Anatomy- Development Of Vert. And Spinal Cord

Front 1

What bones are part of the axial skeleton?

Back 1

1. skull
2. vertebral column
3. 12 pairs of ribs
4. sternum

Front 2

During week 4 what areas are the mesenchymal cells from the sclerotome found?

Back 2

1.around the notochord
2. surrounding the neural tube
3. in the body wall

Front 3

Densely packed sclerotome cells move cranially and form what?

Back 3

intervetebral disc

Front 4

Each centrum develops from 2 adjacent sclerotomes and becomes what?

Back 4

intersegmental structure

Front 5

Peripheral nerves form close to what?

Back 5

intervertebral discs

Front 6

In the thorax, the dorsal intersegmental arteries become what?

Back 6

intercostal arteries

Front 7

Between the vertebrae the notochord expands and forms what?

Back 7

nucleus pulposus

Front 8

The nuclear pulposus is later surrounded by circular fibers called what?

Back 8

annulus fibrosus

Front 9

What are the 2 parts of the intervertebral disc?

Back 9

1.nucleus pulposus
2. annulus fibrosus

Front 10

Remnants of the notochord may persist and give rise to what?

Back 10

chordoma

Front 11

Mesenchymal cells surrounding the neural tube form what?

Back 11

vertebral arch

Front 12

Mesenchymal cell in the body wall form into what?

Back 12

costal processes

Front 13

During what week do chondrification centers appear in each mesenchymal vertebra?

Back 13

week 6

Front 14

During the 6th week what appears in each mesenchymal vertebra?

Back 14

chondrification centers

Front 15

The 2 centers in each centrum fuse at the end of the embyonic period to form what?

Back 15

cartilaginous centrum

Front 16

What do the spinous and transverse processes develop from?

Back 16

extensions of chondrification centers in the vertebral arch.

Front 17

When does ossification of the typical vertebrae begin?

Back 17

1.during the embryonic period and ends by year 25 of life.

Front 18

Where are the 2 primary ossification centers for the centrum and what do they do?

Back 18

1. dorsal and ventral
2. they fuse into one

Front 19

Where are the 3 primary ossification centers at the end of the embryonic period?

Back 19

1.centrum
2. in each half of the vertebral arch

Front 20

Ossification of the vertebral arch is evident by when?

Back 20

around week 8

Front 21

What is the consistency of the vertebra at birth?

Back 21

consists of 3 bony parts connected by cartilage

Front 22

When do the halves of the vertebral arch fuse?

Back 22

during years 3-5

Front 23

Where do lamina first unite in the vert. column?

Back 23

first in the lumbar region and progress cranially

Front 24

Where does the vertebral arch articulate with the centrum during the postnatal period?

Back 24

cartilagenous neurocentral joints

Front 25

What happens to the neurocentral joints during years 3-6?

Back 25

They dissappear when the vert. arch fuses with the centrum

Front 26

What are the 5 ossification centers that appear after puberty?

Back 26

1. tip of the spinous process
2. tip of each transverse process
3. 2 rim (annular) epiphyses. 1 superior and 1 inferior on the vertebral body

Front 27

After puberty what different parts make up the compisite of the vertebral body?

Back 27

1.superior and inferior annular epiphyses
2. mass of bone between them(centrum, parts of vert. arch, and facets for heads of ribs)

Front 28

After puberty when do all secondary ossification centers unite with the rest of the vertebra?

Back 28

around year 25

Front 29

Exceptions of typical ossification occur usually in what areas?

Back 29

1. C1
2. C2
3. C7
4. lumbar vert.
5. sacrum and coccyx

Front 30

The nervous system develops from an area called what and when does it appear?

Back 30

1. neural plate
2. appears during week 3

Front 31

What underlying object induces formation of the neural plate?

Back 31

notochord

Front 32

What arises from the neural plate?

Back 32

1. neural tube
2. neural crest

Front 33

What does the neural tube give rise to?

Back 33

central nervous system

Front 34

What does the neural crest give rise to?

Back 34

peripheral nervous system

Front 35

When does formation of the neural tube begin and where?

Back 35

1.early part of week 4
2. happens in region of 4th to 6th pairs of somites (future cervical region)

Front 36

What folds to form the neural tube?

Back 36

neural folds

Front 37

When does the rostral neuropore close?

Back 37

day 25

Front 38

When does the caudal neuropore close?

Back 38

day 27

Front 39

Walls of the neural tube thicken to form what?

Back 39

brain and spinal cord

Front 40

What is the lumen of the neural tube converted to?

Back 40

1.ventricular system of the brain
2. central canal of the spinal cord

Front 41

What specific parts of the neural tube for the spinal cord?

Back 41

formed from somites caudal to somite 4

Front 42

When is the central canal formed?

