Digestive System • Outermost layer
Created by:its_nikkii • Consists of the peritoneum (smooth
epithelial layer + underlying CT)
Functions of the Digestive System • Adventitia: connective tissue;
1. Ingestion of food. regions of the DT not covered by the
2. Digestion of food. peritoneum
3. Absorption of nutrients.
Peritoneum
4. Elimination of wastes.
1. Visceral Peritoneum / Serosa: serous
Anatomy and Histology
membrane that covers the organs
• Digestive Tract / Gastrointestinal 2. Parietal Peritoneum: serous
Tract: Oral cavity, pharynx, membrane that covers the wall of the
esophagus, stomach, small intestine, abdominal cavity
large intestine, anus • Mesenteries: CT sheets that hold the
abdominal cavity organs in place
Four Tunics
o Lesser omentum: connects the lesser
1. Mucosa curvature of the stomach to the liver
• Innermost tunic and diaphragm
• Consists of mucous epithelium, o Greater omentum: connects the
lamina propria (loose CT), greater curvature of the stomach to
muscularis mucosae (thin SM layer) the transverse colon and posterior
• Mouth, esophagus, anus: resists body wall
abrasion o Omental bursa: a long, double fold
• Stomach, intestine: absorbs and of mesentery that extends inferiorly
secretes from the stomach before looping
2. Submucosa back to the transverse colon to create
a cavity/pocket
• Thick layer of loose CT, consists of
o Mesentery proper: attaches the small
nerves, blood vessels, small glands
intestine to the posterior abdominal
• Plexus: extensive network of nerve
wall
cell processes (innervated by the
• Retroperitoneal: abdominal organs
autonomic nerves)
that have no mesenteries; duodenum,
3. Muscularis
pancreas, ascending + descending
• Consists of circular SM (inner),
colon, rectum, kidneys, adrenal
longitudinal SM (outer)
glands, urinary bladder
• Enteric nervous system: composed of
the nerve plexuses of the submucosa
and muscularis; controls movement
and secretion within the tract Oral Cavity, Pharynx, and
Esophagus
, Anatomy of Oral Cavity o Enamel: extremely hard, acellular
substance that covers the dentin of
• Bounded by the lips and cheeks;
the tooth crown
contains the teeth and tongue o Cementum: covers the surface of the
o Lips: muscular structures formed by dentin in the root; anchors the tooth
the orbicularis oris muscle in the jaw
o Cheeks: buccinators muscles flatten
o Alveoli (along the alveolar process
the cheeks against teeth
of mandible x maxillae): where the
o Mastication: begins the process of teeth are rooted
mechanical digestion o Gingiva: dense fibrous CT and most
o Tongue: plays a major role in the stratified squamous epithelium that
process of swallowing; major
covers the alveolar processes
sensory organ for taste; one of the
o Periodontal ligaments: CT fibers that
major organs of speech extend from the alveolar walls that
o Frenulum: thin fold of tissue inferior hold the teeth in place
to the tongue o Dental caries / Tooth decay: result of
Teeth the breakdown of enamel by acids
produced by bacteria on tooth
• 32 teeth in normal adult mouth surface
• Located in the mandible and o Periodontal disease: inflammation x
maxillae degeneration of the periodontal
1. Incisor: to cut ligaments, gingiva, alveolar bone
2. Canine: to tear
3. Premolars Salivary Glands
4. Molars • Produce saliva (serous + mucous
5. Wisdom teeth: third molars fluids)
• Permanent teeth: secondary teeth o 3 Pairs of SG
• Primary teeth: deciduous teeth; milk 1. Parotid glands: largest; serous glands
or baby teeth located anterior to each ear
• Parts: 2. Submandibular glands: produce
o Crown more serous than mucous secretions
o Cusps 3. Sublingual glands: smallest; produce
o Neck primarily mucous secretions
o Root • Mumps: inflammation of the parotid
o Pulp cavity: center of the tooth; gland caused by viral infection
contains blood vessels nerves, and
pulp (connective tissue) Saliva
o Dentin: bonelike tissue that • Helps keep the oral cavity moist
surrounds the pulp cavity • Contains enzymes that begin the
process of digestion