2C: Processes of cell division, differentiation and specialization Flashcards Preview

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Flashcards in 2C: Processes of cell division, differentiation and specialization Deck (177):
1

Autosomal Cells

Diploid (2n) = 46

2

Haploid Cells

Haploid (n) = 23

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Interphase

Consists of G1, S, G2; actively dividing cells spend most of their time in this phase

4

Interphase

Consists of G1, S, G2; actively dividing cells spend most of their time in this phase

5

G0

The cell is simply living and serving its function without any preparation for division

6

Interphase

Consists of G1, S, G2; actively dividing cells spend most of their time in this phase;

Chromosomes are in less condensed form known as chromatin (so that DNA is available for RNA Pol to transcribe)

7

G0

The cell is simply living and serving its function without any preparation for division

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G1 Stage [Presynthetic Gap]

Cell creates organelles for energy and produces proteins while increases their size; contains a restriction point

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G1 Stage [Presynthetic Gap]

Cell creates organelles for energy and produces proteins while increases their size; contains a restriction point

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S Stage [Synthesis]

Genetic material is replicated so that each daughter cell will have an identical copy; each chromosome consists of two identical chromatids after replication

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G2 Stage [Postsynthetic Gap]

Cell passes through another quality control checkpoint - makes sure that there are enough organelles and cytoplasm for both daughter cells

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M Stage [Mitosis]

Consists of Prophase, Metaphase, Anaphase, Telophase and Cytokinesis

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M Stage [Mitosis]

Consists of Prophase, Metaphase, Anaphase, Telophase and Cytokinesis

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Prophase

Nucleus disappears, spindle forms, DNA condenses into chromosomes

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Metaphase

Sister chromatids align along the equator of the cell by attaching their centromeres to the spindle fibers

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Anaphase

Sister chromatids separate at the centromere and are pulled toward opposite poles of the cell by the mitotic spindle

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Prophase

Chromosomes condense, nuclear membrane dissolves, nucleoli disappear, centrioles migrate and spindle apparatus forms

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Metaphase

Chromosomes align along the equator of the cell by attaching their centromeres to the spindle fibers

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Anaphase

Sister chromatids separate at the centromere and are pulled toward opposite poles of the cell by the mitotic spindle

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Telophase

Nuclear membrane reforms and spindle apparatus disappears

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Cyclins & Cyclin-Dependent Kinases

Rise and fall during the cell cycle controlling the activity of the cell cycle

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Cancer

Occurs when cell cycle control becomes deranged, allowing damaged cells to undergo mitosis without regard for quality or quantity of the new cells produced

23

Metastasize

When cancerous cells produce factors that allow them to escape their site and invade elsewhere

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Cyokinesis

Cytosol and organelles are split between the two daughter cells

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Centriole Function

Organize the centrosome

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Aster Function

Formed around each centrosome

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Kinetochore

Protein structure on chromatids where spindle fibers attach during cell division

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Kinetochore

Protein structure on chromatids where spindle fibers attach during cell division

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Nuclear Membrane Breakdown

During Prophase and allows microtubules to attach at kinetochore

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Nuclear Membrane Reorganization

During Telophase

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How do chromosomes move?

By use of the spindle fibers during metaphase

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Reasons for Growth Arrest

Genomic mutation/damage
Lack of nutrients
Contact Inhibition (once they get in contact with other cells they stop)

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Reasons for Growth Arrest

Genomic mutation/damage
Lack of nutrients
Contact Inhibition (once they get in contact with other cells they stop)

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Mechanisms that Control the Cell Cycle

Checkpoints within the cycle itself (G1 and G2), Spindle checkpoint; cyclins and CDK

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Mechanisms that Control the Cell Cycle

Checkpoints within the cycle itself (G1 and G2), Spindle checkpoint; cyclins and CDK

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Oncogenes

Genes that have the potential to cause cancer; can be due to mutations or excessive expression

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Apoptosis

Programmed cell death; the cells contents are not released to the environment but rather digested intracellularly

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Triggers of Apotosis

Cell Damage
Cell Mutations
Developmental Mechanisms
Immune Response

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Prophase

Chromosomes condense, nuclear membrane dissolves, nucleoli disappear, centrioles migrate and spindle apparatus forms

