Embryology

Question 0

Apoptosis

Answer 0

Programmed cell death

Question 1

Accretion

Answer 1

Increase in size by gradual addition of smaller parts

Question 2

Differentiation

Answer 2

Process by which cells develop a “type”

Question 3

Ectoderm

Answer 3

Outermost germ layer. Forms the skin

Question 4

Embryo

Answer 4

Between the 1st division of a zygote until it becomes a foetus (8 weeks).

Question 5

Gastrulation

Answer 5

Phase where embryo morphology is restructured by cell migration. In humans this is to 3 layers.

Question 6

Hypertrophy

Answer 6

Increase in size due to increase cell size rather than division

Question 7

Induction

Answer 7

Action of inducing cells to undergo a change (signalling)

Question 8

Mesoderm

Answer 8

Germ layer that forms connective tissue, muscles and circulatory system.

Question 9

Morphogenesis

Answer 9

Process that controls the organised spacial distribution of cells that arise during embryonic development. E.g. Neurolation, Gastrulation etc.

Question 10

Neural crest cells

Answer 10

Derived from ectoderm and are able to migrate extensively and generate many differentiated cell types

Question 11

Neural plate

Answer 11

Thick, flat bundle of ectoderm which develops into the neural tube and then the nervous system.

Question 12

Neurolation

Answer 12

Morphogenetic process where the neural plate folds into type neural tube.

Question 13

Proliferation

Answer 13

During tissue growth one cell divides into daughter cells, this is a form of tissue growth.

Question 14

Teratogenesis

Answer 14

Formation of congenital malformations

Question 15

During Gastrulation, what is the Bilaminar disk made up of?

Answer 15

Epiblast and hypoblast. The Bilaminar disk becomes the trilaminar disk when the Epiblast moves inwards between epi and hypoblast into the primitive streak.

Question 16

When does Neurolation start?

Answer 16

Week 3

Question 17

What does the ectoderm form?

Answer 17

Epidermis, CNS, PNS and retina

Question 18

What does the mesoderm form?

Answer 18

Smooth muscle, cv system, blood cells, bone marrow, skeleton, striated muscle, reproductive and excretory organs.

Question 19

What does endoderm form?

Answer 19

Epithelia of the GI, resp tract, gl,adular cells and associated organs.

Question 20

What is the embryo logical mouth and anus called.

Answer 20

Stomodeum and Proctodeum.

Question 21

The yolk sac divides the tubular gut into 3 parts, what are they?

Answer 21

Foregut, midgut and hindgut.

Question 22

Where does the foregut and midgut end?

Answer 22

Foregut @ proximal duodenum

Midgut @ transverse colon

Question 23

What does the septum transversum form?

Answer 23

Ventral mesentary

Question 24

What does the Allantois form?

Answer 24

Median umbilical ligament

Question 25

What does the cloaca form?

Answer 25

Terminal portion of the hindgut. The cloacal membrane covers the anus.

Question 26

What forms the umbilical cord?

Answer 26

Remnants of the yolk sac and connecting stalk. When the intestinal loops herniate into the cord and are pulled back, the yolk sac is destroyed.

Question 27

What arteries supply the hindgut?

Answer 27

Superior 2/3 formed from endoderm and supplied from the inferior mesenteric artery. Inferior 1/3 formed from ectoderm and supplied by the internal pudendal artery.

Question 28

What germ layers form the oesophagus and trachea?

Answer 28

Endoderm forms the epithelium and the mesoderm forms the cartilage and smooth muscle.

Question 29

What happens during the embryonic stage of respiratory development?

Answer 29

Lungs from a bud on the gut tube @ the level of the future oesophagus. This lengthens and pinches off forming 2 separate tubes --> 2 main branches: left and right main bronchi.

Question 30

What happens at the Canalicular stage of respiratory development? (Weeks 17-24)

Answer 30

Alveoli begin to develop. Cells start to form sacs, very thin Epithelia --> type 1 pneumocytes. Capillaries begin to invade.

Question 31

What happens during the secular stage of respiratory development (weeks 25 onwards)

Answer 31

Number of type 1 pneumocytes, alveoli and surface area increase. Type 2 pneumocytes also start to be produced.

Question 32

What stage is between the embryonic and Canalicular stage?

Answer 32

Pseudoglandular stage: Epithelia become ciliated and smooth muscle appeasers.

Question 33

What do neural crest cells differentiate from?

Answer 33

The ectoderm

Question 34

What spinal cord defects occur from cranial or caudal pores not closing?

Answer 34

Cranial pore- Anencephaly | Caudal pore- Spina Bifida

Question 35

What is grey matter?

Answer 35

Ectoderm called Neuroepithelial cells, which become neuroblasts, these form the mantle layer, or grey matter.

Question 36

What forms the white matter?

Answer 36

Neuroblasts send out fibres which form the marginal later or white matter.