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194 Cards in this Set
- Front
- Back
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What is Embryology?
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Study of growth & changes which organisms undergo during their development
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_________ is the period of development before birth where development proceeds rapidly.
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prenatal period
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________ is the period of development after birth where changes take place gradually, followed by aging.
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postnatal period
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What are the developmental periods?
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prenatal & postnatal periods
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What are the prenatal periods?
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Pre-embryonic
embryonic fetal period |
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________ period, is the period of development of the gamates (gametogenesis), their fusion, cleavage, blastulation,gastrulation & up to implantation.
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pre-embryonic period
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________ period, is the period from implantation to the origin of the primordia of the organs & formation of basic body form.
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embryonic period
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_________ period, is the period of growth & maturation of the organ-system, considered the later stages of birth
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fetal period
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_______ is the term used for developing offspring during the embryonic period.
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embryo
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_______ is the term used for developing offspring during the fetal period.
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fetus
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__________ is the term used to describe the embryo/fetus & its membranes.
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conceptus
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What is teratology?
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The study of malformations (abnormalities)
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What are the 2 parts of the theory of recapitulation?
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Ontogeny
phylogeny |
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_______ repeats phylogeny.
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ontogeny
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________ refers to an individual's complete life history. (ex. from fertilization to death.)
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Ontogeny
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What does phylogeny refers to?
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ancestral history of organism, describes evolutionary development
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Human sperm was first seen by Hamm & _________ (1677).
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Leeuwenhock
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Ovarian follicles were first described by ______ (1672)
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De Graaf
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What are the 2 theories of development?
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pre-formation theory
epigenetic theory |
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What is the pre-formation theory?
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sperm or ovum contained the new individual in miniature form
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________ theory, states that development occurs through progressive growth & differentiation through causal interation.
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epigenetic theory
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Who invented the epigenetic theory?
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Wolff
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______ gave the foundation of the knowledge of germ layers.
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Van Baer
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Van Baer (1828) gave the foundation of the knowledge of ______.
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germ layers
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What are the stages of mitosis?
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prophase, prometaphase, metaphase, anaphase, telophase, daughter cells.
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What are the first 4 stages of Meiosis?
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*Pairing begins
*Pairing of chromatids *Chiasma formation (crossingover) *Pulling apart of double-structured chromosomes |
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What are the last 3 stages of Meiosis?
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*Anaphase of 1st meiotic division
*Cells contain 23 double-structured chromosomes-1st meiotic division *Cells contain 23 single chromosomes-2nd meiotic division |
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________ is the process of production of gametes ex. (spermatozoa in male & ovum in female.)
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gametogenesis
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_______ (1834-1914) made the important distinction bt. Soma(body) & the germ cell (gametes)
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Weismann
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________ refers to the process by which germplasm are converted into highly specialized sex cells (gametes)that create a new being.
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gametogenesis
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The process of development of sperm is called ______ & takes place in the testes after puberty.
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spermatogenesis
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_______ germ cells are destined to develop into gametes, are originated in the wall of the yolk sac.
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Primodial
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Spermatogenesis can be subdivided into ________ & ________.
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spermatocytogenesis
spermiogenesis |
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In spermatocytogenesis, the spermatogonia proliferate mitotically resulting in _______ & ________ spermatogonia
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type A (stem cell)
type B |
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The type ____ spermatogonia proceed in spermatogenesis & replicate its DNA in interphase of its cell cycle to form primary spermatocytes.
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B
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The type B spermatogonia proceed in spermatogenesis & replicate its DNA in interphase of its cell cycle to form ________.
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primary spermatocytes
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_______ spermatocytes subsequently undergo 2 successive meiotic divisions.
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Primary
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What is reduction division?
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When chromosomes are equally distributed & each member of a homologous pair goes into one of the daughter cells.
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Where does reduction division occur?
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In the first division that primary spermatocytes go through.
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The resulting products of the first meiotic (reduction division) are called _______.
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secondary spermatocytes
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__________ spermatocytes undergo a equational division,that produces ________.
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secondary
spermatids |
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_________ is when spermatids go through a metamorphosis & form spermatozoa.
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spermiogenesis
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_________ are highly differiated & motile cells that are formed during spermiogenesis.
