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Happy Wednesday!Bellwork: March 5
GO BUFFS!
• Write one similarity and one difference between the nervous and endocrine systems.
CO: I will describe how the digestive system interacts with
other systems.
LO: I will fill in a graphic organizer. I will listen to descriptions. I will
create a brochure.
Think-Pair-Share
• What do animals (includes humans) need to survive?
• How/where do they get what they need?
What do animals need to live?• Animals make energy using:– Food (glucose)– Oxygen
• This process is known as cellular respiration
• Animals build bodies using:– food for raw materials • amino acids, sugars,
fats, nucleotides – ATP energy for synthesis– Water for hydrolysis and
dehydration synthesis
O2
food
ATP
mitochondria
Take Off, Touch Down! Stand up for true, sit down for false.
• Food spends 2-6 hours partially digested in the stomach
• In 12 to 24 hours, any undigested material passes through the large intestine, and feces are expelled through the anus
• Your stomach can stretch to fit ~1/2 gallon of food in it.
Getting & Using Food• Ingest
– taking in food• Digest
– mechanical digestion• breaking up food into smaller pieces
– chemical digestion• breaking down food into molecules small enough
to be absorbed into cells• enzymes
• Absorb– absorb nutrients across cell membranes
• diffusion• active transport
• Eliminate – undigested material passes out of body
intracellulardigestion
extracellulardigestion
Digestive systemsEverybody’s got one!
Human digestive system
Mouth• Functions– mechanical digestion• teeth– break up food
– chemical digestion (saliva)• amylase enzyme– digests starch
• mucus – protects soft lining of digestive system– lubricates food for easier swallowing
• buffers – neutralizes acid to prevent tooth decay
• anti-bacterial chemicals – kill bacteria that enter mouth with food
All thatin spit!
Swallowing (& not choking)
• Epiglottis (flap of cartilage)– closes trachea (windpipe) when swallowing– food travels down esophagus
• Peristalsis
– involuntary muscle contractions to move food along • (NERVOUS SYSTEM)
mouthbreak up fooddigest starchkill germsmoisten food
Stomach
• Functions–disinfect food• hydrochloric acid = pH 2–kills bacteria
–food storage• can stretch to fit ~2L food
–digests protein• pepsin enzyme
But the stomach is made out of protein!What stops the stomach from digesting itself?
mucus secreted by stomach cells protects stomach lining
stomachkills germs break up fooddigest proteinsstore food
sphincter
sphincter
mouthbreak up fooddigest starchkill germsmoisten food
Pancreas • Produces digestive enzymes – digest proteins• trypsin, chymotrypsin
– digest starch• amylase
– digest lipids• lipase
• Buffers – neutralizes
acid from stomach
smallintestin
e
pancreas
stomachkills germs break up fooddigest proteinsstore food
mouthbreak up fooddigest starchkill germsmoisten food
pancreasproduces enzymes to digest all foods
Liver & Gall Bladder • Produces bile– breaks up fats– gallbladder only stores bile• that’s why you can have your gall bladder removed
bile contains colors from old red blood cells collected in liver =
iron in RBC rusts & makes feces brown
bile contains colors from old red blood cells collected in liver =
iron in RBC rusts & makes feces brown
pancreasproduces enzymes to digest proteins & starch
stomachkills germs break up fooddigest proteinsstore food
mouthbreak up fooddigest starchkill germsmoisten food
liverproduces bile
- stored in gall bladderbreak up fats
Small intestine• Functions– digestion• digest carbohydrates– amylase from pancreas
• digest proteins– trypsin & chymotrypsin from pancreas
• digest lipids (fats)– bile from liver & lipase from pancreas
– absorption• nutrients move into body cells by:– diffusion– active transport
This iswhere all thework is done!
Absorption in Small Intestines• Absorption through villi & microvilli– finger-like projections– increases surface area for absorption
SMALL INTESTINES6 meters long,but can stretchto cover a tennis court
small intestinesbreakdown food
- proteins- starch- fats
absorb nutrients
stomachkills germs break up fooddigest proteinsstore food
mouthbreak up fooddigest starchkill germsmoisten food
pancreasproduces enzymes to digest proteins & starch
liverproduces bile
- stored in gall bladderbreak up fats
• Function– re-absorbs water• use ~9 liters of water every day in
digestive juices– if don’t reabsorb water
would die of dehydration
• > 90% of water re-absorbed– not enough water re-absorbed
» diarrhea» can be fatal
– too much water re-absorbed» constipation
• reabsorb by diffusion
Large intestines (colon)
stomachkills germs break up fooddigest proteinsstore food
mouthbreak up fooddigest starchkill germsmoisten food
small intestinesbreakdown food
- proteins- starch- fats
absorb nutrients
pancreasproduces enzymes to digest proteins & carbs
liverproduces bile
- stored in gall bladderbreak up fats
large intestinesabsorb water
You’ve got company!• Living in the large intestine is a community
of helpful bacteria– Escherichia coli: E. coli• digest cellulose– digests fruits & vegetables
• produce vitamins – vitamin K & B vitamins
• BUT generate gases– by-product of bacterial metabolism – methane, hydrogen sulfide– STINKY!
