The Excretory System

1. The Excretory System The Body’s Filter

2. Function of the Excretory System • The human excretory system functions to remove waste from the human body. • During this process animals get rid of nitrogenous waste products of metabolism, including ammonia, urea, and uric acid. • Although excretory systems are diverse, nearly all produce urine in a process that involves several steps.

3. Function of the Excretory System • STEPS : • 1. Filtration: the excretory tubule collects filtrate from the blood. Water and solutes are forced by blood pressure across the selectively permeable membranes of a cluster of capillaries and into the excretory tubule. • 2. Reabsorption: The transport epithelium reclaims valuable substances from the filtrate and returns them • 3. Secretion: Other substances are extracted from body fluids and added to the contents of the excretory tube. • 4. Excretion: The filtrate leaves the system and the body

4. Structure of the Excretory System • This system consists of specialized structures and capillary networks that assist in the excretory process. • The human excretory system includes the kidney and its functional unit, the nephron. • The excretory activity of the kidney is changed by specialized hormones that regulate the amount of absorption within the nephron.

5. Structure of the Excretory System • Kidney: • Blood enters the kidneys through renal arteries and leaves through renal veins. • Tubes called ureters carry waste products from the kidneys to the urinary bladder for storage or for release. • During urination, urine is expelled from the urinary bladder through the urethra.

6. Structure of the Excretory System Human excretory system and the details of the kidney and nephron.

7. Structure of the Excretory System • The functional and structural unit of the kidney is the nephron. • The nephron produces urine and is the primary unit of homeostasis in the body. • It is essentially a long tubule with a series of associated blood vessels.

8. Structure of the Excretory System • The upper end of the tubule is an enlarged cuplike structure called the Bowman's capsule. • Below the Bowman's capsule, the tubule coils to form the proximal tubule, and then it follows a turn called the loop of Henle. After the loop of Henle, the tubule coils again as the distal tubule. It then enters a collecting duct, which also receives urine from other distal tubules. • Within the Bowman's capsule is a coiled ball of capillaries known as a glomerulus.

9. Diverse Excretory Systems • In insects, Malphigan tubules function in osmoregulation and removal of nitrogenous wastes from hemolymph • Insects produce a relatively dry waste matter, an important adaptation to terrestrial life.

10. Diverse Excretory Systems • Extracellular fluid is filtered into the flame bulb system in flatworms. • These tubules excrete a dilute fluid and also function in osmoregulation • Each segment of an earthworm has a pair of open ended tubules that collect coelemic fluid and produce dilute urine.

11. The Excretory system word-search! -Urine -Kidney -excretion -eliminated -urinary -urea -urethra -nephron

12. The Excretory System Matching Column! One of a million tiny, filtering structures found in the kidneys that removes wastes from blood and produces urine urea A narrow tube that carries urine from one of the kidneys to the urinary bladder excretion A chemical that comes from the breakdown of proteins and is removed from the body by the kidneys ureters The process by which wastes are removed from the body urethra A small tube through which urine flows from the body nephron

13. The Digestive Tract

14. The Road to digestion • Before our food is processed and released from the anus it has to pass through the various organs • The Path of Food • Mouth Stomach Small Intestine  Large Intestine  Anus

15. The Oral Cavity, Pharynx, and Esophagus • We begin our journey with the mouth • Physical digestion begins with our teeth grinding and smashing our food. This increases the surface area of our food • Next our salivary glands deliver saliva to our oral cavity • Saliva makes our mouths slippery, easier for the food to be swallowed, and contains salivary amylase, an enzyme that hydrolyzes starch and glycogen • Out tongue makes the food into a ball called a bolus. The tongue pushes the bolus into the pharynx

16. When the food travels down the pharynx, the epiglottis is down, covering the windpipe. • The esophagus conducts food from the pharynx down to the stomach by peristalsis.

17. The Stomach • The stomach stores food. • The stomach releases gastric juice. One function of the acid is to disrupt the extracellular matrix that binds cells together in meat and plant material • Also in gastric juice is the enzyme pepsin that begins the hydrolysis of proteins. • Pepsin is secreted in the inactive form called pepsinogen. This allows for the lining of our stomach not to be destroyed from the acidity

18. As a result of mixing and enzyme action, what begins in the stomach as a recently swallowed meal becomes a nutrient rich broth known as acid chyme. • At the opening from the stomach to the small intestine is the plyoric sphincter, which helps regulate the passage of chyme into the intestine, one squirt at a time.

19. The Small Intestine • The small intestine is the major organ of digestion and absorption. • Acid chyme from the stomach mixes in the duodenum with intestinal juice, bile, and pancreatic juice. • Diverse enzymes complete hydrolysis of food molecules to monomers, which are absorbed into the blood and lymph across the lining of the small intestine. • Hormones help regulate digestive juice secretions

20. The Large Intestine • A major function of the colon is to recover water that has entered the alimentary canal as the solvent of the various digestive juices. • The colon reclaims much of the remaining water that was not absorbed in the small intestine • The wastes of the digestive tract, the feces, become more solid as they move along the colon by peristalsis • The terminal portion of the colon is called the rectum, where feces are stored until they can be eliminated. Between the rectum and the anus are two sphincters, one involuntary and the other voluntary.

21. Key Words • anus - the opening at the end of the digestive system from which feces exit the body. • appendix - a small sac located near the start of the large intestine. • esophagus - the long tube between the mouth and the stomach. It uses rhythmic muscle movements (called peristalsis) to force food from the throat into the stomach. • gall bladder - a small, sac-like organ located by the duodenum. It stores and releases bile (a digestive chemical which is produced in the liver) into the small intestine. • large intestine - the long, wide tube that food goes through after it goes theough the small intestine. • liver - a large organ located above and in front of the stomach. It filters toxins from the blood, and makes bile (which breaks down fats) and some blood proteins. • mouth - the first part of the digestive system, where food enters the body. Chewing and salivary enzymes in the mouth are the beginning of the digestive process (breaking down the food). • pancreas - an enzyme-producing gland located below the stomach and above the intestines. Enzymes from the pancreas help in the digestion of carbohydrates, fats and proteins in the small intestine. • rectum - the lower part of the large intestine, where feces are stored before they are excreted from the body. • small intestine - the long, thin winding tube that food goes through after it leaves the stomach. • stomach - a sack-like, muscular organ that is attached to the esophagus. When food enters the stomach, it is churned in an acid bath.

22. DIGESTIVE SYSTEM QUIZ A. B. C. D.

23. A. B. WHICH DIAGRAM DISPLAYS THE CORRECT LABELING OF THE DIGESTIVE SYSTEM? D. C.

24. ORGANISMS WHOSE DIET COSNISTS PRIMARILY OF VEGETABLES WOULD LIKELY BECOME… A. B. Undernourished Obese C. D. Malnourished Overnourished

25. A. An area in the vertebrate throat where air and food passages cross B. Rhythmic waves of contraction of smooth muscle that push food along the digestive tract PERISTALSIS CAN BE DEFINED AS… The portion of the respiratory tube that has cartilagenous rings and passes from the larynx to two bronchi C. D. An integrated group of cells with a common function, structure, or both.

26. Word Bank: • rectum • Small intestine • Large intestine • Pancreas • Liver • Mouth • Esophagus • stomach

27. ANSWER

28. CHECK OUT OUR SOURCES FOR MORE INFORMATION! • Campbell, N, & Reece, J (2005). Biology Seventh edition.San Francisco, C • http://www.enchantedlearning.com/subjects/anatomy/digestive/labeleasy/ • http://www.studystack.com/matching-111474