Digestive System

#6

Digestion = breaking down large food particles into small molecules that can pass through intestinal lining and into blood (absorption)

Stomach = store and break up food. Acidic to kill bacteria Liver = Make enzymes, make bile, store glycogen Gallbladder = Store bile. Bile is for emulsifying fats that you eat (break up fat droplets into small pieces) Pancreas = Make insulin and glucagon +base to neutralize acid+ make dig. Enz’s Small intestine = digest & absorb nutrients Large intestine = absorb water + house flora

Esophagus

The Great Sphicter(s) Any of the ringlike muscles surrounding and able to contract or close a bodily passage or opening. The digestive sphincters: 1. Lips 2. Entrance of stomach 3. Exit of stomach 4. Involuntary anal 5. Voluntary anal

#7 Why has evolution given us a stomach that secretes Hydrochloric acid (and makes stomach fluid pH 2)?

The stomach stores food and breaks up larger pieces into a liquid broth Low pH of ~2 kills most bacteria in food Stomach cells secrete mucous to protect cells from acid

The pancreas secretes: 1. insulin and glucagon 2.It also secretes a strong base into the small intestine so low pH of stomach contents wont harm it 3.Digestive enzymes

#8 Explain the homeostasis of blood sugar (use insulin and glucagon in your answer)

When glucose levels rise the pancreas secretes insulin into the blood. Insulin enhances the transport of glucose into body cells and stimulates the liver and muscle cells to store glucose as glycogen, dropping blood glucose levels. When glucose levels drop below a set point, the pancreas secretes glucagon into the blood. Glucagon promotes the breakdown of glycogen and stimulates the release of glucose into the blood, increasing the blood glucose levels. ***The pancreas regulates the use and storage of glucose, a major cellular fuel.

Duties of the liver: Stores Glycogen Regulates fat storage in the body Aids Digestion by producing enzymes and Bile Regulates Blood Clotting (Manufactures clotting factors) As a fetus the liver, forms blood in place of bone marrow Produces Several (Non-Reproductive) Hormones Manufactures Cholesterol (a certain amount of cholesterol is beneficial) Filters Blood Detoxifies Poisons like alcohol Breaks down old red blood cells Breaks down excess amino acids into urea The liver is a large, complex organ with many functions in the body

The gallbladder is a small sac underneath your liver that stores and secretes bile, a digestive fluid that breaks down fats. Bile is made in the liver, stored in the gallbladder, and dumped into the small intestine when food exits the stomach

#9 What is digestion and where does it occur?

Almost all digestion occurs in the small intestine. Digestion is the breaking down of large macromolecules into smaller units (polymers broken up into monomers) Large polymers are too large to pass into the bloodstream.

The small intestine is a long tube where amino acids, sugars, fats, and nucleotides are absorbed (moved from inside the intestinal tube to inside a blood vessel)

#10 Describe 2 roles of the large intestine.

Water is removed from the leftover waste in the large intestine Waste moves too fast = not enough water absorbed = diarrhea Waste moves too slow = too much water absorbed = constipation End of small intestine

#11 What is gut flora? Why is it a good thing?

Gut Flora Fecal transplant anyone?

12 Body Systems Poster Product: Make a poster Called “The 11 Body Systems” on long piece of paper from roll a.Show organs of each system in a different color b.List the body systems and their overall jobs on the sides c.Work on this with dissection group you will be working in for pig d.This will be due Jan 15 so class time after dissections will be available for working on this The 11 Body Systems: 1. Integument, 2. Skeletal, 3. Muscular, 4. Nervous, 5. Digestive, 6. Circulatory, 7. Respiratory, 8. Endocrine, 9. Excretory, 10. Immune / Lymphatic, 11. Reporductive