Back 3/3 Flashcards by Johannah Crumpton

Ectoderm gave rise to ….

The central nervous system

How well did you know this?

Not at all

Perfectly

The endoderm gave rise to …..

lining of gut, respiratory and urogenital tracks

How well did you know this?

Not at all

Perfectly

Mesoderm gave rise to….

muscles, bones, connective tissue and fat

How well did you know this?

Not at all

Perfectly

Ectoderm also forms the ____

Epidermis

How well did you know this?

Not at all

Perfectly

these tubes come into existence at a time when the embryo is made of three flat sheets of cells - the ____ ______

Trilaminar Embryo

How well did you know this?

Not at all

Perfectly

The _____ signals the ectoderm to fold in upon itself to form a _____ _____.

Notochord. Neural groove

How well did you know this?

Not at all

Perfectly

When the notochord signals the ectoderm to fold in upon itself to form a neural groove. What is this process called?

Neurulation

How well did you know this?

Not at all

Perfectly

Label:
-Notochord
- Intraembryonic coelom
- Neural Groove
- Neural Crest
- Somite

Label:
2-Notochord
3- Intraembryonic coelom
5- Neural Groove
4- Neural Crest
1- Somite

How well did you know this?

Not at all

Perfectly

What level does the Blue represent?
Red?
Yellow?

Blue= Ectoderm
Red= mesoderm
Yellow= endoderm

How well did you know this?

Not at all

Perfectly

The neural groove folds to become the ____ ______, which will give rise to the entire _____.

Neural Tube, CNS

How well did you know this?

Not at all

Perfectly

Name the 3 components of the Central Nervous System.

Brain
Brainstem
Spinal Cord

How well did you know this?

Not at all

Perfectly

A second set of ectoderm cells also move into the mesoderm called ___ ____ _____, which migrate throughout the body

Neural crest cells

How well did you know this?

Not at all

Perfectly

Mesoderm close to the neural tube forms _____.

Somites

How well did you know this?

Not at all

Perfectly

Somites form ______, ______ and ______ of the body wall.

muscles, bones and dermis

How well did you know this?

Not at all

Perfectly

Somites develop on either side of the _______ and ______.

Neural Tube and notochord

How well did you know this?

Not at all

Perfectly

How many occipital somites are there?

Somites have the same number of spinal nerves. Cervical = 8
Thoracic = 12
Lumbar = 5
Sacral = 5
Coccygeal = 2-3

How well did you know this?

Not at all

Perfectly

Each somite breaks into 3 functionally different parts. Name them

Sclerotome
Myotome
Dermatome

How well did you know this?

Not at all

Perfectly

The sclerotomes gives rise to …..

Vertebrae and axial bone

How well did you know this?

Not at all

Perfectly

Identify:
- Sclerotome
- Neural Tube
- Dermatome
- Myotome

2- Sclerotome
1- Neural Tube
3- Dermatome
4- Myotome

How well did you know this?

Not at all

Perfectly

Posterior horn develops into _____

Sensory Neurons

How well did you know this?

Not at all

Perfectly

Anterior horn develops what kind of neurons.

Motor neurons

How well did you know this?

Not at all

Perfectly

The neural crest cells develop into….

Posterior Root Ganglia

How well did you know this?

Not at all

Perfectly

Neurons in the spinal cord’s anterior horn send axons to ______

Skeletal muscles

How well did you know this?

Not at all

Perfectly

Sensory axons from the posterior root ganglia (neural crest) extend laterally towards _______

dermatomes

How well did you know this?

Not at all

Perfectly

Sensory axons from the posterior root ganglia (neural crest) extend medially to reach the .....

posterior horn of spinal cord.

Sensory neurons travel to dermatomes by following ______ that have reached the corresponding _____

motor axons, myotomes

When nerves become compressed, usually ______ precede ______. Why?

Sensory signs precede motor signs. Because the sensory axons are on the outside of the nerve

Anterior horn axons form from _____

myotome

Posterior root ganglion axons form from ...

