chap 11: digestive system

digestion

• an enzyme-facilitated chemical process

• series of chemical reactions, whereby the ingested food is converted into smaller and smaller molecular forms

absorption

small molecular forms are absorbed through the cells of digestive system and pass into blood or lymphatic vessels

liver

large organ located to the right of the stomach that secretes bile for breaking down fats

pancreas

organ that lies behind the stomach and produces insulin and glucagon

• has 3 digestive enzymes: lipase, amylase, and trypsin to make pancreatic juice

• produces bicarbonate

mouth

mechanical and chemical digestion

teeth, saliva with amylase

esophagus

muscular tube that moves food to stomach. uses peristalsis

stomach

chemical and mechanical digestion

Contains HCL, mucus and pepsin

small intestine

finishes digestion and does absorption.

uses villi to increase surface area

large intestine

removes water, minerals, and vitamins

contains bacteria and undigested materials

gallbladder

stores bile with duct to small intestine

green sac

label the diagram

a- mouth

b- liver

c- gallbladder

d- small intestine

e- anus

f- esophagus

g- stomach

h- pancreas

i- large intestines

j- rectum

how the inner structure of small intestine relates to its function of absorption

The inner structure of the small intestine includes villi, small folds that absorb molecules from the lumen, and microvilli, projections that increase surface area for absorption. Each villus also contains a lacteal that absorbs fatty acids and some nutrients.

explain what is absorbed by the large intestines

minerals, vitamins, and water

explain the 3 roles of hydrochloric acid in the digestive process

1. The HCl denatures the 3D protein, and breaks down the hydrogen and ionic bonds, which opens up the protein so that digestive enzymes access peptide bonds

2. Activating pepsinogen to pepsin

3. Control the ingestion of some pathogens

scurvy

serious deficiency disease when vitamin C is not consumed over an extended period of time

rickets

develops when there is insufficient supply of vitamin D and/or Ca⁺

State the order of the digestive system organs that food travels through

mouth to esophagus to stomach to small intestine to large intestine to rectum to anus

leptin

sends message to hypothalamus to suppress appetite

gastrin

hormone that enters the blood and is carried to other cells elsewhere in the stomach and results in higher secretion of HCl and pepsinogen