Chapter 17 Digestive System

I. Introduction A.____________ refers to mechanical (________) and chemical (_________) breakdown of foods so that nutrients can be absorbed by cells. B.The digestive system consists of the ______________ (A.C.), a muscular tube __ meters long leading from the mouth to the anus, and several accessory organs whose secretions aid digestion.

C. Movements of the Tube 1.The motor functions of the alimentary canal are two types: a.. b.. 2._______ movements occur when smooth muscles contract rhythmically in small sections of the tube.

3.Propelling movements include a wavelike motion called _________, which is caused by contraction behind a mass of food as relaxation allows the mass to enter the next segment of the tube.

II. Organs of the Digestive System A._______ 1. First portion of the __________. 2.Receives _______ 3.Begins ___________ digestion by mastication with teeth _____ primary teeth (______) are shed in the order they appeared and replaced by ____ secondary teeth (______ teeth)

4 kinds of teeth: –_________ bite into food –_________ / _________ tear food apart (ex. Meat) –_________ / _________ grind or chew food –_________ grind or chew food 4.Lips contain sensory receptors that judge ___________ and ________ of food. 5.The palates form the roof of the oral cavity and are the _________ _____ palate and the _________ _____ palate

Primary Teeth __ incisors __ cuspids __ molars 17-11

Secondary Teeth 17-12

Section of a Tooth 17-13

6.The soft palate and _______ (hangy ball) function to close off the nasal cavity during swallowing. 7.At the back of the mouth are the _____ and ________ – help to protect the body against infection These are commonly ________ due to chronic illness.

Swallowing Mechanism soft palate and uvula raise hyoid bone and larynx elevate epiglottis closes off top of trachea longitudinal muscles of pharynx contract inferior constrictor muscles relax and esophagus opens peristaltic waves push food through pharynx 17-17

Swallowing Mechanism 17-18

8.Salivary Glands: Secrete ________ To _______ and _______ food particles Bind them together Allow tasting Help to _______ the mouth and teeth Begins the ___________ digestion

B.____________ 1.Cavity lying behind the mouth (upper portion of the throat) C._____________ 1.Muscular tube leading to the _________ 2.Lower ____________ ________ helps to prevent regurgitation of the stomach contents Hopefully no backup of food and ______ in the esophagus

Esophagus 17-19

D.Stomach 1.______________ muscular organ 2.Receives and _____________ food with digestive juices 3.Propels food to small intestines 4.Lower _______ sphincter controls release of food from the stomach into the small intestine 5.Only _________ small amounts of _____ and certain _____, _________, and some _______________________.

Stomach

E.Pancreas 1.Produces ______________ juices that aids digestion 2.Pancreatic juice contains _________ that digest _____________, _________, ________, and ________________.

F.Liver 1.________________ in color & is the ___________ internal organ! 2.Located in upper right quadrant of the abdominal cavity 3.Metabolizes __________, ________, and ____________ 4.Filters the ___________ 5.Removes damaged _________, _________ ___________, and __________ 6.Also secretes _______, a _____________ (breaks down ____ & ______________)

G.Gallbladder 1.____________ sac lying underneath the liver 2.___________ for later release 3.Gall stones Form from insufficient ___________ or excessive ______________ Cholesterol may crystallize into __________

H.Small Intestine 1.Is approximately ten (____) feet long 2.Receives secretions from the _________ and ________ 3.Completes digestion and absorption of nutrients using _________ 4.Transports _______________ waste to the large intestine 5.Has three (___) parts: __________ (_______ inches) __________ (________ feet)

Mesentery suspends portions of the small intestine from the posterior abdominal wall 17-40

Blood vessels (nutrients get into the blood stream)

I.Large Intestine 1.Absorbs _______ and ______________ 2.Forms and stores _________ 3.Has three parts: a)____________ colon (on right side of you; left side on the picture; and it comes from the small intestine’s ileum b)____________ colon (across the top of the small intestine) c)____________ colon (goes down on the left side of your body, and connects to the rectum / anus) 4.__________ here help digestion (ex. Yogurt or cheese)

J.__________ 1.Conveys feces to the anus 2.Both color and odor of feces is due to the action of bacteria (color is from breakdown of bile pigments) K._____________ 1.Opens to the outside as the anus 2.Guarded by an _________ internal anal sphincter and a __________ external anal sphincter muscle L.Vermiform ________________ 1.Prehistorically used to digest wood 2._____________ is a surgery commonly used to remove an inflamed appendix due to bacteria and other substances getting caught inside.