Section 27.1 Summary – pages 721-727

1. Section 27.1 Summary – pages 721-727 What is a mollusk? • The mantle (MAN tuhl) is a membrane that surrounds the internal organs of the mollusk. In shelled mollusks, the mantle secretes the shell. Mantle Snail Shell Gut Head Foot Shell Visceral mass Foot Mantle

2. Section 27.1 Summary – pages 721-727 Excretion in mollusks • Mollusks are the oldest known animals to have evolved excretory structures called nephridia. • Nephridia (nih FRIH dee uh) are organs that remove metabolic wastes from an animal’s body. • Mollusks have one or two nephridia that collect wastes from the coelom, which is located around the heart only.

3. Section 27.1 Summary – pages 721-727 Excretion in mollusks • Wastes are discharged into the mantle cavity, and expelled from the body by the pumping of the gills.

4. Section 27.2 Summary – pages 728-733 What is a segmented worm? • Food is taken in by the mouth, an opening in the anterior end of the worm, and wastes are released through the anus, an opening at the posterior end.

5. Section 27.2 Summary – pages 728-733 What is a segmented worm? • Food is taken in by the mouth, an opening in the anterior end of the worm, and wastes are released through the anus, an opening at the posterior end.

6. Section 27.2 Summary – pages 728-733 Digestion and excretion • Segmented worms have a complete internal digestive tract that runs the length of the body. • Food and soil taken in by the mouth eventually pass to the gizzard.

7. Section 27.2 Summary – pages 728-733 Digestion and excretion Gizzard Crop Mouth • In the gizzard, a muscular sac and hard particles help grind soil and food before they pass into the intestine.

8. Section 27.2 Summary – pages 728-733 Digestion and excretion • Undigested material and solid wastes pass out the worm’s body through the anus. • Segmented worms have two nephridia in almost every segment that collect waste products and transport them through the coelom and out of the body. Nephridia

9. Section 28.1 Summary – pages 741 - 746 Arthropods have other complex body systems • Most terrestrial arthropods excrete wastes through Malpighian tubules. • In insects, the tubules are all located in the abdomen rather than in each segment. • Malpighian tubules are attached to and empty into the intestine.

10. Section 35.1 Summary – pages 917-923 Functions of the Digestive System • The main function of the digestive system is to disassemble the food you eat into its component molecules so that it can be used as energy for your body. • Digestion is accomplished through a number of steps. • First, the system takes ingested food and begins moving it through the digestive tract.

11. Section 35.1 Summary – pages 917-923 Functions of the Digestive System • As it does so, it digests or breaks down mechanically and chemically, the complex food molecules. • Then, the system absorbs the digested food and distributes it to your cells. • Finally, it eliminates undigested materials from your body.

12. Section 35.1 Summary – pages 917-923 Functions of the Digestive System Teeth Salivary glands Mouth Pharynx Tongue Esophagus Diaphragm Stomach Liver Pancreas Gallbladder Small intestine Large intestine Appendix Rectum Anus

13. Section 37.3 Summary – pages 985-987 Nephron: The unit of the kidney • Each kidney is made up of about one million tiny filters. • A filter is a device that removes impurities from a solution. • Each filtering unit of the kidney is called a nephron. • Blood entering a nephron carries wastes produced by body cells.

14. Section 37.3 Summary – pages 985-987 Nephron: The unit of the kidney Bowman’s capsule Nephron Glomerulus From renal artery Renal artery Renal vein To renal vein Tubule Ureter Capillaries To ureter

15. Section 37.3 Summary – pages 985-987 Nephron: The unit of the kidney • As blood enters the nephron, it is under high pressure and immediately flows into a bed of capillaries called the glomerulus. • Because of the pressure, water, glucose, vitamins, amino acids, protein waste products (called urea), salts, and ions from the blood pass out of the capillaries into a part of the nephron called the Bowman’s capsule.

16. Section 37.3 Summary – pages 985-987 Nephron: The unit of the kidney Bowman’s capsule Nephron Glomerulus From renal artery Renal artery Renal vein To renal vein Tubule Ureter Capillaries To ureter

17. Section 37.3 Summary – pages 985-987 Nephron: The unit of the kidney • The liquid forced into the Bowman’s capsule passes through a narrow, U-shaped tubule. • As the liquid moves along the tubule, most of the ions and water, and all of the glucose and amino acids, are reabsorbed into the bloodstream. • Small molecules, including water, move back into the capillaries by diffusion. Other molecules and ions move back into the capillaries by active transport.