Download Chapter 18: Review

Chapter 18: Review
Digestive and Excretory System
Define digestion: process of breaking down food into molecules the body can use
List the parts of the digestive tract and label on diagram. (p.985)
Mouth: mechanical and chemical digestion
Esophagus:
Stomach: mechanical and chemical digestion
Small intestine:
Large intestine: absorption of water, minerals, and vitamins
Accessory organs
Liver: produces bile
Gallbladder:
Pancreas: produces digestive enzymes
Define
Saliva: mixture of water, mucus, and amylase (breaks down starch) moistens food for
swallowing
Bolus:
Peristalsis: rhythmic contractions that move bolus through the esophagus
Gastric fluid: carries out chemical digestion in stomach
Pepsin:
Hydrochloric acid: lowers pH so pepsin can work
Mucus: protective coating for stomach
Ulcer: sore in stomach caused by bacteria
Bile:
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Absorption: end products of digestion are transferred to blood and lymph (nutrients go
into the blood from the small intestines)
Villi: fingerlike projections in the lining of small intestines (do absorption)
Define excretion:
Function of kidneys: Remove nitrogen wastes
Name and label the parts of the kidney (p.994)
Cortex: outer portion
Medulla:
Renal pelvis: funnel-shaped structure in the center
Renal artery: transports nutrients and wastes into kidney
Renal vein:
Describe how the nephrons function
Nephrons: functional units of kidneys that remove wastes
Bowman’s capsule: cup-shaped structure that holds glomerulus
Glomerulus:
Renal tubule: long tube that collects fluid filtered from blood
Steps in the nephron
1. Filtration: Fluids forced from blood into Bowman’s capsule
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Filtrate: Water, urea, glucose, and vitamins move
2. Reabsorption: needed substance move back into the blood, 99% of water is
returned to blood
3. Secretion: substances pass from blood into tubule (wastes go into tubule)
Define
Urea:
Urine: produced in nephrons and contains toxins, urea, water, and salts
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Describe how urine is eliminated
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Collecting ducts enter renal pelvis
Ureter: tube from kidney to bladder
Urinary bladder: sac that stores urine
Urethra: tube from bladder and out of body
Organs of excretory system
Lungs:
Skin: eliminate sweat to remove excess water and salt
Kidneys: nitrogen waste in the form of urine
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