L13 - Development of Face and Ear Flashcards
What are the two components of the head?
Cranium
Face
What is the cranium?
Portion of the head that contains the brain
Which structure is formed during growth of the head process?
Cranium
Which structure is developed from the rostral outgrowths of the frontonasal process and first pharyngeal arch?
Face
Which region of the embryo develops more rapidly?
Cranial region
The presence of which structures characterizes the head region of mammalian embryos?
Pharyngeal arches
Which structure develops in the head region and then migrates caudally?
The heart
Which bones of the head form by intramembranous/direct ossification?
Facial Bones
Roof of the Cranium
Which bones of the head form by endochondral ossification?
Bones of the Cranial Floor
What is intramembranous ossification?
Process of ossification by which mesenchymal cells differentiate into osteoblasts
What are osteoblasts?
Cells that produce osteoid (becomes calcified)
What is endochondral ossification?
Process of ossification by which cartilage is replaced by bone. (cartilage forms first and then gets replaced by bone)
Which bones in the body usually ossify by endochondral ossification?
Long bones
How do osteoblasts form bone in intramembranous ossification?
Osteoblasts line up in a row and continue to secrete osteoid that fills up the luminal space.
- traps osteocytes in the space (resident cells of the bone)
- the osteocytes expand in size and bony area expands and forms trabeculae
What are the two types of ways that bone can be organized?
Spongy bone (Fills up space between the two sheets of compact bone - contains red marrow in cavities) Compact bone (Dense)
What is the name of the connective tissue that surrounds bone?
Periosteum
What are the two structures that form the face by endochondral ossification?
Mandibular Process
Maxillary Process
What does the mandibular process form?
Mandible and soft tissue of the lower jaw
What is the mandibular symphysis?
The line where the right and left mandibular processes fuse rostrally.
What does the maxillary process form?
Upper jaw, caudal to the incisor bone and teeth
What develops into the frontal bone?
Frontonasal prominence that is dorsal to the first pharyngeal arch
What do the medial and lateral nasal processes form?
Nose and Primary Palate
Which pharyngeal arch are do the maxillary and mandibular prominences develop from?
1
Which cranial nerve innervates the maxillary and mandibular process?
V (Trigeminal)
What is mesenchyme?
Undifferentiated Embryonic tissue
What does the surface ectoderm contribute to the development of the face?
Nasal Placode
What is the palate?
A structure that separates the nasal and oral cavities
How is the palate divided?
Into the primary and secondary palate.
Which palate grows caudally from the nasal process and forms the rostral region of the hard palate?
Primary Palate
Which palate extends medially from the maxillary prominences on each side to meet at the midline where they merge with the primary palate and nasal septum?
Secondary Palate
What are surface ectodermal stem cells?
Stem cells on the surface of the head that differentiate into different bones associated with the skin and oral cavity.
