Chapter 24 The Digestive and Urinary Systems. Section 1 The Digestive System Objectives: Compare...
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Transcript of Chapter 24 The Digestive and Urinary Systems. Section 1 The Digestive System Objectives: Compare...
Chapter 24
The Digestive and Urinary Systems
Section 1 The Digestive SystemObjectives:•Compare mechanical digestion with chemical digestion.•Describe the parts and functions of the digestive system.
Major Functions of the Digestive System
• Break down ingested food• Put nutrients into the bloodstream• Remove waste from the body
Organs of the Digestive System• Mouth- teeth, salivary glands, tongue• Esophagus• Stomach• Small Intestine• Large Intestine• Pancreas• Liver• Gall bladder
Accessory Organs
Mouth• Digestion begins here!• Teeth and tongue are used in mechanical
digestion- physical breakdown of food• Saliva and enzymes begin chemical
digestion- chemical breakdown of food
Esophagus• Muscular tube that connects mouth to stomach• Moves food downward by peristalsis, or
muscular contractions• Epiglottis seals off windpipe during swallowing
to prevent choking
Stomach- Mechanical and Chemical Digestion
• Muscular pouch that expands to hold your food
• Hydrochloric acid (HCl) and the enzyme pepsin combine to form gastric juice
• A gummy coating of mucus protects the stomach lining from the strong chemicals
• Chyme, a thick liquid containing partially digested food, is produced here
Pancreas• Makes digestive enzymes• Makes hormones that regulate sugar levels
Small Intestine• Most chemical digestion occurs here!• Inner surface is covered in villi and microvilli,
millions of tiny finger-like projections that absorb nutrient molecules from the chyme
• The villi create a large surface area so as many nutrients as possible can be absorbed
• Longest portion of the digestive tract
Liver• Makes bile to break up fat• Stores nutrients• Breaks down toxins
Gallbladder• Temporarily stores bile and releases it into
the small intestines
Large Intestine• No digestion occurs here• Water is absorbed from remaining food• Waste material, feces, is prepared for
elimination from the body
Rectum• Stores feces until they can be expelled
through the anus.
Section 2 The Urinary SystemObjectives:•Describe the parts and functions of the urinary system.•Explain how the kidneys filter blood.•Describe three disorders of the urinary system.
The Urinary System• Excretion is the process of removing waste
products from the body.• The urinary system removes waste products
like carbon dioxide from the body.
The Kidneys as Filters• The kidneys are a pair of organs that
constantly clean the blood.• Your blood cycles through your kidneys
about 350 times a day.• Inside each kidney are nephrons,
microscopic filters that remove waste from the blood. (especially urea)
Water In, Water Out• The balance of fluids in the body is
controlled by chemical messengers called hormones.• Sweat and thirst• Antidiuretic hormone (ADH)-signals the kidneys
to make less urine• Diuretics-cause the kidneys to make more urine
Urinary System Problems• Bacterial infections-bacteria in the bladder; if
spreads to kidneys, then permanent damage can be caused to nephrons
• Kidney stones-when salts and other wastes collect inside the kidneys and form stones; can interfere with urine flow
• Kidney disease-can be caused by damage to nephrons; dialysis used as treatment to filter blood