Transcript Digestive System Functions

Week #7 (5/2-5/6)
Warm Up – Wed, 5/4 & Thurs, 5/5:
- What is pH & why is it important to your diet?
Anatomy Fun Fact:
Gallbladder stores the
bile juice secreted by the
liver and pours it, when
required, to duodenum of
small intestine. This
commonly happens after
taking food that is rich in
cholesterol or other
lipids.
Agenda:
1. Nutrition notes
2. pH Food Lab
Have out:
 Your sample of
food/liquid
Pick up:
 Nutrition notetaker
Homework:
1.
Digestive System
Quiz – Mon, 5/9
2. pH Food Lab
Abstract (7I &
8I) – Fri, 5/13
Warm-up: What is pH & why is it
important for your diet?
• Brainstorm: What do you think of when you hear the term “pH”?
• What is pH?
• Stands for “potential/power of Hydrogen”
• A measure of the acidity or alkalinity (basicity) of an aqueous solution
• If a solution has an equal amount of acidic (H+ donors) & alkaline (H+
acceptors) molecules, the pH is neutral.
• Scale: 0-14 (7 is neutral)
• 0-6.9 = acidic
• 7.1-14 = basic
• Why is it important to
know about the pH of
your diet?
• Hint: Think back to
the Skeletal System!
Digestive &
Urinary Systems
The “Get In & Get Out” Unit
Learning Goal:
I will understand the structures & functions of the
Digestive & Urinary Systems.
You ARE What you EAT!
• What kinds of stuff is in your food?
• Macromolecules:
• Carbohydrates
• Proteins
• Fats
• In digestion, macromolecules are broken down by acidic
juices & enzymes into smaller molecules your body can take
in & make use of.
• Ever wonder what kind of diet you have?
• In our next lab, you will be testing your favorite food(s) to find out
whether your diet is more acidic, basic or neutral.
USDA Food Guide Pyramid
Nutrition
• Nutrient—substance used by body for growth,
maintenance & repair
• Major nutrients
•
•
•
•
Carbohydrates
Lipids
Proteins
Water
• Minor nutrients
• Vitamins
• Minerals
Dietary Sources of Major Nutrients
• Carbohydrates
– Most are derived from plants
– Exceptions: lactose from milk & small amounts of
glycogens from meats
• Lipids
– Saturated fats from animal products
– Unsaturated fats from nuts, seeds & vegetable oils
– Cholesterol from egg yolk, meats & milk products
• Proteins
– Complete proteins—contain all essential amino
acids
• Most are from animal products
– Legumes & beans also have proteins, but are
incomplete (missing amino acids)
Dietary Sources of Major Nutrients
• Vitamins
• Most vitamins are as
coenzymes
• Found in all major food groups
• Minerals
• Play many roles in body
• Most mineral-rich foods are
vegetables, legumes, milk &
some meats
Carbohydrate Metabolism
• Carbohydrates
• Body’s preferred source to produce cellular energy (ATP)
• Glucose (blood sugar) is the major breakdown product &
fuel to make ATP
Carbohydrate Metabolism
• Hyperglycemia—excessively high levels of glucose in blood
• Excess glucose is stored in body cells as glycogen
• If blood glucose levels are still too high, excesses are converted
to fat
• Hypoglycemia—low levels of glucose in blood
• Liver breaks down stored glycogen & releases glucose into blood
Fat Metabolism
• Handled mostly by liver
• Uses some fats to make ATP
• Releases breakdown products to blood
• Cells remove fat & cholesterol to build membranes &
steroid hormones
Protein Metabolism
Proteins are conserved by body cells
because they are used for most cellular
structures
 Cells remove amino acids to build proteins
Ingested proteins are broken down to amino acids
 Amino acids are used to make ATP only when proteins are
overabundant or there is a shortage of other sources
Body Energy Balance
• Energy intake = total energy output
– Energy intake is liberated
during food oxidation
– Energy output
• Heat is usually about
• Storage energy
– Fat or glycogen
• Body weight is usually relatively stable when…
– Energy intake & output remain about equal
60%
pH Food Lab
• Have out your food &/or drink
samples (at least 4 different foods/
group).
– Food:
• Use the mortar & pestle to break down
your solid food into a fine powder.
• Make into an aqueous solution by adding & mixing in
distilled water.
– Drink:
• Test fluid directly in pH paper.
– Test all group members’ foods & drinks with pH paper.
• Record your results based on the 0-14 scale.
– Answer the Conclusion & Application questions.