PEE-YOO!
AppendixVestigial organVestigial organ
stomachkills germs break up fooddigest proteinsstore food
mouthbreak up fooddigest starchkill germsmoisten food
small intestinesbreakdown food
- proteins- starch- fats
absorb nutrients
pancreasproduces enzymes to digest proteins & carbs
liverproduces bile
- stored in gall bladderbreak up fats
large intestinesabsorb waterappendix
Rectum • Last section of large intestines– eliminate feces– what’s left over?• undigested materials– mainly cellulose from plants– called roughage or fiber – keeps everything moving & cleans out intestines
• masses of bacteria
So don’t forget to wash your hands!
• Need to make sure you get enough protein– 20 amino acids to make protein
• 12 amino acids humans can produce • 8 we have to eat = “essential amino acids”
– Grains (like corn) have 6 amino acids• missing 2
– Beans (like soybean & red beans) have 6 amino acids• missing different 2• mix beans & grains
for complete group of amino acids– rice & beans– taco/tortilla & beans– tofu & rice– peanut butter & bread
Vegetarian diets
liver
pancreas
liver
Balancing Blood Sugar levels
blood sugar level
insulin
body cells takeup sugar from blood
liver storessugar
reducesappetite
glucagon
pancreas
liver releasessugar
triggershunger
high
low
Feedback
Homeostasis
Feedback: Maintaining Homeostasis • Balancing glucose levels in blood
pancreas
pancreas
insulin
liver takes upglucose for storage
cellstake upglucose from blood
liver releasesglucose to blood
depress appetite
stimulatehungerglucagon
• Used to think ulcers were caused by stress– tried to control with
antacids• Now know ulcers
caused by bacterial infection of stomach– H. pylori bacteria– now cure with
antibiotics
Ulcers
inflammation of stomach
inflammation of esophagus
Colonized by H. pylori
Free of H. pylori
white blood cells
cytokines
inflammatory proteins(CagA)
cell damaging proteins(VacA)
helper T cells
neutrophil cells
H. pylori
Eating a balanced diet• What happens if an animal’s diet is missing an
essential nutrient?– deficiency diseases• scurvy — vitamin C (collagen production)• rickets — vitamin D (calcium absorption)• blindness — vitamin A (retinol production)• anemia — vitamin B12 (energy production)• kwashiorkor — protein
Digestion Brochure• Choose and research one of
the following diseases/disorders:– Ulcers– Scurvy– Rickets– Diarrhea – Constipation– Anemia– Acid Indigestion (heartburn)
• Create a brochure (like you might see at a doctor’s office) that explains: – what the disease is– how it’s caused – how to treat it– illustrate the part of the
digestive system it affects
• The front cover needs to have a question as a title. For example, if you were researching lactose intolerance, “Why can’t I drink milk?”
Given the information about the disorder, YOU
have to determine how it could it fixed or treated!
Ulcers Peptic ulcers are holes or breaks in the protective lining of the upper part of the small intestine or the stomach -- areas that come into contact with stomach acids and enzymes
Scurvy A disease resulting from a deficiency (lack) of vitamin C (“pirate disease)
Rickets A softening of bones in immature mammals due to deficiency or impaired metabolism of vitamin D, phosphorus, or calcium, potentially leading to fractures and deformity. It can also be caused by severe diarrhea and vomiting
Diarrhea The condition of having three or more loose or liquid bowel movements per day. The loss of fluids through diarrhea can cause dehydration and electrolyte disturbances such as potassium deficiencies or other salt imbalances
Constipation Refers to bowel movements that are infrequent or hard to pass. Constipation is a common cause of painful defecation. Severe constipation includes obstipation (failure to pass stools or gas) and fecal impaction, which can progress to bowel obstruction and become life-threatening.
Anemia A decrease in number of red blood cells (RBCs) or less than the normal quantity of hemoglobin in the blood. A deficiency in iron can result in anemia.
Acid Indigestion (“Heartburn”)
The pain often rises in the chest and may radiate to the neck, throat, or angle of the jaw. Heartburn is usually associated with regurgitation (bringing back up) of gastric acid.
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