BIOL 102 FINAL EXAM STUDY GUIDE / BIOL102 FINAL EXAM STUDY GUIDE:LATEST-LIBERTY UNIVERSITY

BIOL 102 FINAL EXAM STUDY GUIDE


The Digestive System and Nutrition
Digestive System Brings Nutrients into the Body
 The Digestive System includes:
o Gastrointestinal (GI) tract (Hollow tube)
 Lumen: space within this tube
 Includes mouth, pharynx, esophagus, stomach, small intestine, large intestine,
rectum, anus
o Accessory Organ
 Salivary glands, liver, gallbladder, pancreas

Walls of the GI Tract are Composed of 4 Layers
 Common layers throughout the system
o Mucosa: Innermost layer, mucous membrane in contact within the lumen
o Submucosa: Layer of connective tissue containing blood vessels, lymph vessels, nerves
o Muscularis: 2 or 3 layers of smooth muscle, responsible for movement, motility
o Serosa: Outermost layer
 Sphincters: Thick muscular rings that separate some of the organs
 Stomach has 3 layers, whereas everything else in the digestive tract has 2 layers.

5 Basic Processes Accomplish Digestive System Function
1. Mechanical Processing and Movement
 Chewing and mixing
2. Secretion
 Fluid
 Digestive enzymes and hormones
 Bile, acid, alkali, mucus
3. Digestion
 Breaking down food to smallest absorbable units
 Chemical and mechanical breakdown
4. Absorption
 Through mucosa
 Into blood or lymph vessels
5. Elimination
 Undigested material eliminated

2 Types of Motility Aid Digestive Processes

,  Motility enabled by smooth muscle in the muscularis layer
 Peristalsis: propels food forward
 Segmentation: Mixes food



The Mouth Processes Food for Swallowing
 Teeth: Bite and chew food
o Types: Incisors, canines, premolars, molars
 Children: 20 teeth
 Adults: 32 Permanent Teeth
o Structure: Crown, root
 Tongue: Positions and taste food
o Skeletal muscle
o Moves food in mouth
o Taste
o Important for speech
 Saliva
o Salivary Glands
 Parotid
 Submandibular
 Sublingual
o Composition
 Mucin, salivary amylase, bicarbonate, lysozyme

Pharynx and Esophagus Deliver Food to the Stomach
 Swallowing
o Voluntary phase: tongue pushes bolus of food into pharynx (throat)
o Involuntary phase: swallowing reflex
 Pharynx: Common passageway for air and food
 Epiglottis: Closes airway temporarily so food will not enter the trachea
 Food moves through esophagus with the help of peristaltic contractions
 Food passes through lower esophageal sphincter into the stomach

Stomach Functions
 Food storage
 Digestion of proteins
 Regulation of delivery of partially digested food into the small intestine

Gastric Juice Breaks Down Proteins
Specific cells secrete gastric juice, which contains

 Hydrochloric Acid