– ???s
pH Food Lab
• 1 piece of paper for group
data & conclusions.
• Everyone’s name MUST be on
the paper to receive lab credit!
• Include:
• Data Table with Group’s data
• Answers to the 13 C & A questions in
COMPLETE SENTENCES!
pH Food Lab
• Results “share-out”…pay
attention for trends in our diets!
• You will want to record this info if you
plan on writing up this lab for Abstract!
• ON YOUR WHITEBOARD:
• Include your Group’s data table
• What kind of macromolecules (proteins, lipids,
carbohydrates) were represented in the GREATEST
quantity in each sample?
• Describe ONE connection you can make from your
data about pH & diet!
pH Food Lab
Analysis & Extensions
• Based on the results of our lab, in general, do
Americans have an acidic, basic or neutral diet?
– Highly ACIDIC!!!
• What is the ideal pH of our bodily fluids?
– 7.35 to 7.45; ideal = 7.365
• What can you do to maintain your body’s ideal pH?
– List of Alkaline Foods
• Why is it important to know about the pH of your diet?
– Health Issues Arise When Ideal pH Is not Maintained
• Too low (acidic):
– Inflammation
-Narrowing of arteries
– Corrosion of body tissue
-Cancer, heart disease or diabetes
– Puts unneeded stress on internal organs & processes
• Too high (basic/alkaline):
– Slowed respiration
-Digestive problems
- Confusion
pH Food Lab Abstract
DUE Fri, 5/13
• Title Page: Title of lab, Name, Date & Period
• Data & Observations:
– Data Table with Class’ food pH data
– Graph showing Class’ data
• Don’t forget axis labels, title (IV & DV), key, etc!
• Conclusion & Applications:
– 13 Conclusion questions answered in
paragraph format
– Words Cited (MLA format)
Think about it:
How Can We Maintain Healthy pH
of our Body Fluids?
• Analyzing Dietary Fiber:
• Read the Introduction
• Part A: Dietary Fiber in
Some Foods
• Analyze the
information provided
about fiber content in each of the foods listed
• Answer question #1
• Part B: Fitting Fiber into your Diet
• Act as a dietician or nutritionist & develop a higher fiber
diet for your client.
Week #7 (5/2-5/6)
Warm Up – Fri, 5/6:
- Carbs, Fats, Proteins…Oh My!
Anatomy Fun Fact:
The walls of the small
& large intestines
contains small, fingerlike projections known
as villi, which increase
the surface area from
1/2 m2 to more than
250 m2.
Agenda:
1. Your Food is on the Move Scavenger Hunt
2. Anatomy of the Digestive System notes
Pick up:
 Functions of the
Digestive System
note-takers
 Carbs, Fats &
Proteins wkst
 Digestive System
Scavenger Hunt
Homework:
1.
2.
3.
Digestive System
Quiz – Mon, 5/9
Cardio Fitness Lab
Abstract (7I) –
Wed, 5/11 &
Thurs, 5/12
pH Food Lab
Abstract (8I) –
Fri, 5/13
Organs of the Digestive
System
• 2 main groups
• Alimentary canal
(gastrointestinal or GI
tract)—
continuous coiled
hollow tube
•
•
•
•
Pharynx
Esophagus
Stomach
Small Intestine
• Duodenum, Jejunum,
Ileum
• Large Intestine
• Cecum, Colon,
Rectum, Anus
Organs of the Digestive
System
• 2 main groups
• Accessory digestive
organs
• Oral (buccal) cavity
• Teeth & tongue
• Salivary glands
• Submandibular
• Sublingual
• Parotid
• Pancreas
• Liver
• Gallbladder
Your Food is on the MOVE!
And so are you…in just a moment!
It’s a Selfie SCAVENGER (Digestive System…
get it!) HUNT for ANSWERS!
An IMAGE of each anatomical part & a it’s
function are scattered around the Science
Building (they are NOT in other
classrooms) & our classroom.
GOAL: Collect ALL 11 IMAGES (Name of
organ & its Function) in the form of a
“Selfie”!
RULES:
1.
You MAY NOT HIDE or TAKE AWAY any images!
2.
DO NOT interrupt or disturb classes!
3.
“Selfie” photos MUST include all group members,
the image with the function & at least 1 member’s
paper with the label filled in (& funny faces never
hurt either!) before finally checking in with me!
