Chapter 10- Vertebrate Embryology

Question 1

Embryology

Answer 1

Study of the development of a unicellular zygote into a complete, multicellular organism

Question 2

Cleavage

Answer 2

Series of rapid mitotic divisions– lead to increase in cell number but no growth in protoplasm (total cytoplasm volume remains constant)

Question 3

Cleavage in relation to cell size and nuclear to cytoplasmic material ratio

Answer 3

smaller cells

increasing ratio of nuclear to cytoplasmic material

Question 4

cleavage in relation to surface to volume ratio

Answer 4

Increases surface to volume ratio- improves gas and nutrient exchange

Question 5

morula

Answer 5

What one zygote divides into before turning into a blastula

Question 6

Blastulation begins when..

Answer 6

the morula develops a fluid-filled cavity called the blastocoel which by the 4th day becomes a hollow sphere of cells called the blastula

Question 7

The stage where the embryo implants in the uterus is:

Answer 7

The blastula

Question 8

Gastrula

Answer 8

Once implanted in the uterus, blastula –> gastrula

Question 9

Three layers of gastrula

Answer 9

Ectoderm
Endoderm
Mesoderm

Question 10

Ectoderm

Answer 10

Integument (epidermis, hair, nails, and epithelium of nose, mouth and anal canal), lens of eye, retina, and the nervous system

Question 11

Endoderm

Answer 11

Epithelial linings of the digestive and respiratory tracts (lungs) and parts of liver, pancreas, thyroid, and bladder lining

Question 12

Mesoderm

Answer 12

Musculoskeletal system, circulatory system, excretory system, gonads, connective tissue throughout the body, and portions of digestive and resp. orgams

Question 13

Netrulation

Answer 13

process by which regions of the germ layers begin to develop into a rudimentary nervous system at the end of gastrulation.

Question 14

notochord

Answer 14

A rod of mesodermal cells that develops along the longitudinal axis under dorsal layer of ectoderm

causes ectoderm to bend inward and form groove along dorsal surface of the embryo

Question 15

Notochord forms into the

Answer 15

neural tube, which gives rise to the brain and spinal cord (central nervous system)

Question 16

What happens when the neural tube is formed?

Answer 16

detaches from the surface ectoderm

Question 17

Neural crest cells

Answer 17

cells at the tip of each neural fold

migrate laterally and give rise to PNS- sensory ganglia, autonomic ganglia, adrenal ganglia, adrenal medulla, and Schwann cells

Question 18

Developmental phase can be divided into:

Answer 18

internal and external development

Question 19

Internal development

Answer 19

follows the neurulation process

Question 20

Internal development includes

Answer 20

Organogenesic, growth, and gametogenesis

Question 21

Organogenesis

Answer 21

The body organs begin to form

cells interact, differentiate, change physical shape, proliferate and migrate

Question 22

Growth

Answer 22

Organs increase in size, which is a continual process from infancy to childhood to adulthood

Question 23

Gametogenesis

Answer 23

Eggs and sperm develope

Question 24

External development in eggs (animals)

Answer 24

occurs outside the body

Question 25

Parts of egg in animals

Answer 25

Chorion- lines inside of shell, permits gas exhange

Allantois- Sac-like structure permits respiration and excretion. Contains vessels to transport O2, CO2, water, salt and nitrogenous waste

Amnion- encloses amniotic fluid, which prevents eggs from shock

Yolk sac- encloses yolk. Has blood vessels to transfer food to embryo

Question 26

Nonplacental internal development

Answer 26

Limits food and oxygen exhange.. Maybe born very early in development

Question 27

Specialized circulatory system in placental internal development allows

Answer 27

fetus to get oxygen from mother and also removes CO2 and metabolic wastes

Question 28

Two components of placental internal development system

Answer 28

Placenta

Umbelical Cord

Question 29

Placenta and umbilical cord are outgrowths of the

Answer 29

four extra-embryonic membranes formed during development

Amnion- shock absorber during labor

Chorion- begins placenta formation

Allantois- Becomes umbilical cord

Yolk sac- becomes associated with the umbilical vessels

Question 30

Gestation

Answer 30

human pregnancy

Question 31

First trimester

Answer 31

During first 3 weeks: major organs begin to develop
22 days- Heart begins to beat
Soon after- Eyes, gonads, limbs and liver start to form
7th week- bone
8th week- most organs have formed, brain is developed, and embyo is reffered to as fetus

Question 32

Second trimester

Answer 32

Fetus grows tremendously

Begins to move around in amniotic fluid, face appears human, toes and fingers elongate

Question 33

Third trimester

Answer 33

7th and 8th month- Rapid growth of body and brain
9th month- antibodies are transported by highly selective active transport from mother to fetus
Growth rate slows- fetus becomes less active

Question 34

Labor

Answer 34

series of strong uterine contraction

Question 35

First stage of labor

Answer 35

cervix thins out and dilates and amniotic sac ruptures. Mild contration

Question 36

Second stage of labor

Answer 36

Rapid contractions, birth of baby, cutting of umbilical cord

Question 37

3rd and final stage of labor

Answer 37

Uterus contracts, expelling placenta and umbilical cord

Question 38

Differentiation of cells is complete when

Answer 38

all organs reach adult form