Digestive System Sports Training and Physiology Kociuba http

Digestive System Sports Training and Physiology Kociuba http: //kidshealth. org/Page. Manager. jsp? lic=1&article_set=59299&cat_id=20607

Digestive System - Objectives l l Describe the function of the digestive system Starting with the mouth describe the process of swallowing Explain the whole process of digestion from chewing to excretion Discuss the age-related changes that happen to this system

Function of the Digestive System l Take in food l l l Through the mouth Absorb nutrients l Break down the food from complex molecules to simple l l Mechanical Digestion l Chewing and mixing Chemical Digestion l Enzymes mix to breakdown food further l Simple molecules that were broken down now are absorbed through the walls of the small intestine and used throughout the body Eliminate waste l We do not use all of the food taken in, just what is needed. What is not used is waste and is excreted out of the body

The Digestive System and the Nervous System l The ENS or enteric nervous system is made up of enteric plexus which are sensory neurons which connect the digestive system to the CNS and ANS l l l It helps in moving food through the digestive tract by stimulating smooth muscle Detects chemical changes and causes secretions of enzymes to aid in the digestive process Connects motor neurons to sensory neurons in the digestive system

How do we swallow? l Three phases l l l Voluntary phase: the ball of food we chew (bolus) is pushed to the back of the mouth by our tongue Pharyngeal phase: when it gets to the back of the mouth receptors receive the food and push it further down and the pharyngeal constrictor muscles take over the food down the pharynx Esophageal phase: the swallowing phase takes about 5 -8 seconds and is responsible for getting the food from the pharynx to the stomach

Structure/Anatomy l Digestive Tract l l Tube extended from the mouth to the anus with other organs attached to secrete fluids that aid in the digestion process Gastrointestinal tract (GI tract) is often a synonym, but should only refer to the stomach and intestine

Structure/Anatomy l Oral Cavity l l l Pharynx Salivary Glands l l Contain teeth for manual breakdown of food Secrete enzymes for breakdown of food Esophagus

Structure/Anatomy l Stomach l l Fundus: top part Body: main part Pyloric: joins to small intestine Gastric Juice l Chyme

Structure/Anatomy l Small Intestine (6 m long) l l Duodenum Jejunum Ileum Peristaltic Contractions and Segmental Contractions move the food through the small intestine l Liver l l l l Largest internal organ Produces and stores bile in the gallbladder Stores glycogen Nutrient interconversion Detoxification Phagocytosis Synthesis

Structure/Anatomy l Large Intestine l l l Pancreas l l Part of endocrine system as well Secretes enzymes that aid in the breakdown of all food and proteins in particular l l l Cecum Colon Rectum Anal canal While here, chyme turns into feces

Digestion, Absorption, and Transport Digestion: breakdown of food Absorption: uptake of digestive tract contents by the lining of the tract Transport: the distribution of nutrients throughout the body