2. Vitreus body : it has canal called hyaloid canal .
what is the function of the vetreus body ?! it
pushes the Retina in it's place , so if this jelly
material dehydrated & vitreus body shrink ; what
will happen ?! the retina will detach the vision
field will
9. Between the outermost layer (photoreceptors) and the
intermediate layer (bipolar cells) is a region called the outer
plexiform layer that contains the horizontal cells to connect both
layers. The same between the intermediate layer and the inner
layer , in which there is the inner plexiform layer that contains the
amacrine cells connecting both layers.
10.
11. The optic disc is where the optic nerve leaves the retina. It is
lighter than the surrounding retina and branches of the
central retinal artery spread from this point outward to supply
the retina. As there are no light-sensitive receptor cells in the
optic disc it is referred to as a blind spot in the retina
12. Lateral to the optic disc a small area with a hint of yellowish
coloration is the macula lutea with its central depression the
fovea centralis. This is the thinnest area of the retina and visual
sensitivity here is higher than elsewhere in the retina because
it has fewer rods (light-sensitive receptor cells that function in
dim light and are insensitive to color) and more cones (light-
sensitive receptor cells that respond to bright light and are
sensitive to color).
. In the chiasma, the fibers from the medial half of each
retina cross the midline and enter the optic tract of the
opposite side, whereas the fibers from the lateral half of
each retina pass posteriorly in the optic tract of the same
side 3>>> optic tract >>> Most of the fibers of the optic
tract terminate by synapsing with nerve cells in the lateral
geniculate body 4. A few fibers pass to the pretectal
nucleus and the superior colliculus and are concerned with
light reflexes
To have the Best vision the light should reach to the fovea
body
when we need to stimulate quick actions we won't to wait for synapsing to
occure . we send fibers direct from optic tract to the pre-tectal area
which is connected to the cranial nerves 3,4&6 .
13. the fibers that come from temporal part
of retina;which make most of the visual
field , will not cross . but the other
fibers that come from nasal part of
retina will cross .
lateral Geniculate body "lateral
concerned with vision , the medial with
hearing
14.
15. The lateral geniculate body is a small, oval dark swelling
projecting from the pulvinar of the thalamus. It consists of
six layers of cells, on which synapse the axons of the optic
tract. The axons of the nerve cells within the geniculate
body leave it to form the optic radiation
16. dark ones (2,3,5)
light ones (1,4,6).
fibers from Y
ganglion cells.
They serve the
black and white
visual
information.
These are color
information from
X ganglion cells.
They serve color
visual signal and
are use for
accurate vision
18. .So you have to examine the disc if you
want to diagnose the hydrocephalus
19. The apex of the pyramidal-shaped bony
orbit is the optic canal, opens into the
middle cranial fossa , the optic nerve and
the ophthalmic artery.
- Where is the location of the optic disc
?! it isn't located at the axis of the eye !
it located medial to the eye axis .
21. The supratrochlear notch;
medial to the supraorbital nerve , both
branches of the frontal nerve.
the infraorbital nerve is the anterior
continuation of the maxillary nerve
22. `
Passing through the superior orbital fissure are the superior and
inferior branches of the oculomotor nerve [III], the trochlear nerve
[IV], the abducent nerve [VI], the lacrimal, frontal, and nasociliary
branches of the ophthalmic nerve [V1], and the superior ophthalmic
vein
23.
24. the orbit communicates with the cranial cavity
(the superior orbital fissure, the optic canal and
the anterior ethmoidal openings) the periorbital is
continuous with the periosteal layer of dura
mater.
the periorbita is continuous at the margins of the
orbit with the periosteum on the outer surface of
the skull.
25. levator palpebrae superioris
innervated by sympathetic
fibers from the superior
cervical ganglion.
Clinically; Loss of
oculomotor nerve [III]
function results in complete
ptosis or drooping of the
superior eyelid, whereas
loss of sympathetic
innervation to the superior
tarsal muscle results in
partial ptosis
26. superior rectus (which originates
from the superior part of the
common tendinous ring above
the optic canal and below the
origin of the levator palpebrae
superioris) elevates and adducts
the eyeball. "Up and in“.
the inferior rectus (which
originates from the inferior part of
the common tendinous ring below
the optic canal) depresses and
adducts the eyeball. "down and
in"
28. B. cavernous sinus
cavity at the base of the brain that contains veins,
cerebral nerves (on the lateral wall; the oculomotor,
trochlear, ophthalmic. In the middle is the abducens)
29. Styes are similar to chalazia, but tend to be of
smaller size and are more painful and usually
produce no lasting damage.