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Cytokinesis

Cytosol and organelles are split between the two daughter cells

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Triggers of Apotosis

Cell Damage
Cell Mutations
Developmental Mechanisms
Immune Response

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Meiosis

Produces four non-identical haploid sex cells (gametes)

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Rounds of Meiotic Division

1. Reductional
2. Equational

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Meiosis I

Homologous pairs of chromosomes are separated from each other

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Homologues

Chromosomes that are given the same number but are of opposite parental origin

46

Prophase I

Chromosomes condense, nuclear membrane dissolves, nucleoli disappear, centrioles migrate and spindle apparatus forms; additionally synapsis and crossing over occurs

47

Prophase I

Chromosomes condense, nuclear membrane dissolves, nucleoli disappear, centrioles migrate and spindle apparatus forms; additionally synapsis and crossing over occurs

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Metaphase I

Homologues line up on opposite sides of the metaphase plate

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Anaphase I

Homologues segregate to opposite poles of the cell
-Accounts for segregation and independent assortment

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Anaphase I

Homologues segregate to opposite poles of the cell
-Accounts for segregation and independent assortment

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Telophase I

Chromosomes decondense and the cell may enter interkinesis

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Telophase I

Chromosomes decondense and the cell may enter interkinesis

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Meiosis II

Same process as Mitosis

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Spermatogenesis Outline

Spermatogonium -> Primary Spermatocyte -> Secondary Spermatocyte -> Spermatid

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Spermatogenesis Outline

Spermatogonium -> Primary Spermatocyte -> Secondary Spermatocyte -> Spermatid

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Spermatogonium
[2n]

A diploid cell that undergoes mitosis and creates a primary spermatocyte

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Primary Spermatocyte
[2n]

Undergoes Meiosis I and produces a secondary spermatocyte

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Secondary Spermatocyte
[n]

Undergoes Meiosis II and produces a spermatid

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Spermatid
[n]

Matures into sperm

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Oogenesis Outline

Oogonium -> Primary Oocyte -> Secondary Oocyte -> Ovum

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Oogonium
[2n]

A diploid cell that undergoes mitosis to produce a primary oocyte

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Primary Oocyte
[2n]

A diploid cell that undergoes meiosis I to produce a secondary oocyte

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Secondary Oocyte
[n]

A haploid cell that undergoes meiosis II to produce an ovum

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Site of Sperm Development

Seminiferous Tubules of the Testes

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Sertoli Cells

Nourish sperm

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Interstitial Cells of Leydig

Secretes testosterone and other androgens

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Scrotum

Site of the testes

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Epididymis

Give sperm motility and store sperm until ejaculation

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Epididymis

Give sperm motility and store sperm until ejaculation

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Ejaculation Pathway

Vas Deferens -> Ejaculatory Duct -> Urethra -> Penis

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Seminal Vesicles

Contribute fructose to nourish sperm and produce alkaline fluid

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Prostate Gland

Also produces alkaline fluid

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Bulbourethral Glands

Produce clear viscous fluid that cleans out any remnants of urine and lubricates the urethra during sexual arousal

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Bulbourethral Glands

Produce clear viscous fluid that cleans out any remnants of urine and lubricates the urethra during sexual arousal

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Semen

Composed of sperm and seminal fluid from the bulbourethral glands, seminal vesicles and prostate glands

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Semen

Composed of sperm and seminal fluid from the bulbourethral glands, seminal vesicles and prostate glands

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Sperm Structure

Head, Midpiece and Flagellum

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Head of Sperm

Contains genetic material and covered in an acrosome that contains enzymes that help the sperm fuse and penetrate the ovum

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Midpiece of Sperm

Generates ATP from fructose and contains many mitochondria

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Flagellum of Sperm

Promotes motility

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Flagellum of Sperm

Promotes motility

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Ovum (Ova)

Produced in the follicles of the ovaries

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Ovum (Ova)

Produced in the follicles of the ovaries

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Polar Body

Uneven portion of the cytokinesis product in oogenesis

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Polar Body

Uneven portion of the cytokinesis product in oogenesis

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Zona Pellucida

Surrounds oocytes which is an acellular mixture of glycoproteins that protects the oocyte and contain the compounds necessary for sperm binding

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Corona Radiata

A layer of cells that adhere to the oocyte during ovulation

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Corona Radiata

A layer of cells that adhere to the oocyte during ovulation

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Gonadotropin-releasing Hormone

