Embryology 1 & 2 Flashcards
what is the bronchial tree?
it is the branching system of bronchi and bronchioles, conducting air from the windpipe into the lungs
what is the function of the bronchial tree?
the bronchial tree distributes air to the lungs
what structure is responsible for the primary function of the lungs, exchanging carbon dioxide and oxygen?
the alveoli
what are alveoli?
tiny sacs within our lungs that allow oxygen and carbon dioxide to more between the lungs and bloodstream
what is the process by which male and female gametes are formed?
they are formed during a process of cellular reproduction called meiosis
during meiosis how many times is DNA replicated?
once
how many cells are the cells divided into from one circle of meiosis?
4 separate cells
what is fertilisation?
it is the action or process of fertilising an egg or a female animal or plant, involving the fusion of male and female gametes to form a zygote
what is a blastocyst?
it is a thin walled hollow structure in early embryonic development that contains a cluster of cells called the inner cell mass from which the embryo arises
what does a blastocyst possess which subsequently forms the embryo?
an inner cell mass
what is the trophoblast?
the cells collected in the outer layer of the blastocyst
what gives rise to the placenta?
the trophoblast
what is implanted into the uterine wall?
the blastocyst
what is placenta?
it is a flattened circular organ in the uterus of pregnant eutherian mammals, nourishing and maintaining the foetus through the umbilical cord
basically describe placenta
it is a temporary organ that joins the mother and foetus
what transfers oxygen and nutrients from the mother to the foetus and permits the release of carbon dioxide and waste products from the foetus?
the placenta
what is the upper surface of the placenta like?
smooth
what is the under surface of placenta like?
rough
what is the placenta composed of?
it is composed of both maternal tissue and tissue derived from the embryo
what is the chorion?
it is the embryonic-derived portion of the placenta
what is the chorion composed of?
fatal blood vessels and trophoblasts which are organised into finger-like structures called chorionic villi
what does the placenta remove?
waste products, like carbon dioxide
what does the placenta act to provide?
oxygen and nutrients to the foetus
what is the fatal placenta called?
the chorion frondosum
what develops from the same blastocyst that forms the foetus?
the fatal placenta
what metabolises a number of substances and release metabolic products into maternal and/or fatal circulations?
the placenta
what functions as a fetomaternal organ with 2 compounds ?
the placenta
what are the 2 compounds of the placenta?
the fatal placenta and the maternal placenta
what is the maternal placenta called?
decidua basalis
what does the maternal placenta develop from?
it develops from the maternal uterine tissue
what are chorionic villi?
they are villi that sprout from the chorion to provide maximum contact area with maternal blood
what are an essential element in pregnancy from a histomorphologic perspective?
chorionic villi
what are part of the border between maternal and fatal blood during pregnancy?
villi
what are the main functional units of the placenta?
the chorionic villi
why are the chorionic villi the main functional units of the placenta?
they are within which fatal blood is separated by only 3 or 4 cell layers from maternal blood in the surrounding intervillous space
what is the bilaminar disc?
the bilaminar disc it refers to the epiblast and the hypoblast, evolved from the embryoblast
what are the 2 balloons that the 2 layers the epiblast and the hypoblast are sandwiched between?
the primitive yolk
and the amniotic cavity
when is the bilaminar embryonic disc formed?
it is formed when the inner cell mass forms 2 layers of cells, separated by an extracellular basement membrane
what is the external layer of the bilaminar disc called?
the epiblast
what is the internal layer of the bilaminar disc called?
the hypoblast
what do the epiblast and the hypoblast compose?
the bilaminar embryonic disc
what is the trilaminar disc?
it is an early stage in the development of triploblastic organisms, which include humans and many other animals
what is the bilaminar disc differentiated further into?
the trilaminar disc
what is the trilaminar disc?
it is an embryo which exists as 3 germ layers
what are the 3 germ layers?
the ectoderm,
mesoderm and
endoderm
what is the ectoderm?
it is the primary germ layer in the very early embryo
what is the outermost layer of cells or tissue of an embryo in early development called?
the ectoderm
what parts are derived from the ectoderm?
the epidermis
nerve tissue and
nephridia
what does the ectoderm emerge and originate from?
the outer layer of germ cells
what is the mesoderm?
it is a primary germ layer in the very early embryo
what is the middle layer of cells or tissues of an embryo?
the mesoderm
what parts are derived from the mesoderm?
cartilage
muscles
bone
what germ layer forms connective tissue and muscle throughout the body?
with the exception of in the head region where some of these structures have a neural crest origin
the mesoderm
what is the endoderm?
it is a primary germ layer in the very early embryo
what is the innermost layer of cells or tissue of an embryo in early development?
the endoderm
what parts are derived from the endoderm?
the lining of the gut and associated structures
what is the neural tube?
is it a hollow structure in an embryo
what forms the neural tube?
the brain and spinal cord
what can defects in the development of the neural tube result in?
congenital abnormalities such as spina bifida
what is the formation process of the neural tube called?
neurulation
when does neurulation begin?
it begins when the underlying dorsal mesoderm signals the ectodermal cells above it to elongate into columnar neural plate cells
what does the embryonic structure the neural tube ultimately form?
the brain and spinal cord
what is the process of neurulation divided into?
primary neurulation and secondary neurulation
what is primary neurulation?
it is when the cells surrounding the neural plate direct the neural plate cells to proliferate, invaginate and pinch off from the surface to form a hollow tube
what is the gut tube?
it is the primitive precursor of both the respiratory and digestive systems
how is the formation of the gut tube initiated?
it is initiated by ventrally directed invagination of the anterior intestinal portal and the causal intestinal portal, respectively situated at the anterior and posterior ends of the endoderm
what is the lung bud also known as?
the respiratory bud
name an embryological endodermal structure
the lung bud
what does the lung bud develop into?
the respiratory tract organs such as the larynx, trachea, bronchi and lungs
what does the lung bud originate from?
the lung bud forms from the respiratory diverticulum
what is the respiratory diverticulum?
it is a ventral outgrowth of the foregut endoderm
