saliva by tongue, churning food in stomach and constriction
of intestine.
6 Essential Activities of Digestion cont.
• Chemical Digestion: catabolic steps in which complex food
molecules are broken down to their chemical building blocks
by enzymes.
• Absorption: the passage of digested end products from the
lumen of GI tract through cells by active or passive
transport.
• Defecation: eliminates indigestible substances from the body
via the anus in the form of feces.
Basic Functional Concepts
All digestive tract regulatory mechanisms act to control luminal
conditions so that digestion and absorption can occur as
effectively as possible.
1. Digestive Activity is provoked by a range of mechanical and
chemical stimuli: Sensors in the GI tract initiate reflexes that
activate glands to secrete digestive juices or mix lumen
contents to move them through tract.
2. Controls of digestive activity are both extrinsic and intrinsic:
Nerves running through alimentary canal excite smooth
muscle causing it to contract (intrinsic). Hormones secreted
into the same or different digestive tract organs cause them to
secrete or contract (extrinsic).
Mouth (Oral Cavity) Anatomy
 Lips (labia) – protect
the anterior opening
 Cheeks – form the
lateral walls
 Hard palate – forms
the anterior roof
 Soft palate – forms
the posterior roof
 Uvula – fleshy
projection of the
soft palate
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 14.2a
Slide 14.4
Mouth (Oral Cavity) Anatomy
 Vestibule – space
between lips
externally and teeth
and gums internally
 Oral cavity – area
contained by the
teeth
 Tongue- used for
swallowing and taste
Figure 14.2a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 14.5
Mouth (Oral Cavity) Anatomy
 Tonsils
 Palatine tonsils
 Lingual tonsil
Figure 14.2a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 14.6
Processes of the Mouth
 Mastication (chewing) of food
 Mixing masticated food with saliva
 Saliva begins digestion of
carbohydrates
 Initiation of swallowing by the tongue
 Allowing for the sense of taste
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 14.7
Pharynx Anatomy
 Nasopharynx –
not part of the
digestive system
 Oropharynx –
posterior to oral
cavity
 Laryngopharynx –
below the oropharynx
and connected to
the esophagus
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 14.2a
Slide 14.8
Pharynx Function
 Food movement is by alternating
contractions of the muscle layers
(peristalsis)
 Serves as a passageway for air and
food
 Food is propelled to the esophagus by
two muscle layers
 It’s like pushing a pea down a
straw
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 14.9
Esophagus
 Connects the mouth to the stomach
 Runs from pharynx to stomach through
the diaphragm
 Conducts food by peristalsis
(slow rhythmic squeezing)
 Passageway for food only
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Gross Anatomy and
Major Functions of
Digestive Organs
Stomach Anatomy
 Located on the left side of the
abdominal cavity
 About the size of a fist
 Food enters at the cardioesophageal
sphincter
 Connects the
Esophagus to the
Stomach
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Stomach Anatomy
 Regions of the stomach
 Cardiac region – near the heart
 Fundus- top “bubble” area
 Body- majority/mass of the organ
 Pylorus – funnel-shaped terminal end
 Food empties into the small intestine at
the pyloric sphincter
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Stomach Anatomy
 Rugae – internal folds of the mucosa
 External regions
 Lesser curvature
 Greater curvature
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Stomach Anatomy
 Layers of connenctive tissue attached to
the stomach
 Lesser omentum – attaches the liver to the
lesser curvature
 Greater omentum – attaches the greater
curvature to the posterior body wall
 Contains fat to insulate, cushion, and
protect abdominal organs
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Stomach Anatomy
Figure 14.4a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Stomach Functions
 Acts as a storage tank for food
 Chemical breakdown of protein begins
 Mucus protects the cells from chemical
digestion
 Delivers chyme (processed food) to the
small intestine
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Specialized Mucosa of the
Stomach
 Simple columnar epithelium
 Gastric glands – secrete gastric juice
 Chief cells – produce protein-digesting
enzymes (pepsinogens)
 Parietal cells – produce hydrochloric acid
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Structure of the Stomach Mucosa
Figure 14.4b, c
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Small Intestine
 Functions include:
 Neutralizes acids from stomach
 Uses enzymes to break down
carbohydrates, fats and proteins
 Site of nutrient absorption into the
blood
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Subdivisions of the Small Intestine
“Dogs Just Itch!
 Duodenum (10 inches long)
 Attached to the stomach
 Curves around the head of the pancreas
 Jejunum (8 ft long)
 Attaches anteriorly to the duodenum
 Ileum (12 ft long)
 Extends from jejunum to large intestine
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Digestion in the Duodenum
 Enzymes do the following:
 Break double sugars into simple sugars
 Complete some protein digestion
 Pancreatic enzymes play the major
digestive function
 Help complete digestion of starch
(pancreatic amylase)
 Carry out about half of all protein digestion
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Chemical Digestion in the Small
Intestine
Figure 14.6
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Digestion in the Jejunum/Ileum
 Majority of the nutrients are absorbed in
the lining of the small intestine where
they are transported to the liver for
processing
 Specialized structures, called villi aid in
the absorption by increasing surface
area
Large Intestine
 Larger in diameter, but shorter than the small intestine
 Frames the internal abdomen
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Functions of the Large Intestine
 Absorption of water
 Eliminates indigestible food from the
body as feces
 Does not participate in digestion of food
 Goblet cells produce mucus to act as a
lubricant
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Structures of the Large Intestine
 Cecum – saclike first part of the large
intestine
 Appendix
Accumulation of lymphatic tissue that
sometimes becomes inflamed
(appendicitis)
Hangs from the cecum
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Structures of the Large Intestine
 Colon
 Ascending- upward region
 Transverse-across region
 Descending- downward region
 S-shaped sigmoidal- near the end
 Rectum- stores feces for removal
 Anus – external body opening
