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
mesoderm derivatives:
- connect tissue
- muscle
- ALL OF URINARY SYSTEM
- ALL OF GENITAL SYSTEM
- CV system
- adrenal cortex
endoderm derivatives:
- inner lining of the GI system
- lining of glands
what is a sacrococcygeal teratoma?
- remnants of the primitive streak
- mass of different tissues from the germ layers (bone, teeth, etc)
- most common tumor in newborns
how is the neural plate formed?
aka neuroectoderm
- underlying paraxial mesoderm and the notochord send signals to the overlying ectoderm to form a neural plate (thickening of the overlying ectoderm)
- it extends cranially to become brain
- caudally to become spinal cord
- notochord becomes nucleus pulposus
- -> neural plate begins to invaginate and fold up onto itself into a neural tube
neural crest cells and the neural tube
- neural tube begins to detach from surface ectoderm
- the neural crest cells lie just below surface and undergo a EPITHELIAL–>MESENCHYMAL transition
- and the neural tube lies below this
neural crest cells and its derivatives
- pluripotent
- think PNS structures (ganglia, schwann, CNs)
- myenteric and submucosal plexus
- adrenal medulla
- meninges
- odontoblasts
- melanocytes
- CT and bones of the face and skull
- sclera of the eye
What is DiGeorge Syndrome?
-deletion of chromosome 22
-autosomal dominant
-CATCH 22
Cardiac problems
Abnormal face and brain
Thymic hypoplasia
Cleft Palate
Hypoparathyroidism
*it is a result of abnormal migration of neural crest cells
what are the 4 types of tissues?
- epithelial
- connective-joins tissues
- muscular-movement
- nervous-communication
polarization of epithelial tissues
- has apical and basal layers
- lines ALL free surfaces except for synovial jt. capsules and anterior surface of the iris
- basal surfaces are attached to the basement membrane (adhesive)
apical surfaces
- nonadhesive
- in order for organs to move freely against one another without sticking
- adhesions will occur when epithelial layers break down and the CT adheres to one another
what is endothelium?
- simple squamous epithelium
- all the epithelium that lines the CV system
- this is why there is a lumen for blood flow/cells don’t stick to one another because of the apical stuff
what is mesothelium?
- simple squamous epithelium
- lining of body cavities (pericardial, pleural, peritoneal)
what are examples of modifications to apical layers?
- microvilli: increase cell SA [small intestine]
- cilia and flagella [trachea for movement of stuff]
- sterocilia: longer than cilia, less motile [epididymis]
organization of organelles in a cell dependent upon secretion
-if secrete apically then
RER–> Golgi –> Zymogens (basal to apical)
-the reverse is true if secretion happens basally
what are the main functions of epithelial junction complexes? (2)
- holds cells together as sheets
2. isolates different compartments of the tissue
zonula occludens
- tight junction
- most apical
- belt like seal about the cell
- prevents things from entering cells through side gaps between cells
zonula adherens
adherent junction
-holds cells together
macula adherens
desmosomes
- holds cells together even more
- has a protein plaque that serves as an anchoring site for intermediate filaments
gap junctions
-pores between cells that allow for messaging and communication
what is a hemidesmosome?
- half of a desmosome
- BUT on the basal surface of the cell
- anchors the epithelium to the basement membrane
- most abundant in the skin
what is the basement membrane?
- acts as a boundary between epithelium and underneath CT
- has variable thickness in different areas of the body
- it is the connection site between the 2 types of tissues
what are some of the things that are located within the BM?
- collagens (IV)
- laminins
- fibronectin
- proteoglycans
- integrins
simple squamous epithelium: what and where?
- one layer of flat cells
- mesothelium body cavities
- endothelium CV system
simple cuboidal epithelium: what and where?
- one cell layer of cube type cells
- kidney tubules
simple columnar epithelium: what and where?
- one cell layer of tall cells
- small and large intestine: absorption and transport from lumen
pseudo stratified epithelium: what and where?
- looks stratified but it is actually cells of different height that make up ONE layer
- all of the cells rest on the BM but not all of them reach the apical surface
- respiratory system, excurrent ducts in male testis
stratified squamous: what and where?
- multiple cell layers
a. keratinized (epidermis): dead cells without nuclei
b. NONkeratinized (vagina and esophagus) flattened cells with nuclei in apical layer - resists abrasion
transitional epithelium: what and where?
- stratified apical cells that have rounded projections into the lumen
- *urinary system only**–bladder, ureters, and upper urethra
- change in the look of it dependent upon the functional state of the organ
- fluffy and full when it is empty
- flat when it is full
glands and epithelial tissue
-glands are classified based upon the mode of transport and arrangement of cells or ducts can be A. simple or B. compound glands
pemphigus Vulgaris
- IgG autoantibodies attack desmoglein (which is part of desmosomes)
- disrupt the adhesion of desmosomes leading to open sores
MAIN features of connective tissue:
- function: hold things together
- have cells and an extracellular matrix (ECM)
- they are composite materials that give them their features [cushion, support, attachment]
- differing consistencies
- vascular!
what are the 2 components of the ECM? And what are the subdomains of each?
- fibers-collagen, elastic, and reticular
2. amorphous ground substance-glycoproteins and proteoglycans
Most CTs arise from what?
mesenchyme!
What are the classifications of various connective tissues?
