Histology: GI Tract Flashcards
(200 cards)
What are the two portions of the digestive system?
The alimentary canal and associated/accessory digestive organs
Alimentary canal is also called ______.
The GI tract
What are the organs of the alimentary canal?
Mouth, most of pharynx, esophagus, stomach, small intestine, large intestine
What are the associated/accessory organs of the digestive system?
Tongue, teeth, salivary glands, liver, gallbladder
What are the two functions of the associated/accessory organs of the digestive system? Which organs did which function?
Physical breakdown (come in contact with food): tongue, teeth
Secretions (never contact food, secretions reach GI via ducts, good for chemical breakdown): salivary glands, liver, gallbladder
How long is the GI tract in a cadaver vs. living human?
9meters (30feet) in cadaver
Shorter in living humans because smooth muscle contractions
Food in the lumen of the GI tract is ____ the body
outside
What are the 8 processes of the GI tract?
- Ingestion
- Secretion
- Mixing/propulsion
- Digestion (chemical and mechanical)
- Absorption
- Defacation
- Barrier
- Immunological
Describe the ingestion process of the digestive system
Eating/drinking
Describe the secretion process of the digestive system. how much do we secrete a day through GI?
secretions by glands
we secrete 7L of “stuff” a day - water, hydrochloric acid, buffers, enzymes, mucous
Describe the mixing/propulsion process of the digestive system
smooth muscle moves food downward and also works to break down the food particles
Describe the digestion process of the digestive system
mechanical digesiton: breaks down food into smaller pieces of food (still food) so they have high surface area
chemical digestion: enzymes break bonds of macromolecules to make them micromolecules so that they may cross membrane into body
Describe the absorption process of the digestive system
takes place primarily in the small intestine
Describe the defacation process of the digestive system
defecation of feces
Describe the barrier process of the digestive system
Mucosa is the epithelial lining of the mucous membrane in the GI tract. Mucosa is very selective
Describe the immunologic protection process of the digestive system
when things cross the mucosa epithelial lining of the mucous membrane of the GI tract, the lymph along the mucosa is the first line of defense
Mouth aka ___ aka ____
Mouth aka oral cavity aka buccal cavity
What is the oral cavity bounded by?
Cheeks, hard/solf palate, tongue, floor of mouth
What muscle is in the lips?
Orbicularis oris muscle (skeletal muscle)
What is the posterior aspect of the oral cavity? What does it open into?
The fauces open into the oropharynx
What are the two parts of the oral cavity? describe them both.
- Vestibule: between lips/teeth and between cheeks/teeth
- Oral cavity proper: superior border of hard/solf palate; inferior border of tongue/floor of mouth; posterior border of fauces to oropharynx; all other borders are teeth
What is bolus?
Semi-solid mass of food
“Food” is not what is swallowed in the GI tract.
“Bolus” is swallowed
Describe enamel
96-98% HA crystallites
acellular, mineralized tissue without collagen
Describe central pulp cavity
loose connective tissue that is highly vascularized