Lateral Plate Mesoderm and Endoderm

Question 1

what develops on either side of the intermediate mesoderm?

Answer 1

the lateral plate mesoderm

Question 2

the lateral plate mesoderm ultimately forms

Answer 2

• the heart
• blood & lymphatic vessels
• elements of blood
• digestive system
• respiratory system

Question 3

what is the 1st functional organ and system to develop in the embryo

Answer 3

the heart

Question 4

cardiogenic mesoderm is aka

Answer 4

presumptive heart cells

Question 5

the cardiogenic mesoderm is the first to develop in the

Answer 5

primitive streak

Question 6

during the heart formation various inducers stimulate formation of….while inhibitors prevent the abnormal location or formation of….

Answer 6

• specific cell types
• development of heart cells

Question 7

what is known as a collection of stem cells that specifically forms heart related structures?

Answer 7

the cardiogenic mesoderm

Question 8

the cardiogenic mesoderm is specified to form

Answer 8

1. endocardial endothelial cells -> cushion cells -> AV channels
2. atrial myocytes
3. ventricular myocytes -> purkinjie fibers

Question 9

what is one of the 1st genes to get introduced in precardiac cells

Answer 9

GATA 4

Question 10

GATA 4 helps to produce

Answer 10

cadherin

Question 11

cadherin helps to fuse the 2 heart rudiment halves into

Answer 11

1 tube by the 3rd week of gestation

Question 12

initially the human heart is a

Answer 12

2 chambered tube w/ 1 atrium + 1 ventricle

Question 13

the 2 halves of the heart tube are formed from the

Answer 13

medial aspects of the lateral plate mesoderm as they move closer together

Question 14

when does the pulsation of the cardiac cells begin?

Answer 14

as the 2 halves of the tube fuse together

Question 15

pulsation of the heart is dependent on the presence of the

Answer 15

sodium/calcium exchange pump

Question 16

looping occurs at the

Answer 16

5th week of gestation in humans

Question 17

how do transcription factors form the normal adult prototypical shape of the heart

Answer 17

by curving, bending, & reorienting

Question 18

where are the atria and ventricles located prior to looping?

Answer 18

atria: lower/ distal end of tube
ventricles: upper proximal end of tube

Question 19

abnormal looping may lead to

Answer 19

congenital heart defects

Question 20

endocardial cushion cells form from the

Answer 20

endometrium

Question 21

the endocardial cushion cells begin to shape the

Answer 21

atrioventricular channels

where the tricuspid and mitral valves form

Question 22

proteins from the myocardium induce the endocardium to begin the actual formation of

Answer 22

valves in the channels shaped by the cushion cells

Question 23

vasculogenesis is the formation of

Answer 23

new vessels ‘de novo’ from the lateral plate mesoderm

Question 24

angiogenesis is the

Answer 24

remodeling of primary blood vessels into capillaries, arteries, veins

Question 25

what are the precursors of blood cells and vessels?

Answer 25

hemangioblasts

Question 26

what are known as aggregations of hemangioblasts?

Answer 26

blood islands

Question 27

vasculogenesis originates out of

Answer 27

blood islands

Question 28

VEGF is necessary for the

Answer 28

- differentiation & proliferation of angioblasts - development of lymphatic vessels

Question 29

VEGF is secreted by the

Answer 29

mesenchymal cells near the blood islands

Question 30

VEGF dissociates

Answer 30

cell-to-cell contacts & ECM of the blood islands

Question 31

lymphatic vessels are synthesized from the

Answer 31

endothelial cells from the jugular veins

Question 32

explain how lymphatic vessels are synthesized from endothelial cells of jugular veins

Answer 32

by transcription factors that downregulate/suppress the genes encoding for blood vessels but allow the expression of genes for lymphatic vessels

Question 33

hematopoietic stem cells are undifferentiated stem cells used to synthesize

Answer 33

ALL formed elements of blood & lymphatic systems

Question 34

embryonic hematopoiesis originates from

Answer 34

blood islands of the mesoderm

Question 35

during ~ 6th week of gestation red blood cell formation occurs primarily in the

Answer 35

liver & spleen

Question 36

during blood cell formation by ~ the 28th week of gestion the

Answer 36

bone marrow takes over hematopoiesis which then continues through the adult phase

Question 37

erythropoiesis is under the control of the

Answer 37

- kidneys - erythropoietin (hormone)

Question 38

the hormone erythropoietin stimulates the

Answer 38

bone marrow

Question 39

what begins forming at ~18-22 days of gestation in humans

Answer 39

the digestive & respiratory tracts

Question 40

the digestive tube buds off to form the

Answer 40

- liver - gallbladder - pancreas

Question 41

what sprouts from the digestive tube?

Answer 41

the respiratory tube

Question 42

the respiratory tube forms the

Answer 42

- trachea - lower bronchial passages

Question 43

what is known as the "food tube"

Answer 43

the esophagus

Question 44

the esophagus is posterior to the

Answer 44

trachea

Question 45

the esophagus leads to formation of the

Answer 45

- stomach - small intestines - large intestine

Question 46

endoderm germ layer forms the linings of the

Answer 46

digestive tube

Question 47

mesenchymal cells of the mesoderm form the

Answer 47

smooth muscle necessary for peristalsis

Question 48

what is peristalsis

Answer 48

the rhythmic contraction of muscle to propel food through the digestive system

Question 49

the respiratory tube also requires the

Answer 49

- endoderm germ layer - mesenchyme of lateral plate mesoderm

Question 50

what is the last organ to differentiate & develop?

Answer 50

the lungs

Question 51

premature babies typically need to reach the ________ week of gestation. why?

Answer 51

28th - to ensure respiratory system functions enough to meet the aerobic respiratory needs of their cells/tissues/organs

Question 52

in order to meet the aerobic respiratory needs of their bodies doctors are waiting for the production of ___________ in premature babies

Answer 52

surfactant from type II cells in the alveoli

Question 53

surfactant maintains the

Answer 53

compliance of individual air sacs

Question 54

what may speed up the final development of the respiratory system if early delivery of a child is impending?

Answer 54

steroid injections