Anatomy/Histology Flashcards
What kind of information do cranial nerves carry?
motor
sensory
and mixed!
Which cranial nerves are motor ONLY?
3 (III) 4 (IV) 6 (VI) 11 (XI) 12 (XII)
Which cranial nerves are sensory ONLY?
1 (I)
2 (II)
8 (VIII)
Which cranial nerves are mixed?
motor and sensory
5 (V)
7 (VII)
9 (IX)
10 (X)
What subdomains does motor, sensory, and mixed break down into?
motor —> somatic (muscles in neck and head) or parasympathetic (glands… rest and digest)
sensory–> general (touch, pain, temperature) and special (taste, smell, hearing, balance)
mixed is any combo of the above
Which 4 of the 5 senses do special sensory nerves control?
- smell
- vision– can test for this upon physical exam
- hearing/balance
- taste
In terms of general sensory… what things are these nerves assoc. with?
- pain
- temp
- position
- vibration sense
trigeminal (V) is one you can test for
Can all cranial nerves and aspects of each be tested?
no!
for ex. VII–facial can only test motor not parasympathetic of glands and special sense of taste in anterior portion of the tongue
CN II
Optic
special sensory
- visual field
- assesing peripheral and/or temporal visual fields
Which cranial nerves control extra ocular motion? And how do you asses these?
CN III, IV, VI
motor
asses: H test (look at direction of pupil in the eye you are testing
CN III
oculomotor
movements:
- medial
- medial then up
- lateral and up
- lateral and down
CN IV
trochlear
movement: medial and down
CN VI
abducens
movement: abduction (lateral)
Which CNs control pupillary reaction?
CN II (optic) direct response in eye you are testing *special sensory*
CN III (oculomotor) consensual response in opposite eye *motor-parasympathetic*
Which cranial nerve controls palate elevation?
CN X (vagus) *motor*
- should elevate symmetrically
- uvula in midline
side note: CN 9 senses a tongue depressor and CN X elevates the palate (motor)
Which CN is responsible for tongue protrusion?
CN XII Hypoglossal
motor
-tongue should protrude out in straight like from bilateral genioglossus muscles
Which CN is important for facial sensation?
CN V trigeminal
general sensory
- 3 divisions… 1) frontal 2) maxillary 3) mandibular
- use cotton ball or cotton swab
Which CN is responsible for facial muscles?
CN VII facial
motor
- muscles of mouth and obicularis oris
- open eyes
- smile
- frown
- pucker lips
Which CN controls the trapezius muscle?
CN XI Accessory
- shrug shoulders and push down with resistance
- also controls the SCM
What happens to a growing embryo in weeks 1/2/3/4?
week 1: fertilization –> cleavage –> implant
week 2: bilaminar disc –> fully implanted 2 WEEKS 2 layers
week 3: gastrulation and early nearlation 3 weeks 3 layers
week 4: neurulation complete, body plan established!
describe ovulation:
- happens 14 days into cycle-MID CYCLE
- when release it is a 2ndary oocyte (stuck in meiosis 2)
- things included in the release: zone pellucid, corona radiate, and mass of mucus
- swept into lumen by the ciliated epithelia tubes
what is the corpus luteum?
- remainder of follicle after ovulation
- secretes progesterone to promote thickening of the uterus for implantation
what happens during fertilization?
- meiosis 2 finishes.. 2nd polar body released
- block to polyspermy… once one sperm enters it become impermeable to other sperm
- diploidy is reestablished after the sperm and egg nuclei fuse
- developmental program is initiated
- sex is determined
what happens during the process of compaction?
- the blastomeres that are a part of the morula begin to adhere to one another —> creating an outer and inner mass of cells
- the blastomeres begin to divide though —> trophoblast and the embryoblast (ICM)
- *This is the first major differentiation
totipotency and blastomeres
early blastomeres are totipotent
-they can become anything and everything in the human body
in vitro fertilization and the risks
- woman is hormonally primed to release secondary oocytes that are then mixed in culture with sperm
- once fertilization happens they are injected into F
RISKS:
- multiple pregnancies
- chances for birth defects?
what does the morula of blastomeres become?
once the cells begin diving they form 2 types of cells.
-eventually a blastocyst hatches from the zone pellucid
forming…
A. embryoblast which has the ICM which is the pole that becomes implanted into the female
B. trophoblast which is the out cells that proliferate into the uterine wall
i. cytotrophoblast
ii. syncytiotrophoblast-STB
^^these together make the outer syncytium
what do the layers of the trophoblast do?
the CTB divides and forms the STB
- the STB is the invasive layer that breaks down the endometrial epithelium
- this causes the maternal blood to begin to poor onto the STB providing it nutrients to grow
- lacunae are formed by the STB
the growing blastocyst is (2):
- hemochorial: maternal and fetal blood come into contact
- interstitial: completed embedded in the uterine wall
bilaminar disc
- inner cell mass -»> epiblast and hypoblast
2. trophoblast
where does implantation occur?
upper posterior portion of the uterine body
what is ectopic implantation?
- implantation and development outside of the uterine lumen
- often can lead to rupture and bleeding
- 95% occur in the tubes
- very common
what is placenta previa?
implantation in the lower portion of the uterus and the baby is not able to be delivered vaginally… most often through c section
predisposing factors for ectopic preg?
-pelvic surgery
-IUD
-PID
chlamydia infections
syphilis
gonorrhea
Sx/Sy and Tx for rupture?
- sudden onset of lower quadrant pain
- rebound tenderness with firm abdomen
- tachycardia
- low BP
- low hematocrit
- postive for betahCG
tx:
early US
unruprutred: methotrexate or surgical removal
ruptured: urgent surgical removal
where does fertilization occur?
ampullary portion of tubes
hCG
- secreted by the STB
- beta subunit is unique to hCG
- clinical setting can be detected in 7 days
what happens if fertilization occurs?
- the STB becomes the source of hCG
- hCG promotes continues progesterone secretion from corpus luteum until placenta eventually takes over
what are the layers of the bilaminar disc?
- epiblast=floor of amniotic cavity
- hypoblast=roof of the yolk sac
- primitive streak—> form midline of body for epiblast to invaginate
- primitive node—> notochord
process of gastrulation:
- the epiblast begins to invaginate medially onto the primitive streak displacing the hypoblast
- the 3 germ layers are made
- the hypoblast eventually disappears
what happens as a result of gastrulation?
- bilateral symmetry is established
- cranial and caudal ends are established
- 3 primary germ layers–differentiation of the epiblast
- CNS inducer in place
ectoderm derivatives:
- everything one can see with eyes/mouth open
- outer oral cavity
- lower anal canal
- BRAIN
- SPINAL CORD
- NEURAL CREST CELLS