Digestive System

alimentary canal components

• mouth

• esophagus

• pharynx

• stomach

• small and large intestine

Accessory organs?

• teeth

• salivary glands

• tongue

• gallbladder

• liver

• pancreas

Six steps of digestion

1. Ingestion

2. propulsion

3. digestion

4. secretion

5. absorption

6. elimination

describe ingestion

• intake of food into body

• beginning of mechanical digestion (mastication)

Explain propulsion

• movement of food from mouth to anus

• deglutition

• peristalsis

Explain Digestion

• mouth performs mechanical digestion by breaking food into smaller pieces

• mouth, stomach, and intestines perform chemical digestion by breaking food into chemical components

Secretion

• lubricate, liquefy, and digest food using enzymes such as amylases, lipases, and proteases

Absorption

• nutrients from food leave digestive tract and enter blood stream

where does absorption mostly happen

small intestines

what body part(s) form mechanical digestion

the mouth

what body part(s) form chemical digestion

mouth, stomach, intestines

elimination

• solid waste is excreted through anus/large intestine

Hard palate is covered in __ to help with movement of food

rugae (ridges)

Soft palate

posterior roof of mouth

hard palate

anterior roof of mouth

Uvula appearance

fingerlike projection in back of mouth

uvula function

closes off nasopharynx during deglutition

tongue contains…

papillae

papillae AKA ___

taste buds

where are incisors, how many incisors do you have

front four of teeth

incisors func

cut into food

cuspids function

pointed for puncturing and tearing

cuspids AKA …

canine

where are molars

behind bicuspids

Two main parts of teeth

root and crown

where is crown located

above gumline

where is the root located

below the gumline

covering layer(s) of teeth

• enamel

• dentin

whats dentin

bone-like material that covers teeth.

pulp contains…

blood vessels

gingiva is. .

tissue surrounding teeth (gums)

name the salivary glands

• parotid

• submandibular

• sublingual

T/F Salivary glands each come in pairs

T

Lysozyme func

kills bacteria

oropharynx function

passes food from mouth to esophagus

where is the laryngopharynx

under and behind passage to throat

what does the epiglottis close during deglutition

trachea and larynx

What’s a bolus

chewed up food

what process moves a bolus

propulsion

where does food enter the stomach

the cardiac sphincter

what does peristalsis form

chyme

what is chyme

partly digested food

where does food exit

pyloric sphinctor

pyloric def + breakdown

pylor - gate - PTT to the pylorus

Where does food exit the stomach

pyloric sphincter

stomach secretions

• mucin

• hcl

• pepsinogen

• intrinsic factor

• chemical messengers

mucin

produces mucus and protects stomach lining

hcl

breaks up connective tissue in food and destroys pathogens

Pepsinogen

uses hcl to make pepsin (protein digestion)

intrinsic factor

vitamin b12 absorption

what are the chemical messengers

gastrin

gastrin function

produces HCL + pepsinogen

Small intestine portions

1. duodenum

2. jejunum

3. ileum

duodenum func

receives food from stomach bule from liver and gallbladder and pancreatic juice

jejunum func

absorbs nutrients from blood stream

ileum func

• vitamin b12 absorption

why is vitamin b12 absorption important

rbc production, metabolism + Nervous system

where does the ileum end

ileocecal valve

why is the ileocecal valve important

prevents backflow from large intestine

portions of the large intestine

connects to ileum and continues to anus to rectum

large intestine functions

• Absorption

• secretion

• digestion

• peristalsis

• elimination

function of absorption in large intestine

• water and electrolyte balance

function of secretion in large intestine

protects intestinal wall and holds fecal matter together

function of digestion in large intestine

bacteria digests any remaining food

supportive structures

• peritoneum

• mesentery

• greater omentum

peritoneum function

lines abdominal cavity

two components of peritoneum + funcs

parietal - lines wall of abdominal cavity

visceral - lines organs

Mesentary def

membrane of peritoneum

greater omentum def

fatty portion of mesentery that hangs in front of intestines

liver is located..

in ruq

liver functions

• make and exrete bile

• remove billirubin

what does production and exretion of bile do

neutralizes acidic chyme and breaks down fats

what’s bilirubin

yellow pigment from rbc breakdown

what does removal of bilirubin do

• stores and releases glucose

• removes toxins from blood

• removes yellow pigment of skin

gallbladder is located on the..

posterior side of liver

bile is transferred from the ____ to the ____

liver to the galbladder

gallbladder func

• stores bile

• moves bile through biliary tract

biliary tract pathway

1. cystic duct + hepatic duct

2. common bile duct

3. duodenum

pancreas is located…

posterior to stomach

are pancreatic juices more basic or acidic, why?

basic to protect duodenum from neutralize acidic HCL

pancreas functions

• produce pancreatic juices

• produce enzymes

what enzymes are produced by the pancrease

• amylase

• lipase

• protease

• insulin

insulin func

sugar absorption.