Anatomy (Gastrointestinal) Flashcards
What are the 4 functions of the upper GI tract?
Mastication (chewing), taste, deglutition (swallowing) and salivation.
What is the buccinator?
The muscle of the cheek, contraction causes food to move medially.
What of the 8 teeth are which types?
Incisor - 1+2. Canine - 3. Premolars - 4+5. Molars - 6, 7 and 8.
What bone is the head of the condylar process found on?
The mandible.
In the temperomandibular joint (TMJ), where is the head of the condylar process found?
In the mandibular fossa of the temporal bone.
What are the parts of the temporal bone involved in the TMJ?
Mandibular fossa and the articular tubercle.
What nerve supplies the muscle of mastication?
The mandibular division of the trigeminal nerve (CN V3).
What are the 4 muscles of mastication?
Close: temporalis, masseter and medial pterygoid. Open: lateral pterygoid.
What are the attachments of the temporalis muscle?
Coronoid process of mandible to temporal fossa.
What are the attachments of the masseter?
Angle of mandible to zygomatic arch.
What are the attachments of the medial pterygoid?
Angle of mandible (medial side) to pterygoid plates of sphenoid bone.
What are the attachments of the lateral pterygoid?
Condyle of mandible to pterygoid plates of sphenoid bone.
What are the 2 cavities of the TMJs divided by?
An articular disc.
What movements are the inferior and superior cavity for?
Inferior - rotation.
Superior - translation.
What type of nerve fibres does the mandibular division of the trigeminal nerve contain?
Sensory and motor.
What is the course of the mandibular division of the trigeminal nerve?
From pons through foramen ovale to muscle of mastication and sensory area.
What cranial nerve supplied the posterior third of the tongue?
CNIX (glossopharyngeal). Taste and general sensation.
What cranial nerves supply the anterior 2/3rds of the tongue?
Facial CNVII (taste) and V3 (general sensory).
What divides the anterior and posterior tongue?
The terminal sulcus.
What are the papillae with taste buds?
Foliate (folds), vallate (from V shape), fungiform (looks like fungus).
What are the papillae that sense touch and temperature?
Filiform papillae.
What is the course of the facial nerve and what does it supply?
From pontomedullary junction, travels through temporal bone via internal acoustic meatus then stylomastoid foramen. Taste anterior 2/3rds of tongue, muscles of facial expression, glands in floor of mouth.
What is the chorda tympani and what nerve does it connect to?
A branch of the facial nerve. Connects to the lingual nerve (CNV3).
What nerve types does the facial nerve supply the submandibular and sublingual salivary glands with?
Parasympathetic axons .
What cranial nerve supplies general sensation to the superior half of the oral cavity?
CN V2.
What cranial nerve supplies general sensation to the inferior half of the oral cavity?
CN V3.
What cranial nerve carries the sensory part of the gag reflex?
CN IX.
What cranial nerves carry the motor part of the gag reflex?
IX and X.
What happens to the pharynx in the gag reflex?
It is constricted.
What is the course of cranial nerve V2?
From pons through foramen rotundum to sensory area (mid-face).
What is the course of cranial nerve IX (glossopharyngeal)?
From medulla through jugular foramen to posterior wall of oropharynx (sensory), parotid gland (secretomotor) and posterior 1/3rd of tongue (sensation and taste).
What is the surface anatomy of the parotid and submandibular glands?
Parotid: inferoanterior to ear.
Submandibular: below posterior part of mandible.
Where do the ducts of the parotid and submandibular glands go?
Parotid: crosses face, secretes into mouth by upper 2nd molar.
Submandibular: enters floor of mouth and secretes via lingual caruncle.
Where is the sublingual gland and where does it secrete?
In floor of mouth, secretes via several ducts superiorly.
What cranial nerves supply each salivary gland?
Parotid: CNIX. Submandibular and sublingual: CNVII.
What are the names of the 4 pairs of extrinsic muscles of the tongue?
Palatoglossus, styloglossus, hyoglossus, genioglossus.
Where do the extrinsic muscles of the tongue attach other than the tongue?
Palatoglossus - soft palate.
Styloglossus - styloid process.
Hyoglossus - hyoid bone.
Genioglossus - mandible.
What cranial nerve are the tongue muscles innervated by?
CN XII (hypoglossal). Except palatoglossus.
Where are the intrinsic muscles of the tongue mainly located?
Dorsally/posteriorly.
What nerve fibres does the hypoglossal nerve have?
Motor only.
What is the course of the hypoglossal nerve?
From medulla through hypoglossal canal to extrinsic and instrinsic muscles of the tongue
What are the 2 layers of muscle of the pharynx?
An outer layer of circular muscle, an inner layer of longitudinal muscle.
What are the circular muscles of the pharynx called?
Superior, middle and inferior constrictor muscles of the pharynx.
What cranial nerve supplies the circular muscles of the pharynx?
CN X (vagus).
What nerves supply the longitudinal pharyngeal muscles?
CN X and IX.
What is the function of the longitudinal muscles of the pharynx specifically?
They elevate the larynx to close over the laryngeal inlet.
Describe the stages of swallowing.
- tongue pushes bolus of food towards oropharynx (voluntary).
- Soft palate and larynx elevated (involuntary).
- Circular layer of pharyngeal constrictor muscles contracts.
- Bolus of food enters oesophagus and travels inferiorly by peristalsis.
What study can be used to see the shape of the pharynx and oesophagus?
