Digestive and Urinary Systems

Human Digestion

Functions of the Digestive System Digestion includes both mechanical and chemical processes. The mechanical portion involves chewing, mashing, and breaking food into smaller pieces. The chemical process involves digestive juices that change food into simpler substances. Digestion- the mechanical and chemical breakdown of foods for use by the body’s cells. Absorption- the passage of digested food from the digestive tract into the cardiovascular system. Elimination- the expulsion of undigested food or body wastes. The Nervous and cardiovascular systems also play a major role in the digestion process. The nervous system triggers the digestive process Nutrients are carried through the body by the cardiovascular system.

Nutrition Process by which organisms obtain and utilize their food. There are two parts to Nutrition: 1. Ingestion- process of taking food into the digestive system so that it may be hydrolized or digested. 2. Digestion- the breakdown of food (either chemically or mechanically) in order to utilize nutrients

Types of Nutrients Micronutrients- vitamins, minerals, & water Macronutrients- proteins, lipids, carbohydrates, etc…

GI (gastrointestinal) tract = alimentary canal

Structures of the Digestive System The digestive process begins in the mouth which consists of the: (TTS) Teeth – break down the food into smaller pieces. This process is called chewing. The tongue – forms chewed food into a size and shape that can be swallowed and mixes it with saliva. The salivary glands – produce the first digestive juices in the digestive process.

mouth break up food digest starch kill germs moisten food

Pharynx The back of the throat. Larynx- passage for air, closes when we swallow. Is approximately 15cm long.

The Esophagus: A Muscular tube about 10 inches long, that connects the pharynx and the stomach. Food moves through the esophagus, stomach, and intestines. Peristalsis: a series of involuntary muscle contractions that moves food through the digestive tract.)

Swallowing (& not choking) Epiglottis flap of cartilage closes trachea (windpipe) when swallowing food travels down esophagus Peristalsis involuntary muscle contractions to move food along

The Pancreas, Liver, and Gallbladder The pancreas creates enzyme that break down the carbohydrates, fats, and proteins in food. The liver produces another digestive juice called bile (yellow-green bitter fluid important in the breakdown and absorption of fats.) Between meals the bile is stored in the gallbladder.

But the stomach is made out of protein! A hollow saclike organ enclosed in a muscular wall. These muscles help break down food into smaller parts. The stomach contains many gastric juices (secretions from the stomach lining that contain hydrochloric acid and enzymes that digest protein.) Holds food for further digestion. As food is digested in the stomach, it is converted into chyme (a creamy fluid mixture of food and gastric juices.) It has 2 sphincters (muscles that control what goes in or out) one between the esophagus and stomach and another between stomach and the small intestine. But the stomach is made out of protein! What stops the stomach from digesting itself? mucus secreted by stomach cells protects stomach lining

The Small Intestine: The Large Intestine ending with rectum and anus: It is 20 to 23 feet in length and 1 inch in diameter. Consists of three parts: the duodenum, the jejunum, and the ileum. Contains millions of fingerlike projections called villi. The Villi contain smaller structures called microvilli. These are important to increase the surface area for absorption. The Large Intestine ending with rectum and anus: It is 2.5 inches in diameter and 5 to 6 feet in length. Absorbs water, vitamins, and salts. Eliminates wastes (stools).

Absorption by Small Intestines Absorption through villi & microvilli finger-like projections increase surface area for absorption

VILLI

Accessory Organs Pancreas Gall Bladder

Pancreas An organ which secretes both digestive enzymes (exocrine) and hormones (endocrine) ** Pancreatic juice digests all major nutrient types. Nearly all digestion occurs in the small intestine & all digestion is completed in the SI.

mouth break up food digest starch kill germs moisten food stomach kills germs break up food digest proteins store food liver produces bile - stored in gall bladder break up fats pancreas produces enzymes to digest proteins & starch

Health Behaviors and the Digestive System Taking care of your digestive system begins with the choices you make about the food that you eat. The following health behaviors will keep your digestive system healthy: Follow a well balanced diet that includes a variety of foods. Wash your hands before preparing a meal and before eating. Eat slowly and chew food thoroughly. Drink at least eight 8 glasses of water each day.

Urinary system anatomy Main structures of the urinary system: kidneys ureters bladder urethra

Anatomy of the Kidney Main structures of renal cortex renal medula renal pelvis Nephrons are the Building units of the Kidney.

Regulating water Antidiuretic hormone (ADH) is part of a negative feedback system that regulates water in our bodies. ADH increases the permeability of the kidneys to allow greater water recovery.

Functions of the Urinary System Kidneys- The organ responsible for blood filtration to remove wastes and form urine. Release hormones to regulate blood pressure and water contents of the body. Nephrons- The functional units of the kidneys. Ureters- tubes that connect the kidneys to the bladder. Bladder- hollow muscular organ that acts like a reservoir for urine. Urethra- the tube that leads from the bladder to the outside of the body. Urine- Liquid waste material.

Health Behaviors and the Urinary System Here are several factors that can help your urine system: Drink at least eight 8 glasses of water each day Eat a well balanced diet Practice good hygiene Have regular medical checkups Avoid caffeine