Ectodermal Origin:

The ectodermal origin refers to the part of the teen that originates from the ectoderm, which is one of the three primary germ layers of an embryo. The ectoderm gives rise to various tissues and structures in the body, including the skin, hair, nails, and nervous system.

Key Points:
- Skin: The outermost layer of the teen, known as the epidermis, is derived from the ectoderm. The epidermis plays a crucial role in protecting the underlying tissues and organs from external factors.
- Hair and Nails: The hair follicles and nail beds, which are responsible for the growth of hair and nails respectively, are also ectodermal in origin.
- Sweat Glands: The sweat glands, which are involved in regulating body temperature and excreting waste products, are derived from the ectoderm.
- Mammary Glands: In females, the mammary glands that produce milk for breastfeeding are ectodermal in origin.
- Nervous System: One of the most significant structures derived from the ectoderm is the nervous system. This includes the brain, spinal cord, and peripheral nerves.

Mesodermal Origin:

The mesodermal origin refers to the part of the teen that originates from the mesoderm, another primary germ layer. The mesoderm gives rise to various tissues and structures in the body, including muscles, bones, blood vessels, and connective tissues.

Key Points:
- Muscles: The muscles present in the teen, such as the skeletal muscles responsible for movement and the smooth muscles found in organs, are derived from the mesoderm.
- Bones: The skeletal system, including the bones and cartilage, is mesodermal in origin. These structures provide support, protection, and help in locomotion.
- Blood Vessels: The network of blood vessels, such as arteries, veins, and capillaries, are derived from the mesoderm. They transport oxygen, nutrients, and waste products throughout the body.
- Connective Tissues: Various connective tissues, including tendons, ligaments, and adipose tissue, are mesodermal in origin. These tissues provide structural support and help in connecting and cushioning different body parts.
- Reproductive System: The reproductive organs, such as the ovaries and testes, are mesodermal in origin. They play a role in reproduction and the production of gametes.

In summary, the ectodermal origin of the teen includes the skin, hair, nails, sweat glands, mammary glands, and nervous system. On the other hand, the mesodermal origin encompasses muscles, bones, blood vessels, connective tissues, and the reproductive system.

Enamel is ectodermal while dentine is mesodermsl in origin.