The Digestive & Urinary SystemsChapter 10 – Section 1

Digestive system: the organs that break down food so that it can be used by the body

Digestive Tract: include the mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus.

Liver, gallbladder, pancreas, and salivary glands are part of the digestive system but food does not pass through them.

Section 1

Digestion: process of breaking down food. Mechanical digestion: the breaking, crushing and

mashing of food. Teeth or churning of stomach

Chemical digestion: large molecules are broken down into nutrients. Hydrochloric acid in stomach. Both mechanical and chemical digestion occurs in the stomach. When complete food is reduced to a soupy mixture called chyme. Saliva or acids in stomach. You produce 2 or 3 pints of saliva

a day. Enzymes in saliva break down starch. Called salivary amylase. Food stays in stomach between 2-6 hours.

Three major types of nutrients: Carbohydrates Proteins Fats

The Digestive & Urinary SystemsChapter 10 – Section 1

Esophagus: a long, straight tube that connects the pharynx to the stomach. Squeezes food down: peristalsis.

Stomach: the saclike, digestive organ between the esophagus and the small intestine that breaks down food into a liquid by the action of muscles, enzymes, and acids. After a few hours food is a soupy mixture called chyme. Mucus in your stomach protects the walls so they are not dissolved by the acid.

Pancreas: the organ that lies behind the stomach and that makes digestive enzymes and hormones that regulate sugar levels. Also makes fluid that protects small intestine from acids. The chyme is very acidic.

Liver: the largest organ in the body. Helps with digestion by: it makes bile to break up fat stores nutrients breaks down toxins.

The Digestive & Urinary SystemsChapter 10 – Section 1

Small intestine: the organ between the stomach and the large intestine where most of the breakdown of food happens and most of the nutrients from food are absorbed by villi. Villi have nutrient absorbing cells on them. 21 feet long and 2.5cm wide. Has villi which has capillaries for absorption. Chyme is further broken down by juices made in liver, pancreas, and small intestine. Also uses peristalsis.

Gallbladder: a sac-shaped organ that stores bile produced by the liver. Is responsible for breaking down fats. Made by the liver.

Section 2

Large intestine: the wider and shorter portion of the intestine that removes water from mostly digested food and that turns the waste into semisolid feces, or stool. 6 feet long and 6-7.5cm wide. Last stop before excretion.

The Digestive & Urinary Systems

Chapter 10 – Section 2

Urinary system: the organs that produce, store, and eliminate urine

Kidney: one of the pair of organs that filter water and wastes from the blood and that excrete products as urine. You only have between 5-6L of blood. Each kidney is about 10 cm long and 5 cm wide. Blood is cleaned between 350-400 times daily. Therefore, between 2000 and 2250 liters of blood pass through the kidneys each day!

Nephron: the unit in the kidney that filters blood. Like microscopic filters. Each kidney has about 1 million.

Unfiltered blood enters through an artery. Filtered blood leaves through a vein. Pg. 269---read it aloud.

Section 2

Filtered items goes to the urethra and is expelled as urine. Salt and water is removed.

Urine is about 95% water. Other 5% is urea, acids, and salts

Urine is stored in the bladder. Bladder can hold about 1 liter. 1.5 liters (on average) are made daily.

Ureters: move urine from kidneys to the bladder. Narrow tubes that are 10-12 inches long.

Section 2

Bladder is a muscular sac---it expands and contracts.

Urethra: tube that leads from the bladder to out of the body. Last part of the urinary system.

Urine can detect health problems: sugar in urine could mean diabetes. Bacteria=an infection. Protein=problem with kidneys. Blood=possible injury to urinary system.

Dialysis machine cleans blood! Sweat has urea, water, and salt in it.

Water evaporates but the urea and salt remain until you wash it off.