What are the four appendages of the skin?
The skin appendages include sweat glands, nails, and the pilosebaceous unit of the skin, comprised of the hair shaft, hair follicle, sebaceous gland, and arrector pili muscle — these appendages derive from a down growth of the epidermis beginning in the third month of fetal life.
Where is the dermis derived from?
The dermis is derived primarily from mesoderm and contains collagen, elastic fibers, blood vessels, sensory structures, and fibroblasts.
What develops from the embryonic epidermis?
During development, cells of the basal epidermal layer form buds, which are primitive cells of organ development, and invaginate into the dermis ultimately forming the hair follicle appendages, apocrine, and eccrine glands.
How epidermis is formed from ectoderm?
The epidermis begins developing from the surface ectoderm at the end of the fourth week of life as the neural tube separates from the overlying ectoderm to mark the completion of neurulation. Although after the first few weeks of embryogenesis, the epidermis is composed of five strata or layers.
What are examples of appendages?
An example of an appendage is an arm or leg. noun. An appendage is defined as an extra part that is attached to something. An example of an appendage is a leaf added to a dining table for extension.
What part of the fetal tissue gives rise to the epidermis?
The ectoderm gives rise to the nervous system and the epidermis, among other tissues. The mesoderm gives rise to the muscle cells and connective tissue in the body.
What cells are in the epidermis?
Epidermis is the outermost layer and is about 0.05–1 mm in thickness depending on body part. Three main populations of cells reside in the epidermis: keratinocytes, melanocytes, and Langerhans cells.
What are the functional groups in organic chemistry?
A variety of functional groups exist in organic chemistry. Most of them are carbon-based compounds. Some groups form a single bond with most of the hetero-atoms such as oxygen, iodine, nitrogen, sulfur, etc. There is also some other kind of groups having multiple bonds with the hetero-atoms such as oxygen, nitrogen atoms, etc.
What functional groups contain nitrogen and carbon?
Nitrogen-Containing Functional Groups The substituent groups that contain nitrogen may also contain carbon-oxygen bonds. For example, the amide functional group has the formula R- (CO)-NR 2 and therefore has a carbonyl carbon which is bonded to a nitrogen atom, which is in turn bonded to two other alkyl groups.
What are the functional groups in polymers?
In the case of polymers, the functional groups are generally attached to the nonpolar core of the carbon atoms in each repeating unit of the corresponding polymer, infusing the carbon chain with specific chemical characteristics. Some functional groups have an ionic charge on them, as observed in carboxylate salts containing the -COO – ionic group.
What is the ionic charge on a functional group?
Some functional groups have an ionic charge on them, as observed in carboxylate salts containing the -COO – ionic group. When these groups are attached to molecules, they convert the molecule into either complexions or polyatomic ions. In a coordination complex, the functional group that is bound to the central atom is said to be a ligand.