Back 42

by week 9 or 10

Front 43

What type of epithelial cells make up the ventricular zone (ependymal layer)?

Back 43

pseudostratified, columnar neuroepithelium in the walls

Front 44

What arises from the ventricular zone?

Back 44

all neurons and macroglial cells in the spinal cord

Front 45

Outer parts of the neuroepithelial cells differentiate into what?

Back 45

marginal zone

Front 46

What arises from the marginal zone?

Back 46

white matter of the spinal cord

Front 47

Neuroepithelial cells in the ventricular zone differentiate into what and do what?

Back 47

1.neuroblasts
2. form and intermediate zone between the ventricular and marginal zones. This will eventually give rise to neurons

Front 48

After neuroblast formation has stopped, what else arises from neuroepithelial cells and where do they migrate to?

Back 48

1.glioblasts
2. migrate from ventricular zone to intermediate and marginal zones

Front 49

Once the glioblasts migrate to the intermediate and marginal zones what do they become?

Back 49

1.astroblasts-->astroglia
2.oligodendroblasts-->oligodendroglia

Front 50

The neuroepithelial cells that do not differentiate and migrate out of the ventricular zone become what?

Back 50

1. ependymal cells lining the central canal of the spinal cord

Front 51

What are microglia derived from and how and when do they enter the nervous system?

Back 51

1.mesenchymal cells
2. invade the nervous system late in the fetal period after penetrating from blood vessels

Front 52

Proliferation and differentiation of neuroepithelial cells produce what kind of walls and plates?

Back 52

1. thick walls
2. thin roof and floor plates

Front 53

What appears in the lateral walls of the spinal cord and what does it separate?

Back 53

1. sulcus limitans
2. this separates the dorsal alar plate from the ventral basal plate

Front 54

What do alar plates become and what will their function be?

Back 54

1. dorsal horns
2. afferent functions (sensory)

Front 55

What do the basal plates form and what will their function be?

Back 55

1. ventral and lateral horns
2. efferent functions (motor)

Front 56

What are the dorsal root ganglia formed from?

Back 56

neural crest cells

Front 57

How are the meningial layers formed?

Back 57

1. mesenchyme surrounding the neural tube condenses to form the primitive meninx

Front 58

What are the layers of the meninges from outer to inner?

Back 58

1. dura mater
2. arachnoid mater
3. pia mater

Front 59

In the embryo, how far does the spinal cord extend in the vertebral canal?

Back 59

the entire length

Front 60

At month 6 of gestation, where does the end of the spinal cord lie?

Back 60

level of S1

Front 61

Where does the end of the spinal cord lie in a newborn infant?

Back 61

L3

Front 62

In an adult where does the end of the spinal cord lie?

Back 62

L2-3

Front 63

Most congenital malformations are due to what defect?

Back 63

defective closure of the caudal neuropore at the end of week 4

Front 64

A defect in the closing of the caudal neuropore will affect what tissues?

Back 64

1. meninges
2. vertebral arch
3. dorsal muscles and skin

Front 65

When a congenital malformation affects the spinal cord and vertebral arches is it called?

Back 65

spina bifida (nonfusion of the vertebral arch)

Front 66

What is it called when there is a defect in the vertebral arch resulting from failure of the halves of the vertebral arch to grow and fuse normally?

Back 66

spina bifida occulta

Front 67

What levels does spina bifida occulta usually affect?

Back 67

L5 or S1

Front 68

What may be the only evidence of a child having spina bifida occulta?

Back 68

small dimple with a tuft of hair over the affected area

Front 69

What malformation consists of a dimple in the back that may be connected by a fibrous cord with the dura mater?

Back 69

Spinal dermal sinus

Front 70

What are intramedullary dermoids?

Back 70

tumors arising from the surface ectodermal cells incorporated into the neural tube when the neuropore closed

Front 71

What are the two forms of spina bifida cystica and what makes them different?

Back 71

1. both are a protrusion of the spinal cord and/or meninges through the defective neural arch
2. meningocele-only meninges are protruded
3. myelomeningocele-both spinal cord and meninges are protruded

Front 72

What other disorder is also associated with a myelomeningocele?

Back 72

craniolacuna

Front 73

What area of the spine does a myelomeningocele usually occur?

Back 73

lumbar region

Front 74

What is the form of spina bifida where the neural folds fail to fuse?

Back 74

myeloschisis

Front 75

What is meroanencephaly?

Back 75

absence of part of the brain

Front 76

What is a common sign of meroanencephaly and how is it obtained?

Back 76

1. high level of in utero alpha-feroprotein in teh amniotic fluid or in the maternal blood serum
2. amniocentesis at about week 10

Front 77

How do anencephaly and meroanencephaly differ?

Back 77

1.meroanencephaly is a less severe form of anencephaly
2. mero means part