T1 L8 Orbit & nasal cavity Flashcards
What is the function of the nose?
To filter dust entering the respiratory system
What bones make up the nose?
Paired nasal bones
Maxillae
Frontal bone
Septum
What are the cartilages of the nose?
Lateral
Major alar
Septal
What are the 3 projections on the internal surface of the lateral wall?
Superior conchae
Middle conchae
Inferior conchae
What do the supplied arteries to the nose branch from?
Ophthalmic
Maxillary
What is the nerve supply to the nose?
Olfactory nerve
Opthalmic & maxillary
What is the exit of cranial nerve I?
Cribriform plate
What is the type of cranial nerve I?
Special afferent - sensory
What aids olfaction?
Air flowing through the nasal cavity
Where are olfaction receptions?
In the epithelium lining the roof & walls
What do olfaction receptors do?
Epithelium secretes a mucus fluid
Odoriferous gases are dissolved into the fluid & detected by olfactory nerves
What can cause temporal anosmia?
Mucus buildup
What can cause permanent anosmia?
Abscesses
Trauma
Parkinson’s disease
What are the paranasal sinuses?
Air filled extensions of the nasal cavity
What do the paranasal sinuses drain through?
Frontonasal duct
What are ethmoidal cells?
Invaginations in ethmoid bone
Drain into middle meatus if anterior or middle
Drain into superior meatus if posterior
Where do sphenoidal sinuses drain?
Into sphene-ethmoidal recess
What are the 7 bones making up the orbit?
Frontal Maxilla Ethmoidal Lacrimal Sphenoidal Temporal-zygomatic Nasal
What are the 3 layers of the eye?
Outer fibrous - sclera & cornea
Vascular - iris
Inner - retina
What type is cranial nerve II?
Special afferent - sensory
Where does cranial nerve II exit?
Optic canal
Why does cranial nerve II have a special embryology?
Optic stalk grows out & lens vesicle grows in
What are the 7 extraoccular muscles that surround the globe of the eye & are responsible for moving it?
Levator palpebrae Superior oblique Superior rectus Medial rectus Lateral rectus Inferior rectus Inferior oblique
What 3 axes does movement of the eyeball occur around?
Vertical
Transverse
Anteroposterior
What does the superior oblique do?
Depression & abduction
What does the superior rectus do?
Elevation
Adduction
What does the inferior rectus do?
Depression
Adduction
What does the lateral rectus do?
Abduction
What does the medial rectus do?
Adduction
What does the inferior oblique do?
Elevation & abduction
What type is cranial nerve III?
Somatic motor (general somatic efferent) to extra-oscular muscle) & general visceral efferent-parasympathetic via short ciliary nerves to ciliary body & sphincter pupillae
Where does cranial nerve III exit?
Superior orbital fissure
What type is cranial nerve IV?
Somatic motor (general somatic efferent) to superior oblique
Where does cranial nerve IV exit?
Superior orbital fissure
What type is cranial nerve VI?
Somatic motor (general somatic efferent) to lateral rectus
Where does cranial nerve VI exit?
Superior orbital fissure
What is the nerve supply to the orbit?
CN II, III, IV, V1, VI, VII
Sympathetic
Parasympathetic
What does the sympathetic nerve supply to the orbit do?
Stimulates dilator pupillae to let more light in
What does the parasympathetic nerve supply to the orbit do?
Stimulates constrictor pupillae to let less light in
What is the blood supply to the orbit?
Ophthalmic artery
Infra-orbital artery
Central artery
What does the lacrimal apparatus consist of?
Lacrimal gland which secretes lacrimal fluid, which passes across eye & into lacrimal papilla, lacrimal sac & to the inferior meatus via the nasolacrimal duct
What are the 2 parts of the lacrimal gland?
Orbital
Palpebral
What is the nerve supply responsible for crying?
Parasympathetic - secretomotor via VII
Sympathetic - vasoconstrictive (superior cervical ganglion via internal carotid)
