unit 6: body systems miss sabia regents living environment (adapted from mrs. folgia from division...
TRANSCRIPT
UNIT 6: BODY SYSTEMS
Miss SabiaRegents Living Environment
(adapted from Mrs. Folgia from Division Ave High School)
standards
• 1.2c-control mechanisms in body• 1.2d-disruption in human
system=disruption in homeostasis• 5.2a=homeostasis is constantly
threatened…failure to correct results in death or diaseas
• 5.3-feedback mechanisms, respond to stimuli
DIGESTIVE SYSTEM
Essential Question
• What are the main organs of the digestive system and their functions?
Different Diets, Different Lives
• Herbivores: eat only plants• Carnivores: eat only animals (meat)• Omnivores: eat plants and animals
Functions of the Digestive System
• Ingest: taking IN food• Digest: breaking up food into smaller pieces
– Mechanical digestion: breaking up food into smaller pieces
– Chemical digestion: breaking down foods into molecules small enough to be absorbed into cells
– With the help of our friends, ENZYMES
• Absorb: absorb nutrients across cell membranes– Diffusion– Active transport
• Eliminate: undigested material passes out of body
Overview of the MVP’s
Introducing…
THE ORGANS!!!
The Mouth
• Mechanical digestion—chewing breaks food into smaller pieces
• Chemical digestion—breaking down complex molecules into simpler ones– Salivary amylase (in saliva) starts the breakdown
of carbohydrates– Mucus: protects soft lining of digestive system;
lubricates food for easier swallowing– Anti-bacterial chemicals: kill bacteria that enter
mouth with food
Unsalted Cracker Challenge
Don’t Choke!• Epiglottis: flap of tissue that seals off
your trachea (windpipe) and prevents food from entering
• Bolus: mass of chewed food
The Esophagus• Esophagus:
muscular tube that connects mouth and stomach
• Peristalsis: involuntary muscle contractions that move food
Stomach
• Functions:–disinfect food• hydrochloric acid = pH 2–kills bacteria
–food storage• can stretch to fit ~2L food
–Chemical digestion: digests protein• pepsin enzyme
–Mechanical digestion: muscles of stomach contract to produce a churning
But the stomach is made out of protein!What stops the stomach from digesting itself?
mucus secreted by stomach cells protects stomach lining
• 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
Small Intestine• Almost all chemical
digestion and absorption of nutrients occurs here
• 6 meters long, makes up 2/3 of the digestive system– Called “small” because of
its diameter, only 2-3 cm wide
Small Intestine-Organs & Enzymes• Enzymes in small intestines are produced
by other organs– Liver bile (emulsifies fats)– Gallbladder stores bile– Pancreas:• amylase (break down carbs)• trypsin and chymotrypsin (break down proteins)• Lipase (breaks down lipids)
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
Large Intestine (colon)
• 1.5 meters long– Large diameter, about 4-6
cm wide
• The last section of the digestive system– As material moves
through, water is absorbed into the bloodstream
– Everything else is readied for elimination
Water Re-Absorption
• More than 90% of water is reabsorbed– diffusion
• Not enough water re-absorbed…– Diarrheah– Can be fatal!
• Too much water re-absorbed…– constipation
Helping Friends
• 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!
Do Now
• Label the organs of the digestive system on the worksheet provided
Large Intestine (cont’d)
• Ends in the rectum, a short tube that compresses waste into a solid form
• Waste is eliminated through the anus, a muscular opening at the end of the rectum
AppendixVestigial organ
Another function of the Pancreas!
Wait for it…• Buffer: neutralizes
acid from stomach
Different diets; different bodies
• Adaptations of herbivore vs. carnivore– teeth– length of digestive system– number & size of stomachs
Teeth • Carnivore– sharp ripping
teeth– “canines”
• Herbivore– wide grinding
teeth–molars
• Omnivore– both kinds of
teeth
Length of digestive system• Herbivores &
omnivores– long digestive
systems– harder to digest
cellulose (cell walls)• bacteria in intestines
help
• Carnivores– short digestive
systems– protein easier to
digest than cellulose
appendix
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
• 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 & grainsfor complete group of amino acids– rice & beans– taco/tortilla & beans– tofu & rice– peanut butter & bread
Vegetarian diets
2013: “The International Year of the Quinoa”
• (according to the Food and Agricultural Organization of the United Nations)
• A complete protein source—contains all the essential amino acids!
CIRCULATORY SYSTEM
RESPIRATORY SYSTEM
EXCRETION
NERVOUS/ENDOCRINE SYSTEM
standards
• 1.2j-receptor molecules for hormones, if interrupted it can block cellular communication
SKELETAL/MUSCULAR SYSTEM
IMMUNE SYSTEM
standards
• 5.2a=homeostasis is constantly threatened…failure to correct results in death or diaseas
• 5.2-all