Term
| Masticatory, lining, and specialized mucosa make up what percentages of total mucosa? |
|
Definition
| Masticatory 25%; lining mucosa 60%; specialized 15% |
|
|
Term
Is masticatory, lining, and specialized mucosa keratinized?
|
|
Definition
| Masticatory and specialized are keratinized; lining is not |
|
|
Term
| What are 4 factors affecting the color of the oral mucosa? |
|
Definition
1- concentration and state of dilation of blood vessels in underlying CT 2- thickness of epithelium 3- degree of keratinization 4- amount of melanin pigmentation |
|
|
Term
| What is Fordyce's disease? |
|
Definition
| Sebacious glands in the oral cavity; a normal variation |
|
|
Term
| What are rete ridges (pegs)? |
|
Definition
| An irregular interface of downward projections of epithelium and upward projections of CT |
|
|
Term
| Is there a submucosa in all parts of the oral cavity? |
|
Definition
| In gingiva and hard palate no submucosa is seen and lamina propria is attached directly to periosteum (oral mucoperiosteum) |
|
|
Term
| What are the three types of oral epithelium? |
|
Definition
1- orthokeratinized stratified squamous epithelium 2- parakeratinized stratified squamous epithelium 3-nonkeratinized stratified squamous epithelium |
|
|
Term
| Distinguish between ortho-, para- and non-keratinization. |
|
Definition
Ortho - see no nuclei in cornified layer but a granular layer Para - see nuclei in cornified layer but an indistinct granular layer Non - no keratin and no granular layer |
|
|
Term
| What is the turnover time for gingiva and cheek? |
|
Definition
Cheek = 25 days Gingiva = 41 to 57 days |
|
|
Term
| What gives the vermillion zone its red color? |
|
Definition
1 - thin epithelium 2 - epithelium contains eleidin (semi-fluid transparent substance in stratum lucidum) 3 - blood vessels are near surface |
|
|
Term
| Is free and attached gingiva keratinized or not and stippled or non stippled? |
|
Definition
Free is not stippled and keratinized Attached stippled and keratinized (stipled due to deep rete pegs) |
|
|
Term
| What is junctional epithelium? |
|
Definition
| Epithelium attached to tooth (cementum or enamel) continuous with the sulcus |
|
|
Term
| How is junctional epithelium arranged? |
|
Definition
| Flat cells aligned parallel to tooth surface; increases in thickness from apex to crown |
|
|
Term
|
Definition
| A depression of the gingiva interdentally; identical to junctional epithelium |
|
|
Term
| Which nerves supply the gingiva? |
|
Definition
| branches of infraorbital, palatine (lingual), mental, and buccal nn. |
|
|
Term
| What is the hard palate made up of? |
|
Definition
| Mucoperiosteum (lamina propria attached directly to periosteum with no submusoca); fat, and salivary gands?????????? DONT KNOW |
|
|
Term
| Which tongue papilla have taste buds? |
|
Definition
| Foliate, circumvalate, fungiform |
|
|
Term
| What type of taste bud cells make up the majority of the taste bud? |
|
Definition
| Type 1 dark cells make up 60% of the taste bud |
|
|
Term
| Name 4 nonkeratinocytes in oral epithelium and their function: |
|
Definition
1 - Langerhans cell - APC found in stratum spinosum 2 - Merkel cell - found in basal cell layer;touch receptor 3 - melanocytes - found in basal cell layer; contain melanin 4 - lymphocytes and leukocytes - inflammatory response |
|
|
Term
| The first division of the zygote occurs within the first ?? hours of fertilization? |
|
Definition
|
|
Term
| Progression of cell type at beginning of division: |
|
Definition
| Blastomere --> morula --> blastocyst |
|
|
Term
| Trophoblast breaks down into: |
|
Definition
|
|
Term
| The bilaminar germ disc is made up of: |
|
Definition
epiblast (primary ectoderm) hypoblast (primary endoderm) |
|
|
Term
