Digestive System Flashcards
what is digestion
The mechanical and chemical breakdown of food and the absorption of the resulting nutrients by the body’s cells
what are the two parts of the digestive system
Alimentary canal - muscular tube extending from the mouth and anus
Accessory digestive organs - everything else involved in the process of breaking food down in smaller molcules for absorption
How long is the Gastrointestinal tract
5-7 meters
What is included in the alimentary canal
Mouth,Pharynx,Oesophagus,Stomach,Small intestine,Large intestine,Rectum,Anus
What is included in the accessory organs
Inside - Teeth and Tongue
Outside - Salivary glands, Liver,Pancreas and Gall bladder
What are the 6 stages of Digestion
Ingestion
Mechanical digestion
Propulsion
Chemical digestion
Absorption
Elimination
What is ingestion
ingestion takes place in the mouth where food or liquids enter
What is mechanical digestion
involves chewing (mouth),churning (stomach) and segmentation (small intestine).
What is propulsion
this is include swallowing voluntary and peristalsis involuntary - esophagus,stomach,small intestine and large intestine process is where food is pushed through the alimentary canal
What is chemical digestion
uses certain enzymes to break down nutrients such as carbohydrates,proteins and fats into smaller molecules. into the lumen of the alimentary canal come from the accessory organs e.g pancreas and gall bladder.
What is absorption
The process of taking nutrients from the digestive system into the blood so they can be used in the body through the small intestine by active or passive transport
What is elimination
The removal of indigestible wastes through the anus, in the form of feces, is defecation or elimination.
What is segmentation
Happens in the small intestine it mixes food and digestive juices making absorption more efficiently due to moving food all over the walls of the intestine breaking it down further
What is peristalsis
is the contraction and relaxation of waves allowing food to go down alimentary canal
What is basic structure of the GI tract
The layers of the GI tract are broadly the same alll the away from the oesphagus to the anus but the mouth and pharyx are to function differently
What are the four layers of the GI tract
Serosa
Muscularis
Submucosa
Mucosa
What is the mucosa layer
Made up of three layers that secret digestive enzymes,hormones,mucus and absorbs nutrients. protects the alimentary canal - small intestine produce serotonin
What are the variations of epithelial tissues in the alimentary canal
Stratified sqaumous epithelium - short fat cells which are in the mouth,oesphagus,oropharynx and anal canal
Columnar - tall which is everywhere else
What is the lamina propria
it has lots of capillaries and are in the muscosa layer - absorption of nutrients
What is the mucosa associated lymphoiod tissues
Reservoirs for the immune system waiting for pathogen for when a pathogen re enters retains the genetic information
What is muscularias
two layer longitudinal and circular muslces which are used to push down the food through the process perisalsis and segmentation
What is the submucosa layer
is made up of loose areolar connective tissues binds and supports organs and to provide flexibility contains glands and blood vessels has elastic layers to allow stretches
What is the serosa
outer layer covers the abdomen and throax produce serous fluid that lubricates all the area allows for movements
What is the buccal cavity
within the buccal cavity are teeth that is used i mastication of food chewing use of tongue to probe our food with saliva to swallow into a bolus primary breaks down starch but to also lubricate.Saliva protects the inside of the mouth
Mouth features
Parotid salivary - gland lies in front of the ear
Salivary duct - opens into the cheek
Sublingual salivary gland - located under the tongue
Sub-mandibular - deep in the mouth