The primary treatment is by antibiotics. Styes
that do not respond to any type of therapies
are usually surgically removed under local
anesthesia.
It is common for the removed stye to be sent
for histopathological examination to rule out
the possibility of skin cancer.
30. oculomotor
this is a common region of berry aneurysm
aneurysm developed compress on the
oculomotor oculomotor nerve loss it's action
a lot of muscles loss their function the end
result will be like the person in the MM (the eye
is down, lateral & pupil is dilated) .
ptosis
31. The main oculomotor nucleus receives
corticonuclear fibers from both cerebral
hemispheres.
It receives tectobulbar fibers from the
superior colliculus and, through this
route, receives information from the
visual cortex.
It also receives fibers from the medial
longitudinal fasciculus, by which it is
connected to the nuclei of the fourth,
sixth, and eighth cranial nerves
the motor nucleus of the oculomotor, the
trochlear motor nucleus and the abducens
motor nucleus, all receive from the same
sources
32. Accessory parasympathetic nucleus
receives:
corticonuclear fibers for the
accommodation reflex.
and fibers from the pretectal
nucleus for the direct and consensual
light reflexes. (constriction of the pupil
in response to light)
33. The accessory nerve along its course will be divided into superior
and inferior branches, the preganglionic fibers will go with the
inferior branch only, so that the superior branch will be purely
motor. Soon then, the presympthetic fibers will leave the inferior
branch to the ciliary ganglion where it will synapse with the
postganglionic fibers.
34. The oculomotor nerve supplies the following:
■ The extrinsic muscles of the eye via the nerve
fibers of the motor nucleus:
the levator palpebrae superioris, superior
rectus through the superior branch
medial rectus, inferior rectus, and inferior
oblique through the inferior branch
■ The intrinsic muscles of the eye, via the nerve
fibers (preganglionic parasympathetic) of the
edinger-westphal nucleus: The constrictor
pupillae of the iris and the ciliary muscles .These
fibers follow the inferior branch and synapse in
the ciliary ganglion and the postsympatheic fibers
reach the eyeball in the short ciliary nerves.
35.
36. most affected nerve by cavernous sinus
thrombosis and inflammations or internal
carotid aneurysms in the cavernous sinus
is the abducent nerve, so there will be a
problem in the lateral rectus muscle,
inability to move the eyeball laterally.
These signs could be the first presentation
of cavernous sinus thrombosis.
The V3 (mandibular division of trigeminal)
doesn’t pass in the cavernous sinus unlike
V1 and V2 which do so
37. Unique about trochlear:
The only one that exits dorsally.
The only one that decussate.
So it has the longest intracranial
course
So it is the most one that is vulnerable to
damage.
o You have to remember that it is
vulnerable to an increase in the intracranial
pressure as it moves on the free edge of
the tentorium
cerebelli.
o Damage if severe will result in diplopia,
while less severe damage to the nerve will
result in blurred vision.
38. So that the abducens nucleus of the right side, for example, drive the
contraction of the right lateral rectus muscle, moving the right eye to
the right. At the same time, some signals will move to the left
oculomotor nucleus in order to drive the contraction of the left medial
rectus, hence moving the left eyeball to the right. Both pupils will
move to the right.
39. Abducent
As it leaves in between the
pons and the medulla, it
will move anteriorly in
between the pons (above)
and the clivus (below).
What is the clivus? The
part of the occipital bone
that lies directly anterior to
the foramen magnum is
known as the basilar.
The pons sits on the clivus,A patient presents with horizontal
diplopia… Which of the following
nerves are involved: Answer: Abducent
(VI)
46. The Muscles of the auricle are classified
into intrinsic and extrinsic muscles.
The intrinsic muscles pass between
the cartilaginous parts of the auricle and
might change the shape of the auricle.