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spermatozoa
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What part of the nucleus becomes concentrated & forms the bulk of the head of the sperm cell during spermiogenesis?
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chromatin
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The _______ becomes concentrated & reorganized to form the _______ over the head of the sperm cell during spermiogenesis.
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golgi apparatus
acrosomal cap |
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The centriole moves away from the anterior end taking on the shape of the ring to encircle the _______ during spermiogenesis.
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flagellum
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The _______ become concentrated around the proximal part of the flagellum which form the middle piece of the spermatozoa during spermiogenesis
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mitochondria
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The mitochondria becomes concentrated around the proximal part of the flagellum which form the ________ of the spermatozoa
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middle piece
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sperm & secretions from accessory sex gland = _______.
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semem
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In most mammals, spermatogenesis is believed to last _____ days & another _____ weeks may be required for passage through epididymis.
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50-70 days
2-3 weeks |
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What are female germ cells called after the oogonium replicates its DNA in interphase & enters the prophase of first meiotic division.
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primary oocyte
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The first meiotic division is halted in the diplotene stage of prophase 1 & won't resume until when?
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until puberty
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After puberty a number of primary oocytes resume the first meiotic division forming 2 daughter cells called ________ & ________.
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secondary oocyte
first polar body |
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During oogenesis after puberty which 2 of the newly formed daughter cells receive the most cytoplasm?
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secondary oocyte
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What is the smaller daughter cell formed after puberty during oogenesis called?
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first polar body
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The products of second meiotic division after puberty during oogenesis are ________ & _______.
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ovum
secondary polar body |
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____________ is the fusion of the sperm & ovum to initiate the development of a new individual.
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Fertilization
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Fertilization is preceded by ________ & _______.
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Ovulation & Insemination
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__________ is the release of the primary or secondary oocytes from the surface of the ovary.
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Ovulation
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___________ is the deposition of sperms into the female genital tract.
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Insemination
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The __________ is controlled by FSH and LH produced by adenohypophysis
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ovulation
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The ruptured follicles are converted into the __________
under hormonal influence. |
corpus luteum
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Animals such as the cat & rabbit can ovulate only by inducing the coitus, these animals are called ________.
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induced ovulators
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In _______ animals such as bitch, sow, cat & small ruminants,more than 1 oocyte are set free usually from separate follicles.
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polytocous
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In _________ animals only one oocyte is set free during each ovulation period.
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monotocous
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At _________, millions of male germ cells or spermatozoa are deposited into the vagina.
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insemination
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Sperm usually remains viable in the female genital tract for how long?
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1-2 days
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How long does sperm survive in horses,dogs, fowl & turkeys?
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6-7 days-dogs & horses
32 days-fowl 70 days in turkey |
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Where are sperm host glands found?
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avian vagina
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How long does ovum viability last?
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24 hours
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Where does fertilization take place?
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ampullary region of the uterine tube
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Spermatozoa upon arrival in the female genital tract must undergo the process of ________ & ______ before fertilizing the oocyte.
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capacitation
acrosomal reaction |
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________ involves the removal of glycoprotein coat & seminal plasma protein from the plasma membranes that overlies the acrosomal region of the spermatozoa.
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capacitation
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Capacitation is followed by ________ which involves the release of enzymes in the acrosome.
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acrosomal reaction
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What enzymes are released during the acrosomal reaction in the acrosome?
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hyaluronidase & trypsin
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What are chemical changes in the zona pellucida called?
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zona reaction
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What are the 3 steps of sperm penetration?
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1)production of the ovum & 2nd polar body.
2)Zona reaction 3)female & male pronuclei |
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What is the term used when the nuclei of the female & male germ cells swell after the zona reaction?
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female & male pronuclei
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What are the two types of twinning?
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monozygous
Dizygous |
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_______ is when one ovum is fertilized but subsequently divides at the blastocyst stage into two genetically identical masses (same sex) & (same blood group).
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Monozygous
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_______ occurs when two seperate ova are fertilized.
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dizygous
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What usually follows an ectopic implantation?
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early embryonic death
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What is a freemartin?
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Infertile born female caused by dizygous twinning
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What is polyspermy?
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This is when more than one sperm may penetrate the female germ cell.