Released from the hypothalamus and causes the release of FSH and LH

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Function of FSH in Males

Stimulates sertoli cells and triggers spermatogenesis

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Function of LH in Males

Stimulates interstitial cells to produce testosterone

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Function of Testosterone

Responsible for maintenance and development of the male reproductive system and male secondary sex characteristics

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Function of Testosterone

Responsible for maintenance and development of the male reproductive system and male secondary sex characteristics

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Function of FSH in Females

Stimulates development of the ovarian follicles; produce estrogen and progesterone

95

Function of LH in Females

Stimulates ovulation; produce estrogen and progesterone

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Primary Oocyte
[2n]

A diploid cell that undergoes meiosis I to produce a secondary oocyte
[Arrests in Prophase I]

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Secondary Oocyte
[n]

A haploid cell that undergoes meiosis II to produce an ovum
[Arrests in Metaphase II]

98

Function of LH in Females

Stimulates ovulation; produce estrogen and progesterone

99

Reproductive Sequence

Fertilization -> Implantation -> Development -> Birth

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Reproductive Sequence

Fertilization -> Implantation -> Development -> Birth

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Menstrual Cycle Sequence

Follicular Phase -> Ovulation -> Luteal Phase -> Menstruation

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Follicular Phase

GnRH stimulates FSH and LH which promotes follicle development; estrogen is released which stimulates vascularization and glandularization of the decidua (uterine lining)

103

Ovulation

Stimulated by a surge of LH; surge due to estrogens positive feedback effects

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Luteal Phase

LH promotes the ruptured follicle to become the corpus luteum which secretes progesterone that maintains the uterine lining.

105

Negative Feedback of GnRH, LH and FSH

Caused by high levels of estrogen and progesterone

106

Menstruation

Occurs if there is no fertilization; endometrial lining is broken off and the block on GnRH production is removed

107

Fertilization Effects

Blastula produces hcG which maintains the corpus luteum

108

Menopause

Occurs when the ovaries stop producing estrogen and progesterone

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Menopause

Occurs when the ovaries stop producing estrogen and progesterone

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Implantation Sequence

Zygote -> Morula -> Blastocyst

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Developmental Sequence

Blastocyst -> Gastrula -> Neurula

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Developmental Sequence

Blastocyst -> Gastrula -> Neurula

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Where does fertilization occur?

In the ampulla of the fallopian tube

114

What happens after the sperm penetrates the corona radiata and zona pellucida?

The sperm establishes the acrosomal apparatus and injects its nucleus; it also releases calcium ions that prevent additional sperm from fertilizing the ovum

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What is a cortical reaction?

The reaction that prevents additional sperm from fertilizing the egg and increases the metabolic rate of the zygote

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What is a cortical reaction?

The reaction that prevents additional sperm from fertilizing the egg and increases the metabolic rate of the zygote

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How do dizygotic twins form?

Two eggs are fertilized by two different sperm

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How do monozygotic twins form?

Splitting of a zygote into two

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How do dizygotic (fraternal) twins form?

Two eggs are fertilized by two different sperm

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How do monozygotic (identical) twins form?

Splitting of a zygote into two

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How do monozygotic (identical) twins form?

Splitting of a zygote into two

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Cleavage

Early divisions of cells in the embryo; resulting in a larger number of small cells but the volume remains the same

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When is the zygote considered an embryo?

After the first cleavage because its no longer considered to be unicellular

124

Indeterminate Cleavage

Results in cells that are capable of becoming any cell in the organism

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Determinate Cleavage

Results in cells that are committed to differentiating into a specific cell type

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Determinate Cleavage

Results in cells that are committed to differentiating into a specific cell type

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Morula

A solid mass of cells seen in early development that eventually becomes the blastula (blastocyst)

128

Blastula

A structure that contains blastocoel in its interior and contains trophoblasts and inner cell mass

129

Trophoblasts

Become placental structures

130

Inner Cell Mass

Becomes the developing organism

131

Placenta

Formed when the blastula implants into the endometrial lining

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Placenta

Formed when the blastula implants into the endometrial lining; provides oxygen and nutrients to the fetus as well as removes carbon dioxide and waste products

133

Chorion

Contains chorionic villi which penetrates the endometrium and creates the interface between maternal and fetal blood

