Digestion Flashcards
Functions of the digestive system
Ingestion
Digestion
Propulsion
Secretion
Absorption
Elimination of wastes
two categories of organs in the digestive system
digestive
accessory digestive organs
Digestive organs
collectively make up the gastrointestinal tract
oesophagus, stomach, small and large intestines
Accessory digestive organs
organs that secrete into the GI tract
teeth, tongue, salivary glands (parotid, sublingual, submandibular), liver, gallbladder, pancreas
oral cavity contains
cheeks, lips, palate
tongue
salivary glands (parotid, sublingual, submandibular)
teeth
main cheek muscle
Buccinator
gums name
gingivae
internal upper and lower lips attach to gingivae
midline mucosa fold; labial frenulum
name the apex of the soft palate
Uvula
opening of the oral cavity and oropharynx
fauces (throat)
lateral boundary of the fauces
paired muscular folds
palatoglossal arch
palatopharyngeal arch
function of the tongue
manipulate and mix ingested materials during mastication. compresses the partially digested materials into a bolus
Bolus
globular mass of ingested materials that can be easily swallowed
attaches the tongue to the floor of the oral cavity
thin, midline mucous membrane; lingual frenulum
Gustation
sense of taste
taste receptors
gustatory cells; housed in specialised organs called taste buds
taste bud location
dorsal surface of the tongue, in elevated epithelial and CT called Papillae
4 types of tongue papillae
Filiform Papillae
Fungiform Papillae
Vallate Papillae
Foliate Papillae
purposes of saliva
moisten ingested material (becomes slick bolus)
moisten, cleanses, and lubricates the structures of the oral cavity
chemical digestion of ingested materials
antibacterial action
dissolves materials so that taste receptors on the tongue can be stimulated
three pairs of salivary glands located external oral cavity
Parotid glands
sublingual glands
submandibular glands
Parotid duct
25-30% saliva
largest salivary gland
runs parallel to the zygomatic arch and pierces the buccinator muscle just opposite the second molar
produces the most amylase
sublingual duct
3-5% saliva
inferior to the tongue
each gland extends multiple tiny sublingual ducts that open onto the inferior surface of the oral cavity just to the submandibular duct papilla
submandibular duct
60-70% saliva
resides inferior to the body of the mandible
transports saliva from each gland through a papilla in the floor of the mouth on the lateral sides of the lingual frenulum
mucin thickener
two types of secretory cells in salivary glands
mucous cells: secretes mucin, which forms mucus upon hydration
Serous cells: secrete watery fluid containing ions, lysozymes and salivary amylase
5 types of secretory cells of the gastric epithelium
Surface mucous cells
Mucous neck cells
Parietal cells
Chief cells
Enteroendocrine cells
What do Surface Mucous cells secrete
Mucin and create mucus
What do Mucous neck cells secrete
create acid mucin
What do Parietal cells secrete
Release HCl (absorb Vit B12)
What do Chief cells secrete
Release Pepsinogen
What do Enteroendocrine cells secrete
release hormone Gastrine into the blood cells around
Fill in the words: Along and at the base of the gastric___are the openings of gastric___that secrete products into the ___
pits, glands, stomach
What finishes the chemical digestion process and is responsible for absorbing most of the nutrients?
Small intestine
How long do ingested materials spend in the small intestine?
12 hours
About how long is the small intestine in an unembalmed cadaver?
6 metres (20 feet)
Why is the small intestine shorter in a living individual than a cadaver?
muscle tone
What are the three specific segments of the stomach? (proximal to distal) What are their lengths?
Duodenum (25cm)
Jejunum (2.5m)
ileum (3.6m)
Where is the duodenojejunal flexure located?
Small intestine between the duodenum and jejunum.
What shape is the duodenum?
C-shaped
In what quadrant would you find the duodenum?
Upper right quadrant
What joins the duodenum and jejunum?
duodenojejunal flexure (midline)
The major duodenal___is the side where ___ and ___ secretions enter the ___
papilla, bile, pancreatic, duodenum.
What is the Jejunum and what is its main function?
Middle segment of the small intestine. Primary region for chemical and nutrient absorption.
What is the ileum?
The last segment of the small intestine
Distal end of the ileum terminates at the___, a___ that controls the entry of materials into the ___
ileocecal valve, sphincter, large intestine
What is a feature of the ___ and ___ tunics that are thrown into folds called the circular folds?
mucosal, submucosal. Visible to the naked eye
What is the scientific name for the circular folds in the small intestine?
Plicae circularis
outer to inner layer, what is the histology of the small intestine? (first is serosa)
Serosa, Muscularis (Outer longitudinal layer, Inner circular layer), Submucosa, Mucosa, Pilcae circularis, villi, microvilli, Intestinal lumen
What are microvilli?
cytoplasmic projections of the individual cells/ extension of the columnar cells
What are villi?
folds of the mucosa
What do enteroendocrine cells do?
Secrete hormones
Spend some time studying the images
Yes mum
Name the small intestine structures involved in digestion and absorption
Circular folds, villi, microvilli, intestinal glands, submucosal glands
Describe the anatomy of microvilli
Folded, finger-like projections of plasma membrane on apical surface of columnar epithelial cells
Describe the anatomy of
