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