GI Flashcards
At which part of the duodenum does the foregut end?
The junction between the second and third part.
Which layer/s of the trilaminar disk is the primitive gut tube formed from?
Endoderm and visceral mesoderm.
What are the pharyngeal arches formed from?
Masses of mesenchymal tissue (connective tissue derived from mesoderm) which are invaded by cranial neural crest cells.
What is the difference between the pharyngeal clefts and the pharyngeal pouches?
Clefts are the external parts which are covered with endoderm.
Pouches are the internal parts which are covered with ectoderm.
What bones and muscles does the first pharyngeal arch give rise to?
What is its innervation?
MUSCLES:
mastication, tensor tympani, digastric, mylohyoid
BONES:
maxilla, mandible, incus, malleus
INNERVATION = MANDIBULAR BRANCH OF TRIGEMINAL NERVE (CNV3)
What bones and muscles does the second pharyngeal arch give rise to?
What is its innervation?
MUSCLES:
Facial expression, stapedius, stylohyoid
BONES:
stapes, styloid and lesser horn of hyoid cartilage
INNERVATION = FACIAL NERVE (CNVII)
What bones and muscles does the third pharyngeal arch give rise to?
What is its innervation?
MUSCLES:
stylopharyngeus
BONES:
body and greater horn of hyoid cartilage
INNERVATION = GLOSSOPHARYNGEAL NERVE (CNIX)
What bones and muscles does the fourth pharyngeal arch give rise to?
What is its innervation?
MUSCLES:
cricothyroid
BONES:
thyroid cartilage and epiglottic cartilage
INNERVATION = EXTERNAL BRANCH OF SUPERIOR LARYNGEAL NERVE (CNX)
What bones and muscles does the fifth pharyngeal arch give rise to?
What is its innervation?
THERE ARE NO FIFTH ARCHES
What bones and muscles does the sixth pharyngeal arch give rise to?
What is its innervation?
MUSCLES:
intrinsic muscles of the larynx (except cricothyroid)
BONES:
cricoid cartilage, arytenoid cartilages, corniculate and cuneiform cartilages
INNERVATION = RECURRENT LARYNGEAL NERVE (CNX)
Define ligament, in terms of the gastrointestinal system.
Double layer of peritoneum which pass from one organ to another, or from one organ to the body wall.
Describe the rotation of the stomach.
During the 7th week the stomach rotates 90 degrees clockwise around a longitudinal axis.
What initiates swallowing?
Pressure receptors in the walls of the pharynx.
Which nerve innervates the pharyngeal constrictor muscles?
Vagus nerve (CNX)
Which type of muscle forms the upper oesophageal sphincter?
Skeletal muscle
Briefly describe the gag reflex.
Irritation of the oropharynx at the back of the tongue stimulates the glossopharyngeal nerve (CNIX). Vagus nerve (CNX) causes reflex elevation of the pharynx. This is often followed by vomiting.
What is an alternative name for the parotid duct?
Stenson’s duct
What are the surface markings of the parotid gland?
Zygomatic arch
Sternocleidomastoid
Ramus of mandible
What muscle does the parotid duct cross in front of?
Masseter muscle
What is an alternative name for the submandibular duct?
Wharton’s duct
Which muscle is intimately related to the submandibular gland?
Mylohyoid
Describe the drainage of the sublingual gland.
Drains into Wharton’s duct as well as small ducts that enter directly into the floor of the mouth.
What are Von Ebner’s glands and where are they found?
Minor SEROUS salivary glands underlying the circumvallate papillae.
Are the minor salivary glands serous or mucinous?
They are all mucinous except for the serous glands of Von Ebner.
