DH embryology and histology

horse-shoe shaped spaces between the lips and the cheeks anteriorly and laterally and the teeth and the gums medially and posterially

a dense pad of underlying fat tissue at the posterior portion of each vestibule covered by the buccal mucosa

small elevation of tissue on the inner portion of the buccal mucosa that protects the opening of the parotid duct

where pink labial or buccal mucose meets the red alveolar mucosa at the mucobuccal fold

a dense pad of tissue just distal to the last tooth of the mandibular arch

gingiva at the margin of each tooth, also called free gingiva, which forms a cuff above the neck of the tooth

a space that the inner surface of the gingiva faces

gingiva between adjacent teeth, an extension of attached gingiva

lateral to each deep lingual vein, have fringe like projections

• Preimplantation period
• embryonic period

in the first trimester

environmental agents such as infections, drugs, and radiation that may cause malformations to the fetus

the earliest indication of a part or an organ during prenatal develpment

period of unattached conceptus that takes place during the first week of pregnancy

when a woman's ovum is penetrated by a man's sperm

a fertilized egg formed by the union of the ovum and sperm

during fertilization

the ovum's chromosomes join with the sperms chromosomes

diploid number of 46

with meiosis, because during the development of the sperm and ovum, this process emables the ovum and the sperm to reduce by one half the normal number of chromosomes to a haploid number of 23

mitosis

cell division of the zygote

true

the collection of cells after the zygotes division

split into smaller and more numerous cells

about 5 days

• mitosis-during growth or repair
• meiosis-during reproduction

from the site where fertilization took place (fallopian tube) to the uterus

blastocyst becomes embedded in the endometruim and continues to divide.

about 6 days into it

uterin wall

the back wall of the body of the uterus towards the mothers spine

dangerous situation where the blastocyst implants somewhere outside of the uterus

• trophoblast layer
• embryoblast layer

peripheral cell layer, outside cells that will eventually become the prenatal support tissues (placenta, and umbilical circulation)

inner mass of embryonic cells, inner cells that will become the embryo

there is an extra chromosome #21

the second period of prenatal development, extends from the beginning of the second week to the end of the eighth week.

• induction
• proliferation
• defferentiation
• morphogenesis
• maturation

an embryo

because theses physiological processes alson allow the teeth and associated structures, as well as other organ structures, to develop in the embryo.

• Induction (the pow wow)
• action of one group of cells on another that leads to the establishment of the developmental pathway in the responding tissue. The cells decide who they are going to be.

True

a type of physiological process that follows induction. it is controlled levels of cellular growth present during most of embryological development.

uncontrolled growth of cells

• interstitial
• appositional

• growth that occurs from deep within a tissue or organ (like blowing up a balloon)
• soft tissue growth

• a tissue enlarges its size by the addition of layers on the outside of a structure (like paint on cinder block)
• hard tissues such as mature bone or dental tissues

cartilage and growing bone tissue

No. growth involves differential rates for different tissues and organs. for instance tooth eruption in a child, this occurs over many years allowing for the associated growth of the jaw bones.

physiological process where identically genetic cells start to become structurally and functionally different and start to become tissues.

differentiation

• cytodifferentiation
• histodifferentiation
• morphodifferentiation
• morphogenesis
• maturation

development of different cell types

development of different tissues within a structure

development of the differing structure, or morphology

• the complexity of the structure and function of these cells increases
• the process of development of specific tissue structure or shape

Yes. it is a result of the new varieties of cells interacting with eachother producing an increasingly complex organism

tissues and organs growing up in form, function, and size

miscarriage

at the end of the embryonic period, or end of the eigth week

the implanted blastocyst grows by increased proliferation of the embryonic cells as well as cellular morphogenesis and differentiation

forms in the second week. it is the 2 layer meeting point of 2 fluid filled cavities.

