Embryonic Development Quiz
46 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which embryonic tissue contributes to the formation of the ribs?

  • Lateral plate mesoderm only
  • Neural crest cells only
  • Paraxial mesoderm only
  • Both paraxial and lateral plate mesoderm (correct)

Which type of tissue is NOT formed from mesenchymal cells during skeletal development?

  • Chondroblasts
  • Myoblasts (correct)
  • Osteoblasts
  • Fibroblasts

What type of ossification is involved in the formation of the limb bones?

  • Endochondral ossification (correct)
  • Direct ossification
  • Intramembranous ossification
  • Membranous ossification

From which embryonic structure do the vertebrae primarily develop?

<p>Sclerotome (D)</p> Signup and view all the answers

What process explains the migration and fusion of sclerotome cells to form the vertebrae?

<p>Resegmentation (B)</p> Signup and view all the answers

Which part of the somite gives rise to the muscles associated with the vertebral column?

<p>Myotome (B)</p> Signup and view all the answers

Which structures are derived from the lateral plate mesoderm?

<p>Upper and Lower limb bones (C)</p> Signup and view all the answers

Intramembranous ossification occurs when bone develops directly from:

<p>Mesenchyme (B)</p> Signup and view all the answers

Which limb defect is characterized by the complete absence of one or more extremities?

<p>Amelia (D)</p> Signup and view all the answers

An abnormal duplication of which structure is the cause of polydactyly?

<p>Zone of polarizing activity (ZPA) (A)</p> Signup and view all the answers

Cleft hand and foot is marked by an unusual split between which metacarpal/metatarsal bones?

<p>Second and fourth (A)</p> Signup and view all the answers

Which condition involves congenital joint contractures in more than one joint?

<p>Arthrogryposis (D)</p> Signup and view all the answers

Amniotic bands can cause which type of limb defect?

<p>Ring constrictions and amputations (B)</p> Signup and view all the answers

Absence of which muscles and associated digital defects are characteristic of Poland Anomaly?

<p>Pectoralis minor and partial loss of pectoralis major (D)</p> Signup and view all the answers

What is a key characteristic of Prune Belly Syndrome?

<p>Partial or complete absence of abdominal musculature (D)</p> Signup and view all the answers

Which of the following conditions is often associated with severe lung or kidney problems, and a high mortality rate?

<p>Prune Belly Syndrome (D)</p> Signup and view all the answers

Which of the following primarily regulates the patterning of vertebral shapes?

<p>HOX genes (D)</p> Signup and view all the answers

Which structure contributes to the formation of the nucleus pulposus of the intervertebral disc?

<p>Notochord (B)</p> Signup and view all the answers

The bony portion of each rib is derived from what structure?

<p>Sclerotome cells in the paraxial mesoderm (D)</p> Signup and view all the answers

From which germ layer is the sternum primarily developed?

<p>Parietal layer of lateral plate mesoderm (A)</p> Signup and view all the answers

Which of the following is a characteristic of spina bifida occulta?

<p>Defect covered by skin, with no neurological deficits (C)</p> Signup and view all the answers

What is the key difference between meningocele and myelomeningocele?

<p>Myelomeningocele involves exposure of neural tissue but meningocele does not. (D)</p> Signup and view all the answers

From which germ layer do most skeletal muscles originate?

<p>Paraxial mesoderm (D)</p> Signup and view all the answers

What is the origin of smooth muscles surrounding the gut?

<p>Splanchnic/visceral lateral plate mesoderm (A)</p> Signup and view all the answers

Which type of muscle tissue is derived from the somato-pleuric mesoderm?

<p>Smooth muscle (A)</p> Signup and view all the answers

What is the role of BMP4, in the molecular regulation of muscle development?

<p>Signals ventrolateral (VLL) cells to express the muscle-specific gene MyoD (A)</p> Signup and view all the answers

Where do progenitor muscle cells form to create the dermomyotome?

<p>Upper region of the somite (C)</p> Signup and view all the answers

From which region do the limb muscles originate?

<p>Ventrolateral Lip (VLL) cells (C)</p> Signup and view all the answers

Which of these is a muscle derived from the remaining myotome cells?

<p>Intercostal muscles (A)</p> Signup and view all the answers

Which structure directs the formation of muscles in the head region?

<p>Connective tissue elements derived from neural crest cells (A)</p> Signup and view all the answers

What is the primary difference between somitomeres and somites?

<p>Somitomeres are only found in the head region, while somites are found from the occipital to the sacral regions (B)</p> Signup and view all the answers

What is the origin of the skeletal muscles in the trunk?

<p>Somites (C)</p> Signup and view all the answers

Which of the following is NOT a derivative of the somites?

<p>Cardiac muscle (D)</p> Signup and view all the answers

What is the role of the apical ectodermal ridge (AER) in limb development?