Dermatome and posterior horn

_______ split in half as fissures (of von Ebner) develop so axons can pass

Sclerotomes

Sclerotome remnants fuse with their neighbors to become ______

Vertebrae

_____ and the ______ will remain at the site of the fissures.

Intervertebral discs and intervertebral foramina

Sclerotome mesenchyme surrounds the _____ & _____, forming a loose model of the vertebrae and ribs

neural tube and notochord

______ form in the sclerotome and start to replace it with cartilage in the 6th week.

Chondrification centers

In the 7th week, _____ begins replacing cartilage

bone

______ form in the vertebral body (centrum), pedicles, and lamina.

Primary ossification centers

Ossification is not complete until after adolescence when _____ in _____ fuse to the rest of the vertebra

secondary centers of ossification, transverse and spinous processes (and annular epiphyses)

______ are the last part of the vertebrae to ossify

Spinous processes

_____ occurs when ossification fails or the spinous process does not form at all.

Spina Bifida

Spina Bifida is due to the presence of what protein in maternal blood?

Alpha-fetoprotein

_______is failure of the neural arch, specifically the spinous process, to ossify. The defect is not large and is sometimes marked by a tuft of dense hair.

Spina bifida occulta

______ occurs when meninges and CSF herniate through the hole left by the failed neural arch

Meningocele

______ is the same as a meningocele with added herniation of the spinal cord and/or roots

Meningomyelocele

_______ is failure of the neural tube to fold properly. Neural arch cannot form.

Rachischisis

Abnormalities in Hox gene expression may cause ______ of the S1 vertebrae or ______ of the L5 vertebrae

lumbarization sacralization

In adults, the spinal cords ends at what level?

Approximately L1

In embryos, the spinal cord ends at approximately what level?

It doesnt, spinal cord runs the full length of the vertebral canal

At 6 months of gestation, the spinal cords ascends to approximately what level?

approx. S1

A spinal cord of a newborn extends to approx. what level?

Approx. L2-L3

Motor neurons in the _____ of the spinal cord innervate muscles from the ______ as well as other areas of mesoderm

anterior horn, somites (myotome)

The ______ splits to form true back muscles innervated by ______.

myotome, posterior rami

The ______ also forms the muscles of the trunk and limbs, innervated by ________.

myotome, anterior rami

______ travel more or less directly into the muscles and skin that they innervate.

Posterior rami

Anterior rami form complex plexi before reaching their target muscles. Why? What muscles do they become?

Their associated myotomes migrate and pulling the nerves behind. Muscles of the neck, thorax, abdomen, pelvis, limbs, orbit, and tongue.

What is it called when muscle fail to develop during embryonic formation?

Muscle agenesis

Name the syndrome where the abdominal muscles fail to develop?

Prune Belly Syndrome

What gene is responsible for double muscling?

Myostatin

_____ & ________ regions migrate into the upper limb bud

Myotomes and dermatomes from C4-T2 regions

_____ & ______ migrate into the lower limb bud.

Myotomes and dermatomes from L4-S3

Dorsal/posterior muscle mass lead to _____

Extensors

Ventral/anterior muscle mass lead to _____

Flexors

Where do limb bones come from?

lateral mesoderm

Describe the general trend of overall Morphology of limbs

Flipper-like upper limb bud -> Hand plate forms -> Digital rays appear in hand plate -> Apoptosis in the interdigital areas that carves out the digits -> Upper limbs bend at the elbow, fingers are short and webbed -> Fingers and toes are distinct and separated

Programmed cell death is called ....

Apoptosis

Define syndactyly

The webbing between the fingers does not completely go away

Name the condition where the tail segment may rescind early or fail to form, this may result in fusion of the rear limb buds

Sirenomelia

# ******* The dorsal muscle masses make extensor muscles in both upper and lower limbs but the extensors of a mature upper limb are on the posterior side while the extensors of the lower limb are on the anterior side. Why?

Due to fetal positioning in the uterus?????

The outgrowth of the limb buds are initiated and maintained by the...

AER, Apical Epidermal Ridge

What signal is produced in the AER?

FGF8- Fibroblast Growth Factor 8

Define Amelia

without a limb

Define meromelia

The partial absence of at least one limb

Define Phocomelia, what was it caused by?

hands and feet are attached the the trunk, thalidomide (anti-nausea drug)

Name the molecular marker signal protein for medio-lateral patterning.

Sonic Hedgehog (Shh)

Define Polydactyly

More than 5 fingers/toes on one extremity

A herniated disc effects the level above/below?

Below

What artery feeds the horns?

Sulcal artery

Lumbar triangle is generally considered weaker or stronger?

Weaker

What artery feeds the spinal cord?

Greater anterior segmental medullary artery

Define ipsalateral

For a Left muscle contraction, rotate and lean left

Define Contralateral

The opposite side of what you are asking, example: Transversospinalis muscle group