Download The Human Digestive Systems and Disorders

Zachary Lamacraft
Overview/Agenda
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Curriculum expectations
Introduction of human systems
Enzymes
Ingestion-activities
Stomach and Digestion- with a case study
Small intestine and pancreas- video and
activity examples
Accessory organs
Absorption- activity examples
Homeostasis
Energy, Nutrients and Minerals
Curriculum Expectations
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Specific Expectations
E1.1 evaluate the importance of various technologies, including Canadian
contributions, to our understanding of internal body systems (e.g.,
endoscopes can be used to locate, diagnose, and surgically remove digestive
system tumours; lasers can be used during surgery to destroy lung tumours;
nuclear magnetic resonance [NMR] imaging can be used to diagnose injuries
and cardiovascular disorders, such as aneurysms) [AI, C]
E2.2 perform a laboratory or computer-simulated dissection of a representative
animal, or use a mounted anatomical model, to analyse the
relationships between the respiratory, circulatory, and digestive systems [PR,
AI]
E3.2 explain the anatomy of the digestive system and the importance of
digestion in providing nutrients needed for energy and growth (e.g., the body’s
mechanical and chemical processes digest food, which provides the proteins
needed to build muscle, and the fibre, water, vitamins, and minerals needed to
regulate body processes)
E3.4 describe some disorders related to the respiratory, digestive, and
circulatory systems (e.g., asthma, emphysema, ulcers, colitis, cardiac arrest,
arteriosclerosis
Human Systems
Organs: groups of different tissues that
specialize to carry out specific or
particular functions.
 Organ systems: a group of organs that
have related functions
 Important to note that several organ
systems interact and depend on each
other to function
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Importance of Digestion/the
Digestive System
Heterotrophs: organisms that must
consume organic compounds to survive
 Organic compounds (carbohydrates,
fats, proteins, minerals and vitamins) are
digested/ broken down in
gastrointestinal tract and then absorbed
and transported
 Supplies body with energy and raw
materials for synthesis of chemical
compounds
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Enzymes in Digestion
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Recall enzymes are proteins that increase
the rate at which biochemical reactions
occur
The enzymes in the digestive system are
hydrolytic : use water to breakdown various
molecules
Two factors effect digestive enzymes:
-Temperature -pH
Generally increase in temperature=
increase enzyme activity
Enzymes work in specific pH ranges
Enzyme Activity
Figure 1: Effect of temperature
on human enzymes
Figure 2: Effect of pH on
digestive enzymes
blue= pepsin
grey= amylase
Green- trypsin
Discussion Question
Question/Reflection for Student:
“Why do most human enzymes have
efficiency peaks at 37oC
 What impacts do cold and heat have on
our body functioning?
 Why is it dangerous to have a fever?
What may happen to our enzymes?
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Recap: Physical vs. Chemical
Digestion
Physical/Mechanical: is the act of
breaking down food using teeth, beaks
or other structures in many animals as
well as contractions of the stomach
 Chemical: enzymes and water to break
down food so that it can eventually be
absorbed by body cells
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4 Main Processes of The
Digestion System
1. Ingestion
 2. Digestion
 3. Absorption
 4. Egestion/ or Elimination
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Ingestion
Saliva
- Fluid secreted by salivary glands
- Contains amylase which breaks down
complex to simpler carbohydrates
- Lubricates food to be swallowed
- Dissolves food particles
- At this point food can be “tasted”
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Activities:
Ingestion cont.
Teeth:
-incisors: specific for cutting
-canine: sharp for tearing
-pre-molars: grinding
-molars: crushing
 Used for mechanical/physical digestion.
They are necessary for making food into
smaller particles
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Ingestion cont.
Esophagus
 Peristalsis: rhythmic, wavelike
contraction of smooth muscle that
moves food through the esophagus
 Food formed in a bolus after being
broken down by saliva and teeth enters
the esophagus
 http://www.youtube.com/watch?v=rJSKh5wCQU
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The Stomach and Digestion
- Site of food storage and
protein digestion
- J-Shape organ that can
store up to 1.5 L of food
- Movement of food in and out
of stomach is regulated by
sphincters
- Cardiac sphincter: regulates
food from esophagus
- Pyloric sphincter: regulates
food from stomach to small
intestine
The Stomach and Digestion cont.
There are millions of cells that line the wall of
the stomach that secrete many fluids which
called collectively called gastric juice
 Gastric juice : Hydrochloric acid (HCl)
mucus, pepsinogens and other materials
 Pepsinogens: enzymes that when exposed
to a low pH such as conditions in the
stomach, turns into its active form pepsin
which is a enzyme the digests proteins
 What do we know about HCl?
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What stops HCl from burning
a hole in your stomach?
Mucus
A protein produced by a layer of
epithelial cells that provide a protective
coating
 It is alkaline in nature which is basic and
protects lining of the stomach from both
acid from HCl and pepsin from breaking
down proteins of stomach lining
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However when mucus is destroyed or
not being produced…
Disorder: Stomach Ulcer
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Ulcer: a lesion along the surface of an
organ
-when the mucus membrane is destroyed
a peptic ulcer can be formed resulting in
tissue being burned and an allergic
reaction can become stronger resulting in
blood vessels breaking down
Heliobacter pylori
Stomach Disorders: Ulcers cont.
Case Study
Have students in pairs or small groups
uncover this bacteria Heliobacter pylori and
other information about ulcers
 Prevalence, demographics, how to detect
this bacteria, bacterial weight/amount,
effects on every day living/side effects,
treatment etc. are all topics the students
could discover
 Could be in the form of a report, or a
presentation, or even a jigsaw activity
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Small Intestine Introduction
Activities
 http://www.youtube.com/watch?v=4waSJ
qOEJts
 Easy way to get the students thinking
about the small intestine is having 7m of
yard, tubing etc. and having it passed
around the classroom
 After this have them put it in a small box
 Small intestine is not named small
because of its length rather its diameter!
Small Intestine Cont.
3 parts of the small intestine
are the:
 Duodenum:
- most digestion occurs here
 Jejnum: has many folds that continue
breakdown and absorption of remaining
proteins and carbohydrates
 Ileum: less absorption occurs here,
unabsorbed particles are pushed
through and continued
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Digestion in the Small Intestine
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How is the small intestine protected if
HCl and pepsin- soaked food is sent to it
from the stomach?
Small Intestine and Pancreas
Interaction
Small Intestine and Pancreas
Interaction
Liver and Gall Bladder:
Role in Digestion
Absorption and Large Intestine
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Colon is largest part of large
intestine stores waste so that water
as well as some inorganic salts,
minerals and vitamins can be
absorbed
There are several bacteria in the
large intestine such as types of E.coli
that can synthesize vitamins B and K
Cellulose is a carbohydrate that
cannot be broken down by
humans but provides bulk
Absorption: Villi, Microvilli and
Lacteals
Villi: small finger-like projects that
extend into the small intestine which
increase surface area for absorption.
 Microvilli: are a microscopic projection
on cell membrane
 Lacteals: are small vessels that
transport fat to the circulatory system
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Homeostatic Control in Digestion
Build a Body: SPONGELAB
Biology
Food energy
In Canada energy is measured in joules
(J) or kilojoules (kJ)
 One calorie = 4.18 J
One kcal = 4.18kJ
 Basal metabolic rate: the minimum
amount of energy that a resting person
needs to maintain life processes
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Daily Energy Requirements
Calculating Energy Requirements
There is a way to calculate energy
requirements. The equation is
Energy required for 1 day= energy factor
x body mass (kg) x time (24hr)
Energy required for an activity= energy
factor x body mass (kg) x time (hr)
Essential Nutrients
Vitamins: organic molecules needed in
trace amounts for normal growth and
metabolic processes
 Minerals: elements required by the body.
There are inorganic
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Nutrients
Minerals