GENERAL EMBRYOLOGY Flashcards
What is embryology?
Study of the development of single individual from the
egg to the adult condition
What are the two stages of human development?
Prenatal period- Before birth
Postnatal period-After birth
What is ovum/oocyte?
Female germ cell (gamete) produced in the ovaries
What is sperm?
Male germ cell (gamete) produced in the testes
What is fertilization?
Fusion in between male and female pronuclei of male and
female germ cells
What is zygote?
Cell results from the union of an ovum/oocyte and a sperm
during fertilization
How do you calculate expected date of delivery?
Nagele’s rule : EDD = ((LMP + 1 year + 7 days) – 3
months)
What is cleavage?
Series of mitotic cell divisions occurring in the zygote
immediately following fertilization; cell formed -
blastomeres
What is Morula?
Solid mass of 12 to about 32 blastomeres
What is Blastocyst?
Morula that contains a fluid-filled cavity
What is Implantation?
Attachment of blastocyst to the endometrium (lining of uterus)
What is Gastrula?
3-germ layered embryo
What is Nerula?
Development of neural tube from neural plate
What is embryo?
The developing human from conception to 8 weeks after fertilization
What is organogenesis?
Part of embryonic period
weeks 3-8
How is the size of the developing human measured during embryonic period?
Measured as crown-rump length (CRL)-sitting height
What is fetus?
The developing human
after the embryonic
period
What is the length of time in which the developing human is referred to as a fetus?
From week 9 to term or birth (week 38)
How is fetus measured?
Measurement is
crown-heel length-standing height
When is pregnancy said to reach term?
37 - 42 weeks
What is pre-term delivery?
birth before 37 weeks
What is post-term delivery?
birth after 42 weeks
What is abortion and miscarriage?
The birth of the developing human (embryo or fetus)
before it becomes viable: before the 20th week
What is the infant period?
Birth to the first year
An infant aged one month or less is called a newborn or neonate
What is childhood period?
Period from about 13 months until puberty
What is puberty period?
Period during which secondary sexual characteristics develop
12-15 years in girls; 13-16 years in boys
What is adolescence period?
Period from about 11 to 19 years of age, which is characterized by rapid physical and sexual maturation
When is adulthood?
Attainment of full maturity
Generally between ages of 18 and 21 years
What is oblique plane?
Not pass through
any of these
standard plane
Recall the anatomical terms used to describe fetus?
Anterior -ventral
Posterior - dorsal
Superiorcranial/cephalic/rostral
Inferior - caudal (tail)
Proximal or distal relative to source of attachment
Recall the planes used to describe fetus?
Median or midsagittal Parasagittal Transverse Coronal Oblique
What is Spermatogenesis?
Formation of male gamete
What is oogenesis?
Formation of female gamete
What are gametes?
Cells that carry out special function of reproduction
What are gonands?
organs where gametes are
formed
What is the male gamete?
sperm
What is the female gamete?
ovum
From what cells to gametes develop?
primordial germ cells
What are the parts of the male gamete (spermatozoa)?
Head, Neck and Tail
What does the head consist of?
Forms bulk of sperm
- A nucleus which contains 23 chromosomes
- Acrosome (acrosomic cap)
What is acrosome?
covering the anterior two thirds of the nucleus, has enzymes which help the sperm to enter the female gamete
What is neck of spermatozoa?
narrow junction between head and tail, contains a centriole
What is tail of spermatozoa?
consists of 3 segments –
middle piece, principal piece and end piece
Tail provides the
motility of the sperm
Middle piece of tail contains mitochondria
What is Spermatocytogeneis?
Formation of spermatids from spermatogonia
What is Spermiogenesis?
Development of sperm from spermatids