Selfie song
Digestive System Functions
• Ingestion—taking in food
• Propulsion—moving foods from one
region of digestive system to another
• Peristalsis—alternating waves of contraction
& relaxation that squeezes food along GI
tract
• Segmentation— moving materials back &
forth to aid with
mixing in
small intestine
Digestive System Functions
• Secretion – release of water, acids, enzymes & salts by
epithelium of digestive tract
Mechanical & Chemical Digestion
Digestive System Functions
 Digestion—breaking food down both physically &
chemically
 Food breakdown as mechanical digestion
 Mixing food in the mouth by tongue & teeth, churning
food in stomach & segmentation in small intestine
 Mechanical digestion prepares food for further
degradation by enzymes
Digestive System Functions
 Digestion—breaking food down both physically &
chemically
 Food breakdown as chemical
digestion
 Enzymes break down food
into their building
 Each major food group uses
enzymes
 Carbohydrates are broken to
simple sugars
 Mouth & small intestines
 Proteins are broken to amino acids
 Stomach & small intestines
 Fats are broken to fatty acids & alcohols
 Small intestines
molecules
blocks
different
Digestive System Functions
• Absorption—movement of
nutrients into bloodstream
• End products of digestion
are absorbed in blood or
lymph
Digestive System Functions
• Defecation—rids body of
indigestible waste
• Elimination of indigestible
substances from GI tract
in form of
feces/fecal
matter
Your Food is on
the MOVE!!!
Let’s see what’s included
in your Digestive
System & how it all
works!
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Histology & Protection of Digestive
Tract
• 2 major types of tissue that
constantly produce a lubricating
liquid, allowing all components of
digestive tract to slide without
friction
• Visceral peritoneum – covers
organs
• Parietal peritoneum – lines inner
surfaces of body wall
• Mesenteries – layers of tissue that
connect visceral peritoneum to
parietal peritoneum
• Allow for passage of blood
vessels and nerves
• Hold organs in place
Anatomy of Oral
Cavity
• Cheeks – contain fat &
buccinator muscles
• Labia – lips
• Labial frenulum –
attachment of gingiva to
labia
• Gingiva – gums, bound to
underlying bone
• Hard & soft palates –
anterior & posterior
portions of roof of mouth
• Uvula – dangling process
that prevents food from
entering nasopharynx
Saliva & Salivary Glands
• 3 pairs of salivary glands:
– Parotid salivary gland
• 25% of saliva
• Produces saliva that has high
concentration of salivary amylase
– Begins break down of starches
– Sublingual salivary gland
• 5% of saliva
• Produce saliva that acts as buffer
& lubricant
– Submandibular salivary gland
• 70% of saliva
• Produce saliva rich in buffer,
lubricating proteins called mucins
& salivary amylase
Bad Breath
• Clinically termed Halitosis
• Typically caused by breakdown of
epithelial cells, blood cells &
bacteria combined w/saliva
• Low Salivary flow – dehydration &
morning breath
• Garlic & Onion Breath –
compounds taken in blood to
lungs
Like Lady Gaga says…
“Show me your…Teeth!”
• Perform mastication (chewing) by crossing & re-crossing
surfaces
• Mastication
• Breaks down
tough connective
tissues in meat &
plant fibers
• Helps saturate
food w/saliva
Pharynx & Esophagus
• Pharynx
• Passageway for food, liquid & air
• Split into 3 sections:
• Nasopharynx
• Oropharynx
• Laryngopharynx
• Esophagus
• Hollow muscle tube ~25 cm
long & 2 cm in diameter
• Empties into stomach through
cardiac (cardio-esophageal)
sphincter
• Prevents backflow from
stomach into esophagus
Stomach
• Performs 4 major functions:
• Stores ingested food
• Mechanically breaks down
ingested food
• Chemically breaks down
ingested food
• Produces intrinsic factor
(glycoprotein required for
absorption of vitamin B12 in
small intestine)
• Vitamin B12: essential for
normal erythropoesis (RBC
formation)
• Ingested substances combine
with digestive juices of
stomach to form acidic soupy
substance called chyme
Anatomy of Stomach
• Shaped like a “J”
• Lesser curvature (1st part)
• Greater curvature (2nd
part)
• Can be divided into 4
regions:
– Cardia
– Fundus
– Body
– Pylorus
• Pyloric sphincter
regulates the release of
chyme into the small
intestine
Stomach’S Volume
• Volume of stomach
increases while you
eat & decreases as it
releases chyme
• When
FULL
• 1-1.5 liters of material
• USELESS TIDBIT
• In France (French), if
you say “I’m full” it
means you are
PREGNANT!
