Digestive System- Taylor 2 Flashcards
Where does the sphenomandibular ligament connect to the mandible?
Sphenoidal spine to lingula of mandible
Is the digastric muscle one of mastication?
No!
Where do the mandible’s nerves and BVs travel?
Mandibular foramen
What is the head of the mandible called?
Condylar process
What type of joint is the TMJ?
Synovial joint
What structures does the TMJ lie between?
Condylar process
Mandibular fossa
Articulate tubercle (temporal)
How is the bone lining of the TMJ different from other synovial joints?
Fibrocartilage lining as opposed to hyaline cartilage lining
What is synovial fluid?
A distallate of blood plasma
What is the articular disc made of?
Fibrocartilage
When the jaw is widely depressed, the condylar process and articular disc move :
: anteriorly
Where does the mandible lateral ligament run?
From zygomatic arch to neck of mandible
Where does the mandible stylomandibular ligament run?
Styloid process of temporal bone to angle of mandible
What is the projection of bone near the mandibular foramen of the medial aspect of the mandible neck called?
The lingula
Where does the temporalis muscle originate?
From the temporal fascia of temporal fossa
Where does the temporalis muscle insert the mandible?
On top of coronoid process
Primary action of the temporalis
Elevation
Secondary action of the temporalis
Retrusion
Grinding
Where does the masseter muscle originate?
The zygomatic arch
Where does the masseter muscle insert the mandible?
Lateral side of mandibular ramus
Primary action of masseter
Elevation
Secondary action of the masseter
Protrusion
Retrusion
Where does the lateral pterygoid muscle originate?
Sphenoid bone at roof of infratemporal fossa
Lateral surface of sphenoid lateral pterygoid plate
Where does the lateral pterygoid muscle insert the mandible?
Pterygoid fovea of mandibular neck
Articular disc
Primary action of lateral pterygoid
Depression
Secondary action of lateral pterygoid
Protrusion
Grinding
Where does the medial pterygoid muscle originate?
Medial surface of sphenoid’s lateral pterygoid plate
Maxillary tuberosity
Where does the medial pterygoid insert the mandible?
Medial side of ramus
Primary action of medial pterygoid muscle
Elevation
Secondary action of medial pterygoid muscle
Protrusion
Grinding
What branch of CN V3 receives sensory branches to TMJ?
Auriculotemporal branch
What artery does the auriculotemporal revert wrap around?
Middle meningeal artery
4-layered structure of GI (inner to outer)
Mucosa
Submucosa
Muscularis externa
Serosa
Mucosa contents
Mucosal glands (usu)
Muscularis mucosa
GALT
What type of CT is the submucosa?
Dense irregular CT
Which layer is the main pathway and location for the largest BVs?
Submucosa
Submucosa contents
Some submucosal glands
Where is Meissner’s nerve plexus and what does it do?
Between mucosa and submucosa
Sends branches inward to control muscularis mucosa (autonomic) and branches outward to control submucosal glands (secretion)
Muscularis externa contents
Inner circular smooth muscle layer
Outer longitudinal smooth muscle layer
Where is the myenteric nerve plexus of Auerbach located?
Between the circular and longitudinal muscle layers of the muscularis externa
When is the outer layer considered serosa?
If covered by peritoneum
What is visceral peritoneum composed of?
Mesothelium
Loose CT
When is the outer layer considered adventitia?
When that portion of the organ is not covered by peritoneum
The esophagus is between what?
Larynx
Stomach
Where do the fibers of the two vagus nerves intermix with sympathetics?
Abdominal esophagus
Forms prevertebral nerve plexus (where prevertebral ganglion are)
Sites of esophageal constriction
Upper, at junction with pharynx
Aortic arch
Left primary bronchus
Lower, at esophageal hiatus
Does absorption occur in the esophagus?
No!
What type of epi is esophageal mucosa?
Stratified squamous nonkeratinized
Where are most of the multicellular mucosal glands of the esophagus located?
Upper and lower esophagus
What type of muscle is the upper third of the esophagus muscularis externa?
Striated muscle
What type of muscle is the middle third of the esophagus muscularis externa?
Mix of striated and smooth muscle
What type of muscle is the lower third of the esophagus muscularis externa?
Smooth muscle only
Epi cell type change at esophagohastric junction
stratified -> secretory simple columnar
Where does the esophagus attach to the stomach?
At the cardial oriface
Parts of stomach
Cardiac
Fundus
Body
Pyloric
What is the pyloric sphincter?
A thickening of the circular muscle layer of the muscularis externa
Greater curvature of stomach
Inferior
Convex
Lesser curvature of stomach
Superior
Concave
Structure to left of stomach
Spleen
Structure posterior to stomach
Lesser sac -> pancreas
Structure inferior to stomach
Greater omentum
What is omentum?
Peritoneum extensions
A way of connecting organs
What is the lesser sac?
Gap between pancreas and stomach
What is the greater omentum?