| Amnioblasts (amniotic membrane lining the amniotic cavity) are derived from which cell? |
|
Definition
|
|
Term
| What is Heuser's membrane? |
|
Definition
| (aka exocoelemic membrane) the lining of hypoblast cells covering the cytotrophoblast layer |
|
|
Term
| When does the primary yolk sac form? |
|
Definition
| Formed once Heuser's (exocoelemic) cavity forms |
|
|
Term
| What happens immediately following primary yolk sac formation? |
|
Definition
| there is a layer of extraembryonic reticulum formed between heuser's membrane and the cytotrophoblast |
|
|
Term
| From where does extraembryonic mesoderm arise? To where does it migrate? |
|
Definition
Arises from epiblast; migrates around extraembryonic reticulum; separates amnion from cytotrophoblast Heusers membrane --> extraembryonic mesoderm --> extrambryonic reticulum --> extraembryonic mesoderm --> cytotrophoblast --> synctiotrophoblast |
|
|
Term
| How is the definitive (secondary) yolk sac formed? |
|
Definition
| A wave of growth from the hypoblast pushes against the primary yolk sac migrating over the extraembryonic mesoderm and forms the endodermal lining of the secondary yolk sac |
|
|
Term
| What is a major site of hematopoesis in the developing fetus? |
|
Definition
| The extraembryonic mesoderm forming the outer layer of the definitive yolk sac |
|
|
Term
| What is Meckel's diverticulum? |
|
Definition
| Yolk sac remnant persisting after birth; a digestive tract anomaly |
|
|
Term
| When does gastrulation occur? What is the purpose? |
|
Definition
| Beginning in the 3rd week; definition of the left/right; dorsal/ventral; caudal/cranial |
|
|
Term
| Describe first steps of gastrulation |
|
Definition
| Primitive streak forms near caudal end; this includes the primitve groove, primitive pit (toward cranial), and the primitive node (mound of epiblast cells surrounding pit) |
|
|
Term
| During gastrulation the definitive endoderm and intraembryonic mesoderm are derived from ?? How is this achieved? |
|
Definition
epiblast cells; epiblast cells displace hypoblast cells to form the endoderm and migrate between new endoderm and epiblast to form mesoderm |
|
|
Term
| What happens to mesoderm cells migrating through the primitive node? |
|
Definition
| Form the prechordal plate and the notochordal process |
|
|
Term
| After migrating through the primitive node the notochordal process goes from beign hollow to solid by fusing with which membrane? |
|
Definition
|
|
Term
| How is the neural plate formed? |
|
Definition
| The prechordal and notochordal plate (from axial mesodermal origin) induce the overlying ectoderm to |
|
|
Term
| When do cephalic neural crest cells detach from the neural tube? Trunk neural crest cells? |
|
Definition
| Before closure of the cranial neural tube; before lateral lips close |
|
|
Term
|
Definition
Embryological disturbance of the neural crest ectoderm
results in severe enamel hypoplasia, conical and misshapen
teeth, hypodontia, hyperdonita, and impactions. Abnormalities
of migration along the buccal epithelium results in ectopism. |
|
|
Term
| On either side of the notochord the mesoderm is broken into: |
|
Definition
| paraxial; intermediate; and lateral plate mesoderm |
|
|
Term
| The intermediate mesoderm goes on to form: |
|
Definition
| urinary and genital systems |
|
|
Term
| The lateral plate mesoderm goes on to form the: |
|
Definition
| splanchnopleuric and somatopleuric |
|
|
Term
| Where do the muscles of the mouth, jaw and face come from? |
|
Definition
| The first 7 somitomeres of the paraxial mesoderm (which do not go on to form somites) |
|
|
Term
| Number and name the somites: |
|
Definition
44 pairs of somites the caudal most 7 somites disapear leaving 37 pairs
1-4 somites: occipital part of the skull, bones of nose and eyes, & muscles of the tongue.
Next 8 pairs: form in the presumptive cervical region. Give rise to occipital bone and cervical vertebrae, and assoc. muscles.
Next 12 pairs: Thoracic somites--> thoracic vertebrae, and associated muscles.
5 lumbar somites 5 sacral somites,
3 coccygeal somites. |
|
|
Term
| Name the three parts that come from a somite? |
|
Definition
| Dermatome, myotome, sclerotome (future vertebral bodies and arches and base of skull) |
|
|
Term
| The sclerotome migrates toward the notochord and neural tube and forms: |
|
Definition
centrum - future vertebral body vertebral arches - future pedicles, laminae, spinous process, articular processes, and the transverse processes costal processes - future ribs |
|
|
Term
| Intervertebral discs are formed from: |
|
Definition
An intervertebral disk consists of a Nucleus pulposus (remnant of notochord which degenerates by 20 y.o.) and an Annulus
fibrosus (outer rim of fibrocartilage derived from mesoderm found between the vertebral bodies) |
|
|
Term
| Myotomes differntiate into 2 parts: |
|
Definition
dorsal epimeres (intrinsic back muscles - erector spinae) hypomeres - prevertebral, intercostal, and abdominals |
|
|
Term
| Do upper or lower limbs develop faster? |
|
Definition
| Upper begins first but by the end they are synchronized |
|
|
Term
| What induces the formation of limbs? |
|
Definition
| Somites induce the formation of limb buds in the somatopleuric lateral plate mesoderm. |
|
|
Term
| What contributes to limb formation? |
|
Definition
- The lateral plate mesoderm gives rise to the bones, tendons, ligaments, and vasculature of the limbs.
- The somitic mesoderm that migrates into the developing limb gives rise to the musculature
- The neural Crest Cells that migrate into the limb give rise to melanocytes and Schwann cells. |
|
|
Term
| Describe location of muscle compartments after limb rotation: |
|
Definition
Flexior compartment of the upper limb is anterior, whereas the flexor compartment of the
lower limb is posterior.
Extensor compartment of the upper limb is posterior, whereas the extensor compartment of the
lower limb is anterior. |
|
|
Term
| The first arch forms which structures? |
|
Definition
| The maxillary and mandibular arch; the incus forms from mx. cartilage and the malleus from the mn. cartilage |
|
|
Term
| What forms from Reicherts cartilage? |
|
Definition
| 2nd arch cartilage forms stapes and styloid process, stylohyoid ligament, and parts of the hyoid bone |
|
|
Term
| What is formed from 3rd pharyngeal arch? |
|
Definition
|
|
Term
| What do the fourth and sixth arches form? |
|
Definition
| Parts of the larynx: cuneiform, corniculate, thyroid, arytenoid and cricoid cartilages (maybe epiglottis) |
|
|
Term
| What blood vessel structures come from the third arch? |
|
Definition
| Head and neck vessels; L/R common carotid; L/R internal carotid |
|
|
Term
| What blood supply has its origins in the 4th and 6th arches? |
|
Definition
| Upper extremities; dorsal aorta; and lungs |
|
|
Term
| From which arch does ductus arteriosus originate? |
|
Definition
|
|
Term
| In what part of the brain do the sensory and motor neurons develop? |
|
Definition
| Motor develop in the basal (ventral ) columns and sensory are located in cranial nerve ganglia |
|
|
Term
| During what time period is the face developing? |
|
Definition
|
|
Term
| What are the fates of the pharyngeal clefts? |
|
Definition
First pharyngeal cleft forms the external auditory meatus The remaining three are overgrown by the second pharyneal arch |
|
|
Term
| What is the fate of the first pharyngeal pouch? Second? Third? Fourth? |
|
Definition
1 - Develops into the tubotympanic recess which develops into the tympanic cavity of the middle ear cavity and auditory tube 2 - palatine tonsil 3 - inferior parathyroid and thymus 4 - superior parathyroid and ultimobranchial body |
|
|
Term
| The ectodermally derived otic placode is the precursor to which developed structure? What develops following the placode? |
|
Definition
| The membranous labrynth of the inner ear; otic placode --> otic pit --> otic vesicle |
|
|
Term
| What are the 4 major contributers to heart development? Where do they come from and what do they form? |
|
Definition
1 - Primary heart field - splanchnopleuric mesoderm of the cardiac crescent; forming heart chambers 2 - Secondary heart field - splanchnopleuric mesoderm of dorsal mesocardium; outflow tract of heart
3 - Proepicardial organ - splanchnopleuric mesoderm septum transversum; epicardium and coronary arteries 4 - Cardiac neural crest - from neuroectoderm at dorsal aspect of neural tube; septate outflow tract and form anterior PS plexus in heart |
|
|
Term
| Describe the process by which the heart initially forms: |
|
Definition
| 2 lateral endocardial heart tubes form; 2 layers of myocardium form and are the first to fuse followed by the two tubes to form one endocardial heart tube surrounded by two layers of splanchnopleuric derived mesoderm |
|
|
Term
| While the myocardium is fusing to form the heart tube 2 more things happen: |
|
Definition
1 - myocardium secretes jelly and 2 - epicardial cells surround and cover heart tube creating a 4 layer heart tube: endocardium, myocardial jelly, myocardium, and epicardium |
|
|
Term
| In the primary heart tube where do you find venous inflow? What is the first structure encountered? |
|
Definition
| Inflow comes from the inferior; the first structure is the sinus venous |
|
|
Term
| Does septation of the heart occur before or after looping? |
|
Definition
|
|
Term
|
Definition
| Proximal and distal outflow tracts |
|
|
Term
| What can be used to promote closure of a patent ductus arteriosus |
|
Definition
| Prostaglandin synthesis inhibitors |
|
|
Term
| How is the septation of the heart achieved? |
|
Definition
- Septum primum extends caudally closing the osteum primum as it extends
- superior and inferior endcardial cushions meet and fuse to divide the AV canal into R/L forming the septum intermedium
- growing septum primum fuses with septum intermedium
- osteum primum (a foramen) is destroyed
- osteum secundum at superior edge of septum primum opens before osteum primum closes
- septum secundum appears on ceiling of R atrium adjacent to septum primum
- see foramen ovale in this septum secundum
|
|
|
Term
| Throughout fetal life, through which holes is blood shunted between atria? |
|
Definition
| Foramen ovale in the septum secundum and ostium secundum |
|
|
Term
| When is septation of the heart complete? |
|
Definition
| When the trunconal swellings fuse together and fuse with the inferior endocardial cushion and the interventricular septum, thus separating R and L ventricles; end up in a helical arrangement |
|
|
Term
| What would be a common cause of a VSD? |
|
Definition
| Ventricular septal defect could be caused by failure of a muscular and membranous ventricular septa to fuse |
|
|
Term
| What is persistent truncus arteriousus? |
|
Definition
| Failure of trunconal septa to form due to fault in neural crest cells; results in mixing of oxygenated and deoxlygenated blood because both sides have a common outflow tract; usually a VSD occurs as well |
|
|
Term
| What is the Tetralogy of Fallot? |
|
Definition
Primary defect is a malalignment of the muscular outflow septum; Four classic malformations: VSD Pulmonary stenosis Overriding aorta Right ventricular hypertrophy |
|
|
Term
| The expanding fluid-filled amniotic cavity obliterates the chorionic cavity between what weeks? |
|
Definition
|
|
Term
| The foregut and hindgut terminate in which cranial and caudal blind-ended membranes? |
|
Definition
Foregut - buccopharyngeal membrane Hindgut - cloacal membrane |
|
|
Term
| Which structures form the umbilical cord? |
|
Definition
| Vitelline duct and yolk sac |
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