The extrinsic muscles; anterior,
posterior and superior pass from the
scalp or the skull to the auricle and may
also play a role in positioning of the
auricle. Both groups of muscles are
innervated by the facial nerve.
47.
48.
49.
50.
51.
52. Lymphatic drainage of auricle
Lateral superior half of the auricle is drained
via the parotid lymph nodes.
Medial superior half is drained via the mastoid
lymph nodes.
The rest, that is the inferior part of the auricle, is
drained via the superficial cervical lymph nodes.
All these drain ultimately into the deep cervical
lymph nodes.
53. Cleaning of the earwax is difficult and needs a surgical procedure,
its also dangerous because of the presence of the
auriculotemporal nerve
54. Nerve supply to exrenal auditory
meatus
The major sensory input is through
the auriculotemporal branch of the
mandibular nerve and the auricular
branch of the vagus.
Greater auricular nerve.
Lesser occipital nerve.
Minor sensory input is through the
facial nerve.
There is an area in the floor of EAM near the tympanic
membrane supplied by the vagus nerve that if stimulated by a
cotton bud then a cough reflex will occur, because the brain
will receive this as an irritation of the trachea
55. The development of the auricle
The auricle develops from 6 tubercles;
3 of which are from the first
pharyngeal arch, and 3 from the
second pharyngeal arch.
56.
57.
58.
59.
60. Note: Hypertensive patients say there is strange sounds in my ear
(tinnitus), that is because of the turbulence of the internal carotid
The internal carotid artery is the site where the carotid sympathetic
plexus is located, this plexus will give a branch through the anterior
wall to reach something known as the tympanic plexus located in the
61. Posterior and superior to the oval window on the medial wall is the
prominence of facial canal, which is a ridge of bone produced by the facial
nerve [VII] in its canal as it passes through the temporal bone.
Just above the prominence of the facial nerve is the prominence of the
lateral semicircular canal.
65. The membranous labyrinth consists of the semicircular
ducts within the semicircular ducts, the cochlear duct
within the cochlea, and two sacs (the utricle and the
saccule) within the vestibule.
66. myringotomy,
make a little incision with a very sharp knife
and put a tube, then the pus comes out of the
tube
67.
68.
69.
70. we do not want the wave in the ear to come back after it
goes all the way : so round window in the middle ear ,
after the wave goes all the way and comes back, the
round window will bulge to the middle ear and the wave
is killed “ will not return back”.
71.
72.
73.
74.
75. Utricosaccular duct
establishes continuity between all components of the
membranous labyrinth and connects the utricle and
saccule. Branching from this small duct is the
endolymphatic duct, which enters the vestibular
aqueduct (a channel through the temporal bone) to
emerge onto the posterior surface of the petrous part
of the temporal bone in the posterior cranial fossa
reaching the supdural space.
76. the peripheral processes of the bipolar
cochlear neurons will carry impulses from
the hair cells "the receptors" to cochlear
(spiral) ganglions where the cell bodies of
these neurons are located.
The spiral ganglions are located at the
base of the spiral lamina as it winds around
the modiolus. The central processes from
the spiral ganglia will assemble to form the
cochlear nerve.
77. Clinical note:
The vestibulocochlear nerve and the
facial nerve leave the internal acoustic
meatus together, so that a case of tumor
affect one of these nerves (mostly
acoustic schwannoma affecting the
Schwann cells of the vestibular nerve)
will affect the other. So, symptoms like
loss of hearing due to affected cochlear
nerve, loss of balance due to affected
vestibular nerve, and abnormal facial
functioning could happen together I
cases of acoustic schwannoma.
78. The cochlear nerve enters the anterior surface
of the brainstem at the lower border of the
pons on the lateral side of the emerging facial
nerve and are separated from it by the
vestibular nerve. On entering the pons, the
nerve fibers divide, with one branch entering
the posterior cochlear nucleus and the other
branch entering the anterior cochlear nucleus.
79. On reaching the midbrain, the fibers of the lateral lemniscus
either:
Terminate in the nucleus of the inferior colliculus.
relayed in the medial geniculate body which is part of the
thalamus.
80.
81. Vestibule nerve The lateral
vestibulospinal tract. This
tract is for extensor
reflexes which mean that
when you feel like falling
down you immediately
stretch your body to
protect yourself.