Barium swallow study.
Where does the oesophagus begin?
Inferior edge of cricopharyngeus muscle (vertebral level C6).
What nerve supply does the oesophagus get?
The oesophgeal plexus.
What nerve fibres does the oesophageal plexus contain?
Parasympathetic nerve fibres (vagal trunks) and sympathetic nerve fibres.
What do the nerve fibres in the oesophageal plexus do to change the rate of peristalsis?
They influence the enteric nervous system.
What are the 3 constrictions of the oesophagus?
Cervical constriction (cricopharyngeus muscle), thoracic constriction(s) (arch of aorta, left main bronchus) and diaphragmatic constriction (lower oesophageal sphincter).
Is the lower oesophageal sphincter physiological or anatomical?
Physiological.
What factors produce the sphincter effect?
- Contraction of diaphragm.
- Intrabdominal pressure slightly higher than intragastric pressure.
- Oblique angle at which oesophagus enters the cardia of stomach.
What is the function of the lower oesophageal sphincter?
Reduces occurrence of reflux.
What will reduce the effectiveness of the lower oesophageal sphincter?
A hiatus hernia.
Where is the lower oesophageal sphincter?
Immediately superior to gastro-oesophageal junction.
What is the Z-line?
An abrupt change in type of mucosa lining the wall.
What are rugae?
Folds in the stomach.
In what regions does the stomach lies when the patient is supine?
Left hypochondrium, epigastric and umbilical regions.
What are the 4 main parts of the stomach?
Cardia (just after oesophagus), fundus (superior part), body (most of it) and pyloric antrum (the part near the pylorus/pyloric sphincter).
What organs make up the foregut, midgut and hindgut?
Foregut: oesophagus to mid-duodenum, liver and gall-bladder, spleen, 1/2 of pancreas.
Midgut: mid-duodenum to proximal 2/3rds of transverse colon. 1/2 of pancreas.
Hindgut: distal 1/3rd of transverse colon to proximal 1/2 of anal canal.
What are the 2 transverse planes dividing up the abdominal regions?
Subcostal and transtubecular plane.
From superior to inferior, what are the central regions of the abdomen?
Epigastric, umbilical, pubic.
What are the left and right regions of the abdomen?
Hypochondrium, lumbar, inguinal.
In what condition is there guarding of the anterolateral abdominal wall muscles?
Peritonitis.
What does the peritoneum line?
The walls of the abdominopelvic cavity and organs.
What is the peritoneal cavity between?
The visceral and parietal layers.
What does the peritoneal vacity contain and why?
A small amount of lubricating fluid as the gut moves a lot.
What can blood, pus or faeces in the peritoneal cavity cause?
Peritonitis (severe, painful inflammation of the peritoneum).
What are the 3 classes of organs within the peritoneal cavity?
Intraperitoneal, retroperitoneal or organs with a mesentery (technically intraperitoneal).
How mobile are intraperitoneal organs?
Minimally mobile.
Where does the mesentery suspend an organ from and how mobile does this make them?
The posterior abdominal wall. Very mobile.
Where are retroperitoneal organs located and what surface does visceral peritoneum cover?
The retroperitoneum, its anterior surface.
What are the intraperitoneal organs?
Liver and gall bladder, stomach, spleen, parts of small intestine, transverse colon.
What are the retroperitoneal organs?
Kidneys, adrenal gland, pancreas, ascending colon, descending colon.
What are the 3 types of peritoneal formations?
- Mesentery.
- Omentum (greater and lesser).
- Peritoneal ligaments.
What are peritoneal ligaments?
Double layer of peritoneum connecting organs to one another or body wall.
What is contained in the core of the mesentery?
Blood and lymph vessels, nerve, lymph nodes and fat.
What are the 3 mesenteries?
- Mesentery proper (small intestine).
- Transverse and sigmoid mesocolon.
- Mesoappendix.
How many layers does the greater omentum have and what does it attach to?
4, attaches to greater curvature of the stomach to the transverse colon.
How many layers does the lesser omentum have and where does it attach?
2, runs between lesser curvature of stomach and duodenum to liver.
What divides the peritoneal cavity into a greater and lesser sac?
The omenta.
What is the gap between the 2 sacs called and where is it?
Omental foramen (foramen of Winslow). Free edge of the lesser omentum.
What are the 2 ligaments in the lesser omentum?
Hepatogastric ligament, hepatoduodenal ligament (free edge).
What are the ligaments that connect to the spleen?
Gastrosplenic ligament, splenorenal ligament.
What is the pouch in the male formed by the draping of peritoneum over the pelvic organs?
The rectovesical pouch.
What are the pouches in females?
Vesico-uterine pouch and the rector-uterine pouch (pouch of Douglas).
What is a common cause of ascites?
Liver disease (cirrhosis leads to portal hypertension, similar mechanism to pulmonary oedema).
What is the procedure called where ascitic fluid is drained by the peritoneum?
Paracentesis (abdominocentesis).
Where must the needle be places in paracentesis and why?
Lateral to the rectus sheath to avoid the inferior epigastric artery (ascends in anterior abdominal wall deep to rectus abdominus).
Where does the inferior epigastric artery arise from?
The external iliac artery medial to the deep inguinal ring.
What is often used to guide a paracentesis?
Ultrasound.
What are the 4 main questions to ask in abdominal pain?
- Location?
- Character?
- Timing?
- Pain referral pattern?