Embryogenesis and Development Flashcards

1
Q

Ampulla

A

widest part of fallopian tube where fertilization occurs

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2
Q

When sperm meets the ______ in the fallopian tube, it binds to the ____ and releases _____ that allows the head of the sperm to penetrate through the corona radiata and zona pelucida.

A

secondary oocyte ; oocyte; acrosomal enzymes

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3
Q

Acrosomal Apparatus

A

penetrates cell membrane when sperm meets secondary oocyte

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4
Q

Cortical Reaction

A

once sperm penetrates secondary oocyte, a release of calcium ions depolarizes membrane to prevent other sperm from penetrating and increase metabolic rate of zygote.

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5
Q

Fertilization Membrane

A

cellular membrane of zygote once depolarization occurs

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6
Q

Dizygotic/Fraternal Twins

A

Fertilization of two eggs by 2 different sperm ; no more genetically similar than any other sibling pairs

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7
Q

Monozygotic/Identical Twins

A

single zygote splits in two and since genome is same, they are identical

Monochorionic/Monoamniotic Twins or Dichorionic/Diamniotic twins occur based on when seperation occurs

as more gestational structures are shared, more risks for fetus to develop

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8
Q

Conjoined Twins

A

if division of zygote is incomplete and two offspring end up attached

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9
Q

Monochorionic/Monoamniotic Twins

A

they are monozygotic twins which share the same amnion and chorions

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10
Q

Dichorionic/Diamniotic Twins

A

they are monozygotic twins which have their own amnion and chorions

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11
Q

After fertilization in the fallopian tubes, zygote travels to the _____ for implantation.

A

uterus

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12
Q

Cleavage

A

rapid mitotic cell divisions zygote undergoes when moving to uterus

divides into small cells to increase the SA:V and nuclear:cytoplasmic ratio for gas/nutrient exchange

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13
Q

The first cleavage produces ___

A

embryo

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14
Q

Indeterminate Cleavage

A

cells that can develop into complete organisms ; monozygotic twins

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15
Q

Determinate Cleavage

A

cells that are comitted to differentiate into different cells

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16
Q

Morula

A

solid mass of cells that arrive from multiple divisions of the embryo

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17
Q

Blastulation

A

when morula forms the blastula

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18
Q

Blastula/Blastocyst

A

hollow ball of cells from morula that contains fluid filled inner cavity known as a bastocoel

made of trophoblast and inner cell mass

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19
Q

Trophoblast Cells

A

surround the blastocoel (fluid filled cavity) of blastula and give rise to chorion/placenta

interface between embryo and maternal blood supply

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20
Q

Inner Cell Mass

A

cells that prutruve into the blastocoel and rise into the organism itself

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21
Q

Blastula moves through the fallopian tube to the uterus and burrows into the _____

A

endometrium

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22
Q

Sequence of Cell Masses

A

Zygote -> Embryo -> Morula -> Blastula

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23
Q

Chorion

A

risen from trophoblast cells which are a extraembryonic membrane that develops into placenta

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24
Q

Chorionic Villi

A

finger like projections made by the trophoblast cells that develop into the placenta for gas exchange

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25
Q

Umbilical Cord

A

embryo connected to placenta via this ; comes from remnants of yolk sac and allantosis

2 arteries and a vein where vein brings in oxygenated blood/nutrients, the artieris carry waste

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26
Q

Yolk Sac

A

supports embryo until placenta is functional and where blood cell development occurs

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27
Q

Allantosis

A

extraembryonic membrane that does early fluid exchange between yolk sac and embryo

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28
Q

Amnion

A

surrounds allantosis as a shock absorbing membrane

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29
Q

Gastrulation

A

generation of three distinct cell layers from cell mass implantation

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30
Q

Archenteron

A

membrane invagination into the blastocoel, becomes the gut

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31
Q

Blastopore

A

opening of the archenteron

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32
Q

In deuterostomes, such as humans, the blastopore develops into the _____ , in protostomes, it develops into the _____

A

anus; mouth

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33
Q

The Primary Germ Layers

A

Ectoderm
Mesoderm
Endoderm

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34
Q

Ectoderm

A

a primary germ layer, outermost later giving rise to the integyment

epidermis, hair, nails and nervous system/inner ear

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35
Q

Mesoderm

A

primary germ layer, develops in musculoskeletal, circulatory and excretory systems

Gonads, muscular and connective tissue layers of the digestive and respiratory systems and the adrenal cortex

