P. LO BO S C O

THE DIGESTIVE AND URINARY SYSTEM

THE DIGESTIVE SYSTEM

• The Digestive System is a group of organs that work together to digest food so that it can be used by the body.

ORGANS OF THE DIGESTIVE SYSTEM

• The digestive tract is a series of tubelike organs which food passes through.• The digestive tract

includes your mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum and anus.

THE DIGESTIVE SYSTEMCHAPTER 24-1

• Objectives:• Compare mechanical digestions with chemical

digestion.• Describe the parts and functions of the digestive

system.

OTHER ORGANS

• The liver, gallbladder, pancreas and salivary glands are also part of the digestive system. • Food does not pass

through these organs.

BREAKING DOWN FOOD

• Digestion is the process of breaking down food into a form that can pass from the digestive tract into the blood stream.

TWO TYPES OF DIGESTION

• There are two types of digestion : mechanical and chemical.• The breaking, crushing and mashing of food is

called mechanical digestion.• In chemical digestion, large molecules are broken

down into nutrients.• Nutrients are substances in food that the body

needs for growth, maintenance and repair.

CATABOLIC AND ANABOLIC

• Catabolic reactions• Proteins from your food are made up of chains of amino

acids.• Catabolism refers to the breakdown of proteins into

amino acids.• This process releases energy in the form of ATP

• Anabolic reactions• Anabolism refers to the process by which simpler

substances (amino acids) are combined to form more complex molecules.

ENZYMES

• Substances called enzymes break some nutrients into smaller substances that the body can use.• Proteins are changed into smaller molecules

called amino acids.

THE ROLE OF ENZYMES IN DIGESTION

• 1. Enzymes break apart the long chains of amino acids that make up proteins.• 2. The small chains are then split by other

enzymes.• 3. Individual amino acids are then small enough

to enter the bloodstream where they will make new proteins.

THE ROLE OF ENZYMES

DIGESTION

• Nutrients are the usable portions of food. • The six nutrients are protein, fat, carbohydrates,

vitamins, minerals and water.• Proteins are broken down into amino acids.• Fats are broken down into fatty acids and glycerol.• Carbohydrates are broken down into simple sugars.• Food is pushed through the digestive system by waves of

muscular contractions called peristalsis.• Bacteria in the large intestine make vitamins for us.• Nutrients are absorbed in the small intestine.• Water and vitamins are absorbed in the large intestine.

NUTRIENTS

 • Chemical digestion of carbohydrates begins in the

mouth and ends in the small intestine.• Chemical digestion of proteins begins in the

stomach and ends in the small intestine.• Chemical digestion of fats begins and ends in the

small intestine.•  • Fats are broken down into fatty acids and glycerol.• Proteins are broken down into amino acids.• Carbohydrates are broken down into simple sugars.

DIGESTION BEGINS IN THE MOUTH

• Chewing creates small, slippery pieces of food that are easier to swallow.• Small pieces of

food are easier to digest.

DIGESTION IN THE MOUTH

•  • Palate – the “roof” of your mouth, tongue pushes against it to aid swallowing, separates

the mouth and nasal cavities•  • Teeth - crush food into smaller pieces to aid swallowing•  • Tongue – tastes food, mixes food with saliva, pushes food between the teeth, helps in

swallowing•  • Salivary Glands - secrete saliva into the mouth to begin carbohydrate digestion and

moisten food•  • Pharynx – where mouth and nasal passages meet, leads to the trachea and esophagus•  • Epiglottis – flap of tissue that closes over the trachea when you swallow to prevent food

or drinks from going into the trachea which prevents choking•  • Esophagus - connects the mouth and stomach, uses peristalsis (muscular contractions)

to move food along

TEETH

• Teeth break and grind food.• The outermost layer

of the teeth, enamel, is the hardest material in the body.• Enamel protects

nerves and softer material inside the tooth.

TEETH

• Your teeth have different shapes.• The molars are

suited for grinding food.• The premolars are

used for mashing food.• Incisors and canines

are used for shredding food.