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__________ is impregnation by successive acts of coitus, of two or more ovum that were liberated at approximately the same time, by two or more different males
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superfecundation
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________ is when a pregnant female ovulates, conceive & produce a second younger fetus.
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superfetation
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superfecundation occurs most in what species?
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cats & dogs
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superfetation occurs most in what species?
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Pigs
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What is the gestation period of a mare & a cow?
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335-345 days
279-282 days |
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What is the gestation period of a sow,a bitch & a queen?
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114-120 days
60-65 days 60 days |
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_________ is the beginning of the development of a multicellular organism.
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Cleavage
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Cleavage results in the production of many smaller cells called ________.
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blastomeres
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The cleavage that produces a complete division of zygote & where a small amount of yolk is present is called ________.
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Total or holoblastic
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The cleavage that occurs mostly in birds where there is a massive amount of yolk present that prevents the complete division of the zygote is called _______.
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partial or meroblastic
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After 4 to 6 divisions, zygote results in the formation of a solid cluster of cells termed a ________.
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morula
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________ are cells within the morula
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blastomeres
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What do call an embryo in a stage of development that causes the rupture of the zona pellucida & forms the fluid filled cavity called the blastocoel.
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blastocyst
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When the embryo changes size & shape the cells of the blastocyst become different, there is a small area that becomes larger than the rest & constitute the _________ or _________ or __________ from which the embryo will develop.
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embryonic disc
inner cell mass blastodisc |
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The cells on the periphery of the blastocyst are __________ & facilitate the absorption of nutrients early in development.
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trophoblast cells
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What stage of embryonic development forms 3 separate germ layers?
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gastrulation
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The ________ (inner cell mass) becomes rearranged to form three separate layers called germ layers in gastrulation.
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embryonic disc
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The embryonic disc becomes rearranged to form three separate layers called ________.
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germ layers
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The outermost germ layer is called _________, the innermost is __________ & the layer formed in the middle is called _________.
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ectoderm
endoderm mesoderm |
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During the formation of the endoderm a group of cells from the ________ become detached from its inner surface to form a new continuous sheet, lining the interior of the blastocyst.
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inner cell mass (embryonic disc)
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What is the enclosed cavity of the endoderm called ?
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primitive gut or archenteron
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The process of detachment of the cells from the inner cell mass of the endoderm is called _____.
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delamination
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The cells in the upper layer of the inner cell mass soon undergo considerable expansion during gastrulation & constitutes the _______.
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ectoderm
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Most of the cells between the ectoderm & endoderm converge towards the midline, becoming elongated to form the ________.
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primitive streak
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The cranial end of the primitive streak becomes slightly enlarged to form the _______ or _______.
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primitive or Hensen's node
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The primitive streak serves as a center of _______ ______ & gives rise to mesodermal cells.
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cellular proliferation
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After 4 to 6 divisions, zygote results in the formation of a solid cluster of cells termed a
__________. |
morula
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The cells from the primitive streak undergo rapid proliferation and invaginate between the ectoderm and endoderm layers. This population of the cells form the _________.
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mesoderm.
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The ___________ contributes to the formation of the head of the mesoderm as well as notochord.
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primitive node
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The notochord induces the ectoderm to form the _______ .
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neural ectoderm (neural plate)
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Later the notochord regresses and persist in adult as the ___________ of the intervertebral disc.
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nucleus pulposus
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The dorsally proliferating cells from the primitive streak, arranged on either side of the notochord, become thickened to form the _________.
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paraxial mesoderm.
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The laterally proliferating cells from the primitive streak, form the ___________.
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lateral plate or lateral mesoderm
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The junction between the paraxial mesoderm & lateral mesoderm is called _________.
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intermediate mesoderm.
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The lateral mesoderm is split into two layers _______ & _______.
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somatic and splanchnic mesoderm.
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The space between the two layers of the lateral mesoderm is called the ________.
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coelom
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The somatic mesoderm is associated with the ectoderm to form ________.
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somatopleure
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splanchnic mesoderm is associated with endoderm to form _________.
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splanchnopleure.
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Paraxial mesoderm later forms a series of mesodermal thickenings called _________.
