Bio Final - Digestive System

What is the incomplete digestive tract called

gastrovascular cavity

describe the gastrovascular cavity

single opening, food enters and waste enters through the mouth, lacks specialized parts

Give an example of an organism with a gastrovascular cavity

jellyfish

what is the complete digestive tract called

alimentary canal

describe the alimentary canal

two openings, food enters through mouth, exists through anus

give an example of example of organism with alimentary canal

worms, humans

What type of digestive tract do humans

alimentary canal

digestive enzymes are secreted by

lining of digestive tract, nearby glands

What is the oral cavity

the mouth

Where does digestion begin

oral cavity - mouth

What is masticated

chewed

Food is:

chewed by teeth, moistened by saliva

What do salivary glands secrete

amylase and lipase - this begins the digestion of starches and fats

What does the tongue do

it is composed of striated muscle, it mixes chewed food with saliva, and forms mixture into bolus

What is a bolus

a small rounded mass of a substance, especially of chewed food at the moment of swallowing.

What is the pharynx

where digestive and respiratory passages come together

What does the soft palate do

closes off nasopharynx

what does the epiglottis do

covers opening into trachea and keeps food from air passages

What does esophagus do

takes food to stomach by peristalsis

What is peristalsis

rhythmical contraction to move contents in tubular organs

is the human stomach acidic or basic

acidic (1.5-3)

Describe the folds in the stomach wall

folds disappear as the stomach fills to an approximate volume of one liter

What is chyme

food mixed with gastric juices

what is the pyloric sphincter

controls the junction between stomach and small intestine

what happens in the small intestine

digestion and absorption

describe the small intestine

mucous membrane, has ridges and furrows

What are villi

ridges on the surface, which contain even smaller ridges called microvilli

What does villi do

greatly increase absorptive area

What is in the large intestine

cecum, colon, rectum and anus

Describe the large intestine

larger in diameter was shorter in length than the small intestine

What does the large do

absorbs water and salts and some vitamins

Describe constipation

feces are hardened because of excess water removal in the colon

Describe diarrhea

not enough water is removed from the feces

How much of fecal matter is bacteria

1/3

What do accessory do

add secretions that catabolize food into nutrients

What are the accessory organs

salivary glands, liver, pancreas, gallbladder

function of liver

produces bile, processes vitamins and fats and synthesizes many plasma proteins

what is bile

an alkaline digestive juice that is required for the breakdown of fatty components of the food in the duodenum

function of pancreas

makes juice that neutralize the acidic chyme, exiting the stomach and contain enzymes needed to digest protein and carbohydrates

function of gallbladder

aids the liver by storing bile and concentrating bile salts

Where do animals get energy

carbs that turn into glucose which turns to tap

How are starch and glycogen broken down into glucose

amylase and maltase

how are sucrose and lactose broken down

sucrase and lactase

Where does protein digestion take place

stomach

What does pepsin do

breaking down the intact protein to peptides, which are are short chains of amino acids

How are amino acids absorbed

through the small intestines

Where does the bulk of lipid digestion occur

small intestine due to pancreatic lipase

Describe the cephalic phase

neural response to the stimulus provided by food, triggers salivation and gastric juices

describe the gastric phase

begins once the food arrives in the stomach, stimulated by dissension of stomach, decrease in pH of gastric contents, presence of undigested material

describe the intestinal phase

begins when chyme enters the small intestine triggering digestive secretions