Digestion & (Lack of)
Absorption in Stomach
• Preliminary digestion of proteins by pepsin occurs
• Some carbs & lipids continue to be partially digested here due to
presence of salivary amylase & lingual lipase
• These enzymes typically remain active 1-2 hours after eating
• Nutrients are NOT absorbed in stomach because:
• Stomach cells are not in direct contact w/chyme
• Covered by layer of mucus
• Stomach is relatively impermeable to water
• Digestion has
not been
completed by
time chyme
leaves stomach
Onward to….the Small Intestine
• 90% of nutrient absorption
• Averages 6 m (19.7 ft) in
length
• Averages diameter of 2.5-4.0
cm
• Duodenum – “mixing bowl”
• Combines chyme w/digestive
secretions from pancreas &
liver
• Jejunum – region of most
chemical digestion & nutrient
absorption
• Ileum – Longest segment
Histology of Small Intestine
• Plicae circulares
• Folds that line small intestine
• Greatly increasing surface
area for absorption
• Lined by tiny fingerlike
projections called intestinal
villi
Pancreas
• Lies posterior to stomach & is
bound posteriorly to abdominal
cavity
• Produces 1000 ml of digestive
enzymes/day (pancreatic juice)
• Delivers juices to duodenum
through pancreatic duct
• When chyme enters small intestine,
it triggers duodenum to release
hormone secretin
• Stimulates pancreas to release these
enzymes
Liver
• Largest visceral organ
• Weighs ~1.5 kg
• Function: regulate
composition of circulating
blood
• Blood from absorptive
surfaces of digestive tract
enters liver
• Liver cells extract nutrients or
toxins from blood & allows
filtered blood to re-enter
systemic circulation
• Stores excess nutrients &
releases these to correct
nutrient deficiencies
Gallbladder (#2)
• Stores & concentrates
bile immediately before
it is released into small
intestine
Large Intestine
• ~1.5 m long & 7.5 cm wide
• Begins where it meets Ilium & ends at anus
• Major functions:
• Re-absorption of
water
• Compaction of
intestinal contents
into feces
• Absorption of vitamins
• Storage of fecal
material prior to
defecation
Large
Intestine
• Divided into 3 parts:
• Cecum
• Pouch that receives, stores & begins
to compact materials from ileum
• Appendix is attached to
posteriomedial surface of cecum
• Believed to function in
Lymphatic Sys.
• Colon
• Has larger diameter & thinner wall
than small intestine
• Rectum
• Expandable
• Temporarily stores feces, as
movement of feces into rectum
triggers urge to defecate
• Anal canal - last portion of rectum
• Internal anal sphincter – involuntary
(smooth)
• External anal sphincter – voluntary
(skeletal)
Regions of Colon
• Ascending colon
– Going up!
• Transverse
colon
– Going across!
• Descending
colon
– Going down!
• Sigmoid colon
– “S”-shaped
inferior-most
Histology of the Large
Intestine
• Lacks villi
• Does NOT participate in digestion
• Cells produce mucus in response to friction or
exposure to harsh chemicals
• Mucus provides lubrication
for fecal matter as it
becomes drier & more
compact
• Why is it becoming drier?
• How is it becoming more
compact?
Physiology of the Large
Intestine
• Responsible for <10% of digestive tract’s nutrient absorption
• Reabsorbs ~1300 ml water & minerals from feces each day
• Feces = 75% water, 5% bacteria, 20% indigestible materials,
inorganic matter & epithelial cells
• Reabsorbs
•
•
•
•
Bile salts
Vitamin K (liver uses to make clotting factors)
Biotin (necessary for glucose metabolism)
Vitamin B5 (needed to make certain NTs)
• Side note: bacteria that live in your colon
produce roughly half your daily required
amount of Vitamin K
When ya gotta go,
ya gotta go!
Movements of Large Intestine & Defecation
• Movement
• Materials are moved into cecum while you eat
• Movement from cecum to transverse colon takes hours
• Movement from transverse
colon through rest of LI occurs
as stomach & duodenum are
stretched
• This forces remainder of LI to
contract, forcing feces into
rectum
When ya gotta go,
ya gotta go!
Movements of Large Intestine & Defecation
• Defecation
– As feces causes rectum to expand, stretch receptors stimulate
the urge to defecate
– External anal sphincter must
be forcibly relaxed to allow
for feces to pass
• If EAS cannot relax,
peristaltic contractions
more material enters
rectum = urge to defecate
is regenerated
– When pressure reaches
~55 mmHg, external anal
sphincter will involuntarily
relax & defecation will occur
cease until