134

Yolk Sac

Supports the embryo before the placenta is established

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Yolk Sac

Supports the embryo before the placenta is established

136

Allantois

Involved in early fluid exchange between the embryo and the yolk sac

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Amnion

Inside the chorion which produces amniotic fluid

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Amnion

Inside the chorion which produces amniotic fluid

139

Gastrulation

The cells of the blastula rearrange themselves and invaginate into the hollow ball so it creates an inner layer of cells and outer layer of cells and the cells between the two; forms Ecto, Meso and Endoderm

140

Archenteron

Formed with a blastopore at the end through the blastocoel; becomes the anus

141

Ectoderm

Becomes mouth, epidermis, hair, nails, anal canal, epithelia of the nose, lens of the eye and the adrenal medulla

142

Mesoderm

Becomes mostly the musculoskeletal, circulatory and excretory system; gonads; muscular and connective tissue layers of the digestive and respiratory systems; adrenal cortex

143

Mesoderm

Becomes mostly the musculoskeletal, circulatory and excretory system; gonads; muscular and connective tissue layers of the digestive and respiratory systems; adrenal cortex

144

Endoderm

Becomes the epithelial lining of the respiratory and digestive tracts and parts of the pancreas, thyroid, bladder and distal urinary tracts

145

Endoderm

Becomes the epithelial lining of the respiratory and digestive tracts and parts of the pancreas, thyroid, bladder and distal urinary tracts

146

Neurulation

Development of the nervous system that begins after the formation of the three germ layers

147

Notochord

Induces a group of overlying ectodermal cells to form neural folds surrounding a neural groove

148

Neural Tube

Forms from the fusing the neural folds and becomes the central nervous system (brain and spinal cord)

149

Neural Tube

Forms from the fusing the neural folds and becomes the central nervous system (brain and spinal cord)

150

Neural Crest Cells

Located at the tip of the neural folds and become the peripheral nervous system (sensory ganglia, autonomic ganglia, adrenal medulla and schwann cells)

151

Teratogens

Substances that interfere with development causes defects or death of the developing embryo; alcohol, certain drugs, viruses, bacteria and chemicals

152

Folic Acid Deficiency

Cause Neural Tube defects

153

Folic Acid Deficiency

Cause Neural Tube defects

154

Determination

Commitment of a specific cell lineage

155

What causes cellular determination?

Morphogens or uneven segregation of cellular material during mitosis

156

Morphogens

Promote development down a specific cell line

157

What does a cell need to have to respond to a specific morphogen?

Competency (ability to take up dna and become genetically transformed)

158

Differentiation

Changes a cell undergoes due to selective transcription to take on characteristics appropriate to its cell line

159

Differentiation

Changes a cell undergoes due to selective transcription to take on characteristics appropriate to its cell line

160

Stem Cells

Cells capable of developing into various cell types; classified by potency

161

Stem Cells

Cells capable of developing into various cell types; classified by potency

162

Totipotent Cells

Able to differentiate into all cell types, including three germ layers and placental structures

163

Totipotent Cells

Able to differentiate into all cell types, including three germ layers and placental structures

164

Pluripotent Cells

Able to differentiate into all three of the germ layers and their derivatives

165

Multipotent Cells

Able to differentiate only into a specific subset of cell types

166

Multipotent Cells

Able to differentiate only into a specific subset of cell types

167

Inducer

Releases factors to promote differentiation of a competent responder

168

Autocrine Signals

Act on the same cell that released the signal

169

Paracrine Signals

Act on cells in the local area

170

Juxtacrine Signals

Act through direct stimulation of the adjacent cells

171

Endocrine Signals

Act on distant tissues after traveling through the blood stream

172

Endocrine Signals

Act on distant tissues after traveling through the blood stream

173

Growth Factors

Peptides that promote differentiation and mitosis in certain tissues

174

Reciprocal Induction

When two tissues induce further differentiation in each other

175

Programmed Cell Death

Formation of apoptotic blebs that can subsequently be absorbed and digested by other cells; can be used to sculpt certain anatomical structures

176

Regenerative Capacity

Ability of an organism to regrow certain parts of the body; liver has high and heart has low

177

Senescence

Result of multiple molecular and metabolic processes; shortening of telomeres during cell division