Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT Biology > Ch 3 - Embryogenesis and Development > Flashcards

Ch 3 - Embryogenesis and Development Flashcards

You may prefer our related Brainscape-certified flashcards:
MCAT flashcards AP® Biology flashcards Biology 101 flashcards
1
Q

What is fertilization and where does it occur?

A
  • the joining of sperm and an ovum (usually occurs in the ampulla of the fallopian tubes)
  • the sperm uses acrosomal enzymes to penetrate the corona radiata and zona pellucida.
  • once it contacts the oocyte’s plasma membrane, the sperm establishes the acrosomal apparatus and injects its pronucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens when the sperm first penetrates during fertilization?

A
  • it causes the release of calcium ions, which prevent additional sperm from fertilizing the egg and increases the metabolic rate of the resulting diploid zygote (coritcal reaction)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the difference between fraternal (dizygotic) and identical (monozygotic) twins?

A
  • fraternal result from the fertilization of 2 eggs by 2 different sperm
  • identical result from the splitting of a zygote into 2
  • monozygotic twins can be classified by the placental structures they share
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is cleavage?

A
  • refers to the early division of cells in the embryo

- these mitotic divisions result in a larger number of smaller cells, as the overall volume does not change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When does the zygote become an embryo?

A

after first cleavage because it is no longer unicellular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the difference between interdeterminate and determinate cleavage?

A
  • interdeterminate results in cells that are capable of becoming any cell in the organism
  • determinate results in cells that are committed to differentiating into a specific cell type
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the morula?

A

a solid mass of cells seen in early development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the blastula?

A
  • blastocyst
  • has a fluid-filled center called a blastocoel and has 2 different structures: the trophoblast (which becomes placental structures) and the inner cell mass (which becomes the developing organism)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is the placenta formed?

A

the blastula implants in the endometrial lining

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the choirion?

A

contains the chorionic villi, which penetrates the endometrium and create the interface between maternal and fetal blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What supports the embryo before the placenta is established?

A

yolk sac

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the allantois?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where is the amnion and what does it produce

A

lies just inside the choirion and produces amniotic fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What connects the developing organism to the placenta?

A

umbilical cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is formed during gastrulation?

A

the archenteron is formed with a blastopore at the end

- as the archenteron grows through the blastocoel it contacts the opposite side, establishing 3 primary germ layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the ectoderm germ layer?

A

becomes the epidermis, hair, nail,s and the epithelia of the nose, mouth, and anal canal, as well as the nervous system (including adrenal medulla) and lens of the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the mesoderm germ layer?

A
  • becomes much of the musculoskeletal, circulatory, and excretory systems
  • mesoderm gives rise to the gonads and the muscular and connective tissue layers of the digestive and respiratory systems, as well as the adrenal cortex
  • where notochord is formed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the endoderm germ layer?

A

becomes much of the epithelial linings of the respiratory and digestive tracts and parts of the pancreas, thyroid, bladder, and distal urinary tracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is neuralation and when does it begin?

A

development of the nervous system, begins after the formation of the 3 germ layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the process of neuralation?

A
  • the notochord induces a group of overlying ectodermal cells to form neural fold surrounding a neural groove
  • neural folds fuse to form the neural tube, which becomes the CNS
  • tip of each neural fold contains neural crest cells, which become the PNS as well as specific cell types in other tissues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are Teratogens?

A
  • substances that interfere with development, causing defects or even death of the developing embryo
  • alcohol, certain prescription drugs, viruses, bacteria, and environmental chemicals
22
Q

What maternal conditions can affect development?

A
  • diabetes (increased fetal size and hypoglycemia after birth)
  • folic acid deficiency (neural tube defects)
23
Q

What is determination in cell specialization?

A
  • the commitment to a specific cell lineage, which may be accomplished by uneven segregation of cellular material during mitosis or the morphogens, which promote development down a specific cell line
  • committed to specific cell lineage
24
Q

What must a cell have to respond to a specific morphogen?

A

competency

25
Q

What is differentiation in cell specialization?

A
  • refers to the changes a cell undergoes due to selective transcription to take on characteristics appropriate to its cell line
  • assumes the structure, function, and biochemistry of that cell type
26
Q

What are stem cells and how are they classified?