• epiblast (top layer)
• hypoblast (bottom layer)

high columnar cells

small cuboidal cells

the embryo

• amniotic cavity
• yolk sac

faces the epiblast layer

faces the hypoblast layer, and serves as intial nourishment for the bilaminar embryonic disc

the trophoblast (outside cells) layer, and the endometrium.

the placenta and umbilical circulation system

the embryonic period, because of the beginnings of all essential external and internal structures

• Syphillis
• defects in the incisors (hutchinson's incisors) and molars (molberry molars) as well as blindness, deafness, and paralysis

• fetal alcohol syndrome
• learning disabilities and deformed facial features

• tetracycline.
• permanently stains teeth. the antibiotic becomes chemically bonded to the dentin for the life of the tooth.

forms in the third week. It is a thickening of cells that splits the epiblast layer of the bilaminar embryonic disc in half. The right and left sides will be symmetrical. by this point, from a top view, the embryo would resemble the sole of a shoe, with a the head end wider than the tail end, and slightly narrowed in the middle.

increased proliferation of cells in the midline area.

• an embryonic connective tissue
• during the start of the third week

when some cells from the epiblast (superior) layer move or migrate toward the hypoblast (inferior) layer in the area of the primitive streak and get caught in the middle.

what the bilaminar embryonic disc turns into after the mesenchyme is formed. It now consists of 3 layers instead of 2.

• ectoderm (was previously the epiblast layer)
• mesoderm (from mesenchyme)
• endoderm (was previoulsy the hypoblast layer)

• structures on the outside of the body:
• epidermis
• sensory epithelium of the eyes, ears, and nose (senses)
• nervous system
• neural crest cells

• structures more in the middle of the body such as:
• dermis
• connective tissue
• muscle
• bone
• lymphatics
• blood cells
• bone marrow
• carilage
• reproductive organs
• excretory organs

• structures on the very very inside of the body such as:
• respiratory system linings
• digestive system linings
• liver cells
• pancreatic cells

abnormal development of the ectoderm. Affects the teeth, skin, hair, nails, facial structures, and glands. You will survive this situation, usually no miscarriage, and it is usually genetic.

head end of the embryo (wide end of the shoe)

• oropharyngeal membrane consisting of ONLY the ectoderm layer externally, and endoderm layer internally.
• it will eventually become the primitive mouth and beninning of the digestive tract

tail end (more narrow part of the shoe)

• The cloacal membrane (consists of only the ectoderm layer and endoderm layer)
• it will eventually become the anus and terminal end of the digestive tract

during the later part of the third week of prenatal development

specialized group of cells the differentiate from the ectoderm and are localized to the neural plate of the embryo.

where all the neuroectoderm hangs out. A band of cells that extends the length of the embryo from the cephalic end to the caudal end

the plate starts to thicken and deepen further which forms this groove

the plate sinks even deeper and forms this fold

the neural folds meet superior to the neural groove and form this tube which fuses at the top and becomes the spinal cord

• spina bifida
• results as failure of fusion of the neural tube. it is characterized by defects in the verebral arches and various degrees of disability.

folic acid (vitamin B9)

• specialized cells the develop from the neuroectoderm and give rise to:
• connective tissue
• cartilage
• bone
• dental tissues

a fourth embryonic layer

the unergo differentiation into diverse cell types that are in part specified by local environmental influences

• 38 paired blocks of mesoderm along both sides of the neural tube
• give rise to:
• skin
• bones of head and neck

migrate from the crest cells of the neuro folds, and disperse within the mesenchyme

• embryonic folding
• the disc starts to fold-establishing the human axis and placing the tissues in their proper formation for further development by extensive proliferation of the ectoderm, and differentiation of basic tissues.

endoderm is on the inside of the ectoderm, with the mesoderm filling in areas between these two layersl. this forms one hollow tube lined by the endoderm from the cephalic end to the caudal end of the embryo- or from the oropharynegeal membrane to the cloacal membrane.

the digestive tract

• foregut
• midgut
• hindgut

anterior section of the tube which eventually forms the throat. It also inclueds a protion of the primitive yolk sac as it becomes enclosed with folding.

middle section of the tube-forms the rest of the pharynx, and the rest of the digestive tract

posterior section of the tube- forms the rest of the digestive tract

face, neck, and oral structures

beginning of 9th week, or third to ninth month. It is a time of maturation. Allows the newly formed tissues and organs to function

during the fetal period of prenatal development

by the fourth month