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somites
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Somites constitute the vertebral column also called the _______, its associated muscles are called _______ and connective tissues are called ________.
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sclerotome
myotomes dermatome |
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The part of the germ layer which underlies the embryonic disc is called _______.
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intra-embryonic germ layer
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Cells lying peripherally under the trophoblast of the germ layer is called the _________.
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extraembryonic germ layer.
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The surface ectoderm consists of what?
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Epidermis
Epithelium of sense organ, nasal cavity, sinuses Mouth |
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The neural ectoderm consists of what?
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Nervous tissue including hypophysis, adrenal medulla and retina of eye
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_________ mesoderm consists of the Vertebral column and its associated muscles and connective tissue.
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Paraxial mesoderm:
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__________ mesoderm consists of the kidneys, gonads and genital ducts.
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Intermediate mesoderm
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_______ mesoderm consists of the cardiovascular & lymphatic systems, pleura & peritoneum, spleen, muscles & connective tissues
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Lateral
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The epithelium of the endoderm consists of _______.
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Pharynx
Digestive tube including glands Bladder, urethra and associated glands |
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The establishment of body form is mainly accomplished by ________ & ________.
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longitudinal folding
transverse or lateral folding |
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__________ folding is more pronounced in the cranial and caudal end of the embryo, thus head and tail fold are formed.
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longitudinal
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The _________ or _________ folding of embryonic disc obtains a cylindrical appearance, a lateral and ventral body wall of the embryo is established.
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transverse or lateral
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The embryonic disc is converted from a flat-disc into a ________ structure.
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curved cylindrical
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The ____________ develop into extraembryonic or fetal membranes which surround the cylindrical embryo.
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extraembryonic germ layers
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The lateral & ventral body walls develop by the folding of the _______ as a result of body folding.
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intraembryonic somatopleure
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_________ constitutes the amnion & chorion as a result of body folding.
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extraembryonic somatopleure
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The gut is formed by the ___________ as a result of body folding.
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intraembryonic
splanchnopleure |
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What does the extraembryonic splanchnopleure form as a result of body folding?
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yolk sac & allantois
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The yolk sac communicates with gut through __________ or _________.
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vitellointestinal duct or yolk stalk
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The unclosed area on the ventral surface of the embryo at the junction of embryonic & extraembryonic territories make up the _______.
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umbilical cord
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With further development the cranial region grows rapidly forming a _______ which is flexed ventrally due to the development of the cervical flexure in the future neck region.
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relatively large head
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During further development of the embryo, the external structures of the _______, ______, & _______ appear.
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eye, ear and nose
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The limb buds appear as a single paddle-shaped outgrowth of the ________ of the body wall at the sites of the future pectoral and pelvic girdles.
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somatopleure
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The early age of the embryo is expressed by the number of somites, later ________ is used to determine the approximate age of the embryo.
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crown-rump (CR) length
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What are the membranes of the extraembryonic membranes?
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Amnion
chorion yolk sac allantois |
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What are the functions of the extraembryonic membranes?
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protection
nutrition |
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The amnion develops from the _______ _______, which gradually overgrow the embryo & finally fuse together.
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extraembryonic somatopleure
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The fluid of the amnion accumulates in the amniotic cavity & form ______ around the embryo.
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fluid filled sac
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________ is an excess amount of amniotic fluid.
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hydroamnion
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The yolk sac develops from the extra-embryonic ________.
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splanchnopleure
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In most mammals, the yolk sac develops and form temporary contact with chorion, termed _______________.
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Choriovitelline placenta
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_______________ of the yolk sac, regresses immediately, but remains functional for sometime (first quarter of pregnancy) in dog and horses.
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Choriovitelline placenta
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What is another term for well developed blood vessels that absorb the nutrition from the yolk sac.
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vitelline
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Allantois develop from the _________ as a diverticulum of the hindgut.
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extraembryonic splanchnopleure
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The allantois fuses with chorion to develop the __________ placenta.
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chorio-allantoic
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The blood vessels develop in the allantois, are termed _____________ .
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umbilical vessels
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Allantoic calculi is also called _______ in mares.
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hippomanes
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What is hydroallantois?
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Excessive fluid in allantois cavity. ex. pearshaped body
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The process of attachment is called ________.
