1. The Digestive and Urinary System
Chapter 24
The Digestive and Urinary System

2. Section 1 – The Digestive System
Vocabulary Terms
Digestive system –
Esophagus –
Stomach –
Small Intestine –
Pancreas –
Liver –
Gallbladder –
Large Intestine –
The Digestive system

3. The Digestive System
A group of organs that work together to digest food so that it can be used by your body for energy.
The Digestive Tract – includes mouth, Throat, esophagus, stomach, small intestine, large intestine, rectum, and anus. Also your salivary glands, liver, gallbladder, pancreas are also part of the digestive system.

4. Two forms of digestion
a. Mechanical – breaking, crushing, and mashing of food
b. Chemical – large molecules are broken down into nutrients

5. Nutrients – Three major types
Carbohydrates
Proteins
Fats
Enzymes – break nutrients into smaller molecules called amino acids

6. Digestion Begins in the Mouth
You need to chew food so it is broken into smaller pieces, moistened and easier to swallow as well as digest.
Teeth –
Layers – Enamel – hardest material in the body and the outermost layer of teeth
Types of Teeth –
Molars – grind food
Premolars – mashing food
Incisors – shred food
Canines – shredding food
Food gets mixed with saliva which starts the process of digestion chemically.

7. Stomach
Food goes down your esophagus using peristalsis (wave motion) to the stomach. In the stomach the food is squeezed
Your stomach produces enzymes and acid these break down food and kill any bacteria that may have been swallowed.
Your digested food is called chyme

8. Small Intestine
Chyme enters the small intestine through a valve. Chyme is slowly released giving the small intestine time to mix the chyme with juices from the liver and pancreas. Most chemical digestion takes place the small intestine
Villi- Surface area is greater than a tennis court. This is because of villi. Villi are covered with tiny nutrient absorbing cells. These cells dump nutrients into the bloodstream.

9. Pancreas, Liver, Gallbladder
The Pancreas, Liver, and Gallbladder are linked to the small intestine but no food goes through them.
Pancreas – Located between the stomach and he small intestine. Secretes juice into the small intestine. Bicarbonate is released which neutralizes the acid in chyme so it doesn’t eat the intestinal wall lining. The pancreas also helps the endocrine system by regulating blood sugar

10. Pancreas, Liver, Gallbladder
The liver and Gallbladder –
Liver – located above the stomach but linked to the small intestine
makes bile (used in fat digestion)
Stores nutrients
Breaks down toxic substance in the blood (alcohol, drugs)
makes cholesterol for the cell membrane

11. Pancreas, Liver, Gallbladder
Gallbladder – Stores bile from the liver before the bile enters the small intestine where it breaks up fat droplets

12. The Digestive tract Cont.
Nutrients are absorbed into the bloodstream. If they are not needed right away then they are stored in the liver till they are needed.\
Large Intestine – Stores, compacts, eliminates indigestible materials – only called large because the diameter is bigger.
Soupy mixture enters the large intestine where most of the water is reabsorbed. Fiber helps keep the stool soft and moving smoothly. Fiber is found in fruits, veggies, and whole grain

13. The Digestive tract Cont.
Rectum – Stores feces (stool) till it can be expelled
Whole process takes about 24 hours

14. Problems of the Digestive system
Most are related to what you eat but some are diseases.
Heartburn – When acidic chyme flows into the esophagus causing a burning sensation. Happens mostly when you eat too much, et right before bed, eat acidic foods
Constipation and diarrhea – When too much water is removed or too little water is removed.
Colon Cancer – cancer in the long tubular portion of the large intestine. Creates a tumor which can spread easily.
Gastric Ulcer – open sore in the stomach usually caused by bacteria

15. Section 2 – the Urinary System
Vocabulary terms
Urinary System –
Kidney –
Nephron –
Urine –
Urinary Bladder –

16. The Urinary System
One way that excretion takes place. The other two are through the skin and through the lungs. Excretion is only when a substance passes through a membrane in order to leave the body.
Your urinary system cleans your blood by removing all the wastes that are picked up from the cells.
Kidneys – cleans the blood cycles about 350 times per day.
Nephrons – microscopic filters in the kidneys

17. How the Kidneys Filter blood
A large artery brings blood into each kidney.
Tiny blood vessels branch off the main artery and pass through part of each nephron
Water and other small substances, such as glucose, salts, amino acids, and urea, are forced out of the blood vessels and into the nephrons
As these substances flow through the nephrons, most of the water and some nutrients are moved back into the blood vessels that wrap around the nephrons. A concentrated mixture of waste materials is left behind in the nephrons.
The cleaned blood, now slightly less water and much less waste material, leaves each kidney in a large vein to recirculate in the body
The yellow fluid that remains in the nephrons is called urine. Urine leaves each kidney through a slender tube called the ureter and flows into the urinary bladder, where it is stored.
Urine leaves the body through another tube called the urethra. Urination is the process of expelling urine from the body.

18. Your body must regulate water.
When you are hydrated enough your body stops making saliva which is why you feel thirsty
Antidiuretic hormone – ADH signals kidneys to take water back from the nephrons and return it to the bloodstream, your kidneys then makes less urine.
Caffeine is a diuretic which cause the kidneys to make more urine thereby taking more water out of the blood. So caffeine causes you to be more thirsty.

19. Ailments
Bacterial infections – bacteria can spread throughout your urinary system
Kidney stones – salts and wastes collect inside the kidneys. This interferes with urine flow. Shockwaves can sometimes break stones up
Kidney Disease – damage to the nephrons can cause the kidney to stop filtering blood. Dialysis is where blood is taken from a artery and filtered by a machine then pumped back into your body.