KEY CONCEPT Cells require many different nutrients.

Carbohydrates are the main source of energy for the body. simple and complex carbohydrates supply glucose fiber from plant foods helps elimination Simple and Complex Carbohydrates

Proteins are necessary for growth and repair of the body’s cells. body makes 12 out of 20 amino acids other eight essential amino acids come from food Fats provide energy and key building components. fats are saturated and unsaturated essential fatty acids come from food Proteins and Fats

Minerals are inorganic materials. help to build or repair tissues replenished by eating variety of foods

Vitamins are organic molecules that work with enzymes. vitamins are fat-soluble and water-soluble regulate cell functions, growth, development replenished by eating variety of foods

KEY CONCEPT The digestive system breaks down food into simpler molecules.

Several digestive organs work together to break down food. The digestive system breaks down food into energy cells can use. After digestion is complete, nutrients are absorbed and transported to all cells. Undigested materials are eliminated as liquid and solid wastes. mouth esophagus liver gallbladder large intestine small intestine rectum/anus

Digestion begins in the mouth and continues in the stomach. Mechanical and chemical digestion break down food. Peristalsis moves food through the organs. esophagus muscles contract muscles relax food stomach

Digestion of carbohydrates begins in the mouth. Digestion of proteins occurs in the stomach. Digestion of fats and sugars occur in the small intestine.

Digestion is completed in part of the small intestine. Most digestion takes place in the duodenum. The pancreas, liver, and gallbladder aid in digestion. pancreas helps digest fat and protein bile from the liver/gallbladder helps digest fats liver stomach bile chyme bile enzymes gallbladder pancreas duodenum

Saliva contains an enzyme (amylase) Amylase breaks down starches into maltose (disaccaride)

Stomach contains pepsin, an enzyme activated HCl Pepsin breaks down proteins to form amino acids

Small intestine is 6m long! The pancreas secretes many enzymes to break down nutrients in food Gallbladder secretes bile for fat digestion Bile is a mechanical digestion; emulsification; bile and lecithin form droplets of fat called micelles; then the fats are broken down by lipase Pancreas also releases hormones to tell the body it is full

Diarrhea occurs when the muscles are contracting too quickly  not enough time for water to be removed from bolus  watery stool Diarrhea occurs when the muscles are contracting too quickly  not enough time for water to be removed from bolus  watery stool Constipation is opposite

This is defection.

Most absorption of nutrients occurs in the small intestine. Three structures in the small intestine help absorb nutrients. folded lining: adds surface area, slows food villi: absorb nutrients microvilli: cover villi, absorb nutrients

Duodenum- simple sugars, amino acids, and minerals are absorbed and go to liver Jejunum- glucose, amino acids, vitamins and water are absorbed and go to body parts Ileum- absorb fat soluble vitamins, vitamin B12,, fatty acids, cholesterol

Nutrients enter the circulatory or lymphatic systems. Liver stores excess glucose for future use. liver small intestine

The colon helps to maintain the body’s fluid balance. Water is absorbed and solid wastes are eliminated from the large intestine. The colon helps to maintain the body’s fluid balance. Undigested material forms the solid feces. stored in rectum eliminated through anus large intestine rectum/anus

KEY CONCEPT The excretory system removes wastes and helps maintain homeostasis.

Kidney filters blood salt and water absorption located behind the intestines Ureter carries urine from kidney to bladder Bladder holds urine Urethra carries urine from bladder out of body

The excretory system eliminates nonsolid wastes from the body. Nonsolid wastes are eliminated through lungs, skin, and kidneys. Lungs exhale carbon dioxide and water vapor. Sweat glands in skin release excess water and salts. Kidneys filter and clean the blood to produce urine. skin lungs kidneys ureters urinary bladder urethra

The kidneys help to maintain homeostasis by filtering the blood. cortex medulla renal artery renal vein ureter (to bladder) Kidneys are a pair of bean-shaped organs. two layers: medulla and cortex filtering units called nephrons renal artery and renal vein

Kidneys have three basic functions in maintaining homeostasis. remove waste from blood help to maintain electrolyte, pH, and fluid balances release key hormones

Nephrons clean the blood and produce urine. Nephrons are the filtering units in the kidneys. They clean and rebalance the blood to produce urine.

Nephrons clean the blood in a three-step process. The first step is filtration of the blood. FILTRATION Water,electrolytes,aminoacids,glucose,urea, and other small molecules diffuse out of the blood,creating the filtrate. 1 Glomerulus Bowman’s capsule

The first step is filtration of the blood. The second step is reabsorption of materials. The third step is excretion of materials. REABSORPTION As the filtrate enters the rest of the tubule ,most of the materials are reabsorbed into the blood.Materials not reabsorbed make up the urine,which flows into the loop of Henle. 2 from body collecting duct EXCRETION In the loop of Henle,water can be reabsorbed one final time to reduce the volume of urine.The remaining urine flows into a collecting duct that leads to the ureter. 3 to body from other nephrons loop of Henle

Dialysis can be used to filter and clean the blood.