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implantation
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When the embryonic sac lies in the uterine lumen or cavity, e.g. ruminants, equines and porcine. It is called _________ implantation.
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Superficial or Central implantation:
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When the embryonic sac lies in a fold or pocket of uterine wall, e.g. rat and squirrel. It is called _________ implantation.
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Eccentric implantation:
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When the embryonic sac penetrates and embedded into the uterine wall, e.g. guinea pig, carnivores, bats and man. It is called _________ implantation.
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Interstitial implantation:
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What is histotrophic nutrition?
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Nutrition from secretion of uterine gland
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What is hemotrophic nutrition?
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nutrition from maternal circulation
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What is the beginning of implantation for a sow & a bitch?
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13-14 days
17-18 days |
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What is the beginning of implantation for a queen & a ewe?
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13-14 days
15-20 days |
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What is the beginning of implantation for a cow & a mare?
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25-30 days
35-40 days |
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What is the placenta termed as?
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close contact of fetal membranes and maternal tissue for the purpose of physiological exchange between the fetus and mother
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What are functions of the placenta?
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Nutrition
Respiration through gaseous exchange Excretion Barrier Synthesis of hormones |
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What are the classifications of a placenta based on?
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Fetal membranes involved
Shape of Placenta Branching of Chorionic Villi Loss of Maternal Tissues at Parturition Histological Layers |
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What are the different types of placentations based on the fetal membranes involved?
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Choriovitelline or Yolk sac Placetation
Chorioallantoic Placentation |
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__________ placentation is when the yolk sac may combine with the chorion to form choriovitelline placenta. e.g. horse and dog
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Choriovitelline or Yolk sac Placetation:
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__________ placentation is when the allantois fuses with chorion an allantochorion is formed.
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Chorioallantoic Placentation
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What is the most common classification of placenta in domestic animals?
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Chorioallantoic Placentation
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Chorionic villi are uniformly distributed over the entire sac & found in the mare and sow, this described as a __________ shaped placenta.
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Diffuse
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The chronic villi(cotyledons) attach to endometrial prominences (caruncle). The combined fetal (cotyledon) and maternal (caruncle) structures form Placentomes. e.g. ruminants. This is described as a __________ shaped placenta.
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Cotyledonary
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What are the different shapes of the placenta?
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Diffuse
Cotyledonary Zonary Discoidal |
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The chorionic villi form a band around the chorionic sac, e.g. carnivores. This is described as a __________ shaped placenta.
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Zonary
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The chorionic villi form one or two disc-shaped area, e.g. Primates, rodents and bats. This is described as a __________ shaped placenta.
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Discoidal
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What are the different types of placenta based on branching of chorionic villi?
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villous
labyrinthine |
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______ occurs when there is simple branching of chorionic villi. e.g sow, mare & ruminants.
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villous
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______ occurs when there is complicated & anastomotic branching of the chorionic villi, e.g. carnivores & primates.
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labyrinthine
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What are the different type of placentia that are found based on loss of maternal tissues at parturition?
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deciduate
nondeciduate |
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________ placenta is described as an extensive loss of maternal tissue at the time of parturition, due to complicated interlocking of fetal and maternal tissue, e.g. carnivores and primates.
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Deciduate:
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Describe the nondeciduate placenta.
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There is little loss of maternal tissue occuring due to relatively simple feto-maternal contact. e.g sow, mare & ruminants
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What are the different forms of placenta based on Histological Layers.
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Epitheliochorial
Syndesmochorial Endotheliochorial Hemochorial |
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___________ is chorionic epithelium that is in contact with uterine epithelium. All 6 layers are present. e.g sow & mare
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Epitheliochorial
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___________ is chorionic epithelium that is in contact with uterine connective tissue. 5 layers are present. e.g ruminants
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Syndesmochorial
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___________ is chorionic epithelium that is in contact with the endothelium of the uterine blood vessels. Has 4 layers present. e.g carnivores
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Endotheliochorial
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___________ is chorionic epithelium that is in contact with uterine blood. Has 3 layers present. e.g primates
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Hemochorial
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WHere do primordial germ cells originate & develop?
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They originate in the wall of the yolk sac & develop in the gonad.
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