MS devo

Question 1

What does paraxial mesoderm form in skeletal development?

Answer 1

vertebral columns, ribs, neurocranium

Question 2

What does lateral plate mesoderm form in skeletal development?

Answer 2

pectoral girdle, limbs, sternum

Question 3

What do neural crest cells form in skeletal development?

Answer 3

viscerocranium (bones on the front of your face), hyoid bone

Question 4

Why do bones form through intramembranous ossification?

Answer 4

more rapid formation in areas urgently needed by fetus

ex: mandible, need for sucking on boobs

Question 5

What makes up the axial skeleton?

Answer 5

vertebrae
ribs
sternum
skull

Question 6

What makes up the appendicular skeleton?

Answer 6

pectoral girdle
pelvic girdle
limb bones

Question 7

What does the viscerocranium (anterolateral facial bones) form from?

Answer 7

neural crest cells

Question 8

What does the neurocranium form from?

Answer 8

paraxial mesoderm

occipital somites

Question 9

What makes up the chondrocranium and how is it formed?

Answer 9

base of the skull (sphenoid, petrous temporal, portion of occipital)

form by endochondral ossification

Question 10

What is the membranous neurocranium and how is it formed?

Answer 10

everything except the chondrocranium

form by intramembranous ossification

Question 11

At what age do your skull sutures fuse?

Answer 11

5-7 yrs

Question 12

What are the different fontanelles?

Answer 12

fontanelles: enlarged membranous spaces where more than 2 bones form

anterior fontanelle (largest on top of head)
anterolateral/sphenoidal fontanelle
posteriorlateral/mastoid fontanelle
posterior fontanelle

Question 13

What is craniosynostosis?

Answer 13

premature closure of sutures

Question 14

What happens if your saggital suture closes too early?

Answer 14

You have scaphocephaly.

your head is really long and skinny (like your face gets squished on either side

Question 15

What happens if you coronal suture closes too early?

Answer 15

You have brachycephaly.

your head looks like a really wide and ugly football

Question 16

In relation to the axial skeleton, what is NOT formed by paraxial mesoderm?

Answer 16

sternum

part of the skull

Question 17

In relation to axial skeleton formation, what structures are derived from paraxial mesoderm?

Answer 17

vertebrae
annulus fibrosis of intervertebral discs
ribs
neurocranium

Question 18

When do vertebrae start to develop?

Answer 18

4th week: sclerotome cells surround neural tube and notochord

Question 19

What happens during vertebral resegmentation?

Answer 19

sclerotomes are devided in half: a less dense cranial portion, and a more dense caudal portion.

resegmentation: a cranial (less dense) and a caudal (more dense) segment FROM NEIGHBORING SCLEROTOMES meet up and join

Question 20

What forms the annulus fibrosus of IV discs?

Answer 20

Dense (caudal) portion of sclerotome

Question 21

How do the ribs develop?

Answer 21

they grow out as costal processes from developing thoracic vertebrae

Question 22

How and when is the sternum induced to form?

Answer 22

induced to form by ribs growing anteriorly towards midline

10th week

sternum develops as two sternal bars from LATERAL plate somatic mesoderm

Question 23

What does the appendicular skeleton develop from?

Answer 23

lateral plate somatic mesoderm

Question 24

When does endochondral ossification take place?

Answer 24

5th week: mesenchyme buds start to form

6th week: hyaline cartilage models start to form (finished by 8th week)

Question 25

When does ossification begin in long bones?

Answer 25

primary ossification centers appear around 7/8th week

Question 26

What is achondroplasia?

Answer 26

disturbance of endochondral ossification makes you really short like aleah from teen mom

Question 27

What is skeletal muscle derived from?

Answer 27

paraxial mesoderm

Question 28

What is cardiac muscle derived from?

Answer 28

intraembryonic splanchnic mesoderm

Question 29

What is smooth muscle derived from?

Answer 29

intraembryonic splanchnic mesoderm

Question 30

When do myoblasts actively contract?

Answer 30

7th week

Question 31

Where are progenitor cells for muscle tissues located on the dermomyotome?

Answer 31

``` vertrolateral lips (VLL) dorsalmedial lips (DML) ```

Question 32

What does the lateral somatic frontier separate?

Answer 32

paraxial mesoderm from lateral plate mesoderm | primaxial domain and abaxial domain

Question 33

Where is the primaxial domain and what does it contain?

Answer 33

surrounds neural tube contains only somite derived cells from DML, VLL

Question 34

Where is the abaxial domain and what does it contain?

Answer 34

located laterally to primaxial domain parietal layer of lateral plate mesoderm with a few somite derived cells (some VLL cells migrate across lateral somatic frontier)

Question 35

What does the primaxial domain form?

Answer 35

back m. shoulder girdle m. intercostal m.

Question 36

What does the abaxial domain form?

Answer 36

infrahyoid m. pec major and minor m. abdominal wall mm. limb m.

Question 37

What are epaxial muscles and what innervates them?

Answer 37

back muscles dorsal primary rami

Question 38

What are hypaxial muscles and what innervates them/

Answer 38

muscles of limb and body wall ventral primary rami

Question 39

What smooth muscles are derived from ectoderm?

Answer 39

neuroectoderm: dialate eyes surface ectoderm: my epithelial cells of mammary, salivary, sweat glands

Question 40

In general, what germ layer is muscle from?

Answer 40

mesoderm

Question 41

When do limb buds emerge?

Answer 41

end of week 4 upper before lower

Question 42

What is the structure of a limb bud?

Answer 42

mesenchymal core surrounded by surface ectoderm

Question 43

What does the apical ectodermal ridge (AER) do?

Answer 43

signals nearby mesenchyme to keep being undiffentiated and dividing (called the progress zone)

Question 44

What are cells further away from AER doing?

Answer 44

differentiating into cartilage, muscle

Question 45

In what direction do limbs grow?

Answer 45

proximal to distal

Question 46

How do the limbs rotate?

Answer 46

UL: rotates 90 deg laterally (so that thumb faces laterally) LL: rotates 90 deg medially (big toe faces medial)

Question 47

How and when do your hands/feet form?

Answer 47

6th week: cute little paddles end of 6th week: mesechyme grows into paddles forming digital rays (outline of future digits) cells inbetween fingers/toes in AER die end of 8th week: mesenchyme differentiates into hyaline cartilage models

Question 48

meromelia

Answer 48

absence of part of a limb

Question 49

amelia

Answer 49

absence of whole limb

Question 50

polydactyly

Answer 50

extra digits

Question 51

syndactyly

Answer 51

fewer digits

Question 52

What drug fucked up kid's limbs?

Answer 52

thalidomide