- embryonic [mesenchyme and mucous]
- CT proper [loose and dense]
- specialized [cartilage, bone, adipose, blood, BM, lymphatic]
What are the carbohydrate polymers that make up the ECM in CT?
- they are made up of sugar acids and amino acids
- very long (hyaluronic acid)
- branched and sulfated (which makes them water like)
- these macromolecules can bind to one another and to cells [aka how attracts to epithelia and muscle]
collagen fibers
-found in MOST CT’s
elastic fibers
- stain purple
- contain elastin
- abundant in dermis
- large blood vessels (aorta)
reticular fibers
have a collagen variant
- provide the structural framework for many structures
- stain brown when have the special stain
- liver
- lymph nodes
what is common of the way that collagen fibers look?
they have PERIODICITY
-regular stripes which are staggered collagen molecules arranged into a fibril
fibroblasts
- they synthesize and secrete the ECM
- therefore… they have lots of RER and Golgi
- migratory during events like wound healing
Loose CT structure and where?
structure: small number of cells and fibers, random
where: lamina propria (in mucosa of GI)
- mesenteries (suspend organs from body wall)
dense irregular CT structure and where?
structure: more fibers, and SOMETIMES more cells, random
where: dermis of skin
dense regular CT structure and where?
structure: numerous fibers and many cells
- regular linear arrays
- layered pattern
where: tendons usually
large amount of strength!
reticular CT structure and where?
structure: abundance of reticular fibers
where: allows for attachment of cells
- lymph nodes**
- spleen
- bone marrow
- liver**
adipose tissue: types,where and function
function: storage of excess calories in form of fat
where: hypodermis
type:
a. white fat-unilocular
b. brown fat-multilocular; lots in newborns for energy storage and making heat!
marfan syndrome
this is mostly common in really tall people who have a mutation to the ECM glycoprotein FIBRILLIN
- this glycoprotein is important for the elastic fiber integrity
- often have hyper extensible joints
- die often sudden cardiac death from an aortic aneurysm because it cannot withhold the pressure of the blood being pumped into it
What are characteristics of Bone and Cartilage?
- supportive framework
- attachment site for muscles
- protection of organs
- they are endoskeletal tissues
What is in the cartilage ECM?
- collagen— type 2
- elastin
- proteoglycans
- glycoporteins
- water
What is in the Bone ECM?
- collagen–type 1
- elastin
- proteoglycans
- glycoproteins
- water
- HYDROXYAPATITIE
- Ca salts
What is the amorphous ground substance of cartilage?
-its everything but the fibers
-contains glycoprotein linker proteins that attach to hyaluronic acid
^^this binds a lot of water which makes cartilage smooth and wet ish
Hyaline Cartilage structure and function?
structure: avascular (like all) cannot self repair
elastin
function: abundant on articular surfaces of long bones, rib/sternum, trachea, bronchi, layrnx
- cushions
- attaches/supports [flexibly]
- early bone development uses this cartilage before filling in with Ca crystals
Elastic Cartilage structure and function?
structure: similar to hyaline BUT…
- more elastic fibers! need special stain for this
function: pinna, epiglottis, larynx
Fibrocartilage structure and function?
structure: looks similar to a tendon + chondrocytes throughout
function: IV disks
- symphysis pubis
- meniscus
- labrum
What is endochondral ossification?
this is how most bones develop by using a cartilage frame work and then filling this in
-this is also how fracture repair occurs
Unique properties of bone
-highly vascular
-high tensile strength
-has columns and buttresses
-Ca hydroxyapatite crystals
-SLOW turnover
3% compact, 25% spongy/year
-self repairing
-compartment for hematopoiesis
Morphology of Gross Bone
- epi/meta/diaphysis
- epiphyseal plate is where growth occurs in children
- blood vessels from PERIosteum
- compact bone=shell
- spongy bone=epiphyses and metaphysis
Histology of bones
- osteocytes are embedded within lacunae
- the projections from these cells are called canaliculi
- lamellae are the concentric rings that eventually make one osteon aka haversian system— this allows for diffusion of gases and nutrients to the osteocytes in the system
What is characteristic of compact bone?
- haversian systems
- support columns
What is characteristic of spongy bone?
-trabeculae
-arranged around reticulum of blood vessels
REMEMBER! only in the epiphyses and metaphysis
What is the endosteum?
- outside and inside mature bone
- has osteoprogenitor cells (stem cells) that can become osteoblasts very quickly and form new bone
- always activated during fx repair and remodeling of bone
What are different cells of bones?
progenitor cells: fibroblast like and are reserved until activated to osteoblasts
- blasts: make bone
- clasts: break down bone… part of monocular phagocyte system
What are some cardinal features of osteoclasts?
- several nuclei
- large
- uneven surface that has microvilli
- lots of mitochondria
- secretes dilute HCl
Describe bones as a calcium store:
- tightly regulated
- PTH: increases Ca when its low; mobilize osteoclasts
ii. secondarily one can increase Ca in gut and increase phosphate excretion - Calcitonin: lowers Ca: inhibits osteoclasts
What is the process of fx repair?
- after a fx the bone bleeds and creates a soft callus which is hyaline cartilage
- osteoprogenitor cells are then activated to make osteoblasts
- endochondral ossification occurs when the blasts ossify the cartilage to make a bony callus
- after reduction and fixation… 6-12 wks the bony callus repairs the fx
*bone rarely breaks in same place due to the callus being stronger than original bone