82. Trigeminal
The trigeminal ganglion (also named the semilunar ganglion)
is the place where the cell bodies of the sensory neurons
(they are bipolar neurons) are present. Then, the central
branches of the sensory neurons will be redistributed to the
brainstem according to the function rather than the place of
origin, so that the "touch and pressure" sensations from the
ophthalmic, mandibular and maxillary will pass to a special
nucleus of the trigeminal called "the main sensory nucleus",
while the pain and temperature sensations from the
ophthalmic, mandibular and maxillary will pass to another
nucleus known as the spinal nucleus of the trigeminal.
sensations of the trigeminal are
contralateral.
special case, the neurons that carry proprioceptive
sensations from the muscles of mastication and from the
facial and extraocular muscles have their cell bodies located
in the brainstem, in the mesencephalic nucleus, and these
cells are unipolar neurons.
85. The axons of the neurons in the
main sensory and spinal nuclei and
the central processes of the cells in
the mesencephalic nucleus now
cross the median plane and ascend
as the trigeminal lemniscus to
terminate on the nerve cells of the
ventral posteromedial nucleus of
the thalamus. The axons of these
cells now travel through the internal
capsule to the postcentral gyrus
(areas 3, 1, and 2) of the cerebral
cortex.
86. trigeminothalamic
tract (there is a
dorsal
one and a ventral
one; the dorsal on
is in the ipsilateral
side whereas the
ventral one
crosses to the other
side and then things
end up in the
thalamus (in the "
ventral
posteromedial
nucleus (VPM)".
87. Motor Component of the Trigeminal Nerve The
motor nucleus receives corticonuclear fibers from
both cerebral hemispheres. It also receives fibers
from the reticular formation, the red nucleus, the
tectum, and the medial longitudinal fasciculus. In
addition, it receives fibers from the
mesencephalic nucleus, thereby forming a
monosynaptic reflex arc. The cells of the motor
nucleus give rise to the axons that form the
motor root. The motor nucleus supplies the
muscles of mastication (masseter, pterygoid and
temporalis muscles), the tensor tympani, the
tensor veli palatini, and the anterior belly of the
digastric muscle and the mylohyoid.
88. The motor root of the trigeminal nerve is situated below the
sensory ganglion and is completely separate from it.
97. Branches from the Posterior
Division of the Mandibular Nerve
Auriculotemporal nerve, which
supplies the skin of the auricle, the
external auditory meatus, the
temporomandibular joint, and the
scalp. This nerve also conveys
postganglionic parasympathetic
secretomotor fibers from the otic
ganglion to the parotid salivary gland.(
Auriculotemporal nerve loops around
the middle meningeal artery).
98.
99.
100.
101. The great auricular nerve originates from the cervical
plexus, composed of branches of spinal nerves C2 and
C3. It provides sensory innervation for the skin over
parotid gland and mastoid process, and both surfaces
106. The scalp is the part of the head that cover the skull
and extends from superciliary arches anteriorly to
the occipital protuberance and superior nuchal lines
posteriorly. Laterally it
continues inferiorly to the zygomatic arch
107.
108.
109.
110. sometimes an asthmatic patient can’t talk unless his hand on the
table>> to fix the humerus >> in that way he changes the insertion
of the pectoralis major into origin>>and starts to move his ribs >>>
so that he can breath and talk
111.
112.
113.
114. the single axon surrounded by two layers
?? 1- endonureim 2- myelin sheath
122. Vagus
The pharyngeal muscles PULL the Uvula ,
so if there is a lesion in the right Vagus ,
deviation of Uvula will be to the
left(opposite) side .
123. absence of this reflex could lead to
pneumonia and other infections
124. Below the inferior ganglion, at the level of the
pharynx the first branch will originate which is
the pharyngeal branch which contain nerve
fibers from the cranial root of the accessory
nerve . this branch will join the pharyngeal
plexus and supply all the muscles of the
pharynx ( except the stylopharyngeus) and all
the muscles of the soft palate ( except tensor
veli palatini ).
After that the vagus nerve will have 2
branches at the level of the larynx which are :
1. Superior laryngeal nerves :
2. recurrent laryngeal nerves
125.