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36
Q

Endoderm

A

primary germ layer, inner most layer

epithelial linings of the digestive and respiratory tracts including the lungs

Pancreas, thyroid, bladder, distal urinary tracts and liver

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37
Q

Selective Transcription of Genome

A

how cells with the same genes are able to develop into different cell types

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38
Q

Induction

A

ability of surrounding cells influence he fate of other nearby cells

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39
Q

Inducers

A

chemicals which diffuse from organizing cells to responsive cells

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40
Q

Neurolation

A

development of the nervous system occurs once the three germ layers are formed ; comes from ectoderm

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41
Q

Steps of Nervous System Development

A

1) Notochord forms like spinal cord
2) Notochord induces ectodermal cells to form neural folds around neural groove
3) Neural folds fuse into neural tube to rise CNS
4) Neural crest cells at the tip of the folds migrate out to form PNS and tissues (calcitonin thyroid,, malanocytes in skin)
5) Ectodermal cells will migrate to the neural tube and cover the rudimentary nervous system

42
Q

Organogenesis

A

development of organs

43
Q

Teratogens

A

substances which interfere with development and can lead to defects/death of the developing embryo

44
Q

Each teratogen has/does not have the same effect on every embryo/fetus, ______ of the individual embryo influences the effects of the teratogen along with…

A

does not

genetics

route/length of exposure, rate of placental transmission, identity of teratogen

45
Q

Common Teratogens

A

alcohol, prescription drugs, viruses, bacteria, and enviornmental chemicals

46
Q

Maternal health can/cannot influence health of embryo. Some examples are ____

A

can

hyperglycemic mothers resulting in large babies with hypoglecemia due to too much insulin production

Folic deficient mothers can prevent neural tube closure leading to anacephaly

47
Q

Determination

A

commitment of a cell to having a particular function later

48
Q

2 Ways Determination can Occur

A

1) mRNA and protein in parent cell is asymmetrically distributed between daughter cells so presence of mRNA determines which cell is produced
2) May occur due to secretion of specific molecules nearby

49
Q

Morphogens

A

cause nearby cells to follow a particular developmental pathway

50
Q

REMEMBER! Determination is a commitment to a specific cell type, but has not produced the ____ it needs to carry out the functions of the cell- that is the goal of _____

A

products, differentiation

51
Q

Differentiation

A

cell undertakes changes in structure/function/biochemistry to match the cell type it is to become.

52
Q

Stem Cells

A

cells that have not yet differentiated, foundin embryo and certain areas of adult tissue

53
Q

Potency

A

the tissues a particular stem cell can differentiate into

54
Q

Totipotent

A

stem cells which can ultimately differentiate into any type of cell, found in embryo or in placental structures

55
Q

Pluripotent

A

cells can differentiate into any cell type except those in the placenta

56
Q

Multipotent

A

cells can differentiate into multiple types of cells within a particular group

57
Q

Concerns of stem cell use

A
  • ethics of killing embryo
  • immunologic concerns
  • can become cancerous
58
Q

Pros and Cons of Adult Stem cell Usage

A

Pros:

  • no worries of immunologic concerns as cells are transplanted back
  • no ethics

Cons:
- limited potency

59
Q

Determination and differentiation of a cell depends on the _____ of the cell itself as well as the identity of the _____

A

location; surrounding cells

60
Q

Responder

A

cell that is induced, the responsive cell

61
Q

To be induced, a responder must be ____ , or be able to respond to the inducing signal.

A

competent

62
Q

Cell-cell communication can occur viz _______ signals

A

Autocrine, Paracrine, Juxtacrine and Endocrine

63
Q

Autocrine

A

signals act on same cell that secreted the signal

64
Q

Paracrine

A

signals act on cells in the local area

65
Q

Juxtacrine

A

no diffusion, but feature a cell directly stimulating receptors to an adjacent cell

66
Q

Endocrine

A

secreted hormones that travel through blood stream to distant target tissue

67
Q

Growth Factos

A

inducers which are peptides to promote differentiation/mitosis in certain tissues

growth factors can code for particular tissues

68
Q

Reciprocal Development

A

the responding cells induce signals back to the signaling cells to respond (example forming of lens can cause signaling to then form retina)

69
Q

Cell Migration

A

cells must move to their proper location to function

ex: neural crest cells must migrate throughout the body to form the PNS structures like gnaglia

70
Q

Apoptosis

A

programmed cell death to form structures

71
Q

Apoptotic Blebs

A

cell divides into small pieces which can be digested by other cells to recycle materials

membrane bound so harmful substances are not released into the enviornment

72
Q

Necrosis

A

cell death due to injury which leads to harmful substances leaking leading to an immune response

