EXAM 4 Flashcards
Movement of food from one end of digestive tract to another
Propulsion
include a wave of relaxation of circular muscles in front of the mass of food followed by a wave of contraction behind the mass of food
Peristalsis/ waves
lubricate, liquefy, buffer, digest food. contains large amount of h2o that makes digestion and absorption easier.
secretions
secreted along entire digestive tract, lubricates food and lining of tract (protect epithelial cells)
Mucus
secreted by oral cavity, stomach, small intestine, pancreas
Enzymes
the movement of molecules out of digestive tract and into blood vessels or lymphatic system.
Absorption
is the process of removing waste products of digestion from the body
elimination.
where does elimination occur?
large intestine.
Modification of waste occurs, including reabsorption of water & salts.
Creates semi solid waste, called feces which are eliminated by the process of defecation.
what are the 4 major tunics/layers, from inner to outer?
Mucosa
submucosa
Muscularis
serosa/adventitia
which tunic/ layer is epithelium, stratified squamous in mouth, oropharnx, esophagus & anal canal.
Simple columnar in stomach & intestines ?
mucosa
which tunic/layer has connective tissue with nerves, blood & lymphatic vessels, small glands
submucosa
which tunic/layer has muscle, esophagus also has skeletal muscle
muscularis
which tunic/layer includes connective tissue & simple squamous epithelium ?
serosa
a division of the ANS that controls secretions & movement of digestive system.
The enteric nervous system
Oral cavity is lined with what tissue?
stratified squamous epithelium
Labia (lips) are formed by what tissue?
Orbicularis oris muscle & connective tissue
What is the largest muscular organ in oral cavity?
Tongue
What divides the tongue?
Terminal sulcus divides it into , body and root.
There are two different dental arches in the mouth.
Maxillary and mandibular
Each tooth includes
Crown, neck, and root.
Nerves & vessels enter & exit pulp cavity in teeth through
apical foramen
What surrounds pulp cavity? calcified, living, cellular tissue.
Dentin
What protects tooth from abrasion & acids?
Enamel. covers dentin in crown.
What helps anchor tooth and covers dentin in root ?
cementum.
What is a breakdown of enamel by bacterial acids living on sugars from food?
Dental caries. enamel is non living and cannot repair itself so it requires a dental filling.
What may be required to remove pulp?
root canal
Inflammation of gingiva, often due to food accumlation in crevices
Gingivitis, can lead to periodontal disease. May result in tooth loos and halitosis.
What are the muscle involved in mastication?
Temporalis, masseter
3 salivary glands
Parotid, submandibular, and sublingual.
What protects and contain lysozyme, antibodies, and antibacterial to wash bacteria away?
Saliva
Names of sphincter of esophagus
Has an Upper esophageal sphincter, & a lower esophageal sphincter
Structures that food will pass by through the digestive tract
- Oral cavity
- Pharnyx
- Esophagus
- Stomach
- Small intestine, duodenun, jejunum , ilem
- Large intestine , cecum, colon, rectum, anal, canal, anus
In stomach, submucosa & mucosa are folded into ?
Rugae, which disappear as stomach volume increases
What phase use peristaltic waves to move food down esophagus to stomach?
Esophageal phase
in stomach, mucosa lining is simple columnar epithelium that forms invaginations called
gastric pits, which are openings for gastric glands that secrete acids.
IN stomach, there are 5 types of stomach epithelial cells called
- surface mucous cells - on surface around gastric pits, produce alkaline mucous, protects stomach wall from acid.
- Mucous neck cells- produce mucous, deepest portions of gastric pit near openings to gastric glands.
- Parietal cells- produce HCI & intrinsic factor
- Chief cells- produce pepsinogen & gastric lipase
- Enteroendocrine cells- produce regulatory hormones that influence secretion or motility.
Once food enters stomach, it is mixed with stomach secretions to form what?
Chyme
What do secretions include?
Mucus- viscous alkaline; protects stomach wall from acidic chyme & digestive enzymes
Intrinsic factor - by parietal cells, binds with Vit B12, making it more readily absorbed by ileum.
HCI- by parietal cells- makes stomach acidic
Digestive enzymes- such as pepsinogen & gastric lipase by chief cells.
What does HCI do?
Kills bacteria
denaturing proteins so proteolytic enzymes can reach internal peptide bonds
provides optimal pH for activation & function of pepsin
stops carbohydrate digestion (inactivates salivary amylase)
What do chief cells secrete?
Pepsinogen
Where is pepsinogen packed & released?
Into the lumen of stomach via exocytosis.
HCI & previously formed pepsin molecules convert pepsinogen to what?
pepsin
When is pepsin most effective ?
effective at low pH levels.