UNIT 6: BODY SYSTEMS Miss Sabia Regents 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 INTESTINES 6 meters long, but can stretch to 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

Appendix Vestigial 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 B 12 (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 & grains for 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