Growth And Development 1 Flashcards
The day of birth marks the beginning of what period
Postnatal period
When the male sperm and female ovum unite
Fertilization
About how long does the prenatal period last
39 weeks
Science of the development of the offspring before birth
Embryology
What is a fertilized ovum
A zygote
Where is the ovum fertilized
In the Fallopian tube or outter one third of the ova duct
Milton division begins immediately and about three days after fertilization what is created?
Solid mass of cells called morula
Hollow ball of cells when the zygote reaches the uterus
Blastocysts
After ten days, what happens with the embryo
It implants in the lining of the uterus
Two cavities of the blastocyst
Yolk sac and amniotic cavity
What is the function of the yolk sac in humans?
Produces red blood cells
What is the function of the amniotic sac?
Bag of waters in which the embryo floats during development
Develops into an important fetal membrane in the placenta
Chorion
Connects the blood vessels of the chorion to the rest of the placenta
Chorionic villi
Function of placenta
Anchors developing fetus to the fall of the uterus and provides a bridge for the exchange of nutrients and waste products between mother and baby
The placenta also serves as the
Respiratory and endocrine organ
Maternal blood fills what part of the placenta
Lacunae of the placenta
The length of permanent or prenatal development is also called the
Gestation period
The gestation period is broken into 3 periods called
Trimesters
Stage of development that extends from about the third week of gestation until week 8
Embryonic phase
What term is used to define the developing offspring on the first trimester?
Embryo
Stage from week 9 to week 39 after gestation
Fetal phase
During the fetal stage, the baby is referred to as
The fetus
Description of an embryo by day 35
Heart is beating, 8mm long, eyes and limb buds visible
Description of a fetus at the end of the first trimester
7 to 8 cm, apparent facial features, complete limbs, gender identifiable
Description of fetus by 4 months
All organ systems are complete and in place
All of the cells are what at the very beginning of the embryonic stages?
Stem cells
The three layers of stem cells developed early in the first trimester
Primary germ layers
3 primary germ layers
Endoderm, ectoderm, and mesoderm
What do the ectoderm skin cells produce?
Epidermis of skin, tooth enamel, lens and cornea of eye, outer ear, nasal cavity, facial bones, skeletal muscles in head, brain and spinal cord, sensory neuron’s
What do the mesoderm stem cells develop into
Dermis of skin, circulatory system, many glands, kidneys, gonads, muscle, bones (except facial)
Endoderm stem cells develop into
Lining of the gastrointestinal tract, linings of lungs, lining of hepatic and pancreatic ducts, kidney ducts and bladder, anterior pituitary gland, thymus gland, thyroid gland, parathyroid gland, tonsils, adrenal medulla
Process of how the primary germ layers develop into many different types of tissues
Histogenesis
The ways in which tissues form themselves into organs after Histogenesis is called
Organogenesis
Developmental problems present at birth
Birth defects
Environmental factors that cause birth defects
Teratogens
Critical period of development for the central nervous system
Week 3-38
Critical period for the development of the heart
Weeks 3-8
Critical period for development for the upper limbs and lower limbs
Weeks 4-8
Critical period for development for ears
Weeks 4-20ish
Critical period for development for eyes
Weeks 4-38
Critical period for development for teeth
Weeks 6-38
Critical period for development for palate
Weeks 6-9
Critical period for development for external genitalia
Weeks 7-38
Day of birth marks the end of what period
Prenatal period
