Interaction with internal

organsCHAPTER 11

SECTIONS 2,3

TWO KINDS OF DIGESTION

• In mechanical digestion, foods are physically broken down into smaller pieces. – Where does mechanical digestion happen?– Answers: _____________

• In chemical digestion, chemicals produced by the body break foods into smaller chemical building blocks.– Where does chemical digestion happen?– Answers: _____________

Station 1 Mouth1. Take a mirror. Look at you

mouth.2. Open you mouth and look at you

tongue.3. Find the regions of your tongue4. Describe your tongue in your

journal.5. Touch your upper pallet (top of

mouth) with your tongue and look at your blood vessels on the base of your tongue. You will see the openings to your salivary glands.

Station 1: THE MOUTH• The tongue pushes food around, and the

teeth break it into smaller pieces.

• The average person has about 10,000 taste buds and they're replaced every 2 weeks or so. They are called papillae. As a person ages, some of those taste cells don't get replaced and sense of taste diminished.

• Saliva moistens food and contains the enzyme amylase that begins to digest starch.

• The Uvula helps with the process of deglutition (swallowing) and production of speech.

• When you're ready to swallow, the tongue pushes a bit of mashed-up food (called “bolus”) toward the opening of your esophagus.

Draw the tongue (below left). Label the regions of taste. Draw a magnified papillae.

Station 1 Mouth

1. What kind of digestion happens in your mouth?

2. What is the function of the tongue?3. What is the enzyme in your saliva? What

does it break down?4. What do you call the ball of food once it is

chewed and mixed with the saliva and is pushed toward the back of the throat?

Station 2THE SMALL INTESTINE

• Once the food has been changed into a thick liquid, the stomach releases a little at a time into the small intestine thru the pyloric valve.

• Enzymes produced by the gall bladder, the liver, and the pancreas break down the food mixture even more so your body can absorb all the nutrients.

Station 2THE SMALL INTESTINE: VILLI

• The lining of the small intestine is covered with millions of finger-shaped structures called villi.

• The villi absorb nutrient molecules and pass them to blood vessels.

• The blood vessels carry the nutrients directly to the liver for processing.

9Figure 24.17b, c

Station 2The small Intestinal Wall

Station 2 Small intestine1. Draw the small intestine that you have at the lab table2. Describe the small intestine in detail. You can use the

magnifier. 3. What is the function of the lower part of the small

intestine?4. Does the food that you eat go through your small

intestine? 5. What are the finger-like structures inside the intestine

called?6. What kind of muscle tissue makes up the large

intestine?7. Does chemical or mechanical digestion occur in the

upper part of the small intestines (duodenum)? Explain your answer.

Station 3LIVER AND GALLBLADDER

• The liver produces bile, a substance that breaks up fat particles.

• Bile flows from the liver into the gallbladder, and from the gallbladder into the small intestine.

• Bile breaks fats into small droplets. These droplets can then be chemically broken down by enzymes produced in the pancreas.

• The Liver also recycle red blood cells

Station 3Liver and Gallbladder

• Draw the liver that you have at the lab table

• Describe the liver it in detail. You can use the magnifier.

• What is the function of the liver?• Does the food that you eat go to your

liver? • What is the function of the gallbladder?

Station4THE LARGE INTESTINE

• The large intestine is the last section of the digestive system. It contains helpful bacteria that feed on the material passing through.

• By now, most nutrients are absorbed. All that’s left is water and undigested food such as fiber.

• As the material moves through the large intestine, water is absorbed into the bloodstream. The remaining material is readied for elimination from the body.

Station 4Large intestine: COLON AND RECTUM

• The last section of the large intestine is the sigmoid colon. This is the last chance to absorb water and minerals back into the blood.

• The large intestine ends in a short tube called the rectum. Here waste is compressed into a solid form and stored until you’re ready “to go”.

• Waste is removed from the body thru the anus, a muscular opening at the end of the rectum.

• The last section of the large intestine is the sigmoid colon. This is the last chance to absorb water and minerals back into the blood.

• The large intestine ends in a short tube called the rectum. Here waste is compressed into a solid form and stored until you’re ready “to go”.

• Waste is removed from the body thru the anus, a muscular opening at the end of the rectum.

Station 4Large intestine: COLON AND RECTUM

Station 4 Large intestine1. Draw the Large intestine that you have at the lab

table2. Describe the Large intestine in detail. You can use

the magnifier 3. What is the function of the Large intestine?4. Does the food that you eat go through your Large

intestine? 5. What kind of muscle tissue makes up the large

intestine?6. What are the different regions of the Large

intestine?7. Chemical digestion or Mechanical digestion: Why?

Station 5Excretory system: Kidneys

• Function• This system collects the

waste produced by the cells and removes the waste from the body. This process is called excretion.

• Helps maintain homeostasis by regulating the amount of water in your body

Station 5Kidneys:Riñones

• The major organ of the excretory system

• We have 2 kidneys • Function is to eliminate

urea, excessive water and some other waste materials.

• They function like filters: because when the blood flows through the kidneys, they remove waste

Station 5Kidney: The waste• Our body eliminates carbon dioxide

and the water.• The excretory system eliminates

UREA.

• Urea is a chemical that comes from the breakdown of proteins in your cells.

• This is transformed in the kidneys to urine.

Station 5Kidney

• Draw the kidney that you have at the lab table

• Describe the kidney in detail.• What is the function of the kidney?• To which body system do the kidneys

belong? What is the function of this system?

• What is urea? What two substances does your body lose when you exhale?

Station 6Digestive system tissue

• Look under the microscope• In your journal draw and label what you

see in detail.

• Complete the Chapter 11-2 and 11-3 R/R on the Digestive System.