chapter 42: animal development and aging Flashcards

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1
Q

when does an oocyte complete meiosis II

A

after fertilization

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2
Q

what is cleavage

A

results in a multicellular embryo & is cell division without growth

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3
Q

what is morula

A

Formation of a solid ball of cells

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4
Q

what are blastula

A

dividing morula - hollow ball of cells

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5
Q

what is a blastocoel

A

a fluid-filled cavity in blastula

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6
Q

what is gas truly

A

germ layers form in part by invagination

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7
Q

what is the archenteron

A

primitive gut

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8
Q

what is the blastopore

A

opening into the primitive gut

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9
Q

what is the ectoderm

A

Nervous system; epidermis of skin and derivatives of the epidermis (hair, nails, glands); tooth enamel, dentin, and pulp; epithelial lining of oral cavity and rectum

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10
Q

what is the mesoderm

A

Musculoskeletal system; dermis of skin; cardiovascular system; urinary system; lymphatic system; reproductive system—including most epithelial linings; outer layers of respiratory and digestive systems

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11
Q

what is the endoderm

A

Epithelial lining of digestive tract and respiratory tract, associated glands of these systems; epithelial lining of urinary bladder; thyroid and parathyroid glands

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12
Q

what is the neural tube

A

: Tube formed by closure of neural groove. In vertebrates develops into spinal cord & brain

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13
Q

what is the somite

A

mass of mesoderm lateral to notochord in vertebrates; muscles associated with axial skeleton & vertebrae

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14
Q

what is the notochord

A

Cartilage-like supportive dorsal rod; replaced by vertebrae in vertebrates

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15
Q

what is the gut

A

formed by endoderm as body folds into tube

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16
Q

what is the coelom

A

body cavity lined with mesoderm; between digestive tract & body wall

17
Q

what is cellular differentiation

A

Process & developmental stages by which cell becomes specialized for particular function

18
Q

what is morphogenesis

A

Emergence of shape & patterns in tissues, organs, or entire embryo during development

19
Q

what is pattern formation

A

positioning of cells during development determines final shape of organism

20
Q

characteristics of cellular differentiation

A

Zygote is totipotent
Cells specialize lose their totipotency
Cellular specialization caused differential gene expression
Transcription factors: segregation & induction

21
Q

what is totipotent

A

cell that has full genetic potential of the organism, including potential to develop into a complete organism

22
Q

what are maternal determinants

A

substances present in egg that influences course of development

23
Q

what is cytoplasmic segregation

A

is parceling of maternal determinants during mitosis

24
Q

what is induction

A

-Specialization influenced by both maternal determinates but also by signals of neighboring cells
-Induction: ability of one embryonic tissue to influence the development of another tissue

25
Q

what is morphogenesis

A

-Requires cells associate to form tissues & tissues give rise to organs
-Most animals share common sets of genes that direct pattern formation
-Highly conserved among animals with segmented body morphologies, including humans

26
Q

characteristics of anterior/posterior axis

A

-Establishment of anteroposterior polarity
-Polarity present in egg before fertilized
-Results from maternal determinates
-Proteins products (morphogens) diffuse away from area of highest concentration
-Forms gradients that influence patterns of tissue development

27
Q

what is segmentation pattern

A

-Gap genes come into play
-Divide anteroposterior axis into broad regions
-Temporarily activated by gradients anterior & posterior morphogens
-In turn activate pair-rules genes
-Influence segment-polarity genes

28
Q

what are homeotic genes

A

genes that control overall body plan by controlling fate of groups of cells during development

29
Q

what are homeoboxes

A

Developmental genes, shared by all animals, that orchestrate development of body plan

30
Q

what is the homeodomain

A

Conserved DNA-binding region of transcription factors encoded by homeobox of homeotic genes

31
Q

what is chorion

A

functioning for respiratory exchange in birds & reptiles; contributes to placenta formation in mammals

32
Q

what is amnion

A

forms an enclosing fluid-filled sac

33
Q

what is the yolk sac

A

extraembryonic membrane in shelled vertebrates contains yolk for nourishment of the embryo & in placental mammals is first site for blood cell formation

34
Q

what is the allantois

A

accumulates nitrogenous wastes in the eggs of reptiles, including birds; contributes to the formation of umbilical blood vessels in mammals

35
Q

emrbyonic development stages

A

-fertilization, blastocyte
-implantation in wall of uterus, gastrulation
-nervous system and heart, form umbilical cord
-head enlarges, eyes ears nose, nervous system developed
-cervix dilates, baby born, placenta delivered

36
Q

characteristics of the placenta

A

Functions in gas, nutrient, & waste exchange
Tenth week fully developed & producing progesterone & estrogen
Exchange of molecules between fetal & maternal blood take place across walls of chorionic villi

37
Q

how does the aging process work

A

as the cell divides over time the telomeres shorten, eventually signaling the cell to stop dividing (senescence)

38
Q

characteristics of damage accumulation

A

-May involve the accumulation of damage over time
-First accumulation of harmful DNA mutations or the buildup of harmful metabolites
-Second is proteins may become increasingly cross-linked with age
-Inability of organs such as blood vessels, heart, & lungs to function as they once did
-Glucose has the tendency to attach to any type of protein
-First step in a cross-linking process