73
Q

Regenerative Capacity

A

ability of an organism to regrow certain parts of the body

stem cells migrate to initiate refrowth

74
Q

Complete vs Incomplete Regeneration

A

C: lost or damaged tissue is replaced with identical tissue

I: new formed tissue is not identical in structure/function to the injured tissue (Humans)

75
Q

In humans, regenerative capacity varies by ______

A

tissue type; liver is high, heart is very low, kidney is middle

76
Q

Senescence

A

biological againg where molecular and cellular structures begin changing and can lead od eventual failure of cells to divide

77
Q

Telomeres

A

ends of chromosomes that reduce the loss of genetic info from the ends of chromosomes and help prevent the DNA from unraveling

high concentration of guanine and cytosine knots off the end of the chromosome

difficult to replicate and shorten during DNA synthesis

78
Q

Reason for senescence is due to _____ shortening

A

telomere

79
Q

Telomerase

A

reverse transcriptase that is able to synthesize ends of chromosomes to prevent senescence

present in germ, fetal and tumor cells

80
Q

Placenta

A

organ where nutrient, gas and waste exchange occurs

81
Q

It is crucial that maternal and fetal blood do not mix because____ hence ____ is preferred method of nutrient transfer

A

different blood types; diffusion

82
Q

Diffusion requires a gradient, so this implies there is higher _______ in maternal blood than fetal blood

A

partial pressure of oxygen

83
Q

Fetal Hemoglobin (HbF)

A

found in fetal blood that has a greater affinity for oxygen than adult/maternal hemoglobin to help keep oxygen in the fetus

84
Q

Placenta is an _______ organ. This is because it produces _____

A

endocrine ; progesterone, estrogen and human chroionic gonadotropin (hCG) to maintain pregnancy

85
Q

Placental barriers function is also _______ ; _____ cross to serve as protective function

A

immune protection; antibodies

86
Q

Umbilical Arteries

A

carry blood away from fetus toward the placenta, like arteries carrying blood away from heart

87
Q

Umbilical Vein

A

like veins from the heart, they carry blood blood from placenta to the fetus

88
Q

Oxygenation (Gas Exchange) in fetus occurs at the ____ rather than the ____

A

placenta; fetal lungs

89
Q

Differences in Fetal and Adult Circulation

A
  • lungs and liver not significant prior to birth
  • gas exchange at placenta instead of lungs
  • Detoxification and metabolism controlled by mothers liver
90
Q

Shunts

A

constructs in fetus to shield away lungs and liver as they are underdeveloped and sensitive to high blood pressure

91
Q

Foramen Ovale

A

a type of shunt, one way valve connecting the right to the left atrium

pumps blood from inferior vena cava -> right atrium -> left atrium -> aorta

instead of right atrium to right venticle

92
Q

Unlike adult circulation, the ___ side of the heart is at ___ pressure in developing fetus than the ___ side, which pushes blood through the opening. At birth, this pressure differetial switches, ____ the foramen ovale.

A

right, higher, left, shutting

93
Q

Ductus Arteriosus

A

a type of shunt that shunts leftover blood from pulmonary artery to the aorta.

94
Q

Ductus Venosus

A

a type of shunt which bypasses the liver by shunting blood returning fro placenta via umbilical vein directly to the inferior vena cava

liver receives blood supply from smaller hepatic arteries in systemic circulation

95
Q

The larger the animal, the ___ the gestation period and the _____ offspring per pregnancy

A

longer; fewer

96
Q

First Trimester of Human Gestation

A
  • Major Organs Develop
  • Hear Beat Begins to Beat
  • Eyes, Gonads, Limbs, Liver Form
  • Cartilaginous skeleton hardens to bone
  • Embryo has become Fetus
  • 9 cm long
97
Q

Second Trimester

A
  • Fetus grows and moves within amniotic fluid
  • Toes/Fingers Elongate
  • 30-36cm
98
Q

Third Trimester

A

Rapid growth and brain development

Antibodies transported by highly selective active transport from mother to fetus to prepare for outside world

Growth Rate slow and fetus is less active as less room

99
Q

Parturition

A

vaginal childbirth rhythmic contractions coordinated by prostaglandins and oxytocin

100
Q

Three Phases of Birth

A

1) Cervix Thins and Amniotic Sac ruptures
2) Strong uterine contractions to birth fetus
3) Placenta and Umbilical Cord are expelled (Afterbirth)