What is the source of head and neck development?
The lateral plate mesoderm consists of the laryngeal cartilages (arytenoid and cricoid). The three tissue layers give rise to the pharyngeal apparatus, formed by six pairs of pharyngeal arches, a set of pharyngeal pouches and pharyngeal grooves, which are the most typical feature in development of the head and neck.
What is the development of a head?
The Formation of the Head At the time when the head region begins to form, the embryo is composed of three layers of tissue, the ectoderm, mesoderm and endoderm. These three germ layers become distinct during gastrulation in the third week of development.
What Are PHARYNGEAL POUCHES?
A pharyngeal pouch or Zenkers Diverticulum is an outpouching of the pharynx at the level of the larynx (voice Box). Pouches occur in older people and are the result of fibrosis of a band of muscle at the top of the oesophagus callled cricopharyngeus.
What are the processes presented for the development of face?
The external human face develops between the 4th and 6th weeks of embryonic development. Facial swellings arise on the frontonasal process (2 medial nasal and 2 lateral nasal processes) and the first pharyngeal arch (2 mandibular and 2 maxillary processes).
What is the purpose of the neck?
Its primary function is to provide support for the skull, while still allowing for movement. It is the most flexible part of the spine. This flexibility allows for large movements to scan our surroundings. The majority of sensory inputs occur at the head; thus, proper neck movement is vital to our survival.
What is gastrulation biology?
Gastrulation is defined as an early developmental process in which an embryo transforms from a one-dimensional layer of epithelial cells (blastula) and reorganizes into a multilayered and multidimensional structure called the gastrula.
What are the 6 branchial arches?
each pharyngeal arch has a cranial nerve associated with it:
- arch 1: CN V (trigeminal)
- arch 2: CN VII (facial)
- arch 3: CN IX (glossopharyngeal)
- arch 4: CN X (superior laryngeal branch of the vagus)
- arch 6: CN X (recurrent laryngeal branch of the vagus)
How many embryonic layers are involved in facial development?
three embryonic layers
All three embryonic layers are involved in facial development: ectoderm, mesoderm, and endoderm (Table 4-1). Facial development includes the formation of the primitive mouth, mandibular arch, maxillary process, frontonasal process, and nose.
What week does facial development begin?
between weeks four and eight
[1] Facial embryology begins between weeks four and eight and involves a series of highly coordinated events based on preprogrammed data in cellular DNA. The process includes all the primary embryonic tissues, the ectoderm, endoderm, mesoderm.
What is the structure of the neck?
The neck is comprised of seven cervical vertebrae from C1 to C7, hyoid bone, manubrium of sternum and clavicles. The cervical spine has a lordotic curve ( C shaped curve ).
What type of joint is the head and neck?
synovial joints
It consists of three distinct, synovial joints: one medial joint and two lateral atlantoaxial joints. The median atlantoaxial joint’s structure is formed by the dens of C1 vertebrae and two ligamentous structures anteriorly and posteriorly.
What’s the difference between head and neck?
The neck refers to the collection of structures that connect the head to the torso. It is a complex structure composed of many bones, muscles, nerves, blood vessels, lymphatics, and other connective tissues. The cervical spine is the bony part of the neck.
What is the function of neck?
The neck supports the weight of the head and protects the nerves that carry sensory and motor information from the brain down to the rest of the body. In addition, the neck is highly flexible and allows the head to turn and flex in all directions.
Which organ is ectodermal in origin?
Ectoderm, the germ layer covering the surface of the embryo, gives rise to the outer covering of the animal and, in some phyla, to the central nervous system. Thus structures like epidermis, brain and retinal layer of eye are ectodermal in origin.
What are the 3 germ layers?
Three primary germ layers Gastrulation is a key phase in embryonic development when pluripotent stem cells differentiate into the three primordial germ layers: ectoderm, mesoderm and endoderm.
What is the most distinctive feature of the head and neck?
Development of head and neck • The most distinctive feature in development of the head and neck is the presence of pharyngeal arches. These arches appear in the fourth and fifth weeks of development and contribute to the characteristic external appearance of the embryo .
What is the relationship between the head and neck and face?
The related structures of upper lip and palate significantly contribute to the majority of face abnormalities. The head and neck structures are more than just the face, and are derived from pharyngeal arches 1 – 6 with the face forming from arch 1 and 2 and the frontonasal prominence.
What does each pharyngeal arch pouch contribute to the head and neck?
Each of the pharyngeal arch pouches contributes different components of the head and neck, either cavities or endocrine tissues. Pharyngeal Arch 1 pouch elongates to form tubotympanic recess tympanic cavity, mastoid antrum and auditory tube (Eustachian tube).