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Food Breakdown and Absorption in
the Large Intestine
 No digestive enzymes are produced
 Resident bacteria digest remaining
nutrients
 Produce some vitamin K and B
 Release gases
 Water and vitamins K and B are absorbed
 Remaining materials are eliminated via
feces
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Propulsion in the Large Intestine
 Sluggish peristalsis causes defecation
 Mass movements
 Slow, powerful movements
 Occur three to four times per day
 Presence of feces in the rectum causes
a defecation reflex
 Internal anal sphincter is relaxed
 Defecation occurs with relaxation of the
voluntary (external) anal sphincter
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
What are feces made up of?
1. Bilirubin from dead blood cells (which
gives it a brown hue)
2. 75% water
3. 1/3 of the remaining is dead bacteria that
help digest food
4. Remaining portion is indigestible food
(fiber,) fats, proteins, cholesterol,
phosphate salts, and mucus from the
intestines
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Fecal matter
The seven types of stool are:
1. Separate hard lumps, like nuts
(hard to pass)
2. Sausage-shaped but lumpy
3. Like a sausage but with cracks
on its surface
4. Like a sausage or snake,
smooth and soft
5. Soft blobs with clear cut edges
(passed easily)
6. Fluffy pieces with ragged
edges, a mushy stool
7. Watery stool, entirely liquid.
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
What do the different colors mean?
Color variation is normal; however certain persistent changes
in stool color are characteristic for specific conditions:
black, foul-smelling stool: intestinal bleeding (typically
from the stomach and upper small intestine) due to ulcers,
tumors; ingestion of iron or bismuth
maroon stool: intestinal bleeding (from the middle intestine
or proximal colon) due to ulcers, tumors, Crohn's disease,
ulcerative colitis
clay-colored stool: lack of bile due to blockage of the main
bile duct
pale yellow, greasy, foul-smelling stool: malabsorption of
fat due to pancreatic insufficiency, as seen with pancreatitis,
pancreatic cancer, cystic fibrosis, celiac disease
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Accessory Digestive Organs
 Salivary glands
 Teeth
 Pancreas
 Liver
 Gall bladder
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Salivary Glands
 Saliva-producing glands
 Parotid glands – located anterior to ears
 Submandibular glands
 Sublingual glands
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
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
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Teeth
 The role is to masticate (chew) food
 Humans have two sets of teeth
 Deciduous (baby or milk) teeth
 20 teeth are fully formed by age two
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Teeth
 Permanent teeth
 Replace deciduous teeth beginning
between the ages of 6 to 12
 A full set is 32 teeth, but some people do
not have wisdom teeth
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Classification of Teeth
 Incisors
 Canines
 Premolars
 Molars
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Classification of Teeth
Figure 14.9
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Regions of a Tooth
 Crown – exposed
part
 Outer enamel
 Dentin
 Pulp cavity
 Neck
 Region in contact
with the gum
 Connects crown to
root
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 14.10
Slide
Regions of a Tooth
 Root
 Periodontal
membrane
attached to the
bone
 Root canal carrying
blood vessels and
nerves
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 14.10
Slide
Pancreas
 Produces a wide spectrum of digestive
enzymes that break down all categories of food
 Enzymes are secreted into the duodenum
 Alkaline fluid introduced with enzymes
neutralizes acidic chyme
 Endocrine products of pancreas
 Insulin
 Glucagons
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Liver
 Largest gland in the body
 Located on the right side of the body
under the diaphragm
 Consists of four lobes suspended from
the diaphragm and abdominal wall by
the falciform ligament
 Connected to the gall bladder via the
common hepatic duct
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Bile
 Produced by cells in the liver
 Composition
 Bile salts
 Bile pigment (mostly bilirubin from the
breakdown of hemoglobin)
 Cholesterol
 Phospholipids
 Electrolytes
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Role of the Liver in Metabolism
 Several roles in digestion
 Detoxifies drugs and alcohol
 Degrades hormones
 Produce cholesterol, blood proteins
(albumin and clotting proteins)
 Plays a central role in metabolism
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Gall Bladder
 Sac found in hollow fossa of liver
 Stores bile from the liver by way of the
cystic duct
 Bile is introduced into the duodenum in
the presence of fatty food
 Gallstones can cause blockages
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Processes of the Digestive System
 Ingestion – getting food into the mouth
 Propulsion – moving foods from one
region of the digestive system to
another
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Processes of the Digestive System
 Peristalsis – alternating
waves of contraction
 Segmentation – moving
materials back and forth
to aid in mixing
Figure 14.12
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Processes of the Digestive System
 Mechanical digestion
 Mixing of food in the mouth by the tongue
 Churning of food in the stomach
 Segmentation in the small intestine
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Processes of the Digestive System
 Chemical Digestion
 Enzymes break down food molecules into
their building blocks
 Each major food group uses different
enzymes
 Carbohydrates are broken to simple sugars
 Proteins are broken to amino acids
 Fats are broken to fatty acids and alcohols
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Processes of the Digestive System
 Absorption
 End products of digestion are absorbed in
the blood or lymph
 Food must enter mucosal cells and then
into blood or lymph capillaries
 Defecation
 Elimination of indigestible substances as
feces
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Control of Digestive Activity
 Mostly controlled by reflexes via the
parasympathetic division
 Chemical and mechanical receptors are
located in organ walls that trigger
reflexes
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Body Energy Balance
 Energy intake = total energy output
(heat + work + energy storage)
 Energy intake is liberated during food
oxidation
 Energy output
 Heat is usually about 60%
 Storage energy is in the form of fat or
glycogen
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide






