Anatomy Flashcards
Which suture is thought to be particularly pronounced due to more complex bio mechanical forces at this site?
Lambdoid suture
How may the lambdoid suture be identified?
Due to its very characteristic jagged appearance
How may the squamous suture be identified?
Due to its thin and non-jagged appearance
In a developing foetus and at birth, why does the neurocranium develop faster than the viscerocranium?
Neurocranium develops faster due to the level of brain development and growth that is required to sustain some early basic reflexes
Why are the orbits so disproportionately large in fetal skulls?
The eyes are an extension of the brain and are precociously large at birth, therefore requiring a large orbit
Which Fontanelle is last to close? And when?
Anterior fontanelle which closes between 18 months - 2 years old
In a fetal skull, why is there a lack of any substantial aspect to the mastoid part?
Due to the limited muscle mass associated with the SCM muscle in the infant
How many bones make up the developing occipital bone?
4 bones:
- 1 squamous
- 2 lateral
- 1 basilar
What is the ‘foramen of Huschke’?
A developmental defect in the antero-inferior aspect of the bony external auditory meatus
At what typical rate is saliva produced in the oral cavity?
1200mL/day
While eating what happens to the quantity of saliva?
It increases
While sleeping, what happens to the quantity of saliva?
It decreases
what are the five functions of saliva?
- Prevent dehydration of oral mucosa
- Lubrication of mastication and swallowing
- Maintaining proper dental hygiene
- Assist in digestion of carbohydrates
- Act as a solvent for taste and smell
What nervous system supplies salivation?
The autonomic nervous system
What type of saliva is produced by the sympathetic nervous system?
‘Sticky’ saliva
What type of saliva is produced by the parasympathetic nervous system?
‘Runny’ saliva
What is the periarterial plexus?
A network of sympathetic nerves that travel to salivary glands on the surface of arteries
Via what nerves does the parasympathetic nervous system supply salivary glands?
Cranial nerves: CN VII and CN IX
What are stimulatory factors that encourage salivation?
- smell
- taste
- nausea
- conditional reflexes
- pain (teething)
What are inhibitory factors that discourage salivation?
- fatigue
- sleep
- fear
- dehydration
- exercise
What are the three major salivary glands?
- parotid
- submandibular
- sublingual
Where does the parotid gland drain saliva? And via what structure?
Drains near 2nd maxillary molar and via parotid papilla
Where does the submandibular gland drain saliva?
Drains to sublingual caruncle
Where does the sublingual gland drain saliva? And via what structure?
Drains superior into FOM via sublingual fold
what major salivary gland is the largest?
The parotid gland
Which major salivary gland is rich in amylase and produce 25% of daily saliva?
The parotid gland
which layer of deep cervical fascia extends up onto the face and encapsulates the parotid gland?
Investing layer
What are the contents of the parotid gland/region?
- facial nerve plexus
- retro mandibular vein ( superficial temporal vein + maxillary vein)
- external carotid artery ( superficial temporal artery + maxillary artery)
What is the parotid bed?
Structures upon which the parotid gland lie
What are the structures that make up the parotid bed?
- styloid process of temporal bone
- sternocleidomastoid
- stylohyoid
-posterior belly of digastric - masseter muscle
- posterior border of mandibular ramus
Through what foramen does CN IX exit the skull?
Jugular foramen
Where do parasympathetics to parotid gland arise from?
CN IX
What branch of CN IX passes through the petrous part of the temporal bone?
Tympanic branch
When the tympanic branch of CN IX leaves he temporal bone, what is it referred to as?
The lesser petrosal nerve
where does the lesser petrosal nerve synapse?
At the otic ganglion
what type of fibres travel via the auriculotemporal nerve of CN V3 to reach the parotid gland?
Post-synaptic parasympathetic fibres
What type of cells are found in the submandibular gland?
Mixture of serous and mucous cells
What is the superior border of the submandibular triangle?
Inferior border of mandible
What is the anetrior border of the submandibular triangle?
Anterior belly of digastric
What is the posterior border of the submandibular triangle?
Posterior belly of digastric
What is another name for the submandibular duct?
Wharton’s duct
Where does the lingual nerve course in relation to the submandibular duct?
Inferiorly
where does the submandibular duct drain to?
The sublingual caruncle
What shape is the sublingual gland?
Almond shaped
where does parasympathetic innervation to the submandibular and sublingual glands come from?
CN VII
Through what foramen does the facial nerve exit the skull onto the face?
The stylomastoid foramen
What branch does CN VII give off, that runs alongside the lingual nerve of CN V3 to synapse at the submandibular ganglion?
Chorda tympani
What type of epithelium covers the oral cavity, oropharynx and layrngopharynx?
Stratified squamous epithelium
What type of epithelium covers the nasal cavity and nasopharynx?
Respiratory epithelium
What are the three parts of the mucosal layer of the digestive tract?
- Epithelium
- Lamina propria
- Muscularis mucosa
What are the four major layers that compose the digestive tract? (from inside to out)
- Mucosa
- Submucosa
- Muscularis externa
- Serosa or adventitia
What two structures in the body contain mucous glands- usually found in the lamina propria- within the submucosa?
Oesophagus and duodenum
What type of epithelium is found in the stomach?
Simple columnar epithelium
What is the key feature of the mucous membrane of the stomach?
Presence of gastric pits
What are gastric pits?
Invaginations that open up into the lamina propria from the submucosa into multiple gastric glands
What are the four main cells within a gastric gland?
- Parietal cells
- Mucous neck cells
- Chief cells
- Neuroendocrine
What two cells are found predominantly and the lower part of gastric glands?
Chief cell and neuroendocrine cells
What is the role of chief cells within the gastric glands?
Secretes the digestive enzyme, pepsinogen.
What is the role of parietal cells within gastric glands?
Hydrochloric acid producing cell
In which region of the stomach are gastric pits shallow with long, straight gastric glands?
Fundus (body)
In which regions of the stomach are gastric pits deep with branched, coiled gastric glands?
Cardia and pylorus
Which region of the stomach has the deepest gastric pits, with branched coiled gastric glands?
Pylorus
What are the three layers of the Muscularis externa?
- Inner oblique
- Middle circular
- Outer longitudinal
which layer of the Muscularis externa aids the churning action of the stomach?
Outer longitudinal
What does thickening of the inner circular layer of smooth muscle between the pylorus ad duodenum form?
Pyloric sphincter
What small projections are found to line the small intestine?
Villi
What “pits” are found between the bases of adjacent villi of the small intestine?
Crypts of lieberkuhn
How long is the duodenum?
About 25cm
What are the glands contained within the submucosa of the duodenum called?
Brunner’s glands
In what part of the small intestine are villi the tallest?
Jejunum
What part of the small intestine is characterised by shorter villi and aggregations of lymphoid follicles called Peyer’s patches?
Ileum
What is the acidic, partly digested semi fluid material from the stomach that the duodenum receives?
Chyme
What is the digestive tracts nervous system called?
The enteric nervous system
What interconnected network of fibres controls gut motility?
The myenteric plexus