SALIVA

• The roof of the mouth is the palate.• Saliva mixes with food in your mouth.• Saliva is made in the salivary glands.• It contains an enzyme that begins chemical

digestion of carbohydrates by changing them into simple sugars.

ESOPHAGUS

• After the food is very soft, the tongue pushes it into the throat, which leads to the esophagus.• The esophagus

squeezes the food with rhythmic muscle contractions called peristalsis, forcing the food into the stomach.

STOMACH

• The stomach is a muscular saclike digestive organ between the esophagus and the small intestine that breaks down the food into a liquid by the action of muscles, enzymes and acids.

STOMACH

• The stomach continues the mechanical digestion of your meal by squeezing food with muscular contractions. • Glands in the stomach

produce enzymes and acid which break food into nutrients.

CHYME

• Stomach also kills bacteria that you swallow with food.• After a few hours of

chemical and mechanical digestion, food turns into chyme.

SMALL INTESTINE

• The stomach releases the chyme into the small intestine through a small ring of muscle that works like a valve.• The valve keeps the

food in the stomach until it has been mixed with digestive fluids.

SMALL INTESTINE

• Since the stomach releases the chyme slowly, the small intestine has time to mix the chyme with fluids from the liver and pancreas,• This help digest and

stop the acids in chyme from hurting the small intestine.

THE PANCREAS AND SMALL INTESTINES

• When the chyme leaves the stomach, the chyme is very acidic so the pancreas makes fluids to protect. • The pancreas is an

oval organ located between the stomach and small intestine.

SMALL INTESTINE

• The small intestine is a muscular tube that is about 2.5 cm in diameter. It is about 6 m long when stretched out.• The inside wall is

covered with fingerlike projections called villi.• The villi are covered

with tine, nutrient absorbing cells.

DUODENUM

• The duodenum precedes the jejunum and ileum and is the shortest part of the small intestine, where most chemical digestion takes place. The name duodenum is from the Latin duodenum digitorum, or twelve fingers' breadths.

THE LIVER

• The Liver is a large, reddish brown organ that help with digestion. I human liver can be as big as a football.• It is located toward your right side, slightly higher

than you stomach.• The functions of the liver are:

• Store nutrients• Make bile to break up fat• Break down toxins

GALLBLADDER

• Bile is stored in a saclike organ called the gallbladder, which squeezes the bile into the small intestine where the breaking down of fats take place. • The bloodstream absorbs nutrients that have

been broken down.

LIVER AND GALLBLADDER

THE END OF THE LINE

• Material that can’t be absorbed into the blood is pushed into the large intestine.

• The large intestine absorbs most of the water in undigested material and changes the liquid into semisolid waste material called feces, or stool.

• Feces are stored in the rectum until they can be expelled.

RECTUM AND ANUS

Feces pass to the outside of the body through an opening called the anus.

It has taken each of your meals about 24 hours to make this journey through your digestive system.

SUMMARY OF FUNCTIONS OF PARTS OF THE DIGESTIVE SYSTEM

•  • Teeth – crush food into smaller pieces to aid swallowing•  • Liver – secretes bile which breaks fat into smaller pieces•  • Gall bladder – stores bile until needed in the small intestine•  • Large Intestine – absorbs water and vitamins (made by bacteria living in

the large intestine), stores waste, releases waste•  • Small Intestine – all digestion is completed here (no nutrients are broken

down past this point), nutrients are absorbed through the villi into the blood stream

•  • Rectum – end of large intestine, stores solid wastes until they leave the body•  

DIGESTION SUMMARY

• Anus – opening to let out wastes•  • Mouth – allows food to enter the body, contains teeth and tongue,

carbohydrate digestion begins here due to the action of the enzymes in saliva•  • Salivary glands – secrete saliva into the mouth to begin carbohydrate

digestion and moisten food•  • Esophagus – connects the mouth and stomach, uses peristalsis (muscular

contractions) to move food along•  • Stomach – churns food into a thick liquid called chyme, protein digestion

begins here due to the action of gastric juice (enzymes and hydrochloric acid)•  • Pancreas – secretes pancreatic juice into the small intestine to neutralize the

acid from the stomach and to digest all types of food

THE URINARY SYSTEM

• Chapter 24-2• Objectives:• To describe the path and function of the urinary

system• To explain how kidneys filter blood• To describe three disorders of the urinary system

EXCRETION

• Excretion is the process of removing waste from the body.• Three of the body systems have a role in

excretion.• The integumentary system releases waste

products and water when you sweat.• The respiratory system releases carbon dioxide

and water when you exhale.• The urinary system contains the organs that

remove waste products from your blood.