Cirrhosis is a condition in which
the liver slowly deteriorates
and malfunctions due to
chronic injury. Scar tissue
replaces healthy liver tissue,
partially blocking the flow of
blood through the liver
Caused by alcohol and drug
abuse,
Hepatitis C, B, D
Obesity
Cystic fibrosis and other
inherited diseases
Infection
Cirrhosis of the
liver





Esophageal stenosis is a condition
where there is a narrowing of the
esophagus.
With an esophageal stenosis, an
abnormal change or injury may have
caused inflammation (swelling) and
damage to the esophagus.
When the damaged areas heal, scar
tissue forms and make the affected
area of the esophagus hard.
This narrows the esophagus and causes
problems for foods and liquids to pass
through.
Causes: Acid reflux (most common,)
cancer, allergies and trauma
Stenosing web of
the esophagus
Small, pebble-like objects in the
gall bladder made of bile salts and
cholesterol.
The cause of gallstones varies. There
are two main types of gallstones:
 Stones made of cholesterol, which
are by far the most common type.
Cholesterol gallstones have
nothing to do with cholesterol
levels in the blood.
 Stones made of bilirubin, which
can occur when red blood cells are
being destroyed. This leads to too
much bilirubin in the bile. These
stones are called pigment stones.

Gall
Stones
Inflammatory bowel disease
(which is not the same thing as
irritable bowel syndrome, or IBS)
refers to two chronic diseases that
cause inflammation of the
intestines: ulcerative colitis and
Crohn's disease.
 Current evidence suggests that a
genetic defect affects how the
immune system works and how
inflammation is triggered in
response to an offending agent,
like bacteria, a virus, or a protein
in food.

Inflammatory Bowel
Disease



A duodenal ulcer is a type of
peptic ulcer that occurs in the
duodenum, the beginning of
the small intestine.
Peptic ulcers are eroded areas
in the lining of stomach and
duodenum, which result in
abdominal pain, possible
bleeding, and other
gastrointestinal symptoms.
The most common cause of
duodenal ulcer is a stomach
infection associated with the
Helicobacter pylori (H pylori)
bacteria.
Duodenal ulcer
Intussusception (in-tuh-suh-SEP-shun)
is a serious disorder in which part of
the intestine — either the small
intestine or colon — slides into another
part of the intestine.
 This "telescoping" often blocks the
intestine, preventing food or fluid from
passing through. Intussusception also
cuts off the blood supply to the part of
the intestine that's affected.

Intussusception is the most common
cause of intestinal obstruction in
children but it is rare in adults.
 Most cases of adult intussusception are
the result of an underlying medical
condition. In contrast, most cases of
intussusception in children have no
demonstrable cause.

Intussusception
caused by polyp




Peptic ulcer is an area of
damage to the inner lining of
the stomach,
Peptic ulcers were formerly
thought to be caused by stress,
coffee consumption, or spicy
foods.
60% of peptic ulcers are
caused by a bacterial infection
Another 20% are caused by
nonsteroidal anti-inflammatory
drugs (NSAIDs) such as aspirin
and ibuprofen another 20%
have miscellaneous causes
such as cigarettes
Stomach Ulcers
Over 25 million
Americans will have
a peptic ulcer once in
their lifetime

Diverticulitis is small, bulging sacs or pouches of the inner lining of the
intestine (diverticulosis) that become inflamed or infected.

No one knows exactly what causes the sacs, or pouches of diverticulosis
to form. Eating a low-fiber diet is one of the most likely causes.

People who eat mostly processed food, as many Americans eat, do not
get enough fiber in their diet. Processed foods include white rice, white
bread, most breakfast cereals, crackers, and pretzels.
◦ As a result, constipation and hard stools are more likely to occur - causing people to strain
when passing stools. This increases the pressure in the colon or
intestines and may cause these pouches to form.

Diverticulosis is very common. It is found in
more than half of Americans over age 60.