Peritoneum that provides fat curtain
Cnx stomach to transverse colon
What is the lesser omentum?
Peritoneum extension between liver and lesser curvature of stomach
Cnx stomach and liver
What are rugae?
Wrinkles of mucosa with submucosal cores on internal surface of stomach
What type of epi lines the stomach mucosa?
Simple columnar
What’s the name of these epi mucosal cells and what do they do?
Surface mucous cells
Provide lubrication and protection from highly acidic environment
Where are stomach glands located?
Lamina propria
Where is the base of a fundic gland located?
Near muscularis mucosa
Which part of the fundic gland leads into the gastric pit?
Isthmus
Types of cells that line the fundic glands
Parietal Mucous neck Stem Chief Enteroendocrine
Where are parietal cells found in the fundic gland?
Throughout all three parts
What do the parietal cells of the fundic gland do?
Secrete HCl and IF
Where are mucous neck cells located in the fundic gland?
Between parietal cells in the neck
What do the stem cells of the fundic gland do?
Give rise to all cells of the gland and surface mucosa
Where are chief cells located in the fundic gland?
Throughout, mainly in base though
What do chief cells of the fundic gland do?
Have abundant RER
Convert pepsinogen to pepsin
Where are enteroendocrine cells located in the fundic gland?
On the basal lamina
What do the enteroendocrine cells of the fundic glands do?
Secrete hormones to the underlying BVs
Oblique layer of stomach muscularis externa
Most inner
Discontinuous
Circular layer of stomach muscularis externa
Middle layer
Becomes thick at pyloric sphincter
Longitudinal layer of stomach muscularis externa
Most outer
Thicker at curvatures
What is the main absorptive organ of the tract?
The SI
What is the shortest, widest, and most fixed part of the SI?
Duodenum
What does the duodenal cap do?
Attach the SI to the stomach
What does the descending duodenum do?
Receives hepatopancreatic ampulla
Where does the junction between the developing foregut and the hind gut occur?
Major duodenal papilla
Sizes of jejunum and ileum
J: upper 2/5 of 6m
I: lower 3/5 of 6m
Which is thicker and with wider lumen?
Jejunum
What do the circular folds of the jejunum do?
Along with intestinal villi, increase SA
Why is the jejunum more red in color than the ileum?
The jejunum has a different arterial distribution pattern than the ileum
SI mucosa contents
Goblet cells Villi Microvilli Crypts of Lieberkuhn Peyer's patches
What type of epi makes up the SI mucosa?
Simple columnar epithelium
Where are red blood capillaries and lacteals found in the SI?
In the lamina propria of the villi of the mucosal layer
Where does brush border digestive enzyme reside?
On microvilli of SI mucosa layer
What types of complexes are formed between absorptive cells of SI?
ZO, ZA, desmosomes
What types of cells line the crypts of Lieberkuhn?
Absorptive cells Goblet cells Paneth cells Stem cells Enteroendocrine cells
What do paneth cells of the SI do?
Reside at gland base and secrete antibacterial lysozyme (regulate bacterial flora)
What type of cells make up most of the lower intestinal gland of the SI?
Stem cells
Where are Peyer’s patches of the SI found?
Lampro of ileum
What are microfold cells?
Cells that line the intestinal surface over lymphatic nodules
What microfold cells of the SI mucosa layer do?
Pinocytize antigenic proteins
What substances do the Brunner’s glands of the duodenum submucosa secrete?
Alkaline
Lysosymes
IgA antibodies
Structures in LI not present in SI
Taenia coli
Haustra
Omental appendices
Large diameter
What are taenia coli?
Muscularis externa organized into 3 bands of longitudinal muscle
What are haustra?
Folds to keep the short taenia within it
What is the blind-ended first part of the LI?
Cecum
Contents of lampro and submucosa contents
Lymphatic nodules
The name do the bending of the ascending colon
Right colic hepatic flexure
Transverse colon barriers
Right colic hepatic flexure and left colic splenic flexure
What apart of the colon contains the division of the mid and hind guts?
Transverse colon
Blood supply to midgut parts
Superior mesenteric artery
Blood supply to hind gut parts
Inferior mesenteric artery
Histology of colon
No villi
No circular folds
Muscularis externa with inner circular muscle and outer taenia coli
Main cells of the surface and intestinal crypts of Lieberkuhn in the LI
Absorptive columnar
Goblet cells
Type of epi lining rectum
Simple columnar epi
Changes that occur at sigmoid-rectal junction
- Taenia spread into one continuous layer of longitudinal muscle
- Haustra absent
What structures form the portal-systemic anastomosis?
Inferior mesenteric venous vessels (hepatic portal vein)
Internal iliac venous branches (inferior vena cava)
Type of epi in mucosa of upper end of anal canal
Stratified squamous epi
Type of epi in mucosa of lower end of anal canal
Stratified squamous keritinized epi with apocrine glands
From where do the two anal sphincter muscles form?
From the circular muscle of the muscularis externa
