From
Seeley, Stephens & Tate, 2003. Human Anatomy and Physiology. McGraw-Hill.
Reprinted with permission.
Now go to the web site http://www.medtropolis.com/VBody.asp and take the Guided Tour. As you go, create a flow chart showing the path of food down to the small intestine.
What does the pancreas secrete into the small intestine?
What does the liver secrete into the small intestine?
The web site says the liver ‘emulsifies fats.’ What does that mean? To demonstrate it, you need oil, water, a glass bottle with a lid, and dishwashing soap.
Put equal amounts of oil and water in the bottle and shake them up together. This is what will happen in your stomach after you eat an oily food like pizza or buttered popcorn. What happens to the solution in the bottle when you let it sit?
Dishwashing soap is the same kind of compound as bile. Add a
small amount of soap to your oil and water and shake them up again. The soap
will ‘emulsify’ the oil. What do you observe?
Why would this be useful for digestion?
Case Study:
Mr. G drank immense
amounts of alcohol in his youth, and eventually he did damage his liver. He’s lost a lot of weight and feels sick a
lot, but he says what really grosses him out is that his stools are so slippery
and bad smelling. “They’re yellow and full of foam,” he says, “and they won’t
go down the toilet. They float. It’s embarrassing!”
What’s making his stools
yellow and foamy? Why has he lost so much weight?
Mr. G’s aunt told him
to eat fatty, high-calorie foods to regain the weight he lost. Do you think
this will help? Why or why not?
View the sections concerning the small intestine and label the diagram below. If someone had an ileostomy, which part of the small intestine would have been operated on?
From
Seeley, Stephens & Tate, 2003. Human Anatomy and Physiology. McGraw-Hill.
Reprinted with permission.
Now go through the parts dealing with the large intestine, and label this diagram:
From
Seeley, Stephens & Tate, 2003. Human Anatomy and Physiology. McGraw-Hill.
Reprinted with permission.
Your large intestine is filled with hundreds of kinds of bacteria – so many that about 60% of your stools is actually bacteria. They digest some of the food you can’t digest. This is why you get gas in the large intestine when you eat something you can’t digest easily, like beans. If you pay attention, you can feel the gas pass through the different segments of the large intestine.
Want to test yourself again? Here’s another quiz:
The Liver
When you go to the doctor and have blood tests done, they don’t usually ask you what you just ate. Doesn’t that seem odd, when you think about it? Won’t your blood change a lot, depending on whether you just had a steak, a pizza, or a milkshake?
The answer is that the blood in your small intestine changes a lot when you eat. It may have very high glucose levels or be full of fat, or of acids or any other compounds you ate. If you ate a poison or took a drug, it will be full of those too. But by the time the blood reaches the rest of your body, it has been ‘fixed’ to have normal levels of food in it. Most of the toxins you ate have been broken down and some of the drugs you took have been altered – either destroyed or activated. The organ that does all this is the liver.
Use your text to fill in the table below of normal liver functions.
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Normal Liver Function |
Failure in this function would cause: |
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The endocrine pancreas
One of the things the liver does is to store the sugars you eat. When you eat a jelly donut, your liver will store some of the sugar. Later, when you need that sugar for energy, your liver will release it into the blood so it can be carried to your other cells. How does the liver know whether it needs to store the sugar or release it?
Go to http://cal.man.ac.uk/student_projects/2000/mnby7lc2/pancreas.htm and use the information there to answer the following questions. You only need to look at the first two pages and the summary diagram.
What is the difference between the exocrine pancreas and the endocrine pancreas?
What do the Alpha cells of the endocrine pancreas secrete?
What causes the Alpha cells to release this hormone?
What will this hormone tell the liver to do?
What will the effect be for blood glucose levels?
What do the Beta cells of the endocrine pancreas secrete?
What causes the Beta cells to release this hormone?
What will this hormone tell the liver to do?
What will the effect be for blood glucose levels?
What will tell the Beta cells to stop secreting?
CASE STUDY:
Mrs. H. felt weak all the time, shaky and depressed. She got dizzy even when she as sitting down. Finally she passed out. Her sister brought her into the emergency room and doctors found that her blood glucose level was only 25 mg/100 mL blood (normal is 80-120 mg/dL). They gave her an IV with glucose in it, but she only felt better for a little while.
Though Mrs. H tried to manage her diet to keep her blood sugar up, she kept having fainting spells. She had to carry candy around with her all the time, and she was upset about gaining weight. Finally her doctor made a diagnosis. She had an insulinoma, a tumor in her pancreas that was secreting insulin. How did this cause her problems?