126. The posterior vagal trunk (which is the
name now given to the right vagus) is
distributed to the posterior surface of the
stomach and, by a large celiac branch, to the
duodenum, liver, kidneys, and small and
large intestines as far as the distal third of the
transverse colon. This wide distribution is
accomplished through the celiac, superior
mesenteric, and renal plexuses.
The anterior vagal trunk (which is the name
now given to the left vagus) divides into
several branches, which are distributed to the
stomach, liver, upper part of the duodenum,
and head of the pancreas.
127.
128. you'll not wait for the cerebral cortex
to react; you need a quick reflex
129. The jaw reflex: you put your
hands on the jaw and you stretch
muscles of mastication. Impulses
go to the mesencephalic nucleus
then to the motor of the trigeminal.
So it's V3, V3 (the two arms).
130.
131.
132. The posterior triangle of the neck
anteriorly by the posterior edge of the sternocleidomastoid muscle,
posteriorly by the anterior edge of the trapezius muscle,
its base is the middle one-third of the clavicle,
its apex is the occipital bone just posterior to the mastoid process where
the attachments of the trapezius and sternocleidomastoid come together.
133. Superior: descend between the internal
jugular vein and the internal, and then
common, carotid arteries.
Inferior :descends either medial or
lateral to the internal jugular vein
134. Misdiagnosed pain that is due to
greater auricular with molar teeth or
ear is examined by putting cotton pods
and check the pain at the places
supplied by the greater auricular
nerve.
169. 90-95% of the afferent “sensory” fibers of
the cochlear nerve will arise from inner hair
cells,
90-95% of efferent fibers
of the cochlear nerve
(they arise from the mid
brain) will terminate in
the outer cells, the
function of this type of
innervation is to modify
the response of inner
hair cells to sound wave:
by increasing sensitivity
to certain frequencies,
decreasing the
sensitivity to others, or
masking some sounds,
etc. and this will purify
the sound and will help
the brain to concentrate
170.
171.
172.
173.
174.
175. A single PN contains many nerve fibers
(axons) of different types and sizes,
The peak wave is produced by the largest
nerve fiber
176.
177.
178.
179. small tumor at the end of the proximal part
of nerve causing pain and sensitivity for
touch or anything.
180. stimulated by both rate and degree of stretch
but mostly during dynamic stretch response.
stimulated only by degree of stretch and only
during static stretch response
196. Widening of the synaptic junction.
Simplified or flatted postsynaptic folds
due to the decrease of the function of the
receptors.
Normal nerve terminal and transmitter
(No changes).
203. -tachyphylaxis
: is the reduction in the response
following repeated administration or
stimulation , but we cannot go to the
original response even if we increase the
dose and that’s simply because the
stores are depleted by frequent over-
stimulation.
so when we give ephedrine repeatedly it
will release most of the NE in the
vesicles so by subsequent stimulation
we will get lower and lower response and
if we increase the dose we will not get
any response or any increase because
there is no more epinephrine present .
204. -Epinephrine
-Again it is the DOC of :
1- Anaphylactic shock 2-
bronchospasm edema
-It is used in cardiac arrest in addition
to isoproterenol as a cardiac stimulant
and vasoconstrictive agent .
205. in cardiogenic shock patients have very low
blood pressure because of a cardiac reason
now our body will compensate by increasing
vasoconstriction so if we give norepinephrine to
improve blood pressure it will act on both heart
muscle and the vasoconstriction therefore
aggravating the vasoconstriction especially in
kidney (which also has alpha receptors) leading
to renal shutdown . while if we use dopamine
which has beta , alpha and D1 effects we will get
cardiac muscle stimulation , some
vasoconstriction but most importantly dilatation
of renal vessels( which has D1 receptors also) .
So the DOC in cardiogenic shock is Dopamine.(
as well as in septic shock) .
237. Listeria
The disease chiefly affects:
The immunosuppressed and
elderly.
Pregnant women.
Unborn or newly delivered
infants.
238.
239.
240. Clostridium botulinum
They are usually destroyed by moist
heat at120°C within
5min.(autoclaving)
Human disease is almost always
caused by typesA,B,orE.
241. There are difficulties in speech and
swallowing.
(don’t feed your children honey before
they become1year old)