A

stem cells are capable of developing into various cell types:

  • totipotent: able to differentiate into all cell types, including the 3 germ layers and placental structures
  • pluripotent: able to differentiate into all 3 germ layers and their derivatives
  • multipotent: able to differentiate only into specific subset of cell types
27
Q

How do cells communicate?

A

through a number of different signaling methods that often occurs via gradients

  • autocrine: signals act on the same cell that released the signal
  • paracrine: signals act on local cells
  • juxtacrine: signals act through direct stimulation of adjacent cells
  • endocrine: act on distant tissues after traveling through the blood stream
28
Q

What do inducers do?

A

release factors to promote the differentiation of a competent responder

29
Q

What are growth factors?

A

peptides that promote differentiation and mitosis in certain tissues

30
Q

What is reciprocal induction?

A

if 2 tissues both induce further differentiation in each other

31
Q

What is apoptosis?

A
  • programmed cell death via the formation of apoptopic blebs that can subsequently be absorbed and digested by other cells
  • can be used for sculpting certain anatomical structures, such as removing the webbing between digits
32
Q

What is regenerative ability?

A
  • the ability of an organism to regrow certain parts of the body
  • the liver has high regenerative capacity, while the heart has low
33
Q

What is senescence?

A

the result of multiple molecular and metabolic processes, most notably, the shortening of telomeres during cell division

34
Q

Where do nutrient, gas, and waste exchange occur?

A

placenta

35
Q

Why are carbon dioxide and oxygen passively exchanged in fetal circulation?

A

concentration gradients

36
Q

What does fetal hemoglobin (HbF) have a higher affinity for?

A

oxygen than adult hemoglobin

- this affinity assists in the transfer (and retention) of oxygen into the fetal circulatory system

37
Q

What does the placental barrier serve as?

A

immune protection against many pathogens and antibodies are transferred from mother to child

38
Q

What does the placenta secrete?

A

serves endocrine functions, secreting estrogen, progesterone, and human chorionic gonadotropin (hCG)

39
Q

What do the umbilical veins and arteries carry?

A
  • arteries: carry deoxygenated blood from the fetus to the placenta
  • veins: carry oxygenated blood from the placenta back to the fetus
40
Q

What are the 3 shunts of the fetal circulatory system?

A
  • foramen ovale: connects the right atrium to the left atrium, bypassing the lungs
  • ductus arteriosus: connects the pulmonary artery to the aorta, bypassing the lungs
  • ductus venosus: connects the umbilical vein to the inferior vena cava, bypassing the liver
41
Q

What are the milestones of the first trimester?

A

organogenesis occurs (development of heart, eyes, gonads, limbs, liver, brain)

42
Q

What are the milestones of the second trimester?

A

tremendous growth occurs, movement begins, the face becomes distinctly human and the digits elongate

43
Q

What are the milestones of the third trimester?

A

rapid growth and brain development continue and there is transfer of antibodies to the fetus

44
Q

What occurs in each of the 3 phases of birth?

A
  • the cervix thins out and the amniotic sac ruptures
  • then, uterine contractions, coordinated by prostaglandins and oxytocin, result in birth of the fetus
  • finally, the placenta and umbilical cord are expelled
45
Q

How does the blastopore develop in deuterostomes v protostomes?

A
  • deu: into the anus

- pro: into the mouth

46
Q

What is induction and how does it influence development?

A
  • induction is the process by which nearby cells influence the differentiation of adjacent cells
  • this ensures proper spatial location and orientation of cells that share a function or have complementary functions
47
Q

What tissues do neural crest cells develop into?

A
  • neural crest cells become the PNS as well as specific cell types in other tissue
48
Q

Which developmental state has the greatest nuclear-cytoplasmic ratio?

A

blastula
- during the series of rapid mitotic division known as cleavage, the number of cells increases dramatically but the overall volume of the embryo does not change until after blastula has been implanted

49
Q

What does the placenta produce during pregnancy?

A

estrogen and progesterone to maintain the endometrium
- these hormones are necessary for proper gestation of the fetus and should be measurable in maternal blood because they act on maternal organs

50
Q

What are the characteristics of adult stem cells?

A
  • less controversial than embryonic stem cells
  • require treatment with various transcription factors
  • a reduced risk of rejection if the patient’s own stem cells are used
51
Q

Why does apoptosis occur during development?

A

occurs in multiple locations in order to ensure development of the correct adult structures

MCAT Biology (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions