Head Primordia Flashcards
What are pretrematic nerves?
Sensory branches of branchial arch nerves that are out of their arch territory
What is the function of the trochlear nerve (IV)?
Move the pupil downand out (superior oblique somatomotor innervation)
What is the structure of the optic placode?
An ectodermal thickening on the side of the head
What is E?
Stomodeum
Which nerve supplies branchial arch 2?
Facial nerve (VII)
What is the function of the facial nerve (VII)?
Branchiomotor to the muscles of facial expression, source of parasympathetics for lacrimal secretion (tears)/nasal and oral mucosa/salivary gland secretions, and taste to the anterior 2/3 of the tongue
What is the function of the hypoglossal nerve (XII)?
Somatomotor to intrinsic and extrinsic tongue muscles
What is the pathway of postsympathetic parasympathetic neurons of the head?
They synapse in one of four parasympathetic ganglia and then join branches of the trigeminal nerve to get to their target smooth muscle and glands
What structures do the linings of the pharyngeal (branchial) arches contribute to the formation of?
Skin of jaws and mucous membranes of the oral cavity, pharynx, larynx, and middle ear
What is an otocyst?
The primordium of the semicircular canals and cochlea of the inner ear
What type of neurons are associated with the vestibulocochlear nerve (VIII)?
Special sensory neurons
it is associated with the otic placode
What structures flank the embryonic foregut?
Pharyngeal (branchial) arches 2-6
What nerves supply the preotic somites (somitomeres)?
Oculomotor (III), trochlear (IV), and abducens (VI) nerves
Which branchial arch is supplied by the glossopharyngeal nerve (IX)?
Arch 3
What is the endoderm of the head?
Lining of the foregut that extends into the stomodeum - pharynx, larynx, auditory tube, and middle ear cavity
What type of neuron components does the olfactory nerve (I) contain?
Special sensory neurons (for smell and olfaction)
this nerve is associated with the olfactory placode
What nerve is associated with the optic placode?
The vestibulocochlear (auditory) nerve (cranial nerve VIII)
Which nerve contains special sensory neurons for hearing, balance, and equilibrium?
Cranial nerve VIII
Where do all sympathetic neurons in the head originate from?
Lateral horn of the spinal cord (T1-L2)
What is A?
Pharyngeal arches
Which cranial nerve is associated with post-otic somites?
a) facial
b) hypoglossal
c) oculomotor
d) spinal accessory
e) glossopharyngeal
b) hypoglossal
What nerves supply postotic somites?
Somatomotor neurons from the hypoglossal nerve (XII)
Which branchial arch is supplied by the vagus nerve (X)?
Arches 4-6
What nerve does the olfactory placode relate to?
Olfactory nerve (cranial nerve I)
What is the innervation source of the skin of the back of the head and most of the neck?
Cervical spinal nerves
What is the function of the olfactory nerve (I)?
Special sensory for olfaction (smell)
What nerve is the optic cup associated with?
Optic nerve (cranial nerve II)
What is unique about cranial nerve II (compared to other cranial nerves)?
It is a specialized brain fiber tract covered with meninges
What do preotic somites (somitomeres) develop into?
Extraocular eye muscles
What is the structure of the olfactory placode?
It is a thickened section of the surface ectoderm at the anterior end of the embryonic head
Which nerve supplies branchial arches 4-6?
Vagus nerve (X and the cranial part of nerve XI)
What is the function of vestibulocochlear nerve (VIII)?
Special sensory for hearing and balance
Which branchial arch is supplied by the trigeminal nerve (V)?
Arch 1
What structure are the non-retinal parts of the eyeball, dermis of facial skin, most bones of the neurocranium, and meninges derived from?
Head mesenchyme
What structures do the pharyngeal (branchial) arches contribute to the formation of?
Muscles, bones, and other tissues of the head and neck
What do the olfactory epithelium and special sensory neurons for smell differentiate from?
The olfactory placode
What does the optic placode develop into?
It invaginates and pinches off below the surface to form the otocyst (primordium of inner ear)
What is the pathway of post-synaptic sympathetic neurons in the head?
They synapse in the cervical sympathetic ganglia and then leave the sympathetic trunk to enter the head as a plexus on the large arteries. They then follow arteries all the way to the targets (or leave vessels to join branches of the trigeminal nerve)