URINARY SYSTEM

• As the body performs the chemical activities to keep the body alive, waste products, such as carbon dioxide and ammonia are produced.• The body has to get

rid of these wastes to stay healthy.

KIDNEYS

• The kidneys act as filters.• They filter about

2000L of blood a day. (You body can only hold about 5.6 L).• Inside each kidney

is over 1 million nephrons.

NEPHRONS

• Nephrons are microscopic filters. They remove harmful substances, such as urea.• Urea is formed

when cells use protein for energy. It contains nitrogen.

HOW THE KIDNEYS FILTER BLOOD

1. A large artery, called the renal artery, brings blood into each kidney.

2. Tiny blood vessels branch off the main artery and pass through part of each nephron.

HOW THE KIDNEYS FILTER BLOOD

3. Water and other substances are forced out of the blood vessels and into the nephrons.

4. The nephrons filter the wastes out of the blood and water, and allow the filtered blood and water to move back into the blood vessels.

HOW THE KIDNEYS FILTER BLOOD

5. As filtered blood and water go back into the blood vessels, waste materials are left in the nephrons.6. Cleaned blood leaves each kidney in the renal vein to recirculate in the body.7. The yellow fluid that remains in the nephrons is called urine.

HOW THE KIDNEYS FILTER BLOOD

8. Urine leaves each kidney through a slender tube called the ureter and flows into the urinary bladder. 9. Urine leaves the body through another tube called the urethra. 10. Urination is the process of expelling urine from the body.

RENAL ARTERY, RENAL VEIN AND URETER

WATER BALANCE IN BODY

• You drink water everyday but you lose water in sweat and urine. You need to get rid of as much water as you drink or your body will swell up. • When you are too warm, you sweat. The

evaporation of water cools down the body.• As the water content of the body drops when you

sweat, the salivary glands will produce less saliva and you will feel thirsty.• When you get thirsty a hormone, called

antidiuretic hormone or ADH will be released.

ADH

• ADH will signal the kidneys to take water from the nephrons. The nephrons will return the water to the blood stream and the kidneys will make less urine. • When your blood has too much water, small

amount of ADH are released. The kidneys will react by allowing more water to stay in the nephrons and leave the body as urine.

DIURETICS

• Some beverages contain caffeine, which is a diuretic. Diuretics cause the kidney to make more urine, which decreases the amount of water in the blood. • When you drink a beverage that contains water

and caffeine, the caffeine increases fluid loss. So your body will get less of the water from a glass of a caffeinated beverage than from a glass of water.

URINARY SYSTEM PROBLEMS

• Since the job of the urinary system is to remove wastes and regulate body fluids, any problems with water regulation can become dangerous for your body.

BACTERIAL INFECTIONS

• Bacteria can get into the bladder and ureters through the uretha. If not treated, it can spread to the kidneys. Infections in the kidneys can permanently damage the nephrons.

KIDNEY STONES

• Sometimes salts and other wastes will collect inside the kidney and form stones. Some interfere with urine flow. • If the body does not

pass them, they must be removed.

KIDNEY DISEASE

• Damage to nephrons can prevent normal kidney functioning. If the kidneys do not function properly, a machine must be used to filter waste from the blood.

URINARY SYSTEM SUMMARY

• The Urinary System•  • Kidney – filters blood, controls water levels•  • Ureter – carries urine from the kidneys to the bladder•  • Urethra – carries urine out of the body•  • Bladder – stores urine until it leaves the body•  •  • Blood vessels – carries blood to the kidneys to be cleaned and carries cleaned blood

to the body•  • Nephrons – filter the blood, microscopic•  •  • Cortex – contains the nephrons