<p>To maintain an undifferentiated, rapidly proliferating zone in adjacent mesenchyme (B)</p> Signup and view all the answers

Which cell type is primarily regulated by the serum response factor (SRF)?

<p>Smooth muscle cells (A)</p> Signup and view all the answers

What separates the primaxial and abaxial domains?

<p>The lateral somitic frontier (C)</p> Signup and view all the answers

From what structure do tendons originate from?

<p>Sclerotome (D)</p> Signup and view all the answers

What is the function of SCLERAXIS in tendon development?

<p>It regulates the expression of genes involved in tendon differentiation. (C)</p> Signup and view all the answers

During which week of development does rotation of the limbs occur?

<p>7th week (A)</p> Signup and view all the answers

What is the primary function of the ventral primary rami of spinal nerves in limb development?

<p>To provide motor and sensory innervation of limb musculature (D)</p> Signup and view all the answers

What is the origin of the cartilage in the ribs that attach to the sternum?

<p>Abaxial sclerotome cells (D)</p> Signup and view all the answers

What process initiates the formation of a joint cavity?

<p>Apoptosis of cells in the joint interzone (C)</p> Signup and view all the answers

What is the role of WNT14 in joint development?

<p>It acts as an inductive signal for joint positioning (C)</p> Signup and view all the answers

Which of the following best describes the orientation of the big toe after limb rotation?

<p>It lies medially (B)</p> Signup and view all the answers

Which of the following correctly describes the nerve supply of extensor and flexor muscles in the limbs?

<p>Extensor muscles are innervated by dorsal branches, while flexor muscles are innervated by ventral branches (D)</p> Signup and view all the answers

What connective tissue plays a role in the development of the complex pattern of muscles in the limbs?

<p>Lateral plate mesoderm cells (C)</p> Signup and view all the answers

Flashcards

What is the human body's skeleton?

The human body skeleton, divided into two main parts: the axial skeleton and the appendicular skeleton.

What is the axial skeleton?

The axial skeleton, composed of the skull, vertebrae, ribs, and sternum, provides support and protection to the head, neck, and trunk.

What is the appendicular skeleton?

The appendicular skeleton, including the pectoral girdle (upper limb) bones and pelvic girdle (lower limb) bones, provides support and mobility for the limbs.

What are the embryonic origins of the skeletal system?

Paraxial mesoderm contributes to the formation of the skull, vertebrae, and ribs, while the lateral plate mesoderm forms bones of the limbs, costal cartilage, and sternum.

Signup and view all the flashcards

What is intramembranous ossification?

The process by which mesenchyme directly differentiates into bone without forming cartilage, often occurring in the dermis.

Signup and view all the flashcards

What is endochondral ossification?

The process by which mesenchymal cells form cartilage models that subsequently ossify into bone, common for bones like the base of the skull and limbs.

Signup and view all the flashcards

How do vertebrae develop?

Sclerotome cells from opposing somites migrate around the spinal cord and notochord, creating a structure that will form the vertebra.

Signup and view all the flashcards

What is resegmentation in vertebral development?

The process of resegmentation involves the caudal half of each sclerotome fusing with the cephalic half of the adjacent sclerotome, resulting in the formation of a single vertebra from parts of two somites.

Signup and view all the flashcards

Amelia

A complete absence of one or more extremities.

Signup and view all the flashcards

Meromelia

A partial absence of one or more extremities.

Signup and view all the flashcards

Micromelia

All segments of extremities are present but abnormally short.

Signup and view all the flashcards

Syndactyly

Two or more fingers or toes are fused together.

Signup and view all the flashcards

Polydactyly

Presence of extra fingers or toes.

Signup and view all the flashcards

Arthrogryposis

Congenital joint contractures involving more than one joint.

Signup and view all the flashcards

Amniotic Bands

Ring constrictions and amputations of limbs or digits caused by adhesions or tears in the amniotic sac.

Signup and view all the flashcards

Poland Anomaly

Absence of pectoralis minor and partial loss of pectoralis major on one side, often the left, with associated digital defects on the same side.

Signup and view all the flashcards

Somitomeres

Loosely organized, spherical masses of mesoderm found in the head and trunk regions during early development. They contribute to craniofacial structures and head muscles.

Signup and view all the flashcards

Somites

Differentiated, segmented structures forming in the trunk and tail regions. They are segmental blocks of mesoderm derived from somitomeres and give rise to vertebrae, ribs, dermis, skeletal muscles, and tendons in the trunk.

Signup and view all the flashcards

Cardiac Muscle

Cardiac muscles are derived from the lateral plate splanchnic mesoderm surrounding the endothelial heart tube. They adhere to each other through special attachments called intercalated discs.

Signup and view all the flashcards

Smooth Muscle

Smooth muscles are derived from lateral plate mesoderm and neural crest cells. They are found in the walls of blood vessels, the gut, and other organs.

Signup and view all the flashcards

Lateral Somitic Frontier

The border between each somite and the parietal layer of lateral plate mesoderm. It separates mesoderm into the primaxial and abaxial domains.

Signup and view all the flashcards

Primaxial (epaxial) Domain

The region of mesoderm around the neural tube, containing only somite-derived cells.

Signup and view all the flashcards

Abaxial (hypaxial) Domain

The region of mesoderm including the parietal layer of lateral plate mesoderm and migrating somite cells. It lies 'outside' the primaxial domain.

Signup and view all the flashcards

Tendons

Derived from sclerotome cells lying adjacent to myotomes, they help connect muscles to bones.

Signup and view all the flashcards

Apical Ectodermal Ridge (AER)

The apical ectodermal ridge (AER) is a thickened ectoderm at the distal border of the limb bud. It influences adjacent mesenchyme, maintaining it as an undifferentiated, rapidly proliferating zone.

Signup and view all the flashcards

Appendicular Skeleton

The skeleton of the limbs, comprising the pectoral and pelvic girdles and the bones of the upper and lower limbs.

Signup and view all the flashcards

Limb Development

The process of limb development involves the formation of limb buds, the AER's influence on mesenchyme, and the differentiation of cells into cartilage and muscle.

Signup and view all the flashcards

Joint Formation

Joints are formed in cartilaginous condensations when chondrogenesis is arrested. The cells in the interzone increase in number and density, forming a joint cavity through cell death.

Signup and view all the flashcards

Limb Musculature Development

The first indication of limb musculature appears during the 7th week of development. Mesenchyme from the dorsolateral cells of somites migrates into limb buds to form muscles.

Signup and view all the flashcards

Limb Nerve Supply

Spinal nerves play a crucial role in motor innervation and differentiation of limb musculature. They also provide sensory innervation for dermatomes.

Signup and view all the flashcards

What is the Intervertebral Disc?

The intervertebral disc is a cushion-like structure between vertebrae, composed of two parts: the annulus fibrosus and the nucleus pulposus.

Signup and view all the flashcards

What is the Annulus Fibrosus?

The annulus fibrosus is the outer fibrous ring of the intervertebral disc, formed by mesenchymal cells.

Signup and view all the flashcards

What is the Nucleus Pulposus?

The nucleus pulposus is the gelatinous center of the intervertebral disc, formed from the notochord.

Signup and view all the flashcards

How do Myotomes relate to Intervertebral Discs?

During vertebral development, sclerotomes resegment to allow the myotomes to bridge the intervertebral discs and enable movement of the spine.

Signup and view all the flashcards

How do Rib Bones Form?

The bony portion of each rib develops from sclerotome cells in the paraxial mesoderm.

Signup and view all the flashcards

How do Rib Cartilages Form?

The cartilaginous part of each rib (costal cartilage) is formed by sclerotome cells migrating into the lateral plate mesoderm.

Signup and view all the flashcards

Where does the Sternum Develop?

The sternum, located in the chest, develops independently from the parietal layer of lateral plate mesoderm.

Signup and view all the flashcards

What is Spina Bifida?

Spina bifida is a birth defect resulting from imperfect fusion of the bony vertebral arches, leading to a gap in the spine.

Signup and view all the flashcards

What is Spina Bifida Occulta?

Spina bifida occulta is a mild form of spina bifida where the vertebral arches are incomplete, but the spinal cord remains intact.

Signup and view all the flashcards

What is Spina Bifida Cystica?

Spina bifida cystica is a more severe form of spina bifida where the spinal cord is exposed through a gap in the vertebral arches.

Signup and view all the flashcards

What is Meningocele?

Meningocele is a type of spina bifida cystica where only the meninges (membranes surrounding the spinal cord) are exposed in a fluid-filled sac.

Signup and view all the flashcards

What is Myelomeningocele?

Myelomeningocele is a type of spina bifida cystica where both the spinal cord and nerves are exposed in a fluid-filled sac.

Signup and view all the flashcards

Where do Skeletal Muscles Develop?

Most skeletal muscles in the body develop from paraxial mesoderm, forming somites along the body axis.

Signup and view all the flashcards

Where does Most Smooth Muscle Develop?

Smooth muscle surrounding the gut and its derivatives, except some exceptions, develops from the splanchnic/visceral lateral plate mesoderm.

Signup and view all the flashcards

Where does Cardiac Muscle Develop?

Cardiac muscle develops from splanchnic/visceral lateral plate mesoderm surrounding the heart tube.

Signup and view all the flashcards

Study Notes

Musculoskeletal System Development

  • Skeletal System Components: The skeleton is divided into the axial (skull, vertebrae, ribs, sternum) and appendicular (pectoral girdle, pelvic girdle, upper/lower limbs) skeletons.

  • Skeletal Development Sources:

    • Paraxial mesoderm forms the skull, vertebrae, and parts of ribs.
    • Lateral plate mesoderm forms upper/lower limb bones, costal cartilage, and sternum.
    • Neural crest cells contribute to facial and cranial bones.

  • Vertebrae Development:

    • Sclerotome cells from somites (paraxial mesoderm) migrate around the spinal cord and notochord, eventually merging and resegmenting.
    • Resegmentation combines caudal half of one somite with cranial half of the next, forming a vertebra.
    • Myotomes bridge intervertebral discs, enabling spinal movement.

  • Intervertebral Disc Structure: Consists of annulus fibrosus (from sclerotome cells) and nucleus pulposus (from notochord).

  • Rib Development: Bony portion from sclerotome cells, cartilaginous portion from migrating sclerotome cells into lateral plate mesoderm.

  • Sternum Development: Forms from lateral plate mesoderm with two sternal bands fusing to form the sternum (manubrium, sternebrae, xiphoid process).

Bone Ossification

  • Intramembranous Ossification: Mesenchymal cells directly transform into bone without a cartilage stage.

  • Endochondral Ossification: Most bones develop from hyaline cartilage models that subsequently ossify.

Vertebral Developmental Defects

  • Spina Bifida: Imperfect fusion of vertebral arches.

    • Spina Bifida Occulta: Minor, bony arch defect, spinal cord intact.
    • Spina Bifida Cystica: Severe, neural tissue exposure.
      • Meningocele: Fluid-filled sac with meninges; spinal cord spared.
      • Myelomeningocele: Fluid-filled sac containing spinal cord and nerve roots.

  • Prenatal screening tools include ultrasound and amniocentesis (alpha-fetoprotein levels).

Muscular System Development

  • Muscle Types:

    • Skeletal (paraxial mesoderm)
    • Smooth (lateral plate mesoderm)
    • Cardiac (lateral plate mesoderm)

  • Skeletal Muscle Formation: From somites (paraxial mesoderm) and somitomeres (head region).

  • Smooth Muscle Formation: From splanchnic lateral plate mesoderm, with some exceptions from ectoderm (e.g., pupil, mammary, sweat glands).

  • Cardiac Muscle Formation: From splanchnic lateral plate mesoderm surrounding the heart tube.

  • Muscle Formation Regulation: BMP4 and WNT proteins, along with SHH, signal specific muscle groups to express myogenic regulatory factors (MRFs), triggering muscle development.

Limbs Development

  • Limb Bud Formation: Limb buds emerge from lateral body wall during the fourth week, initially consisting of mesenchymal core covered by ectoderm.

  • AER (Apical Ectodermal Ridge): Ectodermal ridge at limb tip promotes undifferentiated growth of mesenchymal cells; differentiation occurs further away.

  • Limb Development Pathway: First, humerus/femur, followed by radius/ulna/tibia/fibula, then carpals/tarsals, metacarpals/metatarsals, and digits.

  • Limb Rotation: Upper limbs rotate laterally, lower limbs medially.

  • Hand/Foot Formation: Hand and foot plates form at 6 weeks, separated by constrictions.

  • Finger/Toe Formation: Cell death in the AER leads to digit separation; outgrowth and condensation of mesenchyme are crucial for formation of digits.

Limb Defects

  • Amelia: Complete limb absence.
  • Meromelia: Partial limb absence.
  • Micromelia: Shortened limbs.
  • Brachydactyly: Shortened digits.
  • Syndactyly: Fused digits.
  • Polydactyly: Extra digits.

Other Concepts

  • Somitomeres vs. Somites: Somitomeres are early, precursors to somites in the head/trunk; somites are segmented blocks in trunk/tail regions.

  • Lateral Somitic Frontier: Border between somites and lateral plate mesoderm, creating primaxial/abaxial domains.

  • Tendons: Derived from sclerotome cells adjacent to myotomes; regulated by scleraxis.

  • Joints Formation: Cartilage-condensation arrest leads to joint formation with cell death creating a joint cavity.

  • Clinical Correlates: Bone age assessed prenatally or postnatally by ossification centres; defects are visible as abnormal development, lack of formation, fusion.

  • Nerve Supply: Spinal nerves innervate specific muscle groups.

  • Muscular System Defects: Various muscle absence issues or malformations, which are not usually critical. Specific cases are discussed individually. eg, Poland Anomaly, Prune Belly Syndrome. Potential life-threatening issues are noted.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Description

Test your knowledge on embryonic tissues and the skeletal development process. This quiz covers questions related to the formation of bones, structures derived from mesoderm, and various limb defects. Perfect